Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| cyclic amp and neuroendocrine influence upon forelimb regeneration in the adult newt, notophthalmus viridescens. | the influence of the nervous and endocrine systems upon successive stages of limb regeneration suggest possible neuroendocrine interaction(s). intraperitoneal injections of various agents had no effects upon blastema formation. chlorpromazine, administered alone or with hormones, retarded morphogenesis. prolactin, dibutyryl camp (db-camp), theophylline, and acetylcholine accelerated morphogenesis. 5'-amp had no effect. only db-camp countered the chlorpromazine-induced retardation of morphogenesi ... | 1975 | 3753 |
| effects of neurotransmitters upon the discharge of secretory product from the cutaneous glands of the red-spotted newt. | the effects of sympathetic and parasympathetic agonists and antagonists on discharge of secretory product by the granular and mucous glands were examined in the red-spotted newt, notopthalmus viridescens viridescens. observations were made also on the south african clawed toad. xenopus laevis, the grass frog, rana pipiens, and the crested newt, triturus cristatus. in contrast to the granular glands of the south african clawed toad and the grass frog, which were stimulated by alpha-adrenergic age ... | 1977 | 21937 |
| polyfunctional antigen-binding specificity in hapten-carrier responses of the newt, triturus viridescens. | 1975 | 53990 | |
| dna replication in the amphibia. | autoradiographic techniques were used to measure rate of replication and length of the replication unit in cultured cells of scaphiopus couchi, bufo cognatus, rana clamitans, and triturus viridescens, having nuclear dna amounts in the ratio 1:4:7:39 respectively. the autoradiographic experiments were designed to show whether the larger amounts of nuclear dna are correlated with more rapid rates of synthesis and/or with longer replication units. -- the dna replication rate was 2.5 mu/minute (corr ... | 1975 | 125187 |
| changes in cyclic gmp levels during forelimb regeneration in adult notophthalmus viridescens. | cyclic 3', 5'-guanosine monophosphate (cgmp) was measured at eight stages of forelimb regeneration in adult newts and compared with the cgmp levels of non-regenerating control limbs. there was a significant increase in cgmp content during dedifferentiation followed by a sharp decrease to minimal levels at the cone stage. a second smaller increase in cgmp occurred between the cone stage and mid-differentiation, followed by a decrease to relatively constant levels approaching control values as dif ... | 1977 | 192831 |
| hormonal effects on mitotic rhythm in the epidermis of the red-spotted newt. | 1977 | 198339 | |
| hormonal regulation of cellular proliferation in the epidermis of the red-spotted newt. | 1977 | 198340 | |
| localization of 5'-ribonucleotide phosphohydrolase in regenerating (and normal) limb tissues of the adult newt notophthalmus viridescens. | the regenerating forelimb of the adult newt, notophthalmus viridescens was investigated for 5'-nucleotidase (5' ribonucleotide phosphohydrolase, 3.1.3.5) acitivity. the newt's humeri were surgically removed, and after a twenty-one-day recovery period, the forelimbs amputated above the elbows. regenerates were sampled at predetermined times for specific phases in the progress of regeneration, frozen, sectioned in a cryostat, and the sections fixed in 10% cold formol calcium. the wachstein and mei ... | 1975 | 241677 |
| the occurrence of a tetrodotoxin-like substance in the red-spotted newt, notophthalmus viridescens. | 1979 | 442108 | |
| effects of parathyroidectomy and of parathyroid extract on levels of calcium and phosphate in the blood and urine of the red-spotted newt. | 1979 | 456879 | |
| retinal ganglion cell response to axotomy and nerve growth factor in the regenerating visual system of the newt (notophthalmus viridescens): an ultrastructural morphometric analysis. | nerve growth factor (ngf) treatment, given as a single 200 bu intraocular injection at the time of optic nerve transection, was found to significantly accelerate the retinal ganglion cell response to axotomy in the newt (notophthalmus viridescens). in the control series the per cent of neurons in the retinal ganglion layer demonstrating nuclear reactivity (i.e. chromatin changes) reaches a peak by 14 days post axotomy (14 dpa), plateaus through 21 dpa and falls thereafter, returning to control l ... | 1979 | 466440 |
| autoradiographic and electron microscopic studies of minced cardiac muscle regeneration in the adult newt, notophthalmus viridescens. | the regenerative response of minced cardiac muscle grafts in the adult newt was studied using autoradiography and electron microscopy. one-sixteenth to one-eighth of the newt ventricle was amputated, minced, and returned to the wounded ventricle. at five days after grafting, no reorganization of graft msucle pieces was apparent and there was degeneration of much of the muscle graft. another, smaller population of 5-day myocytes had euchromatic nuclei and intact sarcolemmae. in 10- and 16-day gra ... | 1979 | 469482 |
| reduction of sodium dependent stump currents disturbs urodele limb regeneration. | we have asked the question whether the natural electric currents which leave urodele limb stumps are in any way needed for their regeneration. as an initial test, we have greatly reduced such currents in the tiger salamander, ambystoma tigrinum, by applying 0.5 mm amiloride to the stump skin or by immersion of the animals in sodium depleted media. we have also reduced such currents in the red spotted newt, notophthalmus viridescens, by such immersion. limb regeneration in half of the amiloride-t ... | 1979 | 490133 |
| separation of the epithelial and mesenchymal components of the newt limb regenerate with salt. | after incubation of isolated forelimb regenerates of notophthalmus (triturus) viridescens at all developmental stages for 60 minutes at 37 degrees c in a salt medium containing 111 mm sodium chloride, 5.6 mm potassium chloride and 100 mm sodium phosphate buffer at ph 7.5, the wound epithelium of each regenerate was removed intact from its underlying mesenchymal component. the suggestion is made that the salt medium is an effective epithelial-mesenchymal separating agent due to a combination of i ... | 1979 | 490137 |
