bluuebunny/crossref_metadata_2025_split huggingface dataset:
The kidney of tapirs: A macroscopical study
Authors: Maluf N. S. R. 
Published: February 2005

AbstractThe renal cortex of tapirs, water‐loving primordial ungulates, was continuous, nonlobed, and about 80% of renal mass in adult and 71% in term‐neonate. In the neonates even the peripheral glomeruli were moderately mature.Tapirus bairdihad about 4 million glomeruli per kidney andT. pinchaqueabout 3 million smaller glomeruli. Number of glomeruli per gm of cortex was 12,444 inT. bairdiand 13,400 inT. pinchaque. Cortical loops were common in the medullary rays.The medulla was the simple crest‐type. The terminal collecting ducts (T.C.D.) opened separately at the crest and not into a tubus maximus. The “outer stripe” of the outer medulla apparently was telescoped into the deep cortex. The medullary loops turned at a thick portion and at nearly all levels of the medulla. The medullary crest was lined by urothelium which extended into the ends of the T.C.D. Otherwise the T.C.D. were made of columnar epithelium.The pelvic urothelium was continuous with that of the medullary crest at the dorsal and ventral fornices. The fornices were well within the inner medulla. Hence only inner medulla could be exposed to pelvic urine.The hilar arteries, unlike the other two perissodactyl families (rhinoceri and equids), passed through the cortico‐medullary (C‐M) border and some large arteries and veins passed through the outer medulla to and from the C‐M border without branches or tributaries. Unlike kidneys with a medullary crest in diverse eutherian mammals, tapirs lacked pelvic extensions along the major intrarenal blood vessels and thus lacked pelvic intervascular eminences.
Experimental analysis of blood vessel development in the avian wing bud
Authors: Feinberg Richard N. , Noden Drew M. 
Published: February 2005

AbstractShortly after its appearance, the avian limb bud becomes populated by a rich plexus of vascular channels. Formation of this plexus occurs by angiogenesis, specifically the ingrowth of branches from the dorsal aorta or cardinal veins, and by differentiation of endogenous angioblasts within limb mesoderm. However, mesenchyme located immediately beneath the surface ectoderm of the limb is devoid of patent blood vessels. The objective of this research is to ascertain whether peripheral limb mesoderm lacks angioblasts at all stages or becomes avascular secondarily during limb development.Grafts of core or peripheral wing mesoderm, identified by the presence or absence of patent channels following systemic infusion with ink, were grafted from quail embryos at stages 16–26 into the head region of chick embryos at stage 9–10. Hosts were fixed 3–5 days later and sections treated with antibodies that recognize quail endothelial cells and their precursors.Labeled endothelial cells were found intercalated into normal craniofacial blood vessels both nearby and distant from the site of implantation following grafting of limb core mesoderm from any stage. Identical results were obtained following grafting of limb peripheral mesoderm at stages 16–21. However, peripheral mesoderm from donors older than stage 22 did not contain endothelial precursors. Thus at the onset of appendicular development angioblasts are present throughout the mesoderm of the limb bud. During the fourth day of incubation, these cells are lost from peripheral mesoderm, either through emigration or degeneration.
Immunohistochemical localization of components of the immune barrier in the olfactory mucosae of salamanders and rats
Authors: Getchell Marilyn L. , Getchell Thomas V. 
Published: February 2005

AbstractImmunohistochemical techniques were used to investigate the cellular distribution of components of the secretory immune system, including secretory immunoglobulin, secretory piece, and J chain, as well as other immunoglobulins and nonspecific defense factors in the olfactory mucosae of salamanders and rats.In the salamander, secretory immunoglobulin M, and J chain were localized in duct and acinar cells of Bowman's glands, in B lymphocytes, and in sustentacular cells in immature regions of the olfactory mucosa. Lactoferrin and lysozyme were also present in Bowman's glands, in sustentacular cells in immature regions of the olfactory mucosa, and in blood cells in the lamina propria. Olfactory nerve section resulted in the presence of increased numbers of secretory immunoglobulin‐immunoreactive B lymphocytes and in an altered distribution of IgM, secretory piece, and lactoferrin.In the rat, secretory immunoglobulin A and J chain were localized in duct and acinar cells of Bowman's glands and in B lymphocytes in the lamina propria. Secretory piece could be demonstrated in Bowman's glands only in rats that had a prior viral infection. Other defense factors, localized in the lamina propria, included IgG in the connective tissue stroma and in B lymphocytes, IgD‐immunore‐active B lymphocytes, and IgE‐immunoreactive cells that were identified as mucosal mast cells. Lactoferrin and lysozyme were present in serous acinar cells of Bowman's glands and in blood cells.These results demonstrate that the olfactory mucosa is protected from pathogenic invasion by the secretory immune system as well as other immunoglobulins, lactoferrin, and lysozyme.
Reconstruction of basement membrane in recombinants of epidermis and dermis of chick embryonic skin in vitro: An electron microscopic study
Authors: Akimoto Yoshihiro , Obinata Akiko , Endo Hiroyoshi , Hirano Hiroshi 
Published: February 2005

