Publications

alteration of cardiac myofibrillogenesis by liposome-mediated delivery of exogenous proteins and nucleic acids into whole embryonic hearts.	a precise organization of contractile proteins is essential for contraction of heart muscle. without a necessary stoichiometry of proteins, beating is not possible. disruption of this organization can be seen in diseases such as familial hypertrophic cardiomyopathy and also in acquired diseases. in addition, isoform diversity may affect contractile properties in such functional adaptations as cardiac hypertrophy. the mexican axolotl provides an uncommon model in which to examine specific protein ...	2000	10794163
apical epithelial cap morphology and fibronectin gene expression in regenerating axolotl limbs.	urodele amphibians (salamanders) are unique among adult vertebrates in their ability to regenerate limbs. the regenerated structure is often indistinguishable from the developmentally produced original. thus, the two processes by which the limb is produced - development and regeneration - are likely to use many conserved biochemical and developmental pathways. some of these limb features are also likely to be conserved across vertebrate families. the apical ectodermal ridge (aer) of the developi ...	2000	10706145
development and regulation of response properties in spinal cord motoneurons.	the intrinsic response properties of spinal motoneurons determine how converging premotor neuronal input is translated into the final motor command transmitted to muscles. from the patchy data available it seems that these properties and their underlying currents are highly conserved in terrestrial vertebrates in terms of both phylogeny and ontogeny. spinal motoneurons in adults are remarkably similar in many respects ranging from the resting membrane potential to pacemaker properties. apart fro ...	2000	11165788
distribution and innervation of taste buds in the axolotl.	adult axolotls have approximately 1,400 taste buds in the epithelium of the pharyngeal roof and floor and the medial surfaces of the visceral bars. these receptors are most dense on the lingual surfaces of the upper and lower jaws, slightly less dense throughout lateral portions of the pharyngeal roof and floor, and more sparse within medial portions of the pharyngeal roof and floor, except for a median oval patch of receptors located rostrally between the vomerine tooth fields. each taste bud i ...	2000	11124515
immunohistochemical demonstration of hyaluronan and its possible involvement in axolotl neural crest cell migration.	hyaluronan (ha), an extracellular matrix component, is involved mainly in the control of cell proliferation, neural crest and tumor cell migration, and wound repair. we investigated the effect of hyaluronan on neural crest (nc) cell migration and its ultrastructural localization in dark (wild-type) and white mutant embryos of the mexican axolotl (ambystoma mexicanum, amphibia). the axolotl system is an accepted model for studying mechanisms of nc cell migration. using a biotinylated hyaluronan b ...	2000	11121304
gdnf and gfralpha-1 are components of the axolotl pronephric duct guidance system.	in mammals, secretion of gdnf by the metanephrogenic mesenchyme is essential for branching morphogenesis of the ureteric bud and, thus, metanephric development. however, the expression pattern of gdnf and its receptor complex-the gpi-linked ligand-binding protein, gfralpha-1, and the ret tyrosine kinase signaling protein-indicates that it could operate at early steps in kidney development as well. furthermore, the developing nephric systems of fish and amphibian embryos express components of the ...	2000	11087631
the odontoclasts of ambystoma mexicanum.	the resorption of teeth in ambystoma mexicanum during postembryonal ontogenesis and induced metamorphosis occurs by means of light-microscopic detectable giant-cells. these have morphological and functional characters similar to those of odontoclasts of other vertebrates. the multinucleated odontoclasts resorb not only the pedicel (base), but the stalk of the tooth, too. when active, the cells form a ruffled border and a sealing zone. in this way they are able to demineralize the hard tissues of ...	2000	11035635
expression of the cardiac actin gene in axolotl embryos.	axolotis are an important model system for studying heart development. patterning of the somitic mesoderm occurs in axolotis in a manner that is much more similar to the pattern observed in higher vertebrates than in xenopus. for these reasons we cloned the axolotl cardiac actin gene, since this gene is expressed during the development of both somitic and cardiac muscle in other vertebrates. in this paper we characterize its expression. expression of cardiac actin rna is switched on during gastr ...	2000	11032182
relationships between neuronal cell adhesion molecule and lhrh neurons in the urodele brain: a developmental immunohistochemical study.	polysialic acid (psa), a homopolymer attached to neural cell adhesion molecule (ncam) is considered a major hallmark of vertebrate cell migration. we studied the distribution of psa-ncam by immunohistochemistry, during brain development, in two urodele amphibians, pleurodeles waltl and the neotenic newt ambystoma mexicanum. in both species a gradual increase of immunolabelling was observed throughout the brain from developmental stage 30 to stage 52. at the onset of metamorphosis, some differenc ...	2001	11759809
specification of pharyngeal endoderm is dependent on early signals from axial mesoderm.	the development of taste buds is an autonomous property of the pharyngeal endoderm, and this inherent capacity is acquired by the time gastrulation is complete. these results are surprising, given the general view that taste bud development is nerve dependent, and occurs at the end of embryogenesis. the pharyngeal endoderm sits at the dorsal lip of the blastopore at the onset of gastrulation, and because this taste bud-bearing endoderm is specified to make taste buds by the end of gastrulation, ...	2001	11714682
expression of axwnt-8 and axszl in the urodele, axolotl: comparison with xenopus.	in both the urodele axolotl and the anuran xenopus, wnt-8 is expressed in posterior lateral plate mesoderm (lpm) in neurula and tailbud stages. in contrast to xenopus, expression in axolotl is more prominent in gastrula endoderm, is not initiated in mesoderm until late gastrulation, and is present in the tailbud and in the brain at tailbud stages. sizzled is expressed in axolotl in the ventral region, similar to its pattern in xenopus. in axolotl, the wnt-8-expressing lpm remains relatively dors ...	2001	11702200
histochemical and immunohistochemical localization of neuronal nitric oxide synthase in the olfactory epithelium of the axolotl, ambystoma mexicanum.	the aim of this study was to describe the anatomic distribution of neuronal nitric oxide synthase immunoreactivity (nnos-ir) and nicotinamide-adenine dinucleotide phosphate-diaphorase (nadph-d) staining in the olfactory epithelium of the axolotl, juvenile, and neotenic adult, ambystoma mexicanum. nitric oxide (no, nitrogen monoxide) is a widespread molecule that has been identified both as a neuromodulator and as an intracellular messenger. in the olfactory system, no has been proposed to play a ...	2001	11485369