| retinal ganglion cell response to axotomy and nerve growth factor antiserum in the regenerating visual system of the newt (notophthalmus viridescens): an ultrastructural morphometric analysis. | one 3.0 mg dose of the nerve growth factor antiserum (anti-ngf) injected into the vitreous chamber of the eye at the time of optic nerve transection elicits significant changes in the normal newt (notophthalmus viridescens) retinal ganglion cell body response to axotomy at 7 and 14 days postaxotomy (dpa). light microscopic observations indicate that anti-ngf treatment significantly reduces the per cent of retinal ganglion cells demonstrating nuclear chromatin reactivity (ie., homogeneous to a mo ... | 1979 | 497824 |
| effect of testosterone and 17-beta estradiol on limb regeneration in the newt, notophthalmus viridescens. | gonadectomy, or injections of testosterone or 17-beta estradiol, had no apparent effect on the rate of regeneration or histological appearance of limb regenerates in the newt, notophthalmus viridescens. neither promotion, nor inhibition of limb regeneration was observed. | 1979 | 520495 |
| the formation of muscles in regenerating limbs of the newt after denervation of the blastema. | the purpose of this experiment was to examine the relationship, if any, between nerve fibers and the formation of muscle pattern in the regenerating amphibian limb. during embryogenesis, nerve fibers grow into the limb bud at the time when the common muscle blastemas subdivide into individual muscle primordia, whereas in regeneration nerve fibers are always present. in order to learn whether or not the muscle pattern could be laid down in the absence of nerves we amputated 58 limbs of newts (not ... | 1979 | 528874 |
| effects of x-rays on nerve-dependent (limb) and nerve-independent (jaw) regeneration in the adult newt, notophthalmus viridescens. | the newt limb requires nerves for successful regeneration, but the jaw appears to be nerve independent. among the current hypotheses for the regeneration-inhibitory action of x-rays is one proposing inactivation of nerves as the main cause. we decided to test this hypothesis by comparing the irradiation levels necessary for inhibition of limb and jaw regeneration. jaws and left front limbs were exposed locally to doses of ionizing x-irradiation ranging from 250 to 2000 r at least 6 weeks prior t ... | 1979 | 536692 |
| lizard and newt tail regeneration: a quantitative study. | almost perfect fits of the gompertz equation to the growth in length of tail regenerates in the lizard, lacerta lepida, and the newt, notophthalmus viridescens, were obtained. comparison of certain parameters of the equation with published mitotic index data suggests that the gompertz equation characterizes each system at least from the time that significant mitotic activity is first observed histologically. an objective method for comparing the regeneration periods of the two species is describ ... | 1979 | 536712 |
| a portion of all major classes of histone messenger rna in amphibian oocytes is polyadenylated. | ovaries of the amphibian triturus viridescens contain a considerable amount of 7 to 12 s rna which fractionates with poly(a)+ rna on oligo(dt)-cellulose column chromatography and directs the synthesis of all five classes of histones in a wheat germ cell-free system. the polyadenylate tracts associated with this 7 to 12 s poly (a)+ rna are heterogeneous in length, ranging from approximately 60 to 120 nucleotides. partially purified subfractions of histone mrna templates were isolated from this rn ... | 1978 | 564902 |
| the jelly envelopes and fertilization of eggs of the newt, notophthalmus viridescens. | fertilization in notophthalmus viridescens is internal and involves passage of the sperm through five layers of egg jelly (j5-j1, from outermost to innermost), each of which is secreted by a discrete region of the oviduct. polyspermy is normal. passage of the sperm through the jelly and into the egg was studied by a technique of artificial insemination similar to natural insemination, in that undiluted fluid from the vas deferens was applied directly to eggs with various layers of jelly present, ... | 1978 | 569209 |
| regenerative repair in the severed optic nerve of the newt (triturus viridescens): effect of nerve growth factor antiserum. | 1978 | 620705 | |
| morphological changes in the ultrastructure of the thyroid epithelium of notophthalmus viridescens after hypophysectomy and tsh- and prolactin stimulation. | in the newt, notophthalmus viridescens, hypophysectomy results in progressive atrophy of the thyroid cells to the point of irreversible degeneration. after exclusive tsh-stimulation of hypophysectomized newts, increased endocytotic activity of the follicular epithelium is observed. prolactin stimulation under the same conditions prevents atrophy but does not result in increased cell activity, as expressed by the reduced amount of microvilli and the lack of endocytotic activity. combined tsh- and ... | 1978 | 630599 |
| repair and reorganization of minced cardiac muscle in the adult newt (notophthalmus viridescens). | 1978 | 633377 | |
| glial reaction to nerve growth factor in the regenerating optic nerve of the newt (triturus viridescens). | 1978 | 639915 | |
| visualization of bispecific antigen-binding in immunized splenic lymphocytes of the newt, triturus viridescens. | 1978 | 640113 | |
| scanning electron microscopy of epidermal cell migration in wound healing during limb regeneration in the adult newt, notophthalmus viridescens. | the epidermal cells which migrate over the wound surface of the amputated limb of the adult newt were examined using the scanning electron microscope. specimens were prepared routinely for scanning electron microscopy or were embedded in epon 812 for light microscopic observations. a cuff of epidermal cells was seen at the edge of the wound, from which cells appeared to migrate over the wound surface. as early as five hours after transection of the limb, the basal layers of this cuff appeared to ... | 1978 | 645617 |
| regenerative ability of double-half and half upper arms in the newt, notophthalmus viridescens. | the upper arms of adult newts (notophthalmus viridescens) were surgically manipulated to create double-half dorsal, double-half ventral, double-half anterior, and double-half posterior upper arms, and longitudinal half-dorsal, half-ventral, half-anterior, and half-posterior upper arms. amputation through the double-half upper arms usually failed to elicit normal distal regeneration, despite the fact that an apparently normal regeneration blastema was initially formed. instead, regeneration in th ... | 1978 | 660137 |
| the morphology of the mucous gland and its responses to prolactin in the skin of the red-spotted newt. | the mucous gland of the red-spotted newt, notophthalamus viridescens viridescens, rafinesque was examined by histochemical and ultrastructural techniques and its cytological responses to various hormonal conditions were studied. its secretory epithelial cells produce and release in merocrine fashion a neutral, unsulphated mucosubstance. the secretory epithelium is bounded peripherally by a thin, but apparent non-functional, myoepithelium. the duct of this mucous gland consists of a single kerati ... | 1978 | 671558 |
| neural and hormonal stimulation of dna and protein synthesis in cultured regeneration blastemata in the newt notophthalmus viridescens. | 1978 | 680355 | |
| testosterone and 5alpha-dihydrotestosterone inhibit both growth and spermatogenesis in the remaining testis in partially castrated adult newts, notophthalmus viridescens. | the testis of the newt, notophthalmus viridescens, undergoes hypertrophy following partial castration. injections of either testosterone or 5alpha-dihydrotestosterone are equally effective in inhibiting the increase in testis weight which follows partial castration. in addition, both of these androgens inhibit spermatogenesis, i.e., spermatogonia appear to be inhibited resulting in early cessation of spermatogenesis and a precocious division of the testis into separate spermatogonia and sperm co ... | 1978 | 702083 |
| re-regeneration of lower jaws and the dental lamina in adult urodeles. | transverse amputations were carried out through one-third fully regenerated jaw segments and through normal tissue of the mandible on the same and opposite sides of the jaw in adults of notophthalmus viridescens. collectively the results suggest that, in adult urodeles, the mandible and the dental lamina can be replaced in an identical manner more than one time. although the major histological events are the same in jaw regeneration and re-regeneration, regrowth is more rapid in re-regeneration. ... | 1978 | 702533 |
| nerve trophic effects: an in vitro assay for factors involved in regulation of protein synthesis in regenerating amphibian limbs. | we have developed a rapid sensitive test for factors that mimic the trophic effects of nerves by maintaining normal rates of protein synthesis in denervated forelimb blastemata of adult newts (notophthalmus viridescens). rates of protein synthesis in secondary blastemata are similar. however, after they are denervated and explanted into organ culture the rates of protein synthesis first increase and later fall below control values. similar changes occur after denervation in vivo. the alterations ... | 1978 | 712346 |
| effect of amputation and limb regeneration on the pars distalis of the newt, notophthalmus viridescens. | a study of the pituitary of the newt, notophthalmus viridescens, during limb regeneration indicated no observable changes in histology or ultrastructure of any of the cells of the pars distalis when compared with the pars distalis of unamputated control newts. | 1978 | 720526 |
| occurrence of trypanosomiasis in the red eft stage of the red-spotted newt, notophthalmus viridescens (rafinesque). | 1978 | 722463 | |
| a scanning electron microscopic and quantitative histologic description of lens regeneration in the newt, notophthalmus viridescens. | 1978 | 722789 | |
| retinal ganglion cell response to axotomy in the regenerating visual system of the newt (triturus viridescens): an ultrastructural morphometric analysis. | 1978 | 729683 | |
| rna transcription on the giant lateral loops of the lampbrush chromosomes of the american newt notophthalmus viridescens. | by counting silver grains in autoradiographs of lampbush chromosomes the rates of incorporation of [3h]adenine, [3h]cytidine, [3h]guanosine and [3h]uridine, administered separately, into rna on the giant loops of chromosome ii of notophthalmus viridescens, were compared with the rates of incorporation of these same precursors into rna on other, unidentified loops. the overall rate of rna transcription on the giant loops is only about half that on the generality of other loops, and the rna transc ... | 1978 | 748343 |
| on the identity of the thyrotropic cell in the red-spotted newt. | although the pars distalis of the red-spotted newt has previously undergone extensive cytological examination, the identity of its thyrotropic cells has remained uncertain. from the present ultrastructural study, cells of type 3 (masur, 1969) containing granules 150-180 nm in diameter are concluded to be the thyrotropes. such cells were found to be present in the regions of the pars distalis where thyroidectomy cells arise after ablation of the thyroid gland. cells of type 3 are probably identic ... | 1976 | 825228 |
| analysis of chromatin-associated fiber arrays. | electron microscopic examination of chromatin from embryonic nuclei of oncopeltus fasciatus and drosophila melanogaster reveals arrays of chromatin associated fibers. the lengths and spacings of these fibers were analyzed to provide a basis for defining and interpreting regions of transcriptionally active chromatin. the results of the analysis are consistent with the interpretation of some fibers as nascent rna with associated protein (rnp). the chromatin segments underlying these fiber arrays w ... | 1976 | 826376 |
| ribosomal rna synthesis in the eastern north-american newt, notophthalmus viridescens. | ribosomal rna (rrna) synthesis, the initiation of which is an early major event during the transformation of iris into lens in the newt, was characterized in the tvi cell-line derived from the eastern north-american newt notophthalmus viridescens. employing the technique of polyacrylamide gel electrophoresis, molecular-weight measurements were made on newt rrnas using xenopus laevis and e. coli rrnas as standards. the molecular weights of n. viridescens 28s and 18s rrna were found to be 1.4 x 10 ... | 1977 | 838209 |
| the relationship between growth, developmental stage and postamputation age of the regeneration blasterma of the newt, notophthalmus viridescens. | the growth of the regeneration blastema of the newt forelimb has been quantitated and analyzed as a function of postamputation age, developmental stage, animal weight, animal length, and cross sectional diameter of the blastemal base in both the anteroposterior and dorsoventral dimensions. correlation coefficients computed for these variables show that growth of the regenerate in both length and volume is more closely correlated with developmental stage than postamputation age. in addition, the ... | 1977 | 839186 |
| water balance responses to dehydration and neurohypophysial peptides in the salamander, notophthalmus viridescens. | 1977 | 844677 | |
| transfilter mitogenic effect of dorsal root ganglia on cultured regeneration blastemata, in the newt, notophthalmus viridescens. | 1977 | 849801 | |
| the early stages of wallerian degeneration in the severed optic nerve of the newt (triturus viridescens). | the initiation of wallerian degeneration in the severed optic nerve of the newt (triturus viridescens) was very rapid and intense. significant degeneration of nonmyelinated axons was observed as early as six hours after lesion (h.a.l.) and was almost complete by 48 h.a.l. initial degeneration of non-myelinated axons began in "extracellular digestion chambers" formed between burgeoning ependymoglial processes. the remaining fragments and debris were later phagocytized by surrounding ependymoglial ... | 1977 | 851236 |
| the effects of hydrocortisone and bacterial lipopolysaccharide on the anti-erythrocyte response in the spleens of adult triturus viridescens. | the effects of hydrocortisone (hc) and bacterial lipopolysaccharide (lps) have been tested separately and in combination, on the antigen-binding response of splenocytes of the newt. triturus viridescens immunized with horse erythrocytes (hrbc). the timing of the presentation of each was made relative to when challenge with either low (0.0025%) or high (25%) doses of the immunogen (hrbc) was effected. our results showed inhibition of both low and high dose responses by hc and additionally suggest ... | 1977 | 859006 |
| repolarization of reversed, regenerating lenses in adult newts, notophthalmus viridescens. | 1977 | 862682 | |
| pituitary enhancement of wolffian lens regeneration in vitro: spatial and temporal requirements. | when irido-corneal complexes (icc's) from eyes of adult newts (notophthalmus viridescens) are cultured on top of pituitary glands they produce advanced lens regenerates in up to 90% of the cases (this report and connelly et al., '73). to determine if the iris and pituitary gland must be in direct contact with each other in order to produce this enhancement of lens regeneration, icc's were cultured next to pituitary glands or separated from them by a nuclepore filter. cultures behaved as icc's cu ... | 1977 | 874445 |
| accumulation of glucocorticoids in regenerating areas of limbs of the newt, notophthalmus viridescens. | evidence is presented that regenerating portions of newt limbs preferentially accumulate 3h-labelled exogeneous cortisol and corticosterone. the ability of such regions to accumulate glucocorticoids is maximal about seven days after amputation and is abolished by interrupting the spinal nerves innervating the limb. either hypophysectomy or ablation of interrenal tissue is without marked effect. the accumulation effect is not shown by aldosterone, testosterone, glucose, cholesterol, or leucine bu ... | 1977 | 886293 |
| the protective action of zinc against the deleterious effects of cadmium in the regenerating forelimb of the adult newt, notophthalmus viridescens. | forelimbs of adult male newts (notophthalmus viridescens) were amputated and immediately dipped in cadmium nitrate for 2 minutes; in addition, some of the newts were injected with zinc chloride 24 hours prior to, or 24 hours after amputation. dipping the amputated forelimb of a newt in a solution of 0.4 m cadmium nitrate completely inhibited or retarded regeneration throughout the 65 days of observation. other effects of cadmium administration included erythema of the limb, an extensive protrusi ... | 1977 | 892583 |
| inversion heterozygosity in females of the newt notophthalmus viridescens and its influence on chiasma distribution. | in a wild population of the american newt notophthalmus viridescens 15 females out of a total of 94 were found to be heterozygous for a paracentric inversion which includes almost the whole of the longer arm of the smallest chromosome (xi). the inversion was recognized in preparations of lampbrush chromosomes because it transfers the sequential loops, which normally lie close to the telomere, to a position neighbouring the centromere. because of inversion the transcriptional polarity of the sequ ... | 1977 | 893540 |
| regenerative repair in the severed optic nerve of the newt (triturus viridescens): effect of nerve growth factor. | 1977 | 923673 | |
| intercalary and supernumerary regeneration in regenerating the mature limbs of notophthalmus viridescens. | 1977 | 925660 | |
| stages of tail regeneration in the adult newt, notophthalmus viridescens. | five distinguishable stages of tail regeneration in the adult newt have been established. the stages are based on external morphological changes and internal histological characteristics rather than chronological age of the regenerate. | 1976 | 932660 |
