bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reversal of primary embryonic induction by cold, and the “fixation” of induction in cells activated by lithium chloride
Authors: Ansevin Krystyna D. 
Published: February 2005

AbstractThe effects of low temperature on embryonic induction were investigated. Presumptive epidermis cells of Rana pipiens were either pretreated with cold (4°C) and then treated with lithium chloride at the same temperature, or activated by lithium chloride at 22°C, then rapidly chilled to 4° and kept at this temperature for a period of time. Cultures were made from the treated cells.It was found that induction at low temperature could occur, although it did not proceed beyond determining neuralization. When, on the other hand, the cells were first induced with LiCl to the point at which they should have been determined to differentiate into melanophores, but were then rapidly chilled and kept in the cold for some time, the effects of induction were suppressed and the cells differentiated into ciliated epithelium. A 15–60 minute lag in time between induction and chilling (during which the cells were kept in the culture medium at room temperature) allowed neural induction to be gradually “fixed,” and a 120–180 minute lag was sufficient for melanphore induction to become insensitive to the subsequent treatment with cold.It is speculated from these results that induction occurs very slowly at low temperature and that the inductive stimulus activates a sequence of reactions, one or several of which are strongly repressed by the cold. In this case, when no products result from these reactions, the sequence is assumed to stop and possible feed‐back mechanisms switch the whole system to its initial condition.
Ultrastructural studies of normal and alloxan‐treated islet cells of the pancreas of the lizard, Eumeces fasciatus
Authors: Burton Paul R. , Vensel William H. 
Published: February 2005

AbstractAlpha and beta cells can be distinguished by differences in mitochondrial and secretion granule structure. Many mitochondria of alpha cells possess “tubular” or prismatic cristae oriented longitudinally and having triangular profiles in cross‐section. The matrix is particulate, with the roughly spherical particles measuring about 100 A in diameter. Evidence is presented indicating that alpha and beta granules are sequestrated in association with Golgi elements. Fully‐condensed beta granules, assumed to be insulin, appear homogeneously dense and crystalline. Recurrent profiles of crystalline beta granules suggest that they possess an octahedral configuration. Alpha cell granules also appear homogeneously dense but have round profiles.Many acinar cell nuclei in both normal and alloxan‐treated pancreata display masses of moderately dense fibrils oriented roughly parallel to each other. These fibrils are about 200 A across and their terminal portions are rebranched and often appear to be continuous with the finely granular or filamentous component of the nucleoplasm. Not infrequently the fibrils show evidence of periodicity.Alloxan has a specific destructive effect on beta cells. An initial effect seems to be the disruption and coalescence of the bounding membranes of beta granules. Lysosome‐like bodies are often seen in beta cell cytoplasm, which ultimately becomes degranulated and necrotic following prolonged administration of large doses of alloxan.
The fine structure of myocytes in the sponges Microciona prolifera (Ellis and Solander) and Tedania ignis (Duchassaing and Michelotti)
Authors: Bagby Roland M. 
Published: February 2005

AbstractMyocytes are long, fusiform cells found in the osculum and other contractile areas of many sponges. Myocytes in the oscular sphincter of Tedania ignis and the osculum and dermal membrane of Microciona prolifera were studied with light‐ and electron‐microscopes to compare their structure to that of muscles. Salient points of similarity between myocytes and smooth muscles were their long, fusiform shape, their red color after staining with Mallory's triple stain, and the presence of filaments running longitudinally in the cytoplasm.Microciona myocytes have thick filaments of 150–250 Å diameter and thin filament of 50–70 Å diameter, and in transverse sections the thin filaments occasionally appear as a ring of dots around a thick filament. Longitudinal sections of Tedania myocytes show only one type of filament, which varies from 100 Å to 200–300 Å diameter in thick regions of the filament. Although transverse sections show light material around the dense filaments, a distinct pattern of thick and thin filaments is not seen in Tedania.Due to infrequent contacts between cells, the large extra‐cellular space observed with the electron microscope (49% in Tedania, 57% in Microciona), and the absence of nerves, each myocyte probably acts as an independent contractile unit.
The effects of thiourea and cortisone acetate on duodenal length and diameter and on morphogenesis of duodenal villi in chick embryos
Authors: Stocum David L. 
Published: February 2005

AbstractSubnormal growth in length and diameter of the duodenum is encountered both in chick embryos injected with thiourea at 11 days of incubation, and in embryos injected with cortisone acetate at 14 days of incubation. Morphogenesis of previllous ridges and villi is retarded in thiourea‐treated embryos. Morphogenesis of previllous ridges and villi in cortisone acetate‐treated embryos at first seems to be slightly accelerated over that of controls, but the acceleration does not appear to be maintained, and the hormone may actually be inhibitory to normal morphogenesis of villi by 19 days of incubation. The results indicate that normal levels of endogenous thyroxine are necessary for normal growth in length and diameter of the duodenum and for normal morphogenesis of previllous ridges and villi. The possibility that adrenocorticoids may also play a role in the normal development of these parameters is indicated, although the evidence is inconclusive.
The post‐ovulatory follicles of blackbirds (Agelaius)
Authors: Payne Robert B. 
Published: February 2005

AbstractPost‐ovulatory follicles of tricolored blackbirds (Agelaius tricolor) and redwinged blackbirds (A. phoeniceus) regress from 6.0 to 3.0 mm in length by two days after ovulation and remain less than 3.0 mm during incubation. The follicles of females feeding young average less than 1.0 mm. Serial sections of ovaries of birds in all stages of the nesting cycle show distinct post‐ovulatory follicles up to 25 days after ovulation.Lymphocytes, granular polymorphonuclear leucocytes, macrophages, and fibroblasts invade the sloughed granulosa and the hemorrhaged theca interna after ovulation. Granulosa cells, epithelioid cells in the theca interna, and connective tissue cells in the theca externa are lipoidal and cholesterol‐positive for at least ten days after ovulation. The rapid regression and histological evidence of degenerating tissue and the invasion of cell types characteristic of the inflammatory response suggest that the ovulated follicles are degenerating rather than secretory organs.
Lipid of normal and regenerating limb tissues of the adult newt, Diemictylus viridescens: Acidic and non‐acidic lipids, phospholipids, and cholesterol
Authors: Schmidt Anthony J. 
Published: February 2005

AbstractCryostat‐cut sections of unamputated and amputated‐regenerating limbs of the adult newt were examined following the Nile blue test for acidic and non‐acidic lipids, the acid hematein and plasmal tests for phospholipids, and a Schultz test for cholesterol.Triglycerides (Nile blue test) are prominent in dermis and macrophages: triglyceride droplets are scattered in epidermis, wound epithelium, and regeneration blastema. Fatty acids (Nile blue test) are present in all tissues of the normal and regenerating limb: nerve myelin contains relatively little free fatty acid, while macrophages appear to contain the least amount of this lipidic substance.Plasmalogens (plasmal test) are prominent in the myelin of nerves, and macrophages: a weak cytoplasmic reaction obtains in the epidermis, subcutaneous glands, striated muscle, tunics of blood vessels, wound epithelium, blastema cells, chondrocytes, perichondrium and periosteum.Mitochondria responding for cephalin, lecithin, and sphingomyelin (acid hematein test) are ubiquitously distributed among the cells and tissues of the normal and regenerating limb. These phosphatides are prominent in nerve myelin, macrophages, and in dermal droplets: a variable response obtains from the myofibrils of striated muscle.Cholesterol (Schultz test) was demonstrated only in nerve myelin and in macrophages associated with injured nerves.Particular attention was paid to the lipid responses of the regeneration blastema, and the conclusion was reached that not all of the lipid previously demonstrated with sudan dyes was characterized by the current series of lipid tests.A modified Nile blue sulfate test that promises greater specificity in distinguishing between acidic and non‐acidic lipids is introduced.
Fine structure of supporting cells in the lateral‐line canal‐organ of Fundulus
Authors: Petraitis Ruth 
Published: February 2005

AbstractPhase and electron microscopic studies have revealed that the supporting cells of the lateral‐line canal‐organ of Fundulus heteroclitus have a fine structure characterized by (1) mitochondria and vacuoles in the apical zone, (2) granular endoplasmic reticulum surrounding a core of Golgi complex in the middle zone, and (3) an indented nucleus in the basal zone. In the middle and basal zones, wide intercellular spaces separate the adjacent supporting cells, whose plasma membranes form long flap‐like interdigitations across the intercellular spaces. Secretion of subcupular fluid and cupula, metabolic regulation through the intercellular spaces, and rigid support for the organ are discussed as possible metabolic and mechanical functions of the supporting cells essential for the lateral‐line canal‐organ.
Polyploidy and reproductive patterns in the root‐knot nematode Meloidogyne hapla
Authors: Triantaphyllou A. C. 
Published: February 2005

AbstractA total of 32 populations and egg mass isolates of Meloidogyne hapla obtained from various geographical areas were studied cytologically and with respect to their mode of reproduction. In 29, maturation of oocytes is by regular meiosis. The reduced chromosome number at metaphase I is 17 in 18 populations, 16 in 8, and 15 in 3 populations. Reproduction in all these populations is by cross‐fertilization, although nonfertilized eggs can develop by parthenogenesis. In the latter case, the two groups of telophase chromosomes of the second maturation division become enclosed in the same pronucleus, thus reestablishing the somatic chromosome number. Maturation of spermatocytes in three populations studied is by regular meiosis and the reduced chromosome number appears to be equal to that of the oocytes. In the remaining three populations, no synapsis takes place and the somatic number of 45 chromosomes is observed at metaphase of the single maturation division of both oocytes and spermatocytes. Reproduction is by obligatory mitotic parthenogensis. It is postulated that the basic chromosome number for the genus is nine and that the facultatively parthenogenetic populations are tetraploid, whereas, the obligatorily parthenogenetic populations are pentaploid. A preliminary scheme of the phylogeny in the family Heteroderidae is given.
A study of regression and budding in Perophora viridis
Authors: Barth Lester G. , Barth Lucena J. 
Published: February 2005

Abstract1. A method has been devised for studying the regression of the zooid of Perophora into a stolon and the subsequent differentiation of a new zooid from this stolon.2. Circulatory cells of the stolon resulting from regression will aggregate into masses larger than the minimal size necessary for differentiation of a zooid, but fail to differentiate into a zooid.3. The cells of a zooid after staining with neutral red appear in the stolon during regression and finally come to lie in the newly formed zooid.4. During the cycle of adult zooid to stolon to newly formed zooid, there is no evidence for cell division from studies with tritiated thymidine.5. It is concluded that under conditions of starvation, an adult zooid furnishes all the cells for the formation of a stolon and the subsequent zooids without cell division.
Early secretory activity in the hypothalamic nuclei and neurohypophysis in the rat; determined by selective staining
Authors: Dawson Alden B. 
Published: February 2005

AbstractVisualization of stainable material in the neural lobe of the rat provided the most reliable index of the age at which secretory activity can first be recognized, though preceded by both hypothalamic synthesis and axonal transportation. A problem of interpretation was encountered in the neural lobes of fetal and infant animals, due to different staining responses obtained during this age period, to the two methods of staining employed; chrome alum hematoxylin‐phloxin and aldehyde fuchsin after oxidation by either acidified potassium permanganate or performic acid. With aldehyde fuchsin the material of the neural lobe is stainable selectively from the eighteenth day of fetal life to adulthood. With hematoxylin phloxine the first staining response also occurred in the posterior lobe but much later, at the end of the first postnatal week.The staining situation in the pars neuralis has its counterpart in the differentiating hypothalamic nuclei; complicated by the differentiation of the supraoptic nuclei some days in advance of the paraventricular nuclei. After aldehyde fuchsin staining, evidences of neurosecretory activity were present in the perikarya of the supraoptic nuclei at birth, but mature neurons were rarely seen in the paraventricularis until at least 24 hours later. Nuclei of fetal hypothalami were not studied, but the demonstration of stainable material in the fetal neural lobes constitutes circumstantial evidence of functional competence of some neurons of either one or both types of nucleus, most likely the supraoptic.
A new intranuclear inclusion body in the frog renal adenocarcinoma
Authors: Lunger Philip D. 
Published: February 2005