redneck, a new mutant of the axolotl (ambystoma mexicanum) likely affects the development of cranial neural crest.	a novel developmental mutant in the mexican axolotl is described. designated redneck (rn), the mutant gene is inherited as a simple mendelian recessive. in homozygotes, rn causes massive haemorrhage in the posterior head, rostrocaudal compression of the craniovisceral skeleton, abnormal differentiation of vertebral cartilage, micrognathia, aglossia, microphthalmia and abnormal hepatic development. affected larvae become evident at the onset of feeding, and eventually die of starvation. based on ...	2001	11461006
the eyeless mutant gene (e) in the mexican axolotl (ambystoma mexicanum) affects pax-6 expression and forebrain axonogenesis.	this study tested the hypothesis that changes in the patterns of pax-6 expression disrupt the anatomy and axonogenesis of the diencephalic areas of the eyeless axolotl. proper pax-6 expression is necessary for eye and hypothalamus morphogenesis. since the expression boundaries of pax-6 also provide a permissive environment for axonal outgrowth, an extensive study examining the effects of the eyeless gene (e) in the mexican axolotl upon pax-6 expression and forebrain axonogenesis was begun. this ...	2001	11461001
in vivo imaging indicates muscle fiber dedifferentiation is a major contributor to the regenerating tail blastema.	during tail regeneration in urodele amphibians such as axolotls, all of the tissue types, including muscle, dermis, spinal cord, and cartilage, are regenerated. it is not known how this diversity of cell types is reformed with such precision. in particular, the number and variety of mature cell types in the remaining stump that contribute to the blastema is unclear. using nomarski imaging, we followed the process of regeneration in the larval axolotl tail. combining this with in vivo fluorescent ...	2001	11456451
creation of chimeric mutant axolotls: a model to study early embryonic heart development in mexican axolotls.	the mexican axolotl (ambystoma mexicanum) provides an excellent model for studying heart development since it carries a cardiac lethal mutation in gene c that results in failure of contraction of mutant embryonic myocardium. in cardiac mutant axolotls (c/c) the hearts do not beat, apparently because of an absence of organized myofibrils. to date, there has been no way to analyze the genotypes of embryos from heterozygous spawnings (+/c x +/c) until stage 35 when the normal (+/c or +/+) embryos f ...	2001	11411308
lateral line placodes are induced during neurulation in the axolotl.	in order to determine the time window for induction of lateral line placodes in the axolotl, we performed two series of heterotopic and isochronic transplantations from pigmented to albino embryos at different stages of embryogenesis and assessed the distribution of pigmented neuromasts in the hosts at later stages. first, ectoderm from the prospective placodal region was transplanted to the belly between early neurula and mid tailbud stages (stages 13-27). whereas grafts from early neurulae typ ...	2001	11356019
complexity of the t cell receptor cbeta isotypes in the mexican axolotl: structure and diversity of the vdjcbeta3 and vdjcbeta4 chains.	we have reported previously the presence of two t cell receptor beta-chain constant region (cbeta) isotypes in the mexican axolotl. specific dbeta and jbeta segments were present at the vbeta-cbeta1 and vbeta-cbeta2 junctions and nine vbeta families which associate with both isotypes were characterized. this report describes two new cbeta isotypes, cbeta3 and cbeta4. about 70 % of the amino acids in cbeta3 are identical to cbeta1 and cbeta2. a dbeta3 and a single jbeta3 were found at the vbeta-c ...	2001	11180104
expression of hoxa5 in the heart is upregulated during thyroxin-induced metamorphosis of the mexican axolotl (ambystoma mexicanum).	widespread external and internal changes in body morphology have long been known to be hallmarks of the process of metamorphosis. however, more subtle changes, particularly at the molecular level, are only now beginning to be understood. a number of transcription factors have recently been shown to alter expression either in levels of message or in isoforms expressed. in this article, we describe a dramatic increase in the expression of the homeobox gene hoxa5 in the heart and aorta of the mexic ...	2001	12213975
action mechanism of betahistine in the vestibular end organs.	betahistine has been used to treat several vestibular disorders of both central and peripheral origin. the objective of this work was to study the betahistine action mechanism at the vestibular end organs. experiments were carried out in wild larval axolotl (ambystoma tigrinum). multiunit extracellular recordings were obtained from the semicircular canal nerve using a suction electrode. betahistine (10 microm to 10 mm, n = 32) inhibited the basal spike discharge of the vestibular afferent neuron ...	2001	11677837
betahistine produces post-synaptic inhibition of the excitability of the primary afferent neurons in the vestibular endorgans.	betahistine has been used to treat several vestibular disorders of both central and peripheral origin. the objective of this work was to study the action of betahistine in the vestibular endorgans. experiments were done in wild larval axolotl (ambystoma tigrinum). multiunit extracellular recordings were obtained from the semicircular canal nerve using a suction electrode. betahistine (10 microm to 10 mm; n = 32) inhibited the basal spike discharge of the vestibular afferent neurons with an ic50 ...	2001	11677735
nitric oxide in the afferent synaptic transmission of the axolotl vestibular system.	this study was performed using intracellular and multiunit extracellular recording techniques in order to characterize the role of nitric oxide in the afferent synaptic transmission of the vestibular system of the axolotl (ambystoma tigrinum). bath application of nitric oxide synthase inhibitors n(g)-nitro-l-arginine (0.01microm to 10microm) and n-nitro-l-arginine methyl ester hydrochloride (0.1microm to 1000microm) elicited a dose-dependent decrease in the basal discharge of the semicircular ca ...	2001	11246160
evidence for multiple sequences and factors involved in c-myc rna stability during amphibian oogenesis.	to investigate the molecular mechanisms regulating c-myc rna stability during late amphibian oogenesis, a heterologous system was used in which synthetic xenopus laevis c-myc transcripts, progressively deleted from their 3' end, were injected into the cytoplasm of two different host axolotl (ambystoma mexicanum) cells: stage vi oocytes and progesterone-matured oocytes (unfertilized eggs; ufe). this in vivo strategy allowed the behavior of the exogenous c-myc transcripts to be followed and differ ...	2001	11284969
