bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural demonstration of cilia in the adult human ependyma
Authors: Roy Subimal , Hirano Asao , Zimmerman Harry M. 
Published: February 2005

AbstractEpendyma from random sites of lateral, third and fourth ventricles including the aqueduct in five adult human brains was examined by transmission electron microscopy. In all the specimens studied, cilia were present in variable numbers in the ependymal cells. Our study thus establishes that there is widespread presence of cilia in the ependymal cells of the ventricular system in the adult human brain.
Some morphological features of the myoneural junctions in certain normal muscles of the rat
Authors: Ip M. C. 
Published: February 2005

AbstractIn frozen sections and whole mount preparations of the normal soleus, diaphragm, or intercostal muscles of the rat, myoneural junctions of different AChE and silver staining intensities were regularly observed. Muscle fibers of different diameters showed end‐plates of varying staining intensities. No correlation was found between a certain staining intensity and diameter of the end‐plates or between muscle fiber diameters and the ratio of pale to strongly stained end‐plates. There was, however, a tendency for the smaller muscle fibers to have end‐plates of smaller mean diameter than those in the larger muscle fibers.
Ultrastructural features of chick embryo skin cultured in a chemically defined medium
Authors: Wong Y. C. 
Published: February 2005

AbstractExplants of six‐day chick embryo skin, cultivated in a chemically defined medium (Waymouth Medium MB 752/1) for one to eight days were fixed and processed for electron microscopic study. Excellent development and differentiation of chick embryo skin was recorded. The skin cultivated in vitro matured much earlier than in ovo. After one day in vitro the morphology of the skin is similar in the stage of development to that of a 10–12 day embryo skin in ovo. After two or four days in culture, the skins are comparable to those of 12–14 day or 15–16 day in ovo embryos, respectively. The periderm of the epidermis was highly developed and contained a large number of peridermal granules after six days of culture. The skin proper, contained a granular layer, which resembled the skin of a 17‐day embryo. Complete cornification of the epidermis was observed for the first time in vitro after 8 days of incubation. Keratohyalin granules which were claimed to be absent in avian skin, were observed.
Cytochemical demonstration of alkaline phosphatase activity in the ultimobranchial bodies and thyroid parenchyma of the rat
Authors: Calvert R. 
Published: February 2005

AbstractThe localization of alkaline phosphatase activity in the ultimobranchial bodies was studied at the fine structural level in Holtzman rat embryos from the 15th to the 19th day of gestation, and also in four‐week old rats of the same strain. In the embryos, no alkaline phosphatase activity was found before the 17th day of gestation. From that day on, plasma membranes of glycogen‐rich cells show the reaction product regardless of their location in the wall of the ultimobranchial bodies. However, when the same cells are seen on cell cords of the median thyroid, they are negative. In the four‐week old rats, plasma membranes of ultimobranchial cells are strongly reactive. C cells are negative both before and after birth. Small thyroid follicular lumina with positive apical cell membranes are also noted in four‐week old rats. These positive thyroid follicles are not more differentiated than those previously described in 19‐day old rat embryos. It is concluded that new thyroid follicles are formed after birth. These results are discussed in relation to the hypothesis that when ultimobranchial cells are transformed into follicular cells, they undergo the same alkaline phosphatase changes as those observed during the maturation of follicular cells derived from the median thyroid primordium. The cytochemical method used is also criticized.
Stimulation of cell division following unilateral collapse of the lung
Authors: Simnett John D. 
Published: February 2005

AbstractCollapse of the left lung in adult mice is followed by an increased mitotic incidence (MI) in the right lung which persists for approximately four days after operation. This compensatory increase in MI does not occur if the left thoracic cavity is packed with an implant of cotton wool which prevents hyperinflation of the right lung. The rate of incorporation of labelled thymidine per unit of DNA (RIT) is higher in the right than in the left lung of unoperated animals but after collapse of the left lung there is a reduction in the ratio of right to left in respect of RIT. These differences in RIT do not appear to correspond to changes in the rate at which cells enter DNA synthesis and it is suggested that they are due to differences in vascularisation between the right and left lungs. The compensatory increase in MI which follows unilateral collapse is not due to loss of tissue mass, to tissue damage or to the direct effects of the increased physiological load placed upon the remaining functional tissue. It is suggested that hyperinflation of the right lung causes changes in the rate of blood flow through that part of the organ and that, in consequence, there is a change in the local concentration of metabolites including those whose function is to regulate the mitotic rate.
Postnatal changes in the localization of glucose 6‐phosphatase activity within the liver lobule of the mouse
Authors: Kanamura Shinsuke 
Published: February 2005

