Publications

mutant genes in the mexican axolotl.		1974	17756293
[the thyroid gland of the axolotl (ambystoma mexicanum): morphological and functional heterogenicity].		1974	4837802
[some electrophysiological characteristics of the dividing axolotl eggs].		1974	4837557
the influence of l-thyroxine on the change in red blood cell type in the axolotl.		1974	4826287
the occurrence of biochemical metamorphic events without anatomical metamorphosis in the axolotl.		1974	4826286
[electron microscopic study of the endocrine and acinar-islet (transitlonal) cells in the axolotl pancreas].		1974	4601346
the effect of ascorbic acid and potassium ferricyanide as melanogenesis inhibitors on the development of pigmentation in mexican axolotls.		1974	4207619
correlation between karyo- and cytokinesis during the first cell divisions in the axolotl (ambystoma mexicanum cope).		1974	4857046
comparative study of the early embryonic cytology and nucleic acid synthesis of ambystoma mexicanum normal and o mutant embryos.		1974	4820344
patterns of purine synthesis related to iridophore development in the wild type, melanoid, and axanthic strains of the mexican axolotl, ambystoma mexicanum shaw.		1974	4814566
[relation between the periods of cyclic changes in membrane electrical characteristics and phases of cyto- and karyokinesis in cleaving loach and axolotl eggs].		1974	4858162
[study of the growth of cartilaginous tissue using the meckel cartilage of the amphibian axolotl].		1974	4534473
the chiasmata of axolotls.		1974	4469154
a comparison of morphogenesis of muscles of the forearm and hand during ontogenesis and regenerationin the axolotl (ambystoma mexicanum). ii. the development of muscular pattern in the embryonic and regenerating limb.		1974	4446672
a comparison of morphogenesis of muscles of the forearm and hand during ontogenesis and regeneration in the axolotl (ambystoma mexicanum). i. anatomical description of muscles of the forearm and head.		1974	4446671
the ultrastructure of lateral line sense organs in the juvenile salamander ambystoma mexicanum.		1974	4442075
ultrastructure of pigment cells in wild type and color mutants of the mexican axolotl.		1974	4140038
the effects of rotation and positional change of stump tissues upon morphogenesis of the regenerating axolotl limb.		1975	1204936
proceedings: the brain stem of the axolotl ambystoma mexicanum and the frog rana esculenta.		1975	1082712
[influence of environmental salinity on blood ion concentration of the intact and hypophysectomized axolotl. effect of prolactin].		1975	1205118
[effect of prolactin on mucous epidermal cells in the intact and hypophysectomized axolotl].		1975	54279
neural crest and early fore limb development in amphibia.	anterior trunk neural folds were exchanged between neurula stages 15 to 16 (harrison) of several triturus species and ambystoma mexicanum. donor neural crest cells migrated ventrad before and during initial bud formation. they lined the early lumb epidermis and became incorporated into the young blastema. donor melanophores and non-melanophores contributed substantially to host limb buds.	1975	1211655
[studies of the activity and the isoenzyme patterns of ldh during the development ofxenopus laevis, triturus alpestris andvulgaris andambystoma mexicanum].	the present paper deals with studies of the activity and the isoenzyme patterns of ldh during the development ofxenopus laevis, triturus alpestris andvulgaris andambystoma mexicanum. activity measurements have been performed with the optical test method using pyruvate as substrate and the isoenzymes have been separated by vertical starch gel electrophoresis. a) substrate optima for enzyme extracts from embryonic stages 1-38 are identical in the three speciestriturus alpestris, ambystoma mexicanu ...	1975	28304825
[transplantation into the blastocoel of pleurodeles waltlii michah., of blastomers isolated from blocked blastulae obtained from interspecific nuclear transplants between ambystoma mexicanum shaw. and ambystoma dumerilii dugès (urodele amphibians)].	ectodermic blastomeres from arrested nucleocytoplasmic blastulae obtained by nuclear graft between ambystoma mexicanum (a. m.) and ambystoma dumerilii (a. d.), are transplanted in the blastocoele of recipient pleurodeles waltlii blastulae. histo-autoradiographic analysis shows that hybrid cells have cellular affinities and multiplication capacities very different from normal ambystoma mexicanum blastulae isolated cells. the possibility that a revitalisation of lethal blastomeres can occur should ...	1975	813905