structural and biochemical characterization of the lungfish (lepidosiren paradoxa) liver basic fatty acid binding protein.	only one fatty acid-binding protein (fabp) from the liver of the lungfish (lepidosiren paradoxa) was isolated and characterized. the sequence comparison of lungfish fabp with that of the known members of the liver fabp (l-fabp) and liver basic fabp (lb-fabp) subfamilies indicates that it is more closely related to chicken, iguana, frog, axolotl, catfish, and shark lb-fabps than to mammalian and axolotl l-fabps. lungfish liver expression of this single lb-fabp contrasts with the other fish studie ...	2001	11361145
expression of axolotl dazl rna, a marker of germ plasm: widespread maternal rna and onset of expression in germ cells approaching the gonad.	how germ cell specification occurs remains a fundamental question in embryogenesis. the embryos of several model organisms contain germ cell determinants (germ plasm) that segregate to germ cell precursors. in other animals, including mice, germ cells form in response to regulative mechanisms during development. to investigate germ cell determination in urodeles, where germ plasm has never been conclusively identified, we cloned a daz-like sequence from axolotls, axdazl. axdazl is homologous to ...	2001	11397009
conserved vertebrate chromosome segments in the large salamander genome.	urodele amphibians (salamanders) are important models for embryological, physiological, and natural history research and are also a biomedically important group because they are the only vertebrates capable of regenerating entire organ systems. to enhance the utility of salamanders for biomedical research and for understanding genome evolution, genetic linkage analysis was used to identify chromosome segments that are homologous between ambystomatid salamanders and distantly related vertebrate m ...	2001	11404337
amiloride blocks salt taste transduction of the glossopharyngeal nerve in metamorphosed salamanders.	studies in the last two decades have shown that amiloride-sensitive na(+) channels play a role in nacl transduction in rat taste receptors. however, this role is not readily generalized for salt taste transduction in vertebrates, because functional expression of these channels varies across species and also in development in a species. glossopharyngeal nerve responses to sodium and potassium salts were recorded in larval and metamorphosed salamanders and compared before and after the oral floor ...	2001	11595673
interaction of chicken liver basic fatty acid-binding protein with fatty acids: a 13c nmr and fluorescence study.	two different groups of liver fatty acid-binding proteins (l-fabps) are known: the mammalian type and the basic type. very few members of this second group of l-fabps have been characterized and studied, whereas most of the past studies were concerned with the mammalian type. the interactions of chicken liver basic fatty acid-binding protein (lb-fabp) with 1-(13)c-enriched palmitic acid (pa) and oleic acid (oa) were investigated by (13)c nmr spectroscopy. samples containing fatty acids (fa) and ...	2001	11601984
axbrn-1: a maternal transcript encodes a pou transcription factor that is later expressed in the developing central nervous system of axolotl embryos.	axbrn-1 encodes a class iii pou protein with a pou-specific domain and a pou homeodomain that is most similar to rhs2 from rat. in embryos axbrn-1 transcripts are maternally inherited and persist through cleavage. new transcripts accumulate beginning at the mid-blastula transition. in gastrulating embryos axbrn-1 rna is in the dorsal marginal zone and by neurula it is in the neural folds and neural plate. later, it is specific to the developing brain and anterior spinal cord. transcriptional act ...	2001	11685581
crystallization and preliminary x-ray study of two liver basic fatty acid-binding proteins.	the fatty acid-binding proteins (fabps) are a very well known protein family which includes the liver basic fabps (lb-fabps), a subgroup so far characterized in several vertebrates but not in mammals. the most important difference recognized between the proteins in this subgroup and the better known mammalian liver fabps (l-fabps) is the stoichiometry of ligand binding: two fatty acid molecules in l-fabps compared with one in lb-fabps. the only lb-fabp with a known three-dimensional structure is ...	2001	11717512
expression patterns of fgf-8 during development and limb regeneration of the axolotl.	fgf-8 is one of the key signaling molecules implicated in the initiation, outgrowth, and patterning of vertebrate limbs. however, it is not clear whether fgf-8 plays similar role in development and regeneration of urodele limbs. we isolated a fgf-8 cdna from the mexican axolotl (ambystoma mexicanum) through the screening of an embryo cdna library. the cloned 1.26-kb cdna contained an open reading frame encoding 212 amino acid residues with 84%, 86%, and 80% amino acid identities to those of xeno ...	2001	11146506
expression of hoxb13 and hoxc10 in developing and regenerating axolotl limbs and tails.	the expression of hox complex genes in correct spatial and temporal order is critical to patterning of the body axis and limbs during embryonic development. in order to understand the role such genes play in appendage regeneration, we have compared the expression of two 5' hox complex genes: hoxb13 and hoxc10 during development and regeneration of the body axis and the limbs of axolotls. in contrast to higher vertebrates, hoxb13 is expressed not only in the tip of the developing tail, but also i ...	2001	11150241
axolotl mhc class ii beta chain: predominance of one allele and alternative splicing of the beta1 domain.	the axolotl mhc is composed of multiple polymorphic class i loci linked to class ii b loci. in this report, evidence of the existence of one class ii b locus (amme-dab) that codes for two different transcripts is given. a 2.1-kb transcript is translated to a complete beta chain and a shorter transcript of 1.8 kb encodes a molecule lacking the beta1 domain. for two complete class ii b mrna synthesized, up to one mrna devoid of the beta1 domain is synthesized. alternative splicing involving a pept ...	2001	11180116
fibroblast growth factors in regenerating limbs of ambystoma: cloning and semi-quantitative rt-pcr expression studies.	urodele amphibians (newts and salamanders) have the ability to regenerate amputated limbs throughout their life span. because fibroblast growth factors (fgfs) play important roles in developing limbs, we initiated studies to investigate these growth factors in regenerating limbs. partial cdnas of fgf4, 8, and 10 were cloned from both the mexican axolotl, ambystoma mexicanum, and locally collected spotted salamander, ambystoma maculatum, two salamanders well recognized for their regenerative capa ...	2001	11555861
surfactant proteins and cell markers in the respiratory epithelium of the amphibian, ambystoma mexicanum.	the respiratory tract is lined by diverse epithelial cell types whose morphology, gene expression and functions are highly specialized along the cephalo-caudal axis of the lung. pulmonary gas exchange, surface tension reduction, host defense, fluid and electrolyte transport are functions shared by various vertebrate species, each organism facing similar requirements for adaptation to air breathing. consistent with this concept, we have identified distinct respiratory epithelial cell populations ...	2001	11369539