AbstractThe tarsometatarsal skin from 13‐day‐old chick embryos was treated with EDTA and/or Dispase to separate it into epidermis and dermis, and the basal lamina was removed. The isolated epidermis and dermis were then recombined and cultured on Millipore filters in a chemically defined medium (BGJb). Beginning at 3–4 days after recombination, short fragments of new basal lamina and subbasal dense plaque were formed along the epidermal basal cell outer surface immediately subjacent to hemidesmosomes. After 6–8 days of culture, fragments of the basal lamina started to fuse together and the lamina became progressively continuous. At the same time, anchoring fibrils were formed to attach to the basal lamina. The hemidesmosome formation preceded the basement membrane formation. When normal embryonic epidermis was recombined with retinolpretreated dermis and cultured for 7 days in BGJb, short fragments of the basal lamina, the subbasal dense plaque, and anchoring fibrils were formed, but the basement membrane remained discontinuous with many interruptions in the interspace between hemidesmosomes. These results demonstrate that pretreatment of dermis with retinol causes the changes noted in the basement membrane.
Endothelial cell origin and migration in embryonic heart and cranial blood vessel development
Authors: Douglas J. , Poole Thomas J. 
Published: February 2005

AbstractUsing the QH‐1 monoclonal antibody as a marker for quail endothelium, blockage and transplant experiments were carried out to construct fate maps for the embryonic endocardium, to determine whether preendocardial angioblasts are migratory, and, if these cells are migratory, to outline the pathways that they use for directed migration in embryonic blood vessel development. Recent descriptive studies using QH‐1 to make immunofluorescent whole mounts have described a sequence of events leading to the establishment of the embryonic heart tube. These reports suggest that the pattern for the endocardium and cranial vasculature is established by migrating angioblasts that form vascular cords which mature into blood vessels. Blockage experiments showed that the ventrolateral edge of the anterior intestinal portal serves as a substrate for the directed migration of pre‐endocardial angioblasts and that the pattern of the cranioventral vasculature forms independent of the source of angioblasts. Transplant experiments showed that the origin for endocardial angioblasts lies in mesodermal tissue just anterior to Henson's node, that these cells undergo directed migration to the pericardial area, and that angioblasts are pluripotent with the ability to form different blood vessels. The transplant studies also showed that the embryonic mesoderm may contribute to extraembryonic blood vessels on the embryonic yolksac. These results support the hypothesis that embryonic blood vessels may develop by either the vasculogenesis or by the angiogenesis mechanism, and show that the endocardium of the primitive heart tube forms by vasculogenesis.
Epithelial cells of the epididymis show regional variations with respect to the secretion or endocytosis of immobilin as revealed by light and electron microscope immunocytochemistry
Authors: Hermo L. , Oko R. , Robaire B. 
Published: February 2005

AbstractThe localization of immobilin, a glycoprotein known to be present and to immobilize spermatozoa in the lumen of the epididymis, was investigated using light and electron microscope immunocytochemistry. In the light microscope, a distinct immunoperoxidase reaction product was observed in the lumen over the brush border of the epithelial nonciliated cells of the efferent ducts, while only a faint reaction was seen over their supranuclear region. In the proximal area of the initial segment of the epididymis no immunoperoxidase staining was observed either over epithelial cells or in the lumen. In the middle area of the initial segment, several epithelial principal cells became intensely immunostained but the majority were unstained; a weak reaction appeared in the lumen. In the distal area of the initial segment, more principal cells became immunostained, and while some were intensely reactive, others were moderately or weakly stained or unreactive. In the intermediate zone and proximal caput epididymidis, the principal cells showed the maximal immunoreactivity with all principal cells being reactive; staining in the lumen also reached its maximal reactivity in these areas. Immunostaining of principal cells gradually decreased along the epididymal duct and disappeared in the cauda epididymidis, however, an intense reaction persisted in the lumen. In the distal area of the cauda epididymidis, clear cells were reactive. In the electron microscope, immunogold labeling of reactive principal cells of the middle and distal areas of the initial segment, intermediate zone, and caput epididymidis was detected over cisternae of endoplasmic reticulum, stacks of Golgi saccules, and spherical electron lucent (200–400 nm in diameter) vesicles. The latter were present on the trans face of the Golgi stack, in the vicinity of the Golgi apparatus, and close to the apical cell surface; they are considered as secretory vesicles involved in the secretion of immobilin. In the distal area of the cauda epididymidis, epithelial clear cells showed an intense immunogold labeling over their endocytic apparatus. Immunogold labeling in the lumen of the epididymis was found over a fine flocculent material dispersed between the sperm. This material was especially abundant in the cauda epididymidis and did not appear to be bound to the surface of the sperm. The present results suggest that principal cells of the epididymis are involved in the secretion of immobilin, but that a differential secretory pattern exists between epididymal segments with maximal secretory activity occurring in the intermediate zone and proximal caput epididymidis, while no secretion takes place in the cauda epididymidis. Excess immobilin appears to be endocytosed for degradation by clear cells of the cauda epididymidis.
Female syrian hamster harderian gland: Development and effects of high environmental temperature and melatonin injections on histology and porphyrin deposits
Authors: Rodriguez‐Colunga Maria J. , Fernandez Covadonga , Rodriguez Carmen , Tolivia Delio , Menendez‐Pelaez Armando 
Published: February 2005