| regeneration from different levels along the tail of the newt, notophthalmus viridescens. | some aspects of the influence of position on regeneration have been examined by comparing regeneration from different levels along the newt tail. tails amputated such that either three-fourths one-half or one-fourth of the tail was removed pass through the same morphological and histological stages at the same times after amputation. in tails amputated at these three different levels, the rate of elongation of regenerates from more proximal levels is greater than that of regenerates from more di ... | 1976 | 932661 |
| a light and electron microscopic investigation of the hepatic parenchyma of the adult newt, notophthalmus viridescens. | this light and electron microscopic study demonstrates that the liver of the adult newt, notophthalmus viridescens, consists of a mass of hepatocytes interrupted by blood sinusoids which allow blood to percolate through the parenchyma. the plates separating adjacent sinusoids are usually two or more cells thick and the bile canaliculi lie between 2-6 neighboring cells. fine structural characteristics of hepatocytes include abundant lipid and glycogen inclusions. melanophores with developing mela ... | 1976 | 937737 |
| dose-dependent effects of methylmercury on limb regeneration of newts (triturus viridescens). | 1976 | 949962 | |
| muscle satellite cells in urodele amphibians: faciliatated identification of satellite cells using ruthenium red staining. | the ruthenium red (rr) stained forelimb musculature of three species of urodeles triturus (notophthalmus) viridescens, amblystoma maculatum, amblystoma opacum in various stages of growth were examined with the electron microscope for the presence of satellite cells. it was found that rr staining facilitated greatly the identification of satellite cells. in young larvae of all three species satellite cells were detected with a frequency of 29% to 48% per total number of nuclei. in adult triturus ... | 1976 | 978162 |
| regenerative failure of double half limbs in notophthalmus viridescens. | 1976 | 980112 | |
| the actions of restriction endonucleases on lampbrush chromosomes. | lampbrush chromosomes from oocytes of notophthalmus viridescens were dispersed in media containing restriction endonucleases isolated from haemophilus and e. coli. these endonucleases cleave duplex dnas at specific palindromic sequences of nucleotides, and several sensitive sites occur per micron of dna. the overwhelming majority of the lateral loops of lampbrush chromosomes are extensively fragmented by these endonucleases, but an occasional pair of loops is refractory. a notable example of loo ... | 1976 | 987047 |
| fine structure of active ribosomal genes. | the structure of active ribosomal genes in the newt notophthalmus viridescens has been studied at the higher resolution permitted by negative staining. spherical particles, 70 a to 100 a in diameter are seen on the non-transcribing "spacer" regions, but were absent from certain regions of the transcribing "matrix". the matrix core often appears thicker than a double strand of dna. these results are discussed in the light of the recently discovered subunit structure of chromatin, and in relation ... | 1976 | 1001149 |
| an established cell line from the newt notophthalmus viridescens. | an established cell line, derived from the dorsal iris of the eastern north american newt, notophthalmus viridescens, is described. the cells display an epithelial-like behaviour in culture, grow relatively slowly, possess considerably larger chromosomes than mammals and are heteroploid, although some near-diploid cells are present in the culture. the line is characterized by a strong tendency to overlapping and aggregation in spite of its origin from adult tissue. | 1976 | 1010157 |
| on the diversity of sperm histones in the vertebrates. i. changes in basic proteins during spermiogenesis in the newt notophthalmus viridescens. | sperm histones display great variability in contrast to the conservation of most classes of somatic histones. to study this paradox, this series of papers examines the variation of histone patterns in the testis and sperm of vertebrates, particularly amphibians and reptiles, and attempts to relate such variation to genetically based sex determination as hypothesized by bloch [genetics supplement 61, 93 (1969)]. in the present study we have investigated spermiogenesis in the newt notophthalmus vi ... | 1976 | 1010162 |
| the effect of dimethyl sulfoxide on forelimb regeneration of the adult newt, triturus viridescens. | 1975 | 1055546 | |
| the role of a normal lens in wolffian lens regeneration. | the mid-ventral third of the iris was excised from 61 adult notophthalmus viridescens hosts, and the mid-dorsal third of the iris from donor eyes was implanted in its place. after the iris healed and the host lens was removed, two lens regenerates developed, one from the host and one from the transplanted iris. the host regenerate was removed 53-91 days after the first lentectomy. animals were sacrificed 1-40 days after the second lentectomy. a lens developed from the host dorsal iris in the pre ... | 1975 | 1113070 |
| the ultrastructure of wallerian degeneration in the severed optic nerve of the newt (triturus viridescens). | wallerian degeneration in the severed newt's (triturus viridescens) optic nerve is complete between the 10-14th post operative day (p.o.d.). consequently, the newt optic nerve displays one of the most rapid degenerative responses yet reported for the central nervous system of vertebrates. in most cases it also exhibits the speed of degenerative phenomenon in the vertebrate peripheral nervous system. the degeneration of unmyelinated axons is most rapid and is completed by 2-3 p.o.d., compared to ... | 1975 | 1115356 |
| a light and electron microscopic study of the respiratory epithelium of the adult aquatic newt, notophthalmus viridescens. | 1990 | 1131745 | |
| prolactin-induced modification on visual pigments in the eastern red-spotted newt, notophthalmus viridescens. | 1992 | 1132673 | |
| non-glial phagocytes within the degenerating optic nerve of the newt (triturus viridescens). | two non-glial phagocytes were found to participate along with ependymoglial cells in wallerian degeneration of the severed optic nerve of the newt (triturus viridescens). the first type of non-glial cell (polymorphonuclear phagocyte) was positively identified as a neutrophil and participates in the early stages of degeneration. cells of this type make a brief appearance, reaching a peak by the second postoperative day (2 p.o.d.), and quickly diminish until few can be found by 4 p.o.d. neutrophil ... | 1975 | 1141845 |
| a light and electron microscopic study of myelopoietic cells in the perihepatic subcapsular region of the liver in the adult aquatic newt, notophthalmus viridescens. | the liver of the newt, notophthalmus viridescens, consists of several incompletely separated lobes of parenchymal tissue each of which is covered by a perihepatic subcapsular region (ssr) of the myeloid tissue. this tissue contains neutrophils and eosinophils in various stages of differentiation. as neutrophils developfrom myeloblasts to late neutrophilic myelocytes, two types of granules appear. the primary granules (type of granules formed first) are more electron dense and smaller than the se ... | 1975 | 1149091 |
| the developmental cytology of the nuptial pad in the red-spotted newt. | 1975 | 1158027 | |
| dna synthesis in the thymus of the adult newt notophthalmus viridescens. | lymphocytic activity was examined in thymuses of adult newts by studying the number, location, morphology and fate of cells within thymuses which had been processed for autoradiography 15 min, 2 and 4 h, and 2, 4, and 10 days subsequent to the injection of tritiated thymidine. results of this study indicate (1) that the adult thymus is a highly proliferative organ, (2) that large and medium-sized lymphocytes present in the peripheral parenchyma give rise to smaller lymphocytes which move central ... | 1975 | 1163206 |
| progesterone-induced in vitro maturation in oocytes of notophthalmus viridescens (amphibia urodela) and some observations on cytological aspects of maturation. | maturation in vitro of oocytes of the newt, notophthalmus viridescens, is inducible with progesterone after in vivo treatment of females with gonadotropin; few oocytes mature in vitro in the absence of such gonadotropin treatment. chromosomes of most large oocytes of animals not receiving gonadotropin are still in the lampbrush condition; chromosomes from gonadotropin-treated animals are shorter and the lateral loops are less profuse and somewhat retracted. the chromosome condition, then, can be ... | 1975 | 1194840 |
| disruption of normal forelimb regeneration in adult notophthalmus viridescens by sublethal concentrations of trypan blue. | the effects of the vital dye trypan blue (tpb) on the regeneration of amputated newt forelimbs were examined. administration of the dye (10 mug/g body weight) via ip injection during the early wound healing and dedifferentiation phases of regeneration inhibited the normal regenerative response. the accumulation phases of regeneration are similarly halted but only by greater concentrations of tpb (50 mug/g body weight) while redifferentiation and morphogenesis are only affected by still greater c ... | 1975 | 1194876 |
| morphogenesis of the carpal elements in the regenerating forelimb of adult notophthalmus viridescens viridescens. | this study is concerned with the morphogenesis of the carpal elements in the regenerating forelimb of the adult newt. blastema cells surrounding the remnant bony stumps begin to differentiate into cartilage on the twentieth post-amputation day. subsequently, masses of carilage build up from the radial and ulnar stumps. the radial mass is larger and differentiates more rapidly than the ulnar mass. by the fifty-fifth post-amputation day, the eight basic carpal elements are formed, with fusion of t ... | 1975 | 1200330 |
| the mitotic chromosomes of notophthalmus (=triturus) viridescens: localization of c banding regions and dna sequences complementary to 18s, 28s and 5s ribosomal rna. | the metaphase chromosomes of notophthalmus (triturus) viridescens have been studied by c-banding and in situ hybridization. the chromosomes show the pericentric c-banding seen in many organisms and in addition have interstitial c-bands located a short distance from the pericentric c-bands on each chromosome arm. a few c-bands are seen in telomeric regions. regions which hybridize in situ with 18s and 28s ribosomal rna were found on three chromosome pairs. the animals studied fell into three grou ... | 1975 | 1201683 |
| identification of the lampbrush chromosome loops which transcribe 5s ribosomal rna in notophthalmus (triturus) viridescens. | the loops which transcribe 5s ribosomal rna in lampbrush chromosomes of the newt, notophthalmus (triturus) viridescens, were identified by hybridizing purified 5s dna to nascent 5s rna in situ. the genes which code for 5s rna were found near the centromeres of chromosomes 1, 2, 6, and 7 by hybridizing iodinated 5s rna to denatured lampbrush and mitotic chromosomes in situ. these genes and their intervening spacer dna were isolated from xenopus laevis using sequential silver-cesium sulfate equili ... | 1975 | 1201684 |
| an autoradiographic study of the origin of intestinal blastemal cells in the newt, notophthalmus viridescens. | 1975 | 1204929 | |
| supernumerary limgs in amphibians: experimental production in notophthalmus viridescens and a new interpretation of their formation. | 1976 | 1269829 | |
| regenerative abnormalities in notophthalmus viridescens induced by repeated amputations. | the fidelity of the regenerative response in the adult newt, notophthalmus viridescens, was examined following repeated amputations at the level of the distal one-third of humerus. three to four months following amputation, all regenerates were scored for gross morphology, reamputated, and stained with methylene blue for skeletal elements. the occurrence of abnormal regeneration with respect both to gross morphology and to skeletal structure was found to increase directly with the number of time ... | 1976 | 1271038 |
| collagen metabolism in the regenerating forelimb of notophthalmus viridescens: synthesis, accumulation, and maturation. | 1976 | 1278591 | |
| patterns of dystrophin expression in developing, adult and regenerating tail skeletal muscle of amphibian urodeles. | the patterns of expression of dystrophin were investigated by indirect immunofluorescence and by immunoblotting in developing, adult and regenerating tail skeletal muscle of newts pleurodeles waltl and notophthalmus viridescens. in this study, a monoclonal antibody h-5a3 directed against the c-terminal region (residues 3357-3660) and a polyclonal antibody raised to the central domain (residues 1173-1738) of the chicken skeletal muscle dystrophin were used. western blot analysis showed that these ... | 1992 | 1295566 |
| homeobox-containing genes in the newt are organized in clusters similar to other vertebrates. | in vertebrates, the majority of homeobox (hbox) genes are found in four clusters and this structural organization is believed to be of functional importance. many hbox genes sustain their expression in the appendages of the adult newt. to further understand their regulation, the genomic loci of four newt hbox genes (two from the human hbox (hox)-2 complex and two from the hox-3 complex) were analysed and compared with homologous loci in other vertebrates. notophthalmus viridescens hbox (nvhbox) ... | 1992 | 1351019 |
| stimulation of dna synthesis by pdgf in the newt cardiac myocyte. | the adult newt cardiac ventricular myocyte has been successfully placed in cell culture and has been shown to undergo in vitro dna synthesis. although several growth factors have been reported to increase dna synthesis in cardiac myocytes in vitro, pdgf has not been reported to do so, but has been shown to be active in other systems. ventricles were removed from the adult red-spotted newt and were enzymatically and mechanically dissociated in a solution containing trypsin and collagenase. cells ... | 1992 | 1433320 |
| introduction of a retinoid reporter gene into the urodele limb blastema. | after amputation of the limb of an adult urodele amphibian at any point along the proximodistal axis, blastemal cells (the progenitor cells of the regenerate) give rise only to the missing structures. retinoic acid (ra) is able to respecify the positional identity of the blastema to a more proximal value, thus raising the possibility that the ra response system is activated during limb regeneration. cultured newt (notophthalmus viridescens) limb cells were transfected by nuclear microinjection o ... | 1992 | 1454825 |
| identification of proteins potentially involved in proximal-distal pattern formation in the regenerating forelimb of the newt. | we have used high resolution two-dimensional gel electrophoresis to identify and characterize proteins that may represent products of genes involved in establishing positional information along the proximal-distal axis of the regenerating forelimb of the newt notophthalmus viridescens. at least 24 proteins have been found whose synthesis and (or) abundance is increased in proximal (midstylopodial) regenerates relative to midzeugopodial (distal) regenerates at either of two regeneration stages, t ... | 1992 | 1497856 |
| newt squamous carcinoma proves phylogenetic conservation of tumors as caricatures of tissue renewal. | although regeneration-competent newts like notophthalmus viridescens have been reported to be resistant to carcinogenesis, we have been able to induce transplantable epidermal squamous cell carcinomas with 10-20% incidence by implanting 20-methylcholanthrene s.c. into the scapular region, a tissue that cannot regenerate. as soon as 1 week after exposure to this carcinogen, malignant cells were present in the treated skin, and after 4 weeks, macroscopic tumors of infiltrating squamous carcinoma c ... | 1992 | 1516043 |
| analysis of opsin mrna and protein expression in adult and regenerating newt retina by immunology and hybridization. | rod photoreceptor cells were analysed in adult and regenerating notophthalmus viridescens retinae using a combination of immunochemical and molecular biological approaches. monoclonal anti-rhodopsin antibody (rho-4d2) labelled rod but not cone photoreceptors in adult newt retinae. the antibody bound to the entire cell body, from the synaptic ending through to the outer segment, as examined by light and electron immunocytochemistry. the antibody labelled two bands of 35 and 56 kda in western blot ... | 1992 | 1532825 |
| morphology and glycoconjugate histochemistry of the palpebral glands of the adult newt, notophthalmus viridescens. | the eyelids of the newt were studied in 10 microns serial paraffin and 1-2 microns plastic sections using standard histological stains and special stains for glycoconjugates. the eyelids contain four different glands. simple acinar serous and simple acinar mucous glands occur in the skin; unicellular mucous glands occur in the conjunctiva; and convoluted tubular seromucous glands are present in connective tissue beneath the conjunctiva. the first two are identical to cutaneous glands found elsew ... | 1992 | 1556738 |
| localization of beta-endorphin-like immunoreactivity in the nervous system of the adult newt, notophthalmus viridescens. | using indirect immunofluorescence methods, we have localized for the first time in the newt, notophthalmus viridescens, beta-endorphin (beta-ep)-like immunoreactivity in the neurons of spinal ganglia (spg), spinal cord (spc), as well as in the hypothalamic region of the brain. an examination of serially sectioned spg showed that the beta-ep-positive neurons, cell bodies, and nerve fibers were distributed at all levels of spg. peripheral regions of the perikarya of beta-ep-positive spg neurons ex ... | 1992 | 1583460 |