ontogeny of neurohormonal peptides, serotonin, and nitric oxide synthase in the gastrointestinal neuroendocrine system of the axolotl (ambystoma mexicanum): an immunohistochemical analysis.	the ontogeny of the neurohormonal peptides vasoactive intestinal polypeptide (vip), neurotensin (nt), substance p (sp), calcitonin gene-related peptide (cgrp), gastrin/cholecystokinin (gas/cck), and somatostatin (som) as well as serotonin (ser) and nitric oxide synthase (nos) was investigated in the gastrointestinal tract of the urodele ambystoma mexicanum, the axolotl, using immunohistochemical techniques. the first regulatory substances to appear were sp, som, and ser that could be immunohisto ...	2001	11161772
urodeles remove mesoderm from the superficial layer by subduction through a bilateral primitive streak.	urodeles begin gastrulation with much of their presumptive mesoderm in the superficial cell layer, all of which must move into the deep layers during development. we studied the morphogenesis of superficial mesoderm in the urodeles ambystoma maculatum, ambystoma mexicanum, and taricha granulosa. in all three species, somitic, lateral, and ventral mesoderm move into the deep layer during gastrulation, ingressing through a "bilateral primitive streak" just inside the blastopore. the mesodermal epi ...	2002	12167400
expression of fibroblast growth factors 4, 8, and 10 in limbs, flanks, and blastemas of ambystoma.	members of the fibroblast growth factor (fgf) family of molecules are critical to limb outgrowth. here, we examine the expression of fgfs in three types of limbs-embryonic (developing), mature (differentiated), and regenerating-as well as in the surrounding non-limb tissues in the mexican axolotl, ambystoma mexicanum. we have previously cloned partial cdnas of fgf4, 8, and 10 from the axolotl (christensen et al., 2001); the complete fgf10 cdna sequence is presented here. axolotl fgf10 showed ded ...	2002	11836784
cloning and modeling of cd8 beta in the amphibian ambystoma mexicanum. evolutionary conserved structures for interactions with major histocompatibility complex (mhc) class i molecules.	mammalian and avian t-cells exhibit a large number of well characterized surface molecules associated with their maturation degree. very little is known in comparison with t-cell differentiation in ectothermic vertebrates. this is mainly due to the lack of probes to identify t-cell subsets. we cloned and sequenced the first ectothermic cd8 beta dna complementary to rna from an amphibian species, the mexican axolotl. the cd8 beta chain was 30-36% identical with its avian and mammalian homologues. ...	2002	12034498
a novel striated tropomyosin incorporated into organized myofibrils of cardiomyocytes in cell and organ culture.	striated muscle tropomyosin is classically described as consisting of 10 exons, 1a, 2b, 3, 4, 5, 6b, 7, 8, and 9a/b, in both skeletal and cardiac muscle. a novel isoform found in embryonic axolotl heart maintains exon 9a/b of striated muscle but also has a smooth muscle exon 2a instead of exon 2b. translation and subsequent incorporation into organized myofibrils, with both isoforms, was demonstrated with green fluorescent protein fusion protein construct. mutant axolotl hearts lack sufficient t ...	2002	12044866
cell cycle reentry of ventricular and atrial cardiomyocytes and cells within the epicardium following amputation of the ventricular apex in the axolotl, amblystoma mexicanum: confocal microscopic immunofluorescent image analysis of bromodeoxyuridine-labeled nuclei.	to understand how to reinitiate cell division in adult human myocardium, a heart regeneration model was examined in the amphibian axolotl salamander, amblystoma mexicanum. the ventricular apex was surgically amputated and resected for 3 weeks. at 14 days of recovery, the thymidine analog 5-bromo-2'-deoxyuridine (brdu) was injected intraperitoneally to identify cell types undergoing s-phase by indirect immunofluorescence using primary anti-brdu antibodies. this is the first report showing a conce ...	2002	12107494
cyclopamine induces digit loss in regenerating axolotl limbs.	axolotls, with their extensive ability to regenerate as adults, provide a useful model for studying the mechanisms of regeneration in a vertebrate, in hopes of understanding why other vertebrates cannot regenerate. although the expression of many genes has been described in regeneration, techniques for gain and loss of function analyses have been limited. we demonstrated in a previous study that gain of function for secreted proteins was possible in the axolotl using the vaccinia virus to drive ...	2002	12115913
membranes, minerals, and proteins of developing vertebrate enamel.	developing tooth enamel is formed as organized mineral in a specialized protein matrix. in order to analyze patterns of enamel mineralization and enamel protein expression in species representative of the main extant vertebrate lineages, we investigated developing teeth in a chondrichthyan, the horn shark, a teleost, the guppy, a urodele amphibian, the mexican axolotl, an anuran amphibian, the leopard frog, two lepidosauria, a gecko and an iguana, and two mammals, a marsupial, the south american ...	2002	12430167
gallium nitrate: effects on cartilage during limb regeneration in the axolotl, ambystoma mexicanum.	gallium nitrate, a drug shown to have efficacy in paget's disease of bone, hypercalcemia of malignancy, and a variety of experimental autoimmune diseases, also inhibits the growth of some types of cancer. we examined dose and timing of administration of gallium nitrate on limb regeneration in the mexican axolotl, ambystoma mexicanum. administered by intraperitoneal injection, gallium nitrate inhibited limb regeneration in a dose-dependent manner. gallium nitrate initially suppressed epithelial w ...	2002	12210121
identification and expression of helios, a member of the ikaros family, in the mexican axolotl: implications for the embryonic origin of lymphocyte progenitors.	transcription factors of the ikaros gene family are critical for the differentiation of t and b lymphocytes from pluripotent hematopoietic stem cells. to study the first steps of lymphopoiesis in the mexican axolotl, we have cloned the helios ortholog in this urodele amphibian species. we demonstrated that the axolotl helios contains a 144-bp deletion at the 5' end of the activation domain. helios is expressed in both the thymus and spleen but not in the liver of the pre-adult axolotl. during on ...	2002	12115658
intraperitoneal protein injection in the axolotl: the amphibian kidney as a novel model to study tubulointerstitial activation.	a substantial body of experimental evidence suggests that protein loading causes activation of proximal tubular epithelial cells with consecutive interstitial fibrosis. these studies have mostly been performed using mammalian in vivo models of glomerular damage or tissue cultures of mammalian tubulointerstitial cells. the kidney of the axolotl contains not only closed nephrons, but also nephrons with ciliated peritoneal funnels called nephrostomes that have access to the peritoneal fluid. inject ...	2002	12081563