proceedings: development of the ipsilateral visual projection in axolotls treated with thyroxine.		1975	1177125
[demonstration of rna synthesis during segmentation in the axolotl embryo].	study of the incorporation of 3h-uridine in cleaving embryo of axolotl has shown a nuclear rna synthesis during the period of synchronous cleavage (6th cycle) as well as after the onset of asynchronous divisions (9th or 10th cycle). in the early development of the axolotl, the extent of the transcription phase looks to be an essential element of the quantitative control of gene activity.	1975	811409
[evolution of xenografts of embryonic gonads and juvenile ovaries from ambystoma mexicanum shaw, transplanted into triturus alpestris laur].	gonad primordium of ambystoma mexicanum when grafted at tail-bud stage on triturus alpestris is indefinately tolerated. testis or ovaries derived from those grafted embryonic gonads follow their differentiaion and reach sexual maturity. axolotl juvenile ovaries transplanted in triturus alpestris are also tolerated; the ovocytes achieve the entire vitellogenesis but are not able to be laid.	1975	809199
inter- and intramyotomal gap junctions in the axolotl embryo.		1975	1181218
multiple regeneration from axolotl limb stumps bearing cross-transplanted minced muscle regenerates.		1975	1181217
re-innervation of axolotl limbs. ii. sensory nerves.		1975	237288
re-innervation of axolotl limbs. i. motor nerves.		1975	237287
[morphogenesis of the anterior limb primordium and its histochemical aspects in the pleurodele and the axolotl].	in both species, the primary mesodermal blastema of the forelimb bud derives from a regional proliferation of somatopleural cells under the ectoderm. a cellular sheet of somitic origin invades the limb blastema early. morphological and histochemical changes suggest the establishment of early ecto-mesodermal interactions in the young limb bud.	1975	808278
cell cycles in the early development of axolotl.	in axolotl embryos, during the course of development, the generation time increases, chiefly on account of a lengthening of the phase of dna synthesis, the longest in the cell cycle. at the stages of the middle blastula and early gastrula, the g1 phase is shorter than in the g2 phase, while at the neurula stage, the g1 phase is far longer than the g2 phase. cells of the chordamesoderm pass through the cycle nonuniformly during gastrulation: a period with a very low index of labeled nuclei and sl ...	1975	1124434
proceedings: axolotl-liver in organ culture. i. some morphological and biochemical parameters.		1975	1163296
isozymic patterns of lactate dehydrogenase in whole embryos and adult tissues of the mexican axolotl.		1975	1109827
normal stages of development of the axolotl. ambystoma mexicanum.		1975	1167837
hormonal stimulation as an aid to artificial insemination in ambystoma mexicanum.		1975	1116071
[a change in the concentration of potassium and sodium during early axolotl embryogenesis].		1975	1214990
pathological changes of golgi complex in hemocytoblasts of spleen of young axolotls after x-irradiation.		1975	1172336
experimental studies on a lethal gene (1) in the mexican axolotl, ambystoma mexicanum.	1. gene ł is a recessive lethal factor found in the white strain of axolotls. animals heterozygous for the gene are phenotypically normal. when mated with each other they give offspring 25% of which exhibit the lethal effects of the gene. 2. the ł/ł homozygotes develop normally to an advanced embryonic stage (harrison stage 40) before the effects of the gene are first manifested. they then come to display a characteristic combination of abnormalities, including a disproportionately small head, s ...	1975	1167371
[axolotl 1975].		1975	1164736
growth and respiration of regenerating tissues of the axolotl tail.	changes in the weight and oxygen consumption were studied during regeneration of the tail in adult axolotls and larvae. the curve of the increase in weight of the regenerating tail in both age groups is s-shaped. the intensity of respiration of the regenerating tail increases in adult axolotls and in larvae at the blastema stage; in adult axolotls there is also a second increase in the intensity of respiration of the regenerating tail during differentiation of the muscles. the relationship betwe ...	1975	1114357