AbstractThe change in the localization of glucose 6‐phosphatase activity within the liver lobule of the mouse was studied during development. From one day before birth to three days after birth, a uniform localization of the activity was observed throughout the lobule. This uniform localization of the activity gradually changed to that of the adult type, characterized by a relatively higher activity in periportal areas, between three to ten days of age. This indicates that the postnatal growth of the liver is accompanied by a change in the pattern of the localization of this enzyme activity within the liver lobule. Further, the biochemical results showed that the elevated activity after birth was reduced to the level seen in adult at ten days of age. Thus, the reduction in the level of the enzyme activity during ten days after birth corresponds to a redistribution of the enzyme activity within the liver lobule.
Spatial distribution of rat fungiform papillae
Authors: Miller Inglis J. , Preslar Arthur J. 
Published: February 2005

AbstractThe objective of this study was to determine the spatial distribution of fungiform papillae on the rat's tongue. Since each fungiform papilla in the rat has a single taste bud, the spatial distribution of fungiform papillae is equivalent to the location of taste buds on the anterior tongue. A mean total number of 187 fungiform papillae per tongue were found which were about equally divided between the two lateral halves of the tongue. Over 50% of the total number of fungiform papillae were located on the tongue tip for an average density of 3.4 papillae/mm2, while the dorsal surface of the tongue had an average density of 1.3 papillae/mm2 of tongue surface. Papillae were absent on the dorsal midline, but a paracentral line of papillae running from anterior to posterior was a consistent finding. Though not identical, the distribution of papillae was essentially the same on different tongues. The functional significance of the papilla distribution is not understood, but electrophysiological experiments show evidence of neural interaction of papillae which are clustered together. The distribution of papillae and the distribution of nerve fibers which innervate them must be evaluated together in order to appreciate the significance of the distribution of fungiform papillae and their associated taste bunds.
A comparison of secondary palate development with different in vitro techniques
Authors: Smiley Gary R. , Koch William E. 
Published: February 2005

AbstractPalatal processes from 14‐day fetal C57BL mice were cultured under varying conditions for 48 hours and prepared for light and electron microscopy. Disruption of the epithelium along the medial border occurred when single palatal processes were explanted onto Millipore filters, plasma clots, or lens paper in subjacent contact with nutrient medium. Paired processes under the same culture conditions demonstrated typical midline epithelial disruption and mesenchymal fusion. Regions of mesenchymal necrosis occurred in processes growth on nutrient agar in a dish or submerged in nutrient medium. In similar cultures medial epithelial disruption did not occur in single processes and mesenchymal fusion of paired processes was either delayed or did not occur. Disruption of the epithelium along the medial border in single palatal processes, and mesenchymal fusion in paired palatal processes, occurred when palates weregrown on nutrient agar supported above but in contact with nutrient medium. The results indicated that responses of palatal epithelium and mesenchyme may be altered by different in vitro procedures. These observations emphasize that many factors must be considered in interpreting developmental changes in palatal processes grown in vitro.
On the development of the lymphoid follicles of the bursa of fabricius
Authors: Edwards Joshua L. , Murphy Robert C. , Cho Yongock 
Published: February 2005