AbstractThe morphology and possible functional significance of a new intranuclear inclusion body associated with the frog renal adenocarcinoma is described. The inclusion consists of particles, 40 to 50 mμ in diameter, arranged in an orderly pattern suggestive of a crystalline array. Individual particles eventually appear to be involved in the production of “doughnut” type virions characteristically associated with this malignancy.
Neurosecretory cells in the central nervous system of the adult blowfly Phormia regina meigen (diptera: Calliphoridae)
Authors: Hsiao Catherine , Fraenkel G. 
Published: February 2005

Abstract
Neurosecretary cells in the central nervous system of the adult blowfly, Phormia regina Meig., have been examined histologically using the parparaldehyde‐fuchsin and Gomori's staining method. Six groups of the neurosecretory cells occur in each hemisphere of the brain, the medial, frontal, lateral A, lateral B, posterior I and posterior II groups. In the subesophageal ganglion, four B‐cells and two A‐cells are present. In the thoracico‐abdominal ganglion, ten A‐cells are found in the thoracic region and a total of about 50 A‐ and B‐cells in the hind part of the abdominal region.
A comparison with the neurosecretory system of two other species of blowfly, Calliphora erythrocephala Meig., Sarcophaga bullata Parker, and the housefly, Musca domestica L., showed similar arrangements and grouping.
Neurosecretory granules have been observed along the axons originating from the medial neurosecretory cells of the brain, and the thoracico‐abdominal ganglion. The granules originating from the medial groups can be traced directly to the corpus cardiacum from which they move to the aorta, crop duct and cardia through axons.
There is with advancing age a gradual increase in the size of cell bodies and nuclei of the median neurosecretory cells in both females and males of Phormia regina, and also a decrease in stainable granules. This increase in size is dependent on nutrition, with no increase in water alone, a slight increase on sugar, and a maximum increase on sugar and liver. Corresponding increases in size occur in the ovaries in connection with feeding the same substances.
The gastric argentaffin cell population of the rat
Authors: Gregg Robert V. 
Published: February 2005

AbstractThe distribution and morphology of the argentaffin cell population within the stomach of the albino rat has been investigated histologically. The argentaffin cell's situation is restricted to and evenly distributed over the antrum, lying usually in the basal third of the mucosa among mucous cells. A band of mucosa, less than a millimeter wide, containing argentaffin cells, extends from the antrum and encircles the stomach just caudal to the forestomach. The argentaffin cell population is found in less than three‐tenths of the total stomach by weight, a point for consideration in serotonin assay.
A study of a hereditary cataract in the mouse
Authors: Davidorf Frederick , Eglitis Irma 
Published: February 2005

AbstractThis report presents a study of cataracts seen in a random‐bred strain of Swiss mice with Balb/c mice used as a control group. The embryonic development, and histological and slit lamp observations of the lenses in the two groups of animals are contrasted.The cataract is dominant in its inheritance (Tissot, '62). It appears either unilaterally or bilaterally as a dense white opacity in the lens substance. The earliest sign of abnormal formation occurs at 14 days of embryonic development. This is associated with a defect in the primary lens fibers formation. Progressive degeneration of these fibers occurs until they are reduced to a mass of cellular debris seen at the last day of gestation. The secondary fibers are also laid down in an abnormal manner. The normal lamellar arrangement of the secondary fibers is not seen in cataractous lenses.The abnormal lens fiber development leads to progressive vacuolization.The mature cataract seen in the adult is filled with many vacuoles, the largest ones occurring at the equatorial region. The nuclear region consists of a clumpy eosinophilic mass with scattered calcified areas. The rate of growth of the secondary fibers is different from that of the normal group. Most of the mature cataracts in the adult contain a vascularized epithelium.There are three possible areas of primary involvement which may lead to the development of the cataract. This are: (1) A defect in the development of the primary lens fibers; (2) A defect in the development of the secondary lens fibers; (3) An abnormal lens epithelium which may interfere with nutrition of the lens and thus initiate cataract formation.
Chemoreceptor sensillum structure in Limulus
Authors: Hayes Wilbur F. 
Published: February 2005

