bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efferent projections of the ventral anterior nucleus of the thalamus in the monkey
Authors: Carmel Peter W. 
Published: February 2005

AbstractEfferent projections of the ventral anterior (VA) thalamic nucleus were investigated in 20 monkeys. In half of these animals degeneration was traced following stereotaxic lesions in the magnocellular (VAmc) or parvocellular (VApc) portions of the nucleus. Chronic cell changes in the VA nucleus were studied following various cortical ablations in the remaining animals.Stereotaxic lesions in the VA nucleus produced extensive subcortical degeneration (Nauta or Marchi stains). Within the VA nucleus was a dense pattern of degenerated fibers, largely oriented in the sagittal plane. Fibers from the VAmc nucleus projected laterally into the VApc nucleus. Numerous caudally directed fibers arose in the VA nucleus and projected intrathalamically to the rostral intralaminar and parafascicular nuclei. Fibers also entered portions of the centromedian and dorsomedial nuclei. Rostrally directed fibers from the VA nucleus entered the anterior limb of the internal capsule and were distributed widely to the frontal lobe cortex. Rostral projections from the medial VA (VAmc) nucleus were, in part, localized to a portion of the orbitofrontal cortex.Degeneration was absent or sparse in other ventral tier thalamic nuclei, and no degeneration was seen in the striatum, pallidum or insular cortex.Restricted cortical lesions in area 4, area 6, orbital cortex, medial frontal cortex, or insular cortex produced no cellular alteration in the VA nucleus. Large lesions involving several frontal cortical areas resulted in cellular changes, which were not as severe as in the adjacent ventrolateral nuclei; after extensive ablations approximately half of the VA cells remained normal.The VA nucleus appears to be an important link in the thalamic nonspecific system. Efferent projections reach both the nonspecific thalamic nuclei and widespread areas of frontal cortex.
Ultrastructural studies of cleavage stage t12/t12 mouse embryos
Authors: Hillman Nina , Hillman Ralph , Wileman Geraldine 
Published: February 2005

AbstractA statistical study of embryos obtained from both spontaneously ovulated and superovulated +/t12 females, mated inter se, shows that the range of the lethal phenocritical period of the t12 allele in a homozygous condition is from the 8–12 cell stage to the early blastocyst stage. The majority of t12 homozygotes are developmentally arrested as late morula and the nuclei of these embryos contain lipid droplets and fibrillo‐granular bodies. These same inclusions are found in other t12 embryos which are developmentally arrested either earlier or later than the late morula stage and distinguish 30–40% of the embryos (presumably t12 homozygotes) from their litter‐mates at the 2‐ and 4‐cell stages. Ultrastructural‐cytochemical studies of the fibrillo‐granular bodies show that the fibrillar areas are sensitive to pepsin and the granules to ribonuclease and are thus structurally and chemically similar to definitive nucleoli. Binucleate cells are also present in a high frequency of t12 homozygous embryos. This condition is considered an additional phenotypic expression of the genotype.Prior to developmental arrest, the nuclear and cytoplasmic organelles of t12 embryos do not differ from those of similarly staged litter‐mates or control +/+ embryos. Homozygous mutant embryos examined shortly following developmental arrest contain cells ranging from structurally normal to degenerative. Asynchronous cell death is common to all t12 homozygous embryos. A chronological description of degenerative cellular changes is presented.
The fine structure of the stannius body of the guppy and its response to deionized water
Authors: Tomasulo Joseph A. , Belt W. Duane , Hayes E. Russell 
Published: February 2005

AbstractThe Stannius corpuscle of the guppy, Lebistes reticulatus, was studied with light and electron microscopy. The relation of the cells to the rich vascular supply is described. The fine structure of the parenchymal cells is consistent with protein synthesis. When animals were subjected to an environment depleted in mineral content, the cells of the Stannius corpuscle showed striking alterations: a prominent swelling of the cisternae of the endoplasmic reticulum and perinuclear cisternae, a reduction in the electron‐opaque material within the Golgi saccules, the appearance of intramitochondrial granules, and vacuolization of the secretory granules. The role of the Stannius body in osmoregulation is discussed.
Innervation of the avian tonus latissimus dorsi anterior muscle
Authors: Hikida Robert S. , Bock Walter J. 
Published: February 2005