AbstractThe structural features of the development of the bursa of Fabricius in white Leghom chick embryos are depicted at carefully timed intervals during embryogenesis, with emphasis on the sequence of events between the ninth and twelfth days of incubation. The direction and character of the migration of lymphoid cell precursors and granulocytes from the intravascular space to intraepithelial sites, where the formation of the primitive lymphoepithelial nodule takes place, is demonstrated. The mechanism of the mode of migration of these cells through the stromal epithelial interface is described and illustrated with electron micrographs and their role in the development of the primitive lymphoid follicles is described and discussed.
A simple, single‐injection method for inducing long‐term paralysis in embryonic chicks, and preliminary observations on growth of the tibia
Authors: Hall Brian K. 
Published: February 2005

AbstractA method for inducing paralysis in embryonic chicks is described. This involves single injections of the neuromuscular blocking agents, D‐tubocurarine Chloride or decamethonium iodide, into 10‐day embryos. The dose which optimises survival and paralysis is determined along with the effect of the drugs on embryonic growth. Decamethonium iodide at a dose of 1 mg per embryo gave maximum survival and paralysis to 18 days of incubation. Paralysis was assessed by observation of treated embryos in ovo and by examination of embryos removed from their shells between 11 and 18 days of incubation. Embryos were completely paralysed 24 hours post‐injection and remained paralysed until 18 days of incubation. Paralysed embryos failed to hatch. Development of the leg musculature was severely retarded in paralysed embryos. This method of inducing paralysis has considerable advantages over previous continuous infusion methods. The growth and collagen content of the tibia in the paralysed embryos was reduced and these results, and other applications of the method, are discussed.
The development of the granular convoluted duct in the rat submandibular gland
Authors: Srinivasan R. , Chang W. W. L. 
Published: February 2005

AbstractThe development of the granular convoluted duct in the submandibular gland of male rats, 4 to 12 weeks of age, was investigated. During this period, the average weight of the gland increased from 213 to 526 mg, the total DNA and RNA contents doubled, and the protein content tripled. Radioautographs were prepared from Epon embedded sections of the gland of the rats given 3H‐thymidine and stained with toluidine blue. The glands of 4‐week‐old rats consisted mainly of acinar cells (45%), intercalated ductal cells (20%) and striated ductal cells (16%). A few granular convoluted ductal cells were seen in the striated duct close to the intercalated duct. The frequency (and absolute number) of granular convoluted ductal cells increased linearly from 1% (3 × 106) at four weeks to 26% (68 × 106) at eight weeks, while the calculated number of striated ductal cells remained stationary. The absolute number of acinar cells and intercalated ductal cells nearly doubled between four to eight weeks of age. The proliferative activity of all cell types declined with age but between six and ten weeks of age the rate of proliferation of ductal cells was relatively higher than the rate of proliferation of the acinar cells. Morphologically the size and number of granules in the granular convoluted ductal cells increased with age. Based on the above data it is concluded that the granular convoluted ductal cells developed from that segment of the striated ductal cells which is in close proximity with the intercalated ductal cells. The heterogeneity of the granules in the granular convoluted ductal cells observed from six weeks of age might denote the functional diversity of the cells.
Ultrastructure of the oocytes of the egyptian spiny mouse (Acomys cahirinus)
Authors: Kang Yuan‐Hsu , Anderson Winston A. 
Published: February 2005

AbstractThe oocytes of types 2, 3, 4 and 5 follicles from the normal spiny mouse were examined with the electron microscope. Multiple juxtanuclear Golgi bodies, mitochondria associated with flattened granular endoplasmic reticulum, and large nucleus are the main features of the type 2 follicle oocyte. The numbers of mitochondria and Golgi apparati increase significantly at later stages. Small mitochondrial aggregates lacking “intermitochondrial cement” are seen in the ooplasm of types 3, 4 and 5 follicles. “Lamellar complexes” comprising two to six elongate flattened rough ER cisternae and intercisternal filaments begin to appear in the oocyte of the type 3 follicle. The intercisternal filaments may be observed as punctate‐, dashed‐, and solid‐lines in cross sections. In tangential sections the filaments display a paracrystalline structure. In the type 4 follicle oocytes, the “lamellar complex” becomes more extensive; polysomes and ribosomal fibrils are juxtaposed to the “lamellar complexes.” Bundles of ribosomal fibrils are abundant in the ooplasm of the type 5 follicle. The origin of ribosomal filaments and the functional significance of “lamellar complexes” are discussed.
Scanning electron microscopy of a second type of supraependymal cell in the monkey third ventricle
Authors: Coates Penelope W. 
Published: February 2005