| biogenesis of myeloid bodies in regenerating newt (notophthalmus viridescens) retinal pigment epithelium. | myeloid bodies are believed to be differentiated areas of smooth endoplasmic reticulum membranes, and they are found within the retinal pigment epithelium in a number of lower vertebrates. previous studies demonstrated a correlation between phagocytosis of outer segment disc membranes and myeloid body numbers in the retinal pigment epithelium of the newt. to test the hypothesis that myeloid bodies are directly involved in outer segment lipid metabolism and to further characterize the origin and ... | 1992 | 1628309 |
| the effect of environmental ph on sodium balance in the red-spotted newt, notophthalmus viridescens. | sodium influx and efflux of the red-spotted newt, notophthalmus viridescens, at two phs were investigated in efts and adults in water and on land. the sodium efflux rate constant was not affected by ph. efflux was generally greater under aquatic than terrestrial conditions, and for efts than for adults. in an aquatic setting, both adults and efts were able to maintain sodium balance at ph 5, but exhibited net sodium loss at ph 3. sodium influx was greater in efts at ph 5 than in any other group. ... | 1992 | 1637201 |
| a search for immunoreactive substance p and other neural peptides in the limb regenerate of the newt notophthalmus viridescens. | immunochemical studies demonstrate that the undecapeptide substance p (sp) may be detected by radioimmunoassay in newt limb regenerates and that sp is localized in the blastemal epidermis by immunofluorescence and peroxidase-antiperoxidase staining. immunoreactive sp is predominantly distributed at the periphery of epidermal cells, suggesting the presence of sp binding sites on the cell surface; the basal germinative layer of the epidermis and blastemal mesenchyme cells remain unreactive. the pa ... | 1990 | 1693394 |
| tenascin localization in skin wounds of the adult newt notophthalmus viridescens. | earlier studies have shown that the extracellular matrix (ecm) protein tenascin (tn) is present between uninjured epidermal cells of urodele appendages, but is absent from most of the mesenchymally derived ecm. following appendage amputation, this distribution is reversed. tn is lost from the epidermis and appears in the ecm of the stump and the regeneration blastema. in the present study, monoclonal and polyclonal antibodies to tn were used to localize this protein immunohistochemically in limb ... | 1991 | 1718188 |
| early innervation of skeletal muscle during tail regeneration in urodele amphibians. | the innervation pattern of skeletal muscles was studied in the normal and regenerating tail of notophthalmus viridescens. silver staining for nerve endings and histochemical localization of acetylcholinesterase (ache) were used for light microscopy. in in normal musculature, ache positive reactions were localized at the ends of the muscle fibers where they are anchored on connective tissue septa by myotendinous junctions. at this level, silver staining shows nerve terminals forming endplates. du ... | 1991 | 1744616 |
| intrinsic electric fields promote epithelization of wounds in the newt, notophthalmus viridescens. | the lateral electric fields (lfs) in the vicinity of small wounds made in hindlimb digit tip skin of notophthalmus viridescens have been measured and manipulated. healing of these wounds was assessed by crystal violet staining and by histology. paired experiments were conducted on the animals: the healing of one digit's wound was compared with healing of the contralateral digit's wound whose lf was changed from that of its contralateral wound. when currents were passed through the animal (into o ... | 1991 | 1864462 |
| amphibian prolactins: activity in the eft skin transepithelial potential bioassay. | the effects of purified prolactins isolated from frogs (fprl; rana catesbeiana) and newts (nprl; cynops pyrrhogaster) were compared with those of ovine prolactin (oprl) and thyrotropin releasing hormone (trh) in the eft (notophthalmus viridescens) skin transepithelial potential (tep) bioassay. at total doses as low as 0.4 micrograms/animal, both fprl and nprl were as effective as oprl in reducing eft skin tep. by contrast, trh at total doses as high as 400 micrograms/animal was ineffective in al ... | 1991 | 1908395 |
| autonomic control of heart rate in the adult, aquatic notophthalmus viridescens viridescens. | 1. we investigated the role of the autonomic nervous system in the control of the heart rate using an isolated heart preparation. 2. addition of the parasympathetic blocker, atropine, to the organ bath resulted in an increase in heart rate as expected. 3. addition of the sympathetic blocker, ergotamine, to the organ bath showed no change in the heart rate. 4. addition of the sympathetic blocker, propranolol, to the organ bath resulted in the expected decrease in heart rate. 5. both the sympathet ... | 1990 | 1980871 |
| two dispersed highly repeated dna families of triturus vulgaris meridionalis (amphibia, urodela) are widely conserved among salamandridae. | two bamhi families of repeated sequences were characterized from the genome of the italian smooth newt, triturus vulgaris meridionalis (amphibia, urodela). the first family, which is divided into subfamilies, consists of tandemly arranged arrays whose basic repeat is around 398 bp long; these arrays are dispersed throughout the entire chromosome sets of the various species of triturus tested. moreover the family is widely conserved among salamandridae, being detected by genomic dna blotting of n ... | 1991 | 2009819 |
| the monoclonal antibody 22/18 recognizes a conformational change in an intermediate filament of the newt, notophthalmus viridescens, during limb regeneration. | previous work has shown that the monoclonal antibody 22/18 identifies progenitor cells (blastemal cells) which depend on the nerve for their division in the early stages of limb regeneration in the newt, notophthalmus viridescens. this antibody also reacts with cultured cells derived from the newt limb, and the intensity of immunoreactivity appears related to cell density and differentiation into myotubes. we report here that the monoclonal antibody 22/18 recognizes a polypeptide (22/18 antigen) ... | 1990 | 2317841 |