AbstractThe motor and cutaneous nerves associated with the pigeon's anterior latissimus dorsi tonus muscle are described. The motor nerve is traced from its origin within the brachialis longus superior nerve of the brachial plexus to within the epimysium of the muscle by means of serial cross sections. The nerve fibers differ in mean diameter at various sites along the nerve. They originate as small fibers within the plexus, become larger as they emerge and then gradually decrease in diameter as they approach the muscle. The number of nerve fibers remains relatively constant until the nerve divides into more than two branches, at which time the number increases.The cutaneous nerve passing through the anterior latissimus dorsi is described and is assumed not to play any role in the innervation, either sensory or motor, of the fibers in this muscle.
The fine structure of perinotochordal microfibrils in control and enzyme‐treated chick embryos
Authors: Frederickson Richard G. , Low Frank N. 
Published: February 2005

AbstractMicrofibrils in the notochordal sheath of chick embryos of two to four days incubation age were analyzed electron microscopically. Collagenase, trypsin, hyaluronidase and alpha amylase were administered to both “living” and “fixed” embryos. Living embryos were either explanted on an agar‐albumen growth medium or were allowed to survive within the shell during experimental procedures. Fixed embryos were immersed in Karnovsky's aldehyde fixative prior to enzyme digestion. Both living and fixed specimens yielded similar results.Control embryos possessed microfibrils of ca. 200 Å, ca. 100 Å and less than 100 Å in diameter in the notochordal sheath. The smaller fibrils (100 Å and less) were present in all regions of the sheath, but were especially concentrated near the notochordal boundary (basement) membrane. The larger fibrils (200 Å) were farther removed from the notochord. Flaky amorphous material was attached to all fibrils and was abundant especially in the inner region of the sheath.Collagenase produced elimination of the 200 Å microfibrils, but the smaller ones remained intact. Trypsin caused digestion of all fibrils. Hyaluronidase digested fibrils chiefly 100 Å and less in diameter. Alpha amylase was similar to hyaluronidase in digesting the small fibrils. This study supports the hypothesis that microfibrils are primarily mucopolysaccharide‐protein precursors of larger collagen‐rich fibrils.
Morphologic evidence that the renal calyx and pelvis control ureteric activity in the rabbit
Authors: Gosling J. A. , Dixon J. S. 
Published: February 2005

AbstractThe structure of the renal calyx, pelvis and upper ureter has been investigated in the adult rabbit. The methods employed for light microscopy were designed to demonstrate smooth muscle, cholinesterase and catecholamine‐containing nerves, elastic and collagenous fibers, and glycogen. Selected areas of the upper urinary tract were also examined using the electron microscope. The wall of the calyx and pelvis includes two layers of muscle cells the inner one of which appears to be continuous with the muscle coat of the ureter. The external layer extends across the renal pelvis from the calyx and ends abruptly in the pelvi‐ureteric region. In some regions cells from this layer run towards and intermingle with the muscle of the inner layer. The muscle cells forming the outer layer are associated with many adrenergic nerves which run in the connective tissue separating individual muscle cells. Numerous elastic fibrils are closely related to these cells which usually contain glycogen. In contrast, the muscle cells forming the inner layer of the pelvis and those of the upper ureter have a relatively poor innervation, are closely packed together without intervening connective tissue, and are usually devoid of glycogen. These observations provide structural evidence in support of the concept that specific regions of the renal calyx and pelvis influence and possbily control the activity of the ureter.
The fine structure of fungiform papillae and epithelium of the tongue of a South American toad, Calyptocephalella gayi
Authors: Stensaas L. J. 
Published: February 2005