association of an ultraviolet irradiation sensitive cytoplasmic localization with the future dorsal side of the amphibian egg.	drastic alterations in neural morphogenesis can be induced by ultraviolet irradiation of the amphibian egg. the target area of u.v. was determined either by direct irradiation of various regions of the egg or by comparing the area of the u.v. hit with the location of the dorsal lip. axolotl eggs which displayed easily recognizable gray crescents were employed for the direct irradiation experiments and albino axolotl eggs were used for a comparison of the u.v. sensitivity of the animal and vegeta ...	1975	1078573
[early activation of ribosomal rna synthesis in axolotl embryos].	the incorporation of labeled precursors (3h- and 14c-uridine) into the fractions of salt-insoluble rnas and or rrna was studied in the axolotl embryos at different stages of early development (from the end of synchronous cleavage divisions until the end of gastrulation). rna preparations isolated from the embryos at all stages studied contained incorporated radioactivity. the radioactivity of salt-insoluble rnas markedly increased at the beginning of blastulation and continued to grow, but less ...	1975	1052341
[oxygen consumption and cytochrome oxidase activity of muscle tissue from the limbs of axolotls following restoration of regenerative capability suppressed by x-ray irradiation].	the intensity of oxygen consumption and the activity of cytochrome oxidase have been studied in the homogenate, mitochondria and nuclei of the limb muscle tissue in axolotls after the suppression of regenerative ability by x-irradiation and its experimental restoration. under the suppression of regenerative ability, the oxygen consumption was inhibited. the cytochrome oxidase activity in the homogenate and mitochondria decreased and in the nuclei remained at the same level or even increased as c ...	1975	175338
[meiosis: role of a histone kinase in the condensation of ovarian oocyte chromosomes of xenopus laevis and ambystoma mexicanum].	by injecting heterologous histone-kinase preparations into ovarian axolotl oocytes, it has been possible to speed up the progesterone-induced process of chromosome condensation. moreover, in some instances, this condensation and even complete maturation have been obtained after injection of protein kinase alone, thus in the absence of hormone stimulation. two different histone kinase preparations have been used: one was prepared from ascites cell chromatin and the other from in vitro ovulated xe ...	1975	177222
incorporation of labeled amino acids into proteins of the cell organelles of muscle tissue during the restoration of the regenerative capacity of the limbs of axolotl, suppressed by x-irradiation.	the incorporation of labeled amino acids into the total proteins of muscle tissue and cell organelles during the regeneration of limbs of axolotls and after the suppression of the regenerative capacity by x-irradiation and its experimental restoration were investigated. in the case of suppression of the regenerative capacity of the limbs by x-irradiation, the protein synthesis in the muscle tissue is impaired. the intensity of the incorporation of labeled amino acids into the proteins of a homog ...	1975	1129636
[activity and isoenzymes of lactate dehydrogenase in tissues of amphibians (xenopus laevis, ambystoma mexicanum, triturus alpestris and vulgaris) and the response in the fat body of xenopus males to gonadotropin injection (author's transl)].	lactate-dehydrogenase activity was determined by the optical test method using pyruvate as substrate and the isoenzymes were separated by vertical starch gel electrophoresis. species-specific and organ-specific characteristics of the total activity and the isoenzyme patterns of the four amphibian species are compared with those of rat and mouse. application of gonadotropin increases the amount of soluble protein and the lactate-dehydrogenase activity in the fat body of xenopus and the isoenzyme ...	1975	1176091
long-term biological investigations in space.	missions in space within the next two decades will be of longer duration than those carried out up to the present time, and the effects of such long-term flights on biological organisms are unknown. results of biological experiments that have been performed to date cannot be extrapolated to results in future flights because of the unknown influence of adaptation over a long period of time. prior experiments with axolotl, fishes, and vertebrates by our research team (in part with sounding rockets ...	1975	11841093
