bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glycoconjugate distribution and mobility on apical membranes of absorptive cells of suckling rat ileum in vivo
Authors: Gonnella Patricia A. , Neutra Marian R. 
Published: February 2005

AbstractThe luminal membrane of ileal absorptive cells in suckling rats includes two domains: microvillar membranes and deep invaginations between microvilli. We examined the fates of foreign macromolecules that bind to anionic or saccharide sites on these domains after infusion into ligated loops in vivo. Cationized ferritin (CF) and ferritin‐RCAI (β‐galactosyl) binding sites were distributed over the entire apical membrane. Ligands bound to apical invaginations were rapidly endo cytosed, but ligands on microvilli were not. After CF binding, anionic sites on microvilli were mobile in the plane of the membrane and formed CF clusters at the tip and base of each microvillus. RCAI binding sites did not cluster. Wheat germ agglutinin (WGA, sialic acid) labeling was restricted to microvillus tips of mature cells but was dispersed over the microvillar surfaces of lower villus cells. Ferritin conjugates of Concanavalia ensiformis (Con A), Ulex europaeus agglutinin (UEA), and Dolichos biflorus agglutinin (DBA) did not bind to cell surfaces in vivo. Aldehyde fixation dramatically altered lectin binding patterns, resulting in unmasking and labeling of Con A, WGA, and DBA binding sites that were unavailable in vivo.
Anatomical relationships between type II pneumonocytes and alveolar septal gaps in the human lung
Authors: Takaro Timothy , Parra Saundra C. , Peduzzi Peter N. 
Published: February 2005

AbstractThis report describes a relationship between type II pneumonocytes and breaks in continuity in the alveolar septum of the human lung. Breaks in continuity of the septum are defined as gaps in the connective tissue matrix of the alveolar septum, with or without discontinuity of the accompanying alveolar epithelium. Septal connective tissue gaps accompanied by epithelial discontinuity are recognized as interalveolar pores of Kohn. When the discontinuity is confined to the connective tissue matrix, epithelial continuity may be maintained by either a single or a double layer of type I epithelium, by a type II cell, or by both type I and type II epithelial cells.Alveolar septal gaps were studied by electron microscopy on random sections in 26 adult human lung specimens and by serially sectioning and montaging the entire circumference of one alveolus to a depth of 103 μm (approximately one‐half a normal alveolus) from one of the specimens. Fixation was by way of the airways in most specimens, but by vascular perfusion in the serially sectioned specimen and in seven others.In lungs studied by random sections, we found that the incidence of septal connective tissue gaps with epithelial continuity per specimen correlated with the incidence of pores (r = .468, P < .016), and also with the incidence of type II cells (r = .422, P < .025) in the specimen. Five precent of all type II cells observed in the random sections in the 26 specimens (103/1,955) occupied septal gaps, and 2.5% (49/1,955) were located at the rim of a pore. In contrast, in the single serially sectioned montaged alveolus, 69% of all type II cells occupied some type of septal gap, with 24% of all type II cells forming part of the rim of a pore. Over half of all pores in this alveolus were associated with a type II cell.We concluded that a relationship between the incidence of type II cells and gaps in the alveolar septum could be demonstrated on random sections in normal human lungs, which was much more obvious in a single serially sectioned hemialveolus. Serial section techniques of whole alveoli may be necessary to establish relationships that may not be apparent on random sections and that require the study of whole cells in continuity with their environment in order to be identified.The findings may be significant in suggesting a possible role of the type II cell in alveolar septal repair.
Transient ultrastructural variations of pulmonary lymphatic capillaries during the respiratory cycle of the rat lung
Authors: Roberge Sylvie , Boucher Yves , Roy Paul‐Emile 
Published: February 2005