AbstractThe epithelium covering the surface of the tongue of the South American toad Calyptocephalella gayi has been analyzed using large electron microscope photo‐montages and has been compared with that covering the tongue of the frog, Rana pipiens. In both species four kinds of epithelia are similarly distributed over the surface, and relatively minor differences in the cytoplasm and intercellular relations have been identified. Stratified ciliated epithelium covers the ventral, nonpapillary surface. A simple columnar epithelium of mucous cells covers most of the irregular dorsal surface. A poorly stratified nonkeratinizing epithelium covers the apex of filiform papillae while stratified, columnar epithelium forms the thick epithelial disc of fungiform papillae. Emphasis is given to fungiform papillae as the basis for functional studies since they are the only structures receiving large numbers of nerve fibers. Sensory terminals do not appear to be acted on directly by chemicals since they are located near the base of the epithelium and since tight junctions unite cells at the outer surface. However, axons selectively contact the base of certain elongate cells which extend to the surface and are presumed to be receptor cells. It seems probable that recent intracellular potential changes, recorded from the toad tongue in response to chemical stimulation, originate from mucous cells. It is suggested that these potentials could affect the receptor cells if low resistance pathways are provided by tight junctions.
Interrelationships between cornification and cell migration of fetal rat epidermis in vitro
Authors: Schwartz J. , Stern I. B. 
Published: February 2005

AbstractSamples of dorsal skin were obtained from 18‐, 19‐ and 20‐day rat fetuses. Comparative developmental studies were carried out from a portion of the samples, while the remaining samples were cultured for four days in a medium containing tritiated thymidine and studied autoradiographically.At 18 days the epidermis contained a periderm, a stratum intermedium and a stratum basale. By 19 days the strata granulosum and spinosum had developed. At 20 days, a stratum corneum was present. Cultured samples of 18‐day fetal rat skin resembled those that developed in utero with respect to time, whereas, the samples of 19‐ and 20‐day fetal rat skin developed a more extensive stratum corneum, fewer keratohyalin granules, and a more condensed stratum Malpighii.Autoradiographic studies were made to determine the time taken for cells to migrate from the stratum basale to the outermost layer of the stratum granulosum (transit time). A similar “transit time” was noted for the three fetal ages studied. The rates of cell migration varied. The results of this study suggest that the extent of cornification impedes cell migration by providing a physical resistance or barrier against the outward forces presumably exerted by the division of basal cells.
The ultrastructure of lymphatic valves in rabbits and mice
Authors: Takada Mitsuya 
Published: February 2005

AbstractThe ultrastructure of lymphatic valves was studied in rabbits and mice. The lymphatic valves usually consist of two cusps but three or four are sometimes present. The cusps are covered by endothelium. Along the free edge of the cusps are endothelial cells which can differentiate morphologically from other endothelial cells. They are named “tip‐cells”; they have pseudopod‐like projections and abundant cytoplasmic filaments 60–90 Å in diameter. Vesicles occur in endothelial cells of both lymphatic vessels and their valves; they are on the luminal or connective tissue side and are never provided with a diaphragm like that frequently observed in blood vessels. Joining endothelial cells are zonulae occludentes but desmosomes are not observed. No open intercellular junctions are encountered along the valvular endothelium. A basement membrane (basal lamina) is more frequently observed in valves than in walls of lymphatic vessels. Connective tissue in the cusps consists of collagenous fibrils, fine filaments and fibroblasts.
Slow muscle fibers in the tensor tympani muscle of the guinea pig
Authors: Seiden David 
Published: February 2005

AbstractThe tensor tympani muscle of the adult guinea pig was studied by light and electron microscopy. Extrafusal muscle fibers with centrally located nuclei were found. On the basis of morphological criteria, they were considered to be slow muscle fibers and others, with typical peripheral nuclei, twitch muscle fibers.
Atrioventricular node and purkinje fibers of the guinea pig heart
Authors: Kim Sangsin , Baba Nobuhisa 
Published: February 2005