development of larval and transformed teeth in ambystoma mexicanum (urodela, amphibia): an ultrastructural study.	odontogenesis of early larval non-pedicellate teeth, late larval teeth with a more or less distinct dividing zone and fully transformed pedicellate teeth in ambystoma mexicanum (urodela) was studied to obtain insights into the development of differently structured teeth in lower vertebrates. using transmission electron microscopy we investigated five developmental stages: (1) papilla; (2) bell stage (secretion of the matrix begins); (3) primordium (mineralization and activity of ameloblasts star ...	2002	11989966
structure, diversity and expression of the tcrdelta chains in the mexican axolotl.	mammals and birds have two major populations of t cells, based on the molecular composition and biological properties of their antigen receptors (tcr). alpha beta t cells recognize antigenic peptides linked to major histocompatibility complex (mhc) molecules, and gamma delta t cells recognize native peptide or non-peptide antigens independently of mhc. very little is known about gamma delta t cells in ectothermic vertebrates. we have cloned and characterized the tcrdelta chains of an urodele amp ...	2002	11981822
characterization of a tm-4 type tropomyosin that is essential for myofibrillogenesis and contractile activity in embryonic hearts of the mexican axolotl.	a striated muscle isoform of a tropomyosin (tm-4) gene was characterized and found to be necessary for contractile function in embryonic heart. the full-length clone of this isoform was isolated from the mexican axolotl (ambystoma mexicanum) and named axolotl tropomyosin cardiac-3 (atmc-3). the gene encoded a cardiac-specific tropomyosin protein with 284 amino acid residues that demonstrated high homology to the xenopus cardiac tm-4 type tropomyosin. northern blot analysis indicates a transcript ...	2002	11968015
electrorotation of axolotl embryos.	the frequency dependent dielectric properties of individual axolotl embryos (ambystoma mexicanum) were investigated experimentally utilizing the technique of electrorotation. individual axolotl embryos, immersed in low conductivity media, were subjected to a known frequency and fixed amplitude rotating ac electric field and the ensuing rotational motion of the embryo was monitored using a conventional optical microscope. none of the embryos in the pregastrulation or neurulation stages of develop ...	2002	11891751
retinoid antagonists inhibit normal patterning during limb regeneration in the axolotl, ambystoma mexicanum.	retinoic acid (ra) has been detected in the regenerating limb of the axolotl, and exogenous ra can proximalize, posteriorize, and ventralize blastemal cells. thus, ra may be an endogenous regulatory factor during limb regeneration. we have investigated whether endogenous retinoids are essential for patterning during axolotl (ambystoma mexicanum) limb regeneration by using retinoid antagonists that bind to specific rar (retinoic acid receptor) or rxr (retinoid x receptor) retinoid receptor subtyp ...	2002	11857478
ectoderm to mesoderm lineage switching during axolotl tail regeneration.	foreign environments may induce adult stem cells to switch lineages and populate multiple tissue types, but whether this mechanism is used for tissue repair remains uncertain. urodele amphibians can regenerate fully functional, multitissue structures including the limb and tail. to determine whether lineage switching is an integral feature of this regeneration, we followed individual spinal cord cells live during tail regeneration in the axolotl. spinal cord cells frequently migrate into surroun ...	2002	12471259
amphioxus and lamprey ap-2 genes: implications for neural crest evolution and migration patterns.	the neural crest is a uniquely vertebrate cell type present in the most basal vertebrates, but not in cephalochordates. we have studied differences in regulation of the neural crest marker ap-2 across two evolutionary transitions: invertebrate to vertebrate, and agnathan to gnathostome. isolation and comparison of amphioxus, lamprey and axolotl ap-2 reveals its extensive expansion in the vertebrate dorsal neural tube and pharyngeal arches, implying co-option of ap-2 genes by neural crest cells e ...	2002	12397104
immunocytochemical localization of keratins, associated proteins and uptake of histidine in the epidermis of fish and amphibians.	keratinization and the role of histidine in some species of fish and amphibians have been analyzed by immunocytochemistry and autoradiography. in cartilaginous and bony fishes, staining of acidic (ae1-positive) and basic (ae3-positive) keratins was strong and their distribution patterns were uniform in all epidermal layers. the ae2 antibody (for keratins k1 and k10 that are typical for keratinization) did not produce any positivity. this was also observed in lungfish epidermis but the ae2 antibo ...	2002	12389745
effects of dexamethasone treatment on iodothyronine deiodinase activities and on metamorphosis-related morphological changes in the axolotl (ambystoma mexicanum).	in amphibians, there is a close interaction between the interrenal and the thyroidal axes. hypothalamic corticotropin-releasing hormone or related peptides stimulate thyroidal activity by increasing thyrotropin synthesis and release, while corticosterone accelerates both spontaneous and thyroid hormone-induced metamorphosis. one of the mechanisms that is thought to contribute to this acceleration is a corticosterone-induced change in peripheral deiodinating activity. the present experiments were ...	2002	12383443
different regulation of t-box genes tbx4 and tbx5 during limb development and limb regeneration.	the t-domain transcription factors tbx4 and tbx5 have been implicated, by virtue of their limb-type specific expression, in controlling the identity of vertebrate legs and arms, respectively. to study the roles of these genes in developing and regenerating limbs, we cloned tbx4 and tbx5 cdnas from the newt, and generated antisera that recognize tbx4 or tbx5 proteins. we show here that, in two urodele amphibians, newts and axolotls, the regulation of tbx4 and tbx5 differs from higher vertebrates. ...	2002	12376111
differential post-transcriptional regulations of wnt mrnas upon axolotl meiotic maturation.	the products of the wntgene family play an essential role in several aspects of embryo patterning. we have investigated the post-transcriptional regulation of three of these genes: awnt-1, awnt-5a and awnt-5b during axolotl (ambystoma mexicanum) oogenesis, oocyte maturation and early development. we show that awnt-1, awnt-5a and awnt-5b mrnas are maternally expressed. the three transcripts are tightly regulated at specific times and display differential mrna stability, poly(a) tail length and lo ...	2002	12216985
cranial neural crest emergence and migration in the mexican axolotl (ambystoma mexicanum).	the timing and pattern of cranial neural crest cell emergence and migration in the mexican axolotl, ambystoma mexicanum, are assessed using scanning electron microscopy (sem). cranial neural crest cells emerge and begin to migrate at the time of neural fold closure and soon form three distinct streams. the most anterior (mandibular) stream emerges first, at the level of the mesencephalon. cells in this stream migrate rostroventrally around the optic vesicle. the second (hyoid) and third (branchi ...	2002	16351868