AbstractThe chemoreceptors of Limulus polyphemus (L.) are polyneuronal sensilla found in the spines of the coxal gnathobases of each walking leg, the spines of the chilarial appendages, and the chelae of all the limbs. Each sensillum contains 6–15 bipolar sensory cells that share a single pore in the cuticle. The dendrites of the sensory cells of each sensillum course to the cuticle together. These attenuate sharply and enter a canal in the cuticle as a very narrow terminal thread. The dendrites retain their identity in the thread, but with the light microscope, they are usually not visible individually. Each thread, consisting of 6–15 dendrites, is accompanied to the cuticular surface by a cuticular tubule found within the canal. The chemoreceptor sensilla of the gnathobase, chilarium, and chela, the temperature organs of Patten, and the flabellar receptor organs all have the same basic organization. In general this is the same structural plan shown by chemoreceptors of other arthropods. Several different mechanisms of peripheral physiological interaction among receptor cells are possible with a sensillum organization like that described here for Limulus.
The development of the osteocranium of Pleurodeles waltlii Michahelles
Authors: Corsin J. 
Published: February 2005

AbstractUnder optimal conditions the development of the osteocranium covers the major part of the larval period and lasts about three and a half months. The earliest ossifications are of dermal origin and concern the tooth‐bearing bones. The poorly developed enchondral ossifications found in Urodela, appear at a much later stage, just before metamorphosis.
Segmental musculature and locomotion in Hermodice carunculata (polychaeta: Amphinomidae)
Authors: Marsden Joan Rattenbury 
Published: February 2005

AbstractThe segmental muscles in the intestinal region of the body of Hermodice carunculata are described as well as the gross anatomy of the associated nervous system.The form of normal locomotion and the characteristic alarm reaction are described and interpreted in terms of fluid pressure within the body cavity and the action of appropriate groups of segmental muscles.Brief remarks on the habits of H. carunculata conclude the paper.
Variation in the circumtesticular leydig cell tunic of teiid lizards (Cnemidophorus and Ameiva)
Authors: Lowe Charles H. , Goldberg Stephen R. 
Published: February 2005

AbstractTesticular structure in bisexual teiid lizards (Cnemidophorus and Ameiva) is apparently unique among vertebrates in having a circumtesticular subtunic band of Leydig (interstitial) cells, that varies in species of Cnemidophorus from 1.2 to 42.1 cells in thickness (transverse cross‐section), between the outer tunic (tunica albuginea) and the seminiferous tubules. The regression on body size, ontogenetic change, seasonal periodicity, and other aspects of structure and function of this subtunic Leydig cell structure are discussed.
Histochemistry of the chick esophagus and trachea II. Enzymes, nucleic acids, proteins, carbohydrates, and fats
Authors: Hinsch Gertrude W. 
Published: February 2005

AbstractTissues of White Leghorn embryos of stages 17–45 and chicks of one day, two days, and three weeks of age were frozen, sectioned in a cryostat and, where appropriate, were fixed in cold calcium formol. Acid phosphatase, non‐specific esterase, adenosine triphosphatase, 5‐nucleotidase, non‐specific glycerophosphatase, nucleotidediphosphatase, and glucose‐6‐phosphatase were localized in these tissues. Ribonucleic acid, acid mucopolysaccharides, triglycerides, and neutral fats were localized in tissues fixed with FAA and embedded in paraffin.Positive acid phosphatase reactions were obtained in the epithelium of the trachea and esophagus at all stages of development. 5‐nucleotidase was found in the muscularis mucosae of the esophagus at all stages. Non‐specific esterase appeared with histodifferentiation of the esophageal epithelium. Ribonucleic acid was localized in the basal regions of the epithelium.Mucous glands of the esophagus are rich in ribonucleic acid and acid phosphatase at all stages of development. With histodifferentiation and the onset of secretion of sulfated acid mucopolysaccharides, the glands and their ducts become highly reactive for adenosine triphosphatase and nucleotide‐diphosphatase, indicating a role of these enzymes in secretion.