AbstractThe third ventricle of monkeys has been examined with the scanning electron microscope (SEM). Two populations of supraependymal (SE) cells were distinguished on the basis of morphology and location. One type has been previously reported (Coates, '72, '73a,b,c). Another, type 2 SE cell, is now described.Type 2 SE cells were found in the third ventricle of both sexes and in all age groups although the numbers varied highly from animal to animal. The most common site for type 2 SE cells was the floor and transition zone of the third ventricle. Visualized with SEM, these cells had variable morphology, but may be characterized by a small cell body, few non‐branching processes some of which were flared and surface features such as ruffled membranes. Type 2 SE cells most likely correspond to Kolmer or epiplexus cells originally described in association with the choroid plexus. As such, they are probably phagocytes.
Hyperglycemia in the NZB/NZW F1 hybrid mouse
Authors: Pansky B. , Kessler H. S. , Senitzer D. 
Published: February 2005

AbstractBoth the NZW and NZB mice exhibit an elevated fasting blood sugar level when compared to Swiss white mice. The NZB/NZW F1 hybrid mouse shows still a higher fasting serum glucose level than either of its parental strains. This elevated glucose level is noted very early in the animals' life, long before definitive signs or symptoms of pathology are evident, and remains elevated at least until the fortieth week of life, the last testing period in our series before sacrificing the animals. There are two major peaking periods for the glucose levels, namely at 4–10 weeks of age and then again at 31–40 weeks of age. These age periods correspond to the very young animal and to the animal that is beyond its prime and most likely sick and near the end of its lifespan due to the animals' inherent disease processes. The NZB and NZB/NZW F1 hybrid succumb to their disease processes at approximately 8–10 months of age. The NZW usually lives until 18 months.The questions are raised: does the altered immunologic state in the NZB and/or the NZB/NZW F1 hybrid produce the elevated blood sugar levels and the pancreatic histopatholgy or is it the early hyperglycemic condition coupled with pancreatic pathology which are in some measure instrumental in producing the lesions discussed and observed, in the beginning of the three to four month period of age, in the various organs? Is there a relationship between the hyperglycemic condition and the immune state or are these independent phenomena in a genetically “mixed up” mouse?
Limitations to the neuroregulation of enzymes in mammalian skeletal muscle
Authors: Yellin Herbert 
Published: February 2005

AbstractMuscle fibers of the sternomastoid and the tongue of the rat were characterized histochemically according to mitochondrial distribution (succinic dehydrogenase), as well as reactivity for the alkali‐ and acid‐stabile “myofibrillar” adenosine triphosphatases. The principal fiber types of the sternomastoid were the large, “white” AαβM fibers and the smaller, “intermediate” BβD and “red” CαL fibers (figs. 1, 2, 3). The unusual musculature of the tongue was populated by diminutive AαM and CαM fibers, and variants thereof; all with relatively high mitochondrial content (figs. 4, 5, 6).Reinnervation of the sternomastoid muscle by the hypoglossal nerve caused most fibers of the sternomastoid to assume histochemical profiles reminiscent of those commonly observed in the tongue. However, the BβD fibers of the sternomastoid persisted in near usual numbers and disposition (fig. 17), despite their reinnervation by a nerve normally destined for a muscle lacking that particular fiber type. Thus, there are as yet unrecognized factors, possibly of neural origin, though more likely of muscle origin (genetic), that impose restrictions on the metabolism‐regulating functions of substitute motoneurons.
Postnatal observations on the diurnal rhythm and the light‐responsiveness in the pineal glycogen content in mice
Authors: Kachi Takashi , Matsushima Shoji , Ito Takashi 
Published: February 2005