AbstractWe have investigated the development of the Harderian glands of female Syrian hamsters from birth to 8 months of age. The effects of melatonin injections on Harderian gland histology and porphyrin deposits of female hamsters exposed to two different temperatures were also studied. The morphology of the Harderian glands from 30‐day‐old female hamsters resembled those of sexually mature adult animals. The intraluminal area occupied by porphyrins increased significantly between 20 to 30 days of age. However, the relative number of mast cells per mm2 rose between 30 to 90 days. Both porphyrins and mast cell numbers appeared clearly reduced in the 8‐month‐old group. Secretory cells characterized by large lipid droplets (type II cells) were not observed.Daily afternoon injections of 25 μg of melatonin to female hamsters exposed to 22°C for 14 weeks resulted in the discontinuity of estrous cyclicity, a marked dccrease in the intraluminal area occupied by porphyrins, a reduction of the number of mast cells per mm2, and in a marked augmentation of the number of type II cells per mm2. Although the administration of similar dosages of melatonin to hamsters exposed to an environmental temperature of 32°C did not interrupt estrous cycles, a clear reduction of the area occupied by porphyrins was observed. However, the number of mast cells and type II cells per mm2 was unaffected in these animals.Our results suggest that hormones other than ovarian steroids are involved in the regulation of the female hamster Harderian glands. The possible role of melatonin on Harderian gland metabolism is discussed.
Sheets of embryonic epidermis can be isolated and cultured with or without the basal lamina
Authors: Reenstra Wende R. , Svoboda Kathy K. H. 
Published: February 2005

AbstractIn the current study, we determine the concentration of Dispase II, a neutral protease, and the incubation time necessary for isolation of embryonic avian epidermis. The epidermis can be isolated from the dermis consistently with or without the basal lamina. Because the action of Dispase II is selective and easily controlled, this study suggests that Dispase can serve as a powerful tool for studying epidermal‐extracellular matrix interactions. In further experiments we study the response of sheets of epidermis isolated with and without its basal lamina to extracellular matrix. When the epidermis is isolated without the basal lamina, the basal surface blebs and the actin in the basal cytoplasm are disrupted. Epidermis isolated without the basal lamina and cultured on extracellular matrix reorganizes the basal actin mat and retracts the blebs. However, epidermis isolated without the basal lamina and cultured in the absence of extracellular matrix continues to have blebs and a disorganized actin cortical mat. In contrast, the control epidermis isolated with the basal lamina retains a flat basal surface and organized actin cortical mat after culturing either with or without extracellular matrix. The extracellular matrix has been shown by many investigators to play an important role in cytoskeletal organization, metabolism, and differentiation. How the extracellular matrix interacts and influences these functions has not been completely elucidated. The ability to isolate tissue consistently with and without its basal lamina using Dispase II will facilitate addressing these and other epithelial cell biology questions.
Gross and microscopic anatomy of the vagal innervation of the rat heart
Authors: Burkholder T. , Chambers Mary , Hotmire Kurt , Wurster Robert D. , Moody Stephanie , Randall Walter C. 
Published: February 2005

AbstractIntrinsic cardiac ganglia and their vagal innervation are described from gross and microscopic dissections and functional studies in the anesthetized, open‐chest, adult rat. Dissecting microscope sketches of the ventral and dorsal aspects of the rat heart provide gross descriptions of the anatomical course of the vagal cardiac nerves. Histological sectioning of adipose tissue packets surrounding the terminal endings of vagal branches distributed to the roots of the great cardiac vessels (aorta, pulmonary artery, precaval veins) revealed clusters of autonomic ganglia. These packets or “fat pads” were located: (1) along the dorsal surface of the right precava and extending medially toward the aortic root, (2) deep to the aortic arch, (3) in the angle between the root of the left precava and the pulmonary artery on the superior‐dorsal surface of the left atrium, and (4) in the rostro‐dorsal interatrial septum. Vagal distributions of small terminal branches were traced to each of these pads, which contained numerous autonomic ganglia. Electrical excitation of right or left cervical vagus elicited varying degrees of sinus slowing, slowing of A‐V conduction, and suppression in atrial contractile force. Very small quantities (0.5 mg in 10 μl saline) of the ganglionic blocking agent, hexamethonium (C6) were injected selectively into a single fat pad, followed by repetition of right or left vagal stimulation, with careful analysis of changes in heart rate (paced and unpaced), A‐V conduction, and contractile force.
Maintenance by androgen and thyroid hormone of androgen‐induced convoluted tubular cells in mouse submandibular glands
Authors: Oda Mariko , Yamamoto Reiko , Terada Nobuyuki , Nishizawa Yasuko , Takatsuka Daishiro , Kitamura Yukihiko , Matsumoto Keishi 
Published: February 2005

AbstractInjection of 5α‐dihydrotestosterone (DHT) into castrated adult female mice stