bluuebunny/crossref_metadata_2025_split huggingface dataset:
The annulate lamellae of chick embryo liver cells in organ culture
Authors: Benzo Camillo A. 
Published: February 2005

AbstractCytoplasmic annulate lamellae are described as occurring in the cells of chick embryo liver during raft‐type organ culture on Eagle's minimum essential medium. These transitory structures, prominent in the cells of early (5‐day) embryonic liver during culture, were closely associated with the outer nuclear membrane and mitochondria, and were frequently continuous with portions of the rough endoplasmic reticulum. In contrast, annulate lamellae were not found in any cell examined during organ culture of older (11‐day) embryonic liver. These observations, together with correlative enzymatic studies, are discussed with regard to the possible role of annulate lamellae in the differentiation of the liver cell, in the light of current hypotheses on the origin and function of these widely‐occurring organelles.
Further evidence for the vitality of chondrocytes in the mandibular condyle as revealed by 35S‐sulfate autoradiography
Authors: Silbermann Michael , Frommer Jack 
Published: February 2005

AbstractHistochemical and autoradiographic studies using 35S‐sulfate indicate that the majority of the cartilage cells in the developing mandibular condyle of the young mouse are active, vital cells. Concomitant with the increase of hypoxic conditions within the deeper layers of the cartilage, an increase in sulfated glycosaminoglucuronoglycans synthesis takes place. Hypertrophic chon‐drocytes in the premineralized and mineralized zones reveal marked 35S‐sulfate uptake in comparison with the less differentiated cells in the chondroblastic and perichondrial zones. These observations of radiosulfate activity support the concept that calcification processes in the condylar cartilage are not necessarily accompanied by degeneration and death of the hypertrophic chondrocytes. The radiosulfate activity of the surviving chondrocytes in the vicinity of the ossification front indicates possible modulation into osteoprogenitor cells.
Studies on the peripheral blood cell parameters and morphology of the red paradise fish, Macropodus opercularis. Effect of food deprivation on erythropoiesis
Authors: Weinberg Sheila R. , Siegel Charles D. , Gordon Albert S. 
Published: February 2005

AbstractA description is presented of the peripheral blood cell values and blood cell morphology of both the normal and the starved red paradise fish. An inhibitory influence of food deprivation upon erythropoiesis was demonstrated in this fish by the significant decrease in red blood cell and hematocrit values. A comparative study showed that the size and numbers of erythrocytes present in teleost blood reflect its habitat, activity, and degree of evolution.
Uptake of adenovirus by intestinal absorptive cells of the suckling rat. I. The Neonatal Ileum
Authors: Worthington Bonnie B. , Graney D. O. 
Published: February 2005

AbstractLight and electron microscopic analysis of adenovirus‐infused ileal loops disclosed virus particles within the tubulo‐vacuolar apparatus of absorptive cells. Tissue observed from five‐minute loops contained virus particles largely within apical tubules and vesicular profiles. Similar particles were observed within cisternae and supranuclear vacuoles as well as within apical tubules in tissue samples from 10‐ and 15‐minute loops. Loops maintained for 30 minutes demonstrated virions predominantly in the supranuclear vacuole of each absorptive cell. In no instance was a virion seen free within the cytoplasm or nucleus and none was apparent elsewhere in the mucosa. It appears that absorptive cells of the ileum are capable of sequestering exogenous virions and conveying them to established lysosomal bodies in the supranuclear cytoplasm. Here they may be either stored or degraded, thus impeding their progress to other intra‐ or extracellular locations. The possible significance of these findings is discussed in detail, and it is proposed that sequestration of ingested virions by the tubulo‐vacuolar apparatus of the ileal absorptive cell may serve some protective function in the developing neonate. It is suggested that direct infusion of “purified” virus into intestinal loop preparations is an efficient means of observing virus‐intestinal cell interactions in the living animal. This experimental model might prove effective in future studies of viral infection in the intestine, particularly if it is combined with both serological and morphological methods.
Uptake of adenovirus by intestinal absorptive cells of the suckling rat. II. The neonatal jejunum
Authors: Worthington Bonnie B. , Graney D. O. 
Published: February 2005

AbstractHistological and ultrastructural observations of adenovirus‐infused jejunal loops revealed virus particles in small apical tubules and in underlying vacuoles and lysosome‐like bodies. Tissue selected from loops maintained for five and ten minutes disclosed virions largely within the intestinal lumen and in sparse tubular profiles beneath the microvilli. Jejunal preparations of longer duration disclosed increasing numbers of virus particles in small and large lysosome‐like bodies above the nucleus. In no instance were virions apparent free within the cytoplasm or nucleus and none was observed elsewhere in the mucosa. It is concluded, therefore, that the jejunal absorptive cell behaves like its ileal counterpart in absorbing and sequestering adenovirus particles in intracytoplasmic lysosomal organelles. It is further proposed that this behavior might serve a protective role during the vulnerable period of immunologic immaturity in the neonatal mammal.
Explants of rat adrenal medulla. A light and electron microscopic study
Authors: Piezzi Roman S. , Cavicchia Juan C. 
Published: February 2005

AbstractUnilateral explants of rat adrenal medulla grown in the anterior chamber of the eye were studied with light and electron microscopy. The surviving chromaffin cells are in proximity to the abundant vessels at 21 days after explantation. However, the typical arrangement of anastomosed cellular cords, such as can be always seen in the normal medulla, is replaced here by clusters, cords and irregular groups of cells. Two types of chroma & cells can be described. The predominant cells are polygonal or elongated in shape and have polymorphous and elongated norepinephrine‐positive granules. The other type, less numerous, has a pale cytoplasm with round chromafh cells. This type is norepinephrine negative. Several cytological characteristics of some of the chromaffin cells are also described. These morphological observations are in agreement with the biochemical findings previously published and confirm that a signscant decrease of epinephrine cells occurs in the explant.
A comparative ultrastructural analysis of the third cerebral ventricle of the North American mink (Mustela vison)
Authors: Scott David E. , Kozlowski Gerald P. , Dudley Gerda Krobisch 
Published: February 2005

AbstractThe third ventricular walls and floor of male and female mink (Mustela vison) were analyzed with comparative light microscopy, transmission and scanning electron microscopy. Distinct regional fine structural variations were noted in the appearance of the dorsal, middle third and lower portions of the ventricular wall and floor. These variations were characterized by an abrupt decrease in the density of ciliated ependymal surfaces in the middle one‐third of the ventricular wall. The ventral walls and floor of the lateral and infundibular recesses displayed smoother contours with numerous bleb‐like protrusions and blunt villiform processes. Occasionally multipolar neuron‐like cells were observed to lie upon the floor of the infundibular recess. Speculation is raised relative to the differing functional capacities of these various ventricular areas.
Differentiation of human limb buds in vitro
Authors: Yasuda Yoshiko 
Published: February 2005

AbstractSeventy‐five human embryos, at stages ranging from XII to XVIII of Streeter's horizon, four to six weeks postconceptional age, were obtained from healthy women by curettage. Limbs were cultured in nutrient agar medium for four to 18 days. Excepting a few cases which resulted in total necrosis, differentiation of mesenchyme into cartilage or bone primordia and other supporting tissues took place similarly to in vivo, though it occurred more slowly compared to in vivo. Such developmental retardation was milder in the lower limbs than in the upper limbs. In horizons XIV through XVIII, the limbs cultured for longer period than four days showed developmental dissociation of mesenchymal tissues, i.e., the maturation of cartilage advanced more than did the development of other tissues of the limb. The time lapse between the curettage and the culture ranged from 1.5 hours to seven days, but this had no close relationship with the occurrence of degenerative changes. Comparing the data obtained here with the corresponding results of a similar study in mice, it was concluded that the differentiation of the human limb occurs far slower than the mouse limb and shows some different patterns. These results suggest that it is possible to study in vitro comparison of effects of some teratogens on human and mouse limbs.
Penetration of the testicular‐tubular barrier by horseradish peroxidase induced by adjuvant
Authors: Willson John T. , Jones Norbert A. , Katsh Seymour , Smith Stuart W. 
Published: February 2005

AbstractAdjuvant‐induced penetration of horseradish peroxidase (HRP) into seminiferous epithelium was studied as a model of adjuvant‐induced entry of other proteins, e.g., immunoglobulins. HRP intravenously injected 20 minutes prior to sacrifice (by peraortic perfusion with Karnovsky's fixative) into male guinea pigs that had received Freund's complete adjuvant (FCA) + saline or FCA + testicular homogenate (TH) intradermally seven days previously, entered the peritubular spaces of a moderate number of seminiferous tubules. In those tubules HRP became uniformly distributed in the cytoplasmic matrices (but very rarely in membrane‐bound vesicles) of some of the Sertoli cells and presumptive type B spermatogonia. By contrast, HRP injected into normal animals, into animals that had received FCA + saline or FCA + TH 3 or 14 days previously or into animals that had received Freund's incomplete adjuvant + saline 3, 7, or 14 days previously gained entry into only occasional peritubular spaces but was never found in any cells of the seminiferous epithelium.These findings are discussed in conjunction with previous findings on immune aspermatogenesis. Hypotheses concerning the intratesticular mechanisms of production of both active and passive immune aspermatogenesis as activated by FCA and the mechanisms whereby FCA may enable or potentiate production of immune globulins are proposed and discussed.
Changes in the protein content of blastocysts from normal and delayed implanting mice
Authors: Weitlauf Harry M. 
Published: February 2005

AbstractTotal protein content of preimplantation mouse embryos was measured at 06.00 and 16.00 hours on day 5 of pregnancy (day 1, the day of vaginal plug formation). During this ten hour period, just prior to implantation, the amount of protein increased from 23 to 35 ng per blastocyst; a net increase of 52%. In contrast, protein content was unchanged in delayed implanting embryos recovered from ovariectomized animals during a comparable period on days 5 or 10 (day 5, 24 ng at 06.00 hours and 24 ng at 16.00 hours; day 10, 29 ng at 06.00 hours and 30 ng at 16.00 hours).These results demonstrate that the different uptake and incorporation of amino acids between normal and delayed implanting embryos (Weitlauf and Greenwald, '65, '68; Weitlauf, '73) reflect a difference in the actual net synthesis of protein by the two types of blastocysts.
Regional variations in endoplasmic reticulum in the vas deferens of normal and vasectomized rats
Authors: Flickinger Charles J. 
Published: February 2005

AbstractThe fine structure of the epithelium of different parts of the rat vas deferens was studied in normal rats and at intervals of up to nine months after vasectomy. The cytology of the columnar epithelial cells showed regional variations particularly in the type and extent of endoplasmic reticulum. Cells of the proximal part of the vas deferens were characterized by basal and perinuclear granular endoplasmic reticulum, a large Golgi apparatus, and numerous apical microvilli, vesicles, and vacuoles. In contrast, the columnar cells of the distal portion of the vas deferens contained large amounts of smooth endoplasmic reticulum, much of which assumed the form of large whorls of smooth membranes. In the distal segment the number of microvilli, vesicles, and vacuoles was less but mitochondria were more numerous than in the proximal part. Cells in the middle portion of the vas deferens showed some features of both proximal and distal parts. These structural characteristics, along with previous experiments, suggest that in the proximal portion of the vas deferens absorption of material from the lumen is an important function, while the cells of the distal part may synthesize steroids. Thus, these regional differences in ultrastructure probably reflect regional differences in function along the length of the vas deferens. After vasectomy the regional specializations were retained and did not appear to be altered. The possibility that this structural and functional sequence is significant for normal fertility and its relation to attempts to reconnect the vas deferens after vasectomy are considered.
Early steps in estradiol‐induced vaginal cornification in spayed mice: Kinetic study with 3H‐thymidine
Authors: Galand P. , Vandenhende J. 
Published: February 2005

AbstractThe formation of a third, intermediate, layer of cells in the mouse vaginal epithelium 12 hours after estradiol administration was investigated. Making 3H‐thymidine continuously available during the first 12 hours following estradiol administration to spayed mice and killing the treated animals after this period, revealed the intermediate layer of cells as constituted essentially of unlabeled cells. To the contrary, when animals were treated with estradiol 48 or 60 hours following pulse‐labeling with 3H‐thymidine, and killed 12 hours after hormone injection, autoradiography showed that labeled cells (which were in some part of G1 at the time estradiol was given) become a part of the intermediate cell layer. Grain count distribution in this material confirmed that they do so without undergoing further division. These results support our assumption that the formation of an intermediate layer of cells in the vaginal epithelium of spayed mice within the 12 first hours of estradiol action does not require division of basal cells under the presence of estrogen.
The substructure of crystalloids in secretory granules of dog pancreatic islet B cells
Authors: Machino Mitsuo 
Published: February 2005

AbstractThe B cells of dog pancreatic islets were studied by electron microscopy. The crystalloid core of secretory granules in B cells is unique. The crystallization of the secretory granule core appears to be accomplished in the Golgi apparatus. The square or hexagonal network with a periodicity of 30–60 Å that is produced suggests that the unit cell is either hexagonal or rhombohedral. The electron opaque dots which constitute the periodic densities may represent the insulin molecule itself in a crystalloid array.
The effect of isoproterenol on the postnatal differentiation and growth of the rat submandibular gland
Authors: Srinivasan R. , Chang W. W. L. , Van Der Noen H. , Barka T. 
Published: February 2005

AbstractAdministration of isoproterenol (IPR), twice daily for five days, to five day old rats resulted in a hypertrophy and hyperplasia of the submandibular gland as indicated by an increase of the total DNA, RNA, and protein contents of the gland. Four different cell types, the acinar cell, the terminal tubule cell, the intercalated duct cell and the striated duct cell were distinguished in 1 μ thick, Epon‐embedded sections and their rates of proliferation were estimated from radioautographs prepared following the incorporation of 3H‐thymidine. IPR treatment increased both the frequency and the absolute number of the acinar cells as compared to those of control animals. Concomitant with this there was a decrease in the number of terminal tubule cells from 50% in the control to about 15% in the IPR‐treated rat submandibular gland. These findings indicate that IPR accelerated the postnatal differentiation and proliferation of acinar cells. Eleven days after withdrawal of the drug the gland showed chemical and morphological evidence of regression of the IPR‐induced hypertrophy and hyperplasia and the numbers of acinar cells and terminal tubule cells in the glands of control and IPR‐treated rats were the same. Thus the IPR‐induced advanced differentiation of the gland was not maintained after the cessation of the IPR‐administration.
Effects of cytochalasin B on the ultrastructure of Rana pretiosa tadpole epidermis
Authors: Larsen John H. 
Published: February 2005

AbstractImmersion of Rana pretiosa tadpole tail integument in 1 μg/ml of cytochalasin B (CCB) for 45 minutes disrupted various cell structures of the two‐squamous cell‐layered epidermis including macromolecular components within microvilli and subjacent to the apical plasmalemma, the unit membrane which bounds mucinogenic vesicles and various other supranuclear structures. Surface cells exhibited the greatest degree of organelle disorganization when pieces of excised tail fin (“discs”) were treated with the antibiotic. This may indicate a differential response to the drug by various regions of the cytoplasm or that the concentration of CCB and/or exposure period was only adequate to penetrate the most superficial layers of this epithelium. The effect(s) of the penetrate the most superficial layers of this epithelium. The effect(s) of the antibiotic on filaments and filament related kinetic processes is discussed and the possibility of dissimilarities in CCB‐sensitivity between immature and differentiated plasmalemma and among unit membrane of various organelles is considered.
Phagocytosis of supernumerary spermatozoa by two‐cell mouse embryos
Authors: Thompson Robert S. , Zamboni Luciano 
Published: February 2005

AbstractPhagocytosis of supernumerary spermatozoa contained within the perivitelline space was observed in 7 of 28 two‐cell mouse embryos cultured for 45 hours post‐insemination (approximately 20–24 hours after cleavage). The spermatozoa were incarcerated as a result of elevations of the blastomere cytoplasm which gradually surrounded the sperm, overlapped and fused, thus forming a typical phagocytic vacuole. Phagocytosis was not observed in two‐cell embryos cultured for less than 20–24 hours after cleavage; this indicates that the blastomeres of two‐cell mouse embryos in vitro require approximately 24 hours to develop one of the characteristics of somatic cells, i.e., the ability to recognize and phagocytize foreign material.
Maturation of nonmyelinated fiber bundles in a strain of dwarf (Snell's) Mice
Authors: Reier P. J. , Froelich J. S. , Sawchak J. A. , Hughes A. F. W. 
Published: February 2005

AbstractPostnatal maturation of nonmyelinated fiber bundles (Schwann bundles) was studied in the sciatic nerves of Snell's dwarf mice. The homozygous recessive of this strain has been previously shown to be characterized by multiple pituitary hormone deficiencies and secondary hypothyroidism.In the normal littermates a reduction occurred between 10 and 14 days in the number of fibers per fascicle, or subdivision, of each Schwann bundle, and by 26 days nearly all of the axons were separately embedded in cytoplasmic furrows of their associated Schwann cells. Only a few large fascicles were seen in normal sciatic nerve specimens at 26 and 50–53 days. In contrast, fiber bundle fascicles in the mutant nerves were still represented, even at 50–53 days, by numerous tightly‐packed axons, as seen in the immature nerves at 10–12 days post‐partum.On the basis of the dwarf's physiological background, these results suggest an involvement of the endocrine system during later stages of peripheral nerve maturation. The possible mechanisms affected by postnatal endocrine deficiency and thereby leading to delayed segregation of nonmyelinated fibers within Schwann bundles are discussed.
The effect of cyclophosphamide on the morphogenesis of the cerebellum in chick embryos
Authors: Singh Shamer , Sanyal A. K. , Kar A. K. 
Published: February 2005

AbstractThe morphogenesis of cerebellum has been studied in 6–19 day old chick embryos after a single injection of 0.05 mg of cyclophosphamide into the yolk sacs on the fifth day of incubation. Besides degeneration of Purkinje cells, rate of development was markedly retarded as evidenced by late appearance of the fissures and folia of the cerebellum. Purkinje cells remained disorganised up to 18 days of incubation, though in controls they were arranged in a single line by the fifteenth day. The thickness of the external granular layer increased and persisted for a longer period in the treated embryos. The cytoarchitecture returned to normal on nineteenth day of incubation, but the size of the cerebellum was significantly smaller than that of controls (P < 0.001). Such transient disorganisation of the morphogenetic events in the neural tube may lead to inadequate and defective induction of surrounding mesenchyme, thereby resulting in defective skull formation through which the brain can herniate, i.e., exencephaly as reported in our earlier studies after cyclophosphamide administration in chicks (Singh et al., '71; Singh and Gupta, '72) and rats (Singh et al., '72).
Survival of neurons in homografts of ganglia in adult rats neonatally treated with bone marrow or lymph node cells
Authors: Zalewski Andrew A. , Silvers Willys K. 
Published: February 2005

AbstractBecause of a major (Ag‐B) histoincompatibility, organs transplanted from Lewis (LE) to Brown Norway (BN) rats are acutely rejected. This immunological rejection can be prevented by inoculating BN rats at birth with (BN × LE)F‐1 hybrid cells. However, the source of these cells is important since only those derived from the bone marrow are effective in inducing tolerance of LE skin grafts whereas both marrow derived cells as well as those originating from the lymph nodes can induce tolerance of LE hearts. The present study was undertaken to compare the efficacy of cells derived from the bone marrow and the lymph nodes of (BN × LE)F‐1 rats to induce unresponsiveness to LE neurons in BN recipients. In untreated rats, all neurons in sensory (vagal nodose) and sympathetic (superior cervical) ganglia transplanted from LE rats to the anterior chamber of the eye or implanted into the sternomastoid muscle of BN recipients were rejected within 35 days. However, when neonatal BN rats were inoculated with adult (BN × LE)F‐1 hybrid bone marrow or lymph node cells and challenged as adults with LE ganglia grafts many neurons survived beyond 100 days. This result demonstrates that tolerance of Ag‐B incompatible neurons can be achieved with either bone marrow or lymph node cells. Moreover, since tolerance can be produced in rats exhibiting major or minor histoincompatibilities, this method of immunosuppression offers one way of preventing neuronal rejection which occurs acutely in Ag‐B incompatible and chronically in Ag‐B compatible ganglia homografts.