AbstractThe effect of respiratory movements on the endothelial wall of lung lymphatic capillaries was investigated by a morphometric study of their ultrastructure using a rodent model. The juxta‐alveolar lymphatic capillaries from lungs were fixed in the inflated phase by vascular perfusion with aldehydes and compared to those from lungs fixed in a deflated phase. Important quantitative differences in lymphatic endothelial wall architecture were observed between the two states. The most salient finding was a marked reduction of the mean endothelium thickness from 320 ± 55 nm in deflated lungs to 210 ± 36 nm (P<.01) in inflated lungs. The endothelial attenuation observed with inflated lungs was accompanied by a reduced frequency of interdigitation, the intricate pattern of intercellular contact (P<.02), and a decreased number of lumenal and ablumenal endothelial projections (P<.05). Despite these important variations in the dilated lymphatic capillaries, no typical open junctions (>30 nm) were found among 105 intercellular contacts. The vesicular system varied slightly after lung inflation. Dilated capillaries showed a significant reduction in cytoplasmic vesicles during inspiration (P<.01); however, the observed increases in lumenal and ablumenal vesicles were not found to be significant. As for numerical density and vesicular diameter, the fraction of cytoplasm occupied by the vesicles remains unchanged. Contrary to previous assumptions, these results suggest that intercellular clefts are not widened to the extent of open junctions (>30 nm) by the mechanical movement of inspiration in normal lungs. Moreover, transient changes to the endothelial architecture seem to preclude any excessive widening of the intercellular cleft.
A comparison of morphological stages and sulfated glycosaminoglycan production during otic capsule formation: In vivo and in vitro
Authors: McPhee Joseph R. , Van De Water Thomas R. 
Published: February 2005

AbstractThe sequence of events leading to otic capsule formation in the normal mouse embryo is described for both in vivo and in vitro development. Specimens were taken from embryos at 9–16 days of gestation. The in vivo results permitted the categorization of the developmental events of capsule formation into five distinct stages: prechondrogenic, aggregation, metachromatic, early chondrogenesis, and late chondrogenesis. Synthesis of sulfated glycosaminoglycans (S‐GAG) by early otic tissue complexes in vivo showed a sharp increase in the rate of S‐GAG production at 14.5 days of gestation (late chondrogenesis stage). The synthesis of S‐GAG in explants excised from embryos 12 days old (metachromatic stage) or older followed this same pattern of a sudden increase in S‐GAG synthesis at the in vitro equivalent of 14.5 days of gestation. These otic explants underwent all five stages of capsule formation up to the morphological equivalent of 16 days gestation. Therefore, otic explants can serve as a valid model in the study of those factors (i.e., tissue interactions and extracellular matrix) which influence and direct otic capsule formation.
Morphogenesis of human cardiac outflow
Authors: Thompson Robert P. , Sumida Hiroshi , Abercrombie Vant , Satow Yukio , Fitzharris Timothy P. , Okamoto Naomasa 
Published: February 2005

AbstractThe developmental anatomy of human cardiac outflow was studied in a series of 16 normal embryos (gestational days 29–39, crown‐rump length 6–20 mm, stages 14–19). Structural features and kinetics during truncal septation (TS) were described from external photographs, serial histological sections, and computer graphic reconstructions of selected tissues.Early in the period studied, the tubular myocardium ensheathed the single cardiac lumen and spiralling conotruncal ridges, which were filled with mesenchymal cells during days 31–33. As TS began (late stage 16), the aorticopulmonary (AP) septum appeared across the dorsal wall of the aortic sac between arches IV and VI. Mesenchymal condensations formed within the AP septum, crossing the lumen bifurcation to extend along the truncal ridges to the myocardium. During days 35–37, the cephalic margin of the myocardium grew or folded in toward these mesenchymal condensations between the developing valves and within the nearby conal ridges, which appeared to fuse to separate the subvalvular outflow channels by day 39.These observations are consistent with studies in chicks and rats which suggest that mesenchymal condensations or cell death foci interact with the distal myocardial rim during TS to form a structural septation complex dividing the two arterial streams.
Modification of the phenotypic expression of murine dystrophy: A morphological study
Authors: Bourke Dianna L. , Ontell Marcia 
Published: February 2005