development of locomotor behavior in wild type and spastic (sp/sp) axolotls, ambystoma mexicanum.	the homozygous recessive spastic mutant found in the mexican axolotl shows violent coiling and thrashing behavior when subjected to strong tactile or electrical stimulation. in order to establish the time of onset of the first behavioral manifestation of the spastic gene, an etiological analysis of the ontogeny of swimming behavior in mutants and wild type siblings was undertaken. the locomotor patterns shown by embryos in response to an electrical stimulus were analyzed quantitatively from the ...	1975	1202151
low resistance junctions between mesoderm cells during development of trunk muscles.	1. electrical connexions between mesoderm cells have been examined during the formation of somites in xenopus laevis, bombina orientalis and ambystoma mexicanum. 2. in xenopus the resting potentials of presumptive myotome cells (-65 + 2 mv, s.e. of mean) and somite muscle cells (-65 +/- 0-6 mv s.e. of mean) were 40 mv, greater than dermatome cells (-25 +/- 0-6 mv, s.e. of mean). similar differences were found in bombina and ambystoma. 3. in all three species cells of the dermatome layer of the m ...	1976	1255515
[participation of irradiated tissues in the formation of limb regenerates in axolotls].		1976	939173
ontogeny of ldh-isozymes in mexican axolotl, ambystoma mexicanum by thin-layer isoelectric focusing.	the ontogeny of lactate dehydrogenase (ldh) isozymes in developing mexican axolotl, ambystoma mexicanum was investigated by thin-layer isoelectric focusing in polyacrylamide gel. the isoelectric points (pi values) of the isozymes were determined. the minor components generally remained masked during conventional electrophoresis, but became sharp as isofocusing progressed. we identified in developing eggs and embryos five major ldh isozymes, which could also be traced in the ovarian eggs. all the ...	1976	992242
on the determination of the dorso-ventral polarity in the amphibian embryo: suppression by lactate of the formation of ruffini's flask-cells.	cells isolated from the vegetal hemisphere of the blastula of ambystoma mexicanum differentiate spontaneously into fibroblast-like cells. similar cells may be formed from animal cells, provided they are induced either by vegetal cells or by li+. we have found that lactate and various inhibitors of rna synthesis suppress the spontaneous cell differentiation. the effect of lactate differs from that of the other agents in so far as lactate must be present before the second day of culture to suppres ...	1976	1003073
apical secretion from taste bud and other epithelial cells in amphibians.	taste buds of the axolotl, ambystoma mexicanum, contain cells, previously undescribed in this species, which have a long apical process, and are similar to the type iii cells of mammalian taste buds, and to the gustatory cells in fish. in the supporting cells, there is evidence of periodic decapitation, in addition to secretion by exocytosis. bilaminar fragments, which are leaf-shaped bodies formed of two dense laminae separated by a lucent gap, protrude from the apical microvilli of the support ...	1976	1086718
regulation of lactate dehydrogenase (ldh) and alcohol dehydrogenase (adh) synthesis in liver nuclei, following their transfer into oocytes.	the regulatory effect of oocyte cytoplasm on the synthetic activity of transferred somatic cell nuclei was studied using an interspecific hybrid combination of ambystoma texanum and ambystoma mexicanum (axolotl). the enzymes lactate dehydrogenase (ldh) and alcohol dehydrogenase (adh) were used as markers of gene activity. in both species of salamanders, ldh is synthesized in the liver and oocytes, while adh is tissue-specific being synthesized in the liver but not oocytes. both ldh and adh show ...	1976	12194433
a staging system for forelimb regeneration in the axolotl, ambystoma mexicanum.	a staging system has been devised for normal regeneration from the upper arm in the mature axolotl. it consists of seven externally definable stages: (1) wound healing (wh): (2) dedifferentiation (dd); (3) early bud (eb); (4) medium bud (mb); (5) late bud (lb); (6) palette (pal), and (7) digital outgrowth (do). serial histological sections of 38 regenerating limbs were used to correlate gross stages with microscopic events in the regenerative process.	1976	966285