myoseptal architecture of sarcopterygian fishes and salamanders with special reference to ambystoma mexicanum.	during axial undulatory swimming in fishes and salamanders muscular forces are transmitted to the vertebral axis and to the tail. one of the major components of force transmission is the myoseptal system. the structure of this system is well known in actinopterygian fishes, but has never been addressed in sarcopterygian fishes or salamanders. in this study we describe the spatial arrangement and collagen fiber architecture of myosepta in latimeria, two dipnoans, and three salamanders in order to ...	2003	16351889
ultrastructure of the external gill epithelium of the axolotl, ambystoma mexicanum with reference to ionic transport.	the ultrastructure of the external gill epithelium of the axolotl, ambystoma mexicanum, has been examined using conventional transmission electron microscopy to elucidate its role in ionic transport. four cell types are identified in the gill filament and primary gill bar epithelium. these are granular, ciliated, leydig and basal cells. a fifth cell type, the flat mitochondria-rich cell is only found in the gill bar epithelium. the predominant granular cells display microvilli at their surface a ...	2003	15137686
the epithelia of the protrusible tongue of eurycea longicauda guttolineata (hoolbrook 1838) (urodela: plethodontidae).	in this study the lingual and sublingual glands, the lingual stem and the epithelial surface of the protrusible secondary tongue were investigated by light, scanning and transmission electron microscopy. the quality of the secretions of the epithelia was characterized histochemically. the lingual epithelium is formed by superficial (pavement) and goblet cells and at the margin of the tongue pad are also regions covered by ciliated cells. on the dorsal part of the tongue there are goblet cells of ...	2003	15121544
endogenous electric fields in embryos during development, regeneration and wound healing.	all embryos that have been investigated drive ionic currents through themselves and these currents will generate internal electric fields. here, those examples in which such fields have been measured directly are discussed. the first such measurements were made in chick embryos and about 20 mv mm(-1) was measured near the posterior intestinal portal in 2-4 day-old embryos. this electric field is important for the development of tail structures because reducing its magnitude results in abnormal t ...	2003	14690282
gustatory neurons derived from epibranchial placodes are attracted to, and trophically supported by, taste bud-bearing endoderm in vitro.	taste buds are multicellular receptor organs innervated by the viith, ixth, and xth cranial nerves. in most vertebrates, taste buds differentiate after nerve fibers have reached the lingual epithelium, suggesting that nerves induce taste buds. however, under experimental conditions, taste buds of amphibians develop independently of innervation. thus, rather than being induced by nerves, the developing taste periphery likely regulates ingrowing nerve fibers. to test this idea, we devised a cultur ...	2003	14651931
axolotl pronephric duct migration requires an epidermally derived, laminin 1-containing extracellular matrix and the integrin receptor alpha6beta1.	the epidermis overlying the migrating axolotl pronephric duct is known to participate in duct guidance. this epidermis deposits an extracellular matrix onto the migrating duct and its pathway that is a potential source of directional guidance cues. the role of this matrix in pronephric duct guidance was assayed by presenting matrix deposited on microcarriers directly to migrating pronephric ducts in situ. we found that reorientation of extracellular-matrix-bearing carriers prior to their present ...	2003	14522870
characterization of glycosaminoglycans during tooth development and mineralization in the axolotl, ambystoma mexicanum.	glycosaminoglycans (gags) involved in the formation of the teeth of ambystoma mexicanum were located and characterized with the cuprolinic blue (cb) staining method and transmission electron microscopy (tem). glycosaminoglycan-cuprolinic blue precipitates (gagcb) were found in different compartments of the mineralizing tissue. various populations of elongated gagcb could be discriminated both according to their size and their preferential distribution in the extracellular matrix (ecm). gagcb pop ...	2003	14517102
tooth development in ambystoma mexicanum: phosphatase activities, calcium accumulation and cell proliferation in the tooth-forming tissues.	prerequisites of tooth formation, cell proliferation in the tooth-forming tissues, calcium accumulation and the enzymatic activities of alkaline (alp) and acid phosphatases (acp) were investigated by immunohistochemical and histochemical methods in various developmental stages of the mexican axolotl, ambystoma mexicanum. during the growth of replacement teeth, the tooth-forming tissues continually recruit cells from the surrounding regions. the basal layer of the oral epithelium, the dental lami ...	2003	12801088
olfactory signal modulation by molluscan cardioexcitatory tetrapeptide (fmrfamide) in axolotls (ambystoma mexicanum).	the terminal nerve, which innervates the nasal epithelia of most jawed vertebrates, is believed to release neuropeptides that modulate activity of sensory receptor neurons. the terminal nerve usually contains gonadotropin-releasing hormone as well as at least one other peptide that has not been characterized, but which bears some structural similarity to molluscan cardioexcitatory tetrapeptide (fmrfamide) and neuropeptide tyrosine (npy). we investigated the effects of fmrfamide on both voltage-g ...	2003	12771020
relationship between cardiac protein tyrosine phosphorylation and myofibrillogenesis during axolotl heart development.	the axolotl, ambystoma mexicanum, is a useful system for studying embryogenesis and cardiogenesis. to understand the role of protein tyrosine phosphorylation during heart development in normal and cardiac mutant axolotl embryonic hearts, we have investigated the state of protein tyrosine residues (phosphotyrosine, p-tyr) and the relationship between p-tyr and the development of organized sarcomeric myofibrils by using confocal microscopy, two-dimensional isoelectric focusing (ief)/sds-polyacryla ...	2003	12747935
selective activation of thrombin is a critical determinant for vertebrate lens regeneration.	the regeneration of structures in adult animals depends on a mechanism for coupling the acute response to tissue injury or removal with the local activation of plasticity in residual differentiated cells or stem cells. many potentially relevant signals are generated after injury, and the nature of this mechanism has not been elucidated for any instance of regeneration. lens regeneration in adult vertebrates always occurs at the pupillary margin of the dorsal iris, where pigmented epithelial cell ...	2003	12747839