AbstractThe extensor digitorum longus muscles of 4–6‐week‐old normal mice (129 ReJ) and dystrophic mice (129 ReJ dy/dy) were orthotopically transplanted. Grafted muscles were examined 1, 3, 7, 14, 20, 50, and 100 days post‐transplantation. The myofibers of both types of grafts underwent a similar time course of necrosis and regeneration. Other than during the initial necrotic response, no evidence of necrotic myofibers was found in either type of grafted muscle. At 100 days post‐transplantation, the grafted normal and dystrophic muscles were essentially similar, except that the dystrophic graft was of smaller size. Based on a comparison of the number of myofibers found at the 100‐day grafts' widest girths [631 ± 59 SEM, for normal grafts (Bourke and Ontell, 1984); 631 ± 74 SEM, for dystrophic grafts], it is suggested that the regenerative capability of traumatized 4–6‐week‐old dystrophic muscle is similar to that of traumatized normal muscle. At 100 days post‐transplantation, the grafted dystrophic muscle appeared “healthier” than untraumatized muscle from age‐matched dystrophic mice, having less variation in myofiber diameter, better fascicular organization, and less connective tissue. The transplantation system demonstrates the possibility of modifying the expression of genetic programming of myopathic disorders using environmental manipulation.
Dynamic features of duct epithelial cells in the mouse pancreas as shown by radioautography following continuous 3H‐thymidine infusion
Authors: Tsubouchi Susumu , Kano Eiichi , Suzuki's H. 
Published: February 2005

AbstractThe possibility of turnover of the epithelial duct cells was examined in the adult mouse pancreas by radioautography following continuous administration of 3H‐thymidine for periods varying from 1 h to 60 days. One hour after an injection of 3H‐thymidine, the label observed in small and large ducts was low but increased with the duration of the continuous infusion of 3H‐thymidine and reached a level of about 67% cells labeled after 60 days. The rate of duct cell labeling was estimated from the regression line of the labeling index vs. time in four types of ducts classified according to their inner diameter and the presence of the adventitia and was given as 0.60% cells per day in small (adventitia‐free) ducts (π 4–12 μm), 0.89%, 1.02%, and 1.23% cells per day in large (adventitia‐including) ducts (π 15–29, 30–49, and 50–160 μm respectively). In contrast, the labeling index of aciner cells after a 60‐day infusion indicated an addition of only 0.02–0.07% per day, and that of islet cells 0.14–0.22% per day.It is known that most parenchymal cells belong to either expanding or renewing cell populations. The acinar cells of the pancreas have been shown to constitute an expanding population, a conclusion confirmed by the low addition of cells observed in the present work. However, the relatively high rate of cell addition in the duct epithelia indicates that they may turn over in a period of 2.7 months in the case of large ducts and 5.6 months in the case of small ducts. It is proposed that the added cells replace cells carried away by the flow of pancreatic juice.
Focal tight junctions between mesenchymal cells of fetal dermis
Authors: Riddle Clara V. 
Published: February 2005

AbstractThis freeze fracture study shows the presence of focal tight junctions (maculae occludentes) between the mesenchymal cells in the connective tissue matrix of embryonic and fetal dermis. The overall outline of these unique junctions varies from circular to very angular. The junctional elements are most frequently present in a groove on the E fracture face. The corresponding P fracture face has ridges delineating the junction. These intercellular junctions may provide a means of informational or metabolic coupling between cells, may serve a structural role as scaffolding in the deposition and orientation of extracellular materials, or may be involved in the early stages of angiogenesis.
A method for explantation of selected areas of the neural retina
Authors: Carri Néstor G. , Ebendal Ted 
Published: February 2005

AbstractA method of obtaining explants of selected areas of the embryonic neural retina is described. Small plugs of the tissue are sucked into a glass capillary tube connected to a micrometer syringe via flexible tubing. The plugs of tissue are separated into their components (neural retina, pigmented layer, and mesenchyme). Retinal explants so obtained have similar shape and size. Polarity of the explants is easily determined. The procedure is simple, rapid, and precise. The method is suitable for studies of retina based on explanted or transplanted tissue.
Ultrastructure of the secretory response of male mouse submandibular gland granular tubules
Authors: Hazen‐Martin Debra J. , Simson J. A. V. 
Published: February 2005