diploid gynogenesis in the mexican axolotl.	gynogenetic diploid axolotls were produced by activating eggs with ultraviolet-inactivated sperm, and then subjecting the activated eggs to heat shock. optimal conditions for ultraviolet inactivation of the sperm, and for suppression of the second meiotic division by heat shock, were established. gynogenetic diploids produced by these procedures included progeny homozygous for recessive alleles carried by a heterozygous mother. gynogenesis could, therefore, be used to uncover new mutations more ...	1976	971806
protein synthesis in lethal nucleocytoplasmic hybrids between the species pleurodeles waltlii michahelles and ambystoma mexicanum shaw (urodele amphibians) obtained by nuclear grafting.	using polyacrylamide gel electrophoresis, proteins stemming from the nucleus of the donor species in nucleocytoplasmic hybrids were determined. the interspecific lethal nucleocytoplasmic hybrids of pleurodeles waltlii and ambystoma mexicanum were studied. the presence of these proteins at the blastula or early gastrula stages attests to the early nuclear control of their synthesis.	1976	965910
thin-layer isoelectric focusing of soluble and insoluble lens extracts from cataractous and normal mexican axolotl (ambystoma mexicanum).		1976	949994
how x-rays inhibit amphibian limb regeneration.	the effects of an inhibiting dose of 2,000 rad of x-rays on the regenerating limbs of axolotl larvae have been examined in a histological and cytological study. particular attention was paid to the mitotic indices of normal and irradiated epidermal and blastemal cells. both the characteristic pattern of epidermal mitotic stimulation which normally follows amputation and the later increase in blastemal mitoses are suppressed by irradiation. in most cells the effects are permanent, but in a small ...	1976	939955
retinofugal pathways in normal and albino axolotls.	the retinofugal pathways of normal and albino axolotls have been studied by tracing the transport of radioactive materials after tritiated proline was injected into one eye. the pathways demonstrated by this method include crossed projections to the diencephalon, pretectum, and tectum, and a small component that goes to the midbrain tegmentum in the basal optic root. ipsilaterally, radioactive label was found in all of the same cerebral regions, but in much smaller quantities. although on the ba ...	1976	1276914
[development of gonads transplanted homoplastically in limbs of sexually immature axolotls].	graft development depends on sexual maturation of the host. three successive steps in development of transplants have been demonstrated: somatic growth, gonial division and germinal maturation. sexual maturity occurs earlier in females than in males.	1976	821644
the cell cycle during amphibian limb regeneration.	the duration of the cell cycle in the blastema of regenerating limbs of axolotls has been measured by means of [3h]thymidine pulse labelling and autoradiography. a chase was required to define the pulse period. an average cell cycle at 20 degrees c takes 53 h, s-phase takes 38 h; including parts of mitosis, g1 is 10 h and g2 is 5 h long. the protracted cycle and s-phase are consonant with the large genome in axolotis and other urodeles. the rapidly growing blastema probably contains a steady pop ...	1976	1270529
horizontal cell potentials: dependence on external sodium ion concentration.	the membrane potential of the horizontal cell of the axolotl is highly dependent on the extracellular concentration of sodium. experimental results reported here are consistent with the suggestion that in the dark the receptors release a synaptic transmitter which increases primarily the sodium conductance of the postsynaptic membrane. externally applied aspartate or glutamate depolarizes the horizontal cell membrane and eliminates the light response of the horizontal cell. however, it appears t ...	1976	1251211
irradiation inhibits the regeneration of aneurogenic limbs.	the developing arms of axolotl larvae from the 2-digit stage onward and the aneurogenic arms of surgically denervated larvae maintained in parabiosis are able to regenerate after amputation. such regeneration is uniformly inhibited by local irradiation of the arm, whether innervated or not. this demonstration refutes a recent hypothesis that x-rays interfere with a special activity of nerves required for regeneration, and supports the earlier concept that x-rays act directly on those cells which ...	1976	1262820