AbstractThe ultrastructure of the atrioventricular node and Purkinje fibers of the guinea pig heart was studied. The atrioventricular node consists of slender, irregularly shaped muscle cells which are arranged in a complex network with frequent interdigitation. Nodal cells contact with each other by means of many desmosomes (maculae adherentes) and rare intercalated discs that contain short nexal regions (gap junctions). The Purkinje fibers are much larger and show less cellular interdigitation than the fibers of the atrioventricular node. Desmosomes are infrequent but there are many intercalated discs with rather a long nexus between the Purkinje fibers. The T‐system is not present in the atrioventricular node or in the Purkinje fibers. The most pronounced morphological differences between the atrioventricular node and Purkinje fibers are the size of the cells and the mode of intercellular connection, which may be related to different conduction velocities in these two regions.
Microscopy of the neonatal line in developing human enamel
Authors: Weber Dennis F. , Eisenmann Dale R. 
Published: February 2005

AbstractThe neonatal line in developing human primary teeth was examined by means of phase contrast microscopy, microradiography and transmission electron microscopy. When thin sections were observed by light microscopy, the lateral dimensions of the line were not as extensive as had been previously reported. The line had a “staircase” configuration and appeared to be identical to published light micrographs of the stria of Retzius. On radiograms, the lateral extent of the hypomineralization was also decreased. The ultrastructural basis for the neonatal line appeared to be a localized change in configuration of enamel prisms along with a possible reduction in crystal concentration. The possibility that some rods actually end at the line could not be excluded, however.
A fine structural study of divalent cation‐mediated epithelial union with connective tissue in human oral mucosa
Authors: Scaletta Lawrence J. , MacCallum Donald K. 
Published: February 2005

AbstractFollowing incubation in an isotonic saline solution containing 20 mM EDTA, human oral mucosa may be separated into its epithelial and connective tissue components. Ultrastructural study of the separated tissues reveals that the plane of separation is through the lamina lucida. Hemidesmosomal structure is altered by the separation process: the peripheral density is absent but a fine, generally filamentous material remains associated with the outer membrane leaflet of the hemidesmosome. Desmosome structure is not altered. An intact lamina densa remains attached to the connective tissue fragment. Oral mucosa incubated in EDTA‐saline containing calcium, or its return to a divalent cation‐supplemented medium after treatment with EDTA, prevents separation. By maintaining the structural integrity of the hemidesmosome, divalent cations appear to play a principal role in uniting oral mucosal epithelium to the lamina propria.
Cellular modification of interrenal tissue induced by corticoid therapy and stress in three avian species
Authors: Bhattacharyya Tapan K. , Ghosh Asok 
Published: February 2005

AbstractCorticotropic regulation of the interrenal tissue was explored in three avian species (quail, parakeet and myna) by application of dexamethasone therapy and stress. In response to corticoid administration, atrophy of all cortical layers from periphery to center was pronounced and no regional differences could be detected by histology and histometric analysis. Following exposure to acute formalin stress at the termination of chronic corticoid therapy, the interrenal tissue regularly responded by hypertrophy in all three types of birds. The absence of zonation in experimental atrophy in these species merits consideration in view of the zonal response observed in other avian species. The prompt response of the atrophic interrenal gland to stress indicates that the hypothalamo‐hypophyseal regulation of the interrenal gland is qualitatively different from mammals.
A comparison of freeze‐substitution with other methods for preservation of the pulmonary alveolar lining layer
Authors: Kuhn Charles 
Published: February 2005

AbstractRapid freezing of expanded lungs and freeze‐substitution in acetone containing OsO4 partially preserved the pulmonary alveolar lining layer for electron microscopy. The lining layer consisted of granular or flocculent material with a surface film at its interface with the air. It filled the spaces between protruding capillaries and other depressions in the alveolar wall. It is unlikely that this lining material is an artifact resulting from transfer of fluid during freezing because similar results were obtained after fixation by vascular perfusion and by immersion of the intact, air‐filled lung in aqueous fixatives containing glutaraldehyde.
Presence of connections between follicles in juvenile mouse ovaries
Authors: Merchant Horacio , Zamboni Luciano 
Published: February 2005