a point mutation in bioactive rna results in the failure of mutant heart correction in mexican axolotls.	ambystoma mexicanum is an intriguing animal model for studying heart development because it carries a mutation in gene c. hearts of homozygous recessive (c/c) mutant embryos do not contain organized myofibrils and fail to beat. the defect can be corrected by organ-culturing the mutant heart in the presence of rna from anterior endoderm or endoderm/mesoderm-conditioned medium. by screening a cdna library made of total conditioned medium rna from normal axolotl embryonic endoderm, we isolated a si ...	2003	12721841
neural crest contributions to the lamprey head.	the neural crest is a vertebrate-specific cell population that contributes to the facial skeleton and other derivatives. we have performed focal dii injection into the cranial neural tube of the developing lamprey in order to follow the migratory pathways of discrete groups of cells from origin to destination and to compare neural crest migratory pathways in a basal vertebrate to those of gnathostomes. the results show that the general pathways of cranial neural crest migration are conserved thr ...	2003	12702647
gonadotropin releasing hormone (gnrh) modulates odorant responses in the peripheral olfactory system of axolotls.	peripheral signal modulation plays an important role in sensory processing. activity in the vertebrate olfactory epithelium may be modulated by peptides released from the terminal nerve, such as gonadotropin releasing hormone (gnrh). here, we demonstrate that gnrh modulates odorant responses in aquatic salamanders (axolotls, ambystoma mexicanum). we recorded electrical field potentials (electro-olfactograms, or eogs) in response to stimulation with four different amino acid odorants, l-lysine, l ...	2003	12672784
surface glycoconjugates in the olfactory system of ambystoma mexicanum.	lectin binding histochemistry was performed on the olfactory system of neotenic and metamorphosed ambystoma mexicanum to investigate the distribution and density of defined carbohydrate residues on the cell surface glycoproteins of the olfactory and vomeronasal receptor cells and their terminals in the olfactory bulbs. the lectin binding patterns indicate that the main olfactory system possesses a high density of n-acetyl-galactosamine and n-acetyl-glucosamine residues, while the vomeronasal sys ...	2003	12655612
ontogeny of the vip system in the gastro-intestinal tract of the axolotl, ambystoma mexicanum: successive appearance of co-existing pacap and nos.	evidence for the presence and potential co-existence of vasoactive intestinal polypeptide (vip), pituitary adenylate cyclase-activating polypeptide (pacap) and nitric oxide synthase (nos) in gastro-intestinal endocrine cells and/or nerve fibers is conflicting and very few results exist on development. this immunofluorescence study aims to clarify the appearance and localization of vip, pacap and nos in the gastro-intestinal tract of the axolotl, ambystoma mexicanum, during ontogeny. vip-immunore ...	2003	12649730
extending the table of stages of normal development of the axolotl: limb development.	the existing table of stages of the normal development of the axolotl (ambystoma mexicanum) ends just after hatching. at this time, the forelimbs are small buds. in this study, we extend the staging series through completion of development of the forelimbs and hindlimbs.	2003	12619140
expression of complement 3 and complement 5 in newt limb and lens regeneration.	some urodele amphibians possess the capacity to regenerate their body parts, including the limbs and the lens of the eye. the molecular pathway(s) involved in urodele regeneration are largely unknown. we have previously suggested that complement may participate in limb regeneration in axolotls. to further define its role in the regenerative process, we have examined the pattern of distribution and spatiotemporal expression of two key components, c3 and c5, during limb and lens regeneration in th ...	2003	12594255
electroporation as a tool to study in vivo spinal cord regeneration.	tailed amphibians such as axolotls and newts have the unique ability to fully regenerate a functional spinal cord throughout life. where the cells come from and how they form the new structure is still poorly understood. here, we describe the development of a technique that allows the visualization of cells in the living animal during spinal cord regeneration. a microelectrode needle is inserted into the lumen of the spinal cord and short rapid pulses are applied to transfer the plasmids encodin ...	2003	12557220
identification of cdna clones encoding hmg 2, a major protein of the mexican axolotl hydrocortisone-sensitive thymocytes.	we have identified and analyzed cdna clones encoding a major 26 kda protein of the hmg1-2 family which is abundant in the cytoplasm and nucleus of axolotl hydrocortisone-sensitive thymocytes. the axolotl hmg2 protein is very similar to proteins belonging to the hmg1-2 family, from teleost fish to mammals. all the molecular features of the hmg1-2 proteins are conserved, including the high proportion of basic and aromatic residues, and the characteristic acidic c-terminus tail. the 3'-untranslated ...	2003	8654668
[origin of the cells in the symmetrical forelimbs of the axolotl ambystoma mexicanum].		2003	2740070
spermatogenesis and 3beta-hsdh activity in the testis of the axolotl.		2003	1012324
sheep heart rna stimulates myofibril formation and beating in cardiac mutant axolotl hearts in organ culture.	in the mexican axolotl, ambystoma mexicanum, recessive mutant gene c, when homozygous, results in a failure of the heart to form sarcomeric myofibrils and contract normally. previous studies have shown that purified rna from normal anterior endoderm or from medium conditioned with anterior endoderm/pre-cardiac mesoderm has the capacity to rescue mutant hearts in organ culture. in the present study, rna extracted from adult sheep heart was tested for its capacity to promote differentiation in the ...	2003	12684761
examination of an amphibian-based assay using the larvae of xenopus laevis and ambystoma mexicanum.	semistatic acute toxicity tests of amphibian larvae (xenopus laevis and ambystoma mexicanum) were conducted at different developmental stages and by different methods to establish a simple amphibian-based assay. test substance was pentachlorophenol sodium salt (pcp-na). the endpoint was mortality and the 24-, 48-, 72-, and 96-h lc50 values were calculated by probit analysis. interspecific differences in larval responses were not clear. larval sensitivity tended to increase with larval age. newly ...	2003	12706392
ph modulates the vestibular afferent discharge and its response to excitatory amino acids.	in the isolated inner ear of the axolotl (ambystoma tigrinum) acid ph decreased and basic ph increased the resting and mechanically evoked spike discharge of semicircular canal afferent neurons. variations in ph also modified the afferent neuron response to n-methyl-d-aspartic acid (nmda) acid and to (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (ampa). responses to both excitatory amino acid agonists increased at ph 7.8 (41% and 22%, respectively) and decreased by perfusion of ...	2003	12876466