topological analysis of the brain stem of the axolotl ambystoma mexicanum.	the ventricular sulcal pattern and the cellular structure of the brain stem of the axolotl ambystoma mexicanum have been studied in transversely cut nissl and bodian stained serial sections. six longitudinal sulci, the sulcus medianus inferior, the sulcus intermedius ventralis, the sulcus limitans, the sulcus intermedius dorsalis, the sulcus medianus superior and the sulcus lateralis mesencephali could be distinguished. a seventh groove, the sulcus isthmi, clearly deviates from the overall longi ...	1976	1270610
mitotic activity and nucleic acid precursor incorporation in denervated and innervated limb stumps of axolotl larvae.	mitotic activity and dna and rna precursor incorporation were compared in innervated regenerating limbs and in denervated, non-regenerating limbs on days 8 and 9 post-amputation. innervated limbs had well-developed cone stage blastemas which showed high cellular mitotic indices and h3-thymidine labeling indices of 0.40-0.50 and h3-uridine labeling indices of 0.50-0.75. in contrast, denervated limbs showed dedifferentiated cells distally under thickened wound epithelia, but essentially no mitotic ...	1976	1262816
alterations in resting membrane properties during neural plate stages of development of the nervous system.	1. the mean resting membrane potential of cells in the neural plate of axolotl embryos increases from -25 to -45 mv (maximum values from -35 to -60 mv) when the embryos move from early to mid-neural plate stages of development. 2. increasing the extracellular [k] to 20 mm shortly before the spontaneous increase in resting potential occurs causes neural plate cells to hyperpolarize. 3. a moderate increase in [k]omicron does not hyperpolarize the membrane of neural plate cells at earlier stages or ...	1976	1255516
non-innervated sense organs of the lateral line: development in the regenerating tail of the salamander ambystoma mexicanum.	new lateral organs (neuromasts) are formed in regenerating tails of the larvae of a urodele, the axolotl (ambystoma mexicanum), even in the absence of the lateral line nerve, as confirmed by electron microscopic examination. the non-innervated organs are similar to normal innervated organs. the hair cells are polarized in opposite directions, and despite the lack of nerve endings, contain synaptic bodies, which in normal innervated organs are found in relation to afferent boutons.	1976	1249591
studies of muscle proteins in embryonic myocardial cells of cardiac lethal mutant mexican axolotls (ambystoma mexicanum) by use of heavy meromyosin binding and sodium dodecyl sulfate polyacrylamide gel electrophoresis.	in the mexican axolotl ambystoma mexicanum recessive mutant gene c, by way of abnormal inductive processes from surrounding tissues, results in an absence of embryonic heart function. the lack of contractions in mutant heart cells apparently results from their inability to form normally organized myofibrils, even though a few actin-like (60-a) and myosin-like (150-a) filaments are present. amorphous "proteinaceous" collections are often visible. in the present study, heavy meromyosin (hmm) treat ...	1976	1107335
stretch receptors in urodele limb muscles.	non-encapsulated, fine beaded nerve endings were found histologically on some muscle fibres in a number of limb muscles in newts and axolotls. they were present in newt muscles that had been chronically de-efferented, and in which no efferent activity survived, and were therefore likely to be sensory. they were located only on muscle fibres on or near the outside surface of the muscle. these small-diameter muscle fibres were characterised histochemically by low lipid, sdh and phosphorylase conte ...	1976	129283
restoration of vision in genetically eyeless axolotls (ambystoma mexicanum).		1976	1082417
[growth of meckel's cartilage in axolotl (urodelean amphibian)].		1976	1070669
regeneration-promoting properties of tribenoside in amblystoma mexicanum.	tribenoside in a dose of 100 mg/kg i.p. significantly accelerates the regeneration of puncture wounds in the caudal membrane of amblystoma mexicanum. a dose of 200 mg/kg exerts a less-pronounced vulnerary effect and is occasionally toxic. tribenoside also stimulates regeneration in this species when added to bath fluid in a concentration of 1:400,000 (exposure for 6 h daily). a concentration of 1:200,000 is less effective and has a slightly irritant effect on the tissue. 14 days after operation, ...	1976	1037626