AbstractOvaries of 1 to 12 day‐old mice contain multilaminar follicles connected by tubular formations of granulosal cells. Conjoined follicles appear to be at synchronized stages of maturation. It is probable that the development of these interfollicular connections, which form during fetal stages of ovarian morphogenesis, is related to the presence of intercellular bridges between primordial germ cells.
The pituitary gland of the musk shrew, Suncus murinus L. (insectivora), with special reference to the cytology of the adenohypophysis
Authors: Naik D. R. , Dominic C. J. 
Published: February 2005

AbstractThe pituitary gland of the musk shrew, Suncus murinus L. was studied with special reference to the cytology of the adenohypophysis. In addition to the agranular cells (chromophobes), seven morphologically and tinctorially distinct chromophilic cell types (four mucoid and three acidophilic) were observed in the pars anterior. These cells have been tentatively named as types one to seven. On the basis of their morphology, topography and staining reactions, cells of types one to six were compared, respectively, with the TSH, FSH, ICSH (LH), LTH (prolactin), STH and ACTH cells of other mammals. The identity of type 7 cells could not be determined. Although mucoid cells (types 1, 2) are more concentrated in the rostroventral region of the pars anterior, a definite “zona tuberalis” seems to be lacking.Since the musk shrew is not a seasonal breeder, the gonadotropic cells (types 2, 3) of the adenohypophysis do not seem to fluctuate in structure during the different times of the year. However, conspicuous hypertrophy, hyperplasia and intense secretory activity of type 4 cells during pregnancy and lactation reinforces the postulation that these cells are lactotropic in function.Follicular cysts and colloid in the residual cleft were observed in a few instances. Their possible origin and significance are discussed.
Truncus arteriosus malformation in a human embryo
Authors: Maron Barry J. , Hutchins Grover M. 
Published: February 2005

AbstractMalformation of the heart and great vessels in a human embryo of 23‐mm crown‐rump length (Horizon XXII) is described on the basis of reconstruction of serial sections. A type I truncus arteriosus malformation with right aortic arch and absent ductus arteriosus was present. The left ventricle was anterior and lateral to the right. It is postulated that the malposition of the ventricles produced an abnormal relationship of the outflow blood streams which led to the truncus arteriosus malformation.
The distribution of osmiophilic lamellae within the alveolar and bronchiolar walls of the mammalian lungs as revealed by osmium‐ethanol treatment
Authors: Kikkawa Yutaka , Kaibara Manabu 
Published: February 2005

AbstractOsmiophilia of the cellular elements of the alveoli and bronchioles was investigated using the new technique of second osmication with a solution containing a mixture of osmium tetroxide and ethanol. Previously this method was used to reveal osmiophilic periodic lamellae of synthetic dipalmitoyl lecithin and the surface film of the acellular alveolar lining layer of the mammalian lung in thin sections.In the present experiments, much of the osmiophilic content of inclusions in type II epithelial cells became visible only after second osmication with osmium‐ethanol but was not visible with the initial osmium tetroxide fixation. The osmiophilic content of the inclusions showed 42 Å periodicity. These results are in accord with those obtained in the study of dipalmitoyl lecithin and the surface film, suggesting that the inclusions are the precursors of the pulmonary surfactant.Several new observations were made with this technique. These include osmiophilic lamellae within Golgi saccules, within the multivesicular bodies of type II cells, in the vesicles of type I epithelial cells, and in the basement membranes of epithelial cells. These observations are consistent with the idea that the Golgi apparatus and multivesicular bodies are closely related to the production of surfactant and that the surfactant may be disposed of by type I epithelial cells after engulfment by pinocytosis. Thereafter, the surfactant may eventually be cleared through the lymphatics.Clara cell granules behaved differently and were thought to be an unlikely site for the synthesis of the pulmonary surfactant.
Placental iron transfer: Relationship to placental anatomy and phylogeny of the mammals
Authors: Seal Ulysses S. , Sinha Akhouri A. , Doe Richard P. 
Published: February 2005

AbstractSerum iron transfer from mother to fetus was measured in near‐term pregnant females from 16 species representing 15 families and 7 orders of eutherian mammals. The amount of transfer at 2 hr was 5% or greater in species with hemochorial placentation and less than 0.1% at 3 hr in species with epitheliochorial or endotheliochorial placentation.