AbstractThe organization and fine structure of granular convoluted tubule cells (GCT) from male mouse submandibular glands have been examined in controls and in animals injected with adrenergic and cholinergic secretagogues. Control submandibular glands exhibited a single population of GCT cells with numerous homogeneous granules filling the apical two‐thirds of the cytoplasm. A zone of transition cells, exhibiting characteristics of both GCT and striated duct cells, was found between the agranular intercalated duct and GCT segments. These transition cells possessed apical granules of variable size as well as prominent basal striations.Dramatic changes in the morphology of GCT cells followed administration of the α‐adrenergic agent, phenylephrine. The extensive degranulation involved formation of “secretory pools” of fused granules and release of secretory material into the lumen. The appearance of numerous smooth vesicles near luminal membranes suggested extensive membrane retrieval. Intracellular membrane‐limited aggregates of membrane fragments suggested that much of the retrieved membrane was destined for degradation. Rough endoplasmic reticulum was highly dilated but there was no indication of increased size or activity of the Golgi complex.Ultrastructural evidence indicated that the secretory responses to isoproterenol, a β‐adrenergic agent, and to pilocarpine, a cholinergic agent, were much more modest, but it is clear that some secretory response to these agents does occur. The other cell types of the duct and tubule system did not exhibit comparable morphological changes in response to the agents used.
A proposed alveolar model for adult human lungs: The regular dodecahedron
Authors: Linhartová Alena , Caldwell William , Andersondr Augustus E. 
Published: February 2005

AbstractIn an endeavor to delineate an alveolar configuration that would reasonably mirror the natural state, polygonal shapes of normal alveoli were tabulated in histologic sections from inflation‐fixed specimens of 16 men aged 16–48 years. The resulting alveolar population varied from three‐ to ten‐sided polygons with a preponderance of tetragons, pentagons, and hexagons. These observations were compared with the possible combinations of polygonal sections through various polyhedral models proposed by other workers and the five classical regular polyhedrons. The potential types of sections through the regular dodecahedron, i.e., a twelve‐sided shape with faces consisting of pentagons, seemed to fit best with present findings, and this is suggested as an idealized configuration that might be useful in various geometric determinations, e.g., estimates of alveolar surface area and volume.
The development of the syrian hamster cheek pouch
Authors: Hardy Margaret H. , Vrablic Olga E. , Covant Howard A. , Kandarkar Shripad V. 
Published: February 2005

AbstractThe objective of this study was to provide a detailed account of the morphogenesis and early cytodifferentiation of the hamster cheek pouch. Although the newborn “cheek pouch” is used for in vitro studies of the effects of retinoids and carcinogens, its rudimentary structure has not been adequately described. Complete paraffin serial sections of the heads of 14‐ and 15‐day fetuses were cut in three planes to determine the location and shape of the earliest pouch rudiments. Complete paraffin serial sections were prepared from pouch rudiments dissected from hamsters at birth and at daily intervals from 3 to 12 days postnatal. Semithin Epon sections were examined by light microscopy and ultrathin sections by transmission electron microscopy. The pouch can appear in the fetus as two solid epithelial ingrowths from the lining of the oral cavity. They are the margins of an ingrowing sheet of oral epithelium which becomes leaflike at about the time of birth, as it grows caudad into the tissue of the cheek. The central cells of the ingrowth accumulate large quantities of glycogen before differentiating as a stratum spinosum 5 days after birth. Within the stratum spinosum, groups of cells containing keratohyalin granules initiate the stratum granulosum. Keratinized cells appear within the stratum granulosum areas. Spaces appear between keratinized cells, and the spaces coalesce to form the pouch cavity between 7 and 12 days postnatal. Soon afterward, this cavity opens to the oral cavity to make a pouch, and the ultrastructure of the cheek pouch epithelium closely resembles that of the adult.
Computer‐assisted morphometry using video‐mixed microscopic images and computer graphics
Authors: Curcio Christine A. , Sloan Kenneth R. 
Published: February 2005

AbstractA microcomputer system has been developed for collection and analysis of morphometric data from video images of histological sections. Microscopic fields of view are visualized on a video monitor and are overlaid with computer‐generated graphics by means of a video mixer. Planimetric data are entered by drawing on a digitizing tablet while observing the drawn image superimposed on the tissue. Programs are available to calculate various geometric parameters, count objects in a field, perform descriptive statistics, and measure volume and surface area of a solid from a series of cross sections. A program for point‐counting stereology presents single points for scoring within a user‐defined reference area. The potential applications of interactive graphics in morphometry are discussed.
An ultrastructural study of the papillary layer and its vascular bed in the kitten enamel organ
Authors: Sasaki Takahisa , Garant Philias R. 
Published: February 2005

AbstractUltrastructure and three‐dimensional architecture of the papillary layer and associated capillaries in the enamel organ of 2–3‐month‐old kittens were examined by means of routine thin sections, freeze‐fracture, and scanning electron microscopy of the tissues digested by HCl‐collagenase and of vascular corrosion casts. Outwardly, the papillary layer formed gently sloping upheavals, but did not show prominent papillary ridges. The papillary cells were characterized by a high concentration of intramembranous particles on the plasma membrane P‐face, by numerous hemi‐annular gap junctions between the cell process of one papillary cell and the cell body of another host cell, and by annular gap junctional vesicles in the subsurface cytoplasm. Some annular gap junctions appeared partially degenerated. These findings led us to speculate that these annular gap junctions are produced by the endocytosis of gap junctional membranes from the cell surface into the subsurface cytoplasm.Capillaries were distributed on the enamel organ within shallow furrows between the papillary upheavals. A part of these capillaries penetrated deeply into the enamel organ but did not contact the ameloblasts. The endothelial walls of the capillaries were pierced with many endothelial fenestrations, especially when facing the papillary layer. The endothelial cell also contained numerous micropinocytotic vesicles throughout its entire cytoplasm. These findings suggest that the papillary cells and associated capillaries are highly specialized for transport of solutes and molecules between the vascular region and the enamel organ during the phase of enamel maturation.
Glucose 6‐phosphatase activity in pregnant and lactating mammary glands of the mouse
Authors: Shugyo Yoshihiko , Watanabe Jun , Kanamura Shinsuke , Kanai Kazuo 
Published: February 2005

AbstractGlucose 6‐phosphatase activity was studied in the secretory epithelial cell and other cell types composing alveoli of the mammary gland (cytochemical study) and in the whole mammary gland (biochemical study) of pregnant and lactating mice.The reaction product for the enzyme activity was seen in the endoplasmic reticulum and nuclear envelope in secretory epithelial cells from all animals examined days 7 and 14 of pregnancy, and days 0, 3, 10, and 20 of lactation. The amounts of the reaction product appeared scarce at day 7 of pregnancy, moderate at day 14 of pregnancy and day 0 of lactation, and abundant at days 3 and 10 of lactation. The reaction product, however, became generally scarce at day 20 of lactation. Biochemical activity was relatively low at days 7 and 14 of pregnancy and days 0 and 20 of lactation, while it was high at days 3 and 10 of lactation.The increased activity is probably related to functions of secretory epithelial cells in the lactating gland.
Clinical and anatomical observations of a two‐headed lamb
Authors: Fisher Kenneth R. S. , Partlow Gary D. , Walker Anne F. 
Published: February 2005

AbstractThe clinical and anatomical features of a live‐born diprosopic lamb are described. There are no complete anatomical analyses of two‐faced lambs in the literature despite the frequency of conjoined twinning in sheep.The lamb had two heads fused in the occipital region. Each head had two eyes. The pinnae of the medial ears were fused. Caudal to the neck the lamb appeared grossly normal. The lamb was unable to raise its heads or stand. Both heads showed synchronous sucking motions and cranial reflexes were present. Nystagmus, strabismus, and limb incoordination were present. The respiratory and heart rates were elevated. There was a grade IV murmur over the left heart base and a palpable thrill on the left side. Each head possessed a normal nasopharynx, oropharynx, and tongue. There was a singular laryngopharnyx and esophagus although the hyoid apparatus was partially duplicated. The cranial and cervical musculature reflected the head duplications. The aortic trunk emerged from the right ventricle just to the right of the conus arteriosus. A ventricular septal defect, patent foramen ovale, and ductus arteriosus were present along with malformed atrioventricular valves. Brainstem fusion began at the cranial medulla oblongata between cranial nerves IX and XII. The cerebella were separate but small. The ventromedial structures from each medulla oblongata were compressed into an extraneous midline remnant of tissue which extended caudally to the level of T2. The clinical signs therefore reflected the anatomical anomalies. A possible etiology for this diprosopus might be the presence early in development of an excessively large block of chordamesoderm. This would allow for the formation of two head folds and hence two “heads.”.