AbstractIn mice of both sexes ranging in age from five days to two years, the development and time course of diurnal rhythm and light‐related variations in pineal glycogen were systematically studied by a semiquantitative histochemical method. When the animals were maintained under the usual diurnal lighting conditions (12L:12D), the diurnal rhythm and light‐related changes in pineal glycogen appeared first at 22 days of age and persisted until two years. The glycogenic response was most prominent between 60 and 150 days, and declined slightly in mice older than one year.The glycogenic response and cell size tended to differ in the distal, middle and proximal portions of the body of the pineal. These regional differences changes with the ages of the animals.When mice were kept in continuous darkness for seven days starting from 15, 23 or 60 days of age, the pineal showed a diurnal rhythm in pineal glycogen.When mice were kept in altered light regimens such as continuous darkness, continuous lighting or 6L:6D from birth up to 30 days, no diurnal variation in pineal glycogen developed.
Ultrastructural studies on postnatal differentiation of neurons in the substantia gelatinosa of rat cervical spinal cord
Authors: Hannah Richard S. , Nathaniel Edward J. H. 
Published: February 2005

AbstractNeuroblasts of the substantia gelatinosa at birth were small with large oval nuclei and scanty cytoplasm. The cytoplasm possessed ribosomes and mitochondria. Granular endoplasmic reticulum and Golgi complexes were generally absent or rudimentary. Electron dense bodies were seldom observed. By the end of the first week, the nuclei of several cells demonstrated early nuclear invaginations; cytoplasm exhibited growth cones, a well developed granular endoplasmic reticulum and Golgi complexes. At several points the channels of endoplasmic reticulum became continuous with the perinuclear space. By the end of the second week, differentiation of the neuroblasts was more advanced. More nuclei showed invagination of their contour. The cytoplasm revealed well developed granular endoplasmic reticulum and multiple Golgi complexes. Numerous vesicles and dense bodies were found adjacent to the Golgi complexes. Arrays of agranular endoplasmic reticulum also appeared late in the second week. By the third week, features of neuronal differentiation, such as nuclear invaginations, granular endoplasmic reticulum, agranular membrane configurations, multiple Golgi complexes and dense bodies in the cytoplasm became well established.
Scanning electron microscopy of epithelia prepared by blunt dissection
Authors: Miller Marcia M. , Revel Jean‐Paul 
Published: February 2005

AbstractSimple dissection techniques of samples to be examined in the scanning electron microscope allow one to visualize easily the three‐dimensional shape of epithelial cells in situ. Such preparations reveal a complex system of ridges and folds on the lateral surface of the cells whose intricacy can best be appreciated with SEM. In many epithelia there is a smooth apical band which corresponds to the region occupied by the junctional complex previously identified with conventional EM techniques. The secretion of chylomicra that result from a fatty meal can be observed. It is possible to study the distribution of concanavalin A binding sites on the lateral surfaces of the cells utilizing hemocyanin as a marker. In the case of the proximal tubule epithelium, the apical cell surface has many more binding sites than the lateral cell surface and there is a sharp demarcation at the level of the apical band. After blunt dissection the relationship of the basal surface of the cells with the basement lamina and the basement membrane can be appreciated as well. Possible physiological meaning of the morphological features observed is briefly discussed.
A circadian rhythm of mitotic activity in the uterine luminal epithelium of the rat: Effect of estrogen
Authors: Krueger Wayne A. , Bo Walter J. , Hoopes Phillip C. 
Published: February 2005

AbstractThe study was designed to determine whether or not the rat uterine luminal epithelium exhibits a mitotic circadian rhythm and to ascertain the effect of estrogen treatment at different time periods on the uterine epithelial mitotic response. Immature rats were injected with either sesame oil (controls) or 60 ng of estradiol‐17 β at eight time periods and were necropsied 24 hours after treatment. Colchicine was administered IP two hours before autopsy. Peak mitotic activity was observed during the nocturnal phase (0300) for both the control and estrogen‐treated rats. The nadirs were recorded during the diurnal phase (1800 and 1200 for the control and estrogen groups, respectively). The differences between low and high values were 1100% for the control rhythm and 101% for the estrogen animals. The data demonstrate the existence of overt circadian rhythms in the uterine epithelium for both control and estrogentreated rats.