morphological and biochemical abnormalities in hearts of cardiac mutant salamanders (ambystoma mexicanum).	the effect of homozygosity for recessive gene c in ambystoma mexicanum is the absence of a heartbeat even though initially heart development appears normal. mutant embryos (c/c) are first distinguishable from their normal siblings (+/+;+/c) at stage 34 (7 days after fertilization) when the normals develop contracting hearts. the mutant hearts at this stage, upon gross examination, appear structurally normal but fail to beat. nevertheless, the mutants survive through stage 41, which is about 20 d ...	1976	1034176
[differentiation tendency in mesodermal germ layer. isolation experiments on morula, blastula and gastrula stadia of axolotl (ambystoma mexicanum)].		1976	1024382
[segregation of amphibian cns. analysis of induction process using combination experiments in ambystoma mexicanum].		1976	1023592
satellite cells in the limb musculature of the axolotl.		1976	1016334
[relationship between mitotic phases at different stages of embryonic development of axolotl].	indices and durations of mitotic phases and interphase have been determined in the axolotl embryos at the late blastula, early gastrula and mid-neurula stages. the data obtained suggest that the ratio of mitotic phases changes during embryogenesis and differs in different rudiments of the embryo at the same developmental stage.	1976	934593
the intracellular localization of carbamoyl-phosphate synthase (ammonia) activity in the liver of the mexican axolotl, ambystoma mexicanum (shaw).		1976	183934
the role of schwann cells in paradoxical regeneration in the axolotl.	the experiments described here examine further the conditions under which paradoxical regeneration occurs and provide support for the hypothesis that a proximal migration of schwann cells is responsible for the phenomenon. when only the hand is shielded from irradiation and the limb is denervated, amputation through the forearm or upper arm sometimes results in regeneration. the effects of variation in the time interval between denervation and amputation, the level of amputation and the method a ...	1977	591863
preferential expression of the maternal allele for alcohol dehydrogenase (adh) in the amphibian hybrid ambystoma mexicanum (axolotl) x ambystoma texanum.		1977	561728
on the differentiation of prospective ectoderm to a ciliated cell pattern in embryos of ambystoma mexicanum.	the differentiation of the ectoderm in ambystoma mexicanum (harrison stage 26--27) was examined under in vivo and in vitro conditions by scanning electron microscopy under different experimental conditions. about one out of three flank epidermal cells was found to be ciliated in the undistrubed or control embryos. the shape of ciliated cells in the explants from the animal region was only slightly affected. in no case was it possible to find two adjacent ciliated cells, implying that these cells ...	1977	73569
cardiac mutant salamanders: evidence for heart induction.	homozygosity for gene c in ambystoma mexicanum results in no detectable heartbeat in situ. alteration of the cardiac environment through organ culture results in rapid initiation of spontaneous heartbeat, indicating that absence of cardiac function in situ is not the result of failure of embryonic induction.	1977	908918
a scanning electron microscopic comparison of the development of embryonic and regenerating limbs in the axolotl.	a comparison between the surface features of embryonic limb development and limb regeneration was made in the axolotl. scanning electron microscopy revealed an overall similarity between embryonic and regenerating limbs. a notable feature was the lack of a morphologically discrete apical epidermal specialization on the surface of any of the limbs. histological preparations revealed no thickening of the apical epidermis in embryonic limbs. there is a definite thickening of the apical epidermis in ...	1977	908913
thyroxine-induced gill resorption in the axolotl (ambystoma mexicanum).		1977	903970
dosage effects of the white (d) and melanoid (m) genes on pigment pattern in the mexican axolotl, ambystoma mexicanum, shaw.		1977	892230
spontaneous release of transmitter from 'repressed' nerve terminals in axolotl muscle.		1977	18677
fiber counts of regenerating peripheral nerves in axolotls and the effect of metamorphosis.	counts have been made of myelinated and unmyelinated fibers in the sixteenth nerve root of the axolotl, before, during and after regeneration following nerve section. there is no loss of myelinated fibers. many collateral sprouts are formed and eventually withdrawn. regeneration during metamorphosis is similar but there is more sprouting. there is no fiber loss from cut nerves in metamorphosis. this suggests that rising thyroid hormone levels are not in themselves detrimental to nerves without p ...	1977	864039
microtubule proteins in axolotl eggs and developing embryos.		1977	559603
control of anteroposterior pattern in the axolotl forelimb by a smoothly graded signal.	(1) it is shown that the number of cartilage elements in an experimentally produced reduplicated limb depends on the width of competent tissue between pieces of flank tissue. (2) seventy well formed reduplications were examined on the assumption that the difference in the number of elements between them results from small differences in graft position. (3) all the reduplications are symmetrical along their entire length. (4) all possess the most posterior structures at both edges with other elem ...	1977	886255
determination of anteroposterior polarity in the axolotl forelimb by an interaction between limb and flank rudiments.	1. it is shown that the mesoderm in the prospective forelimb-bud of the axolotl embryo is thickened and divided into somatic and splanchnic layers, while that of the flank is thinner and divided. the first sign of the limb-bud itself appears at stage 38. 2. a whole, a half or a third of a limb rudiment can develop into a normal or reduplicated limb when transplanted to the flank. 3. an anterior half of a limb rudiment fails to develop when transplanted to the head but will do so if accompanied b ...	1977	886254
experimental studies on a mutant gene (p) causing premature death of ambystoma mexicanum embryos.	the premature death (p) mutation is a recessive lethal, which, in the homozygous condition, gives rise to a complex of abnormalities. the mutant embryos develop only to stage 37, at which time disintegration of superficial tissue begins. many of the abnormalities observed in sections of the stage-37 mutant embryo are related to its failure to establish a functioning circulatory system, or to the resulting edema and/or ascites that distend the abdomen and flanks. there are, however, abnormalities ...	1977	886253
evidence for abnormal heart induction in cardiac-mutant salamanders (ambystoma mexicanum).	homozygosity for simple recessive gene c in axolotl embryos results in the absence of a heartbeat. gene c alters the morphology of the mutant anterior endoderm - the primary heart inductor.	1977	860120
the development of monamine-containing neurons in the brain and spinal cord of the salamander, ambystoma mexicanum.	the distribution of monoamine-containing neurons in the cns of the developing and adult axolotl, ambystoma mexicanum, has been investigated using the histochemical fluorescence technique of falck and hillarp combined with microspectrofluorimetry. the earliest catecholamine-containing neurons to be detected are located in the ventral ependymal zone of the spinal cord at the time of hatching (stage 41). between stages 43 and 46, catecholamine fluorescence can be detected in neurons in the followin ...	1977	856887
the timing of morphogenetic events in the regenerating forelimb of the axolotl, ambystoma mexicanum.		1977	863102
an autoradiographic study of optic fiber projections from eye grafts in eyeless mutant axolotls.		1977	67046
electrophysiological experiments on the mechanism and accuracy of neuromuscular specificity in the axolotl.	the supracoracoideus muscle of the axolotl shoulder girdle is innervated by two nerves, the supracoracoideus nerve (sc) supplying most of the muscle and the posterior supracoracoideus (psc) supplying the posterior corner. all the muscle fibres are multiply innervated and at the border between the two innervations many muscle fibres, when penetrated by a microelectrode, show junction potentials from both nerves. in such cases one junction potential is often very small, below the threshold for exc ...	1977	19787
development of the sympathetic system in the mexican axolotl, ambystoma mexicanum.		1977	557011