regulative germ cell specification in axolotl embryos: a primitive trait conserved in the mammalian lineage.	how germ cells are specified in the embryos of animals has been a mystery for decades. unlike most developmental processes, which are highly conserved, embryos specify germ cells in very different ways. curiously, in mouse embryos germ cells are specified by extracellular signals; they are not autonomously specified by maternal germ cell determinants (germ plasm), as are the germ cells in most animal model systems. we have developed the axolotl (ambystoma mexicanum), a salamander, as an experime ...	2003	14511484
opioid receptors mediate a postsynaptic facilitation and a presynaptic inhibition at the afferent synapse of axolotl vestibular hair cells.	this study was designed to determine the effects of opiate drugs on the electrical activity of afferent neurons and on the ionic currents of hair cells from semicircular canals. experiments were done on larval axolotls (ambystoma tigrinum). the multiunit spike activity of afferent neurons was recorded in the isolated inner ear under both resting conditions and mechanical stimulation. ionic currents were recorded using voltage clamp of hair cells isolated from the semicircular canal. in the isola ...	2003	12676139
injection of exogenous rna in amphibian oocytes leads to rna level fluctuations which are sensitive to cordycepin, an rna chain elongation terminator.	using an in vivo heterologous system to study the stability of xenopus laevis rna injected into axolotl (ambystoma mexicanum) fertilized eggs, we have previously observed unexpected fluctuations in rna level during early development [andéol et al., differentiation 63 (1998) 69-79]. in this study, we further characterize this phenomenon and establish its existence during axolotl and xenopus oogenesis, suggesting a phylogenetically conserved mechanism. the phenomenon can occur with a variety of ex ...	2003	14746268
responses to amputation of denervated ambystoma limbs containing aneurogenic limb grafts.	the developing neural tubes and associated neural crest cells were removed from stage 30 ambystoma maculatum embryos to obtain larvae with aneurogenic forelimbs. forelimbs were allowed to develop to late 3 digit or early 4 digit stages. limbs amputated through the mid radius-ulna regenerated typically in the aneurogenic condition. experiments were designed to test whether grafts of aneurogenic limb tissues would rescue denervated host limb stumps into a regeneration response. in experiment 1, an ...	2003	12911114
albino axolotls from an albino tiger salamander through hybridization.		2003	6055330
candidate gene analysis of metamorphic timing in ambystomatid salamanders.	although much is known about the ecological significance of metamorphosis and metamorphic timing, few studies have examined the underlying genetic architecture of these traits, and no study has attempted to associate phenotypic variation to molecular variation in specific genes. here we report on a candidate gene approach (cga) to test specific loci for a statistical contribution to variation in metamorphic timing. three segregating populations (sp1, sp2 and sp3) were constructed utilizing three ...	2003	12694285
time relationships between the onset of rna synthesis and the manifestation of the morphogenetic function in axolotl nuclei.		2003	4668026
radioresistance of regenerating axolotl tissues.		2003	4778512
cortical reaction in axolotl eggs.		2003	5154619
[autoradiographic study of rna synthesis during the restoration of regenerative capacity of the extremities of the axolotl supressed by x-radiation].		2003	5343939
[induction of haploid androgenesis in the axolotl by ultraviolet irradiation and a cytomorphological study of the mechanism of its origin].		2003	5896234
identification of angiotensin i in several vertebrate species: its structural and functional evolution.	in order to delineate further the molecular evolution of the renin-angiotensin system in vertebrates, angiotensin i (ang i) has been isolated after incubation of plasma and kidney extracts of emu (dromiceus novaehollandiae), axolotl (ambystoma mexicanum), and sea lamprey (petromyzon marinus). the identified sequences were [asp1, val5, asn9] ang i in emu, [asp1, val5, his9] ang i in axolotl, and [asn1, val5, thr9] ang i in sea lamprey. these results confirmed the previous findings that tetrapods ...	2004	14723880
cloning and analysis of axolotl isl2 and lhx2 lim-homeodomain transcription factors.	we cloned and characterized the isl2 and lhx2 lim-homeodomain transcription factors of the mexican salamander, or axolotl, ambystoma mexicanum. using a degenerate pcr approach, partial cdnas representing five lim-homeodomain genes were cloned, indicating conservation of this class of transcription factors in urodeles. full-length cdnas for isl2 and lhx2 were identified and sequenced. the predicted isl2 and lhx2 proteins are well conserved, especially in the lim and dna-binding domains. the isl2 ...	2004	15048808
patterns of spatial and temporal visceral arch muscle development in the mexican axolotl (ambystoma mexicanum).	vertebrate head development is a classical topic that has received renewed attention during the last decade. most reports use one of a few model organisms (chicken, mouse, zebrafish) and have focused on molecular mechanisms and the role of the neural crest, while cranial muscle development has received less attention. here we describe cranial muscle differentiation and morphogenesis in the mexican axolotl, ambystoma mexicanum. to determine the onset of differentiation we use antibodies against d ...	2004	15216519
expression of a novel cardiac-specific tropomyosin isoform in humans.	tropomyosins are a family of actin binding proteins encoded by a group of highly conserved genes. humans have four tropomyosin-encoding genes: tpm1, tpm2, tpm3, and tpm4, each of which is known to generate multiple isoforms by alternative splicing, promoters, and 3' end processing. tpm1 is the most versatile and encodes a variety of tissue specific isoforms. the tpm1 isoform specific to striated muscle, designated tpm1alpha, consists of 10 exons: 1a, 2b, 3, 4, 5, 6b, 7, 8, and 9a/b. in this stud ...	2004	15249230
cell contact-dependent mechanisms specify taste bud pattern during a critical period early in embryonic development.	after gastrulation, the pharyngeal endoderm is specified to give rise to taste receptor organs without further signaling from other embryonic tissues. we hypothesized that intercellular signaling might be responsible for the specification of taste buds. to test if and when this signaling was occurring, intercellular contacts were transiently disrupted in cultures of pharyngeal endoderm from axolotl embryos, and the number, size, and distribution of taste buds analyzed. disruption of cell contact ...	2004	15254897
the scarless heart and the mrl mouse.	the ability to regenerate tissues and limbs in its most robust form is seen in many non-mammalian species. the serendipitous discovery that the mrl mouse has a profound capacity for regeneration in some ways rivalling the classic newt and axolotl species raises the possibility that humans, too, may have an innate regenerative ability. the adult mrl mouse regrows cartilage, skin, hair follicles and myocardium with near perfect fidelity and without scarring. this is seen in the ability to close th ...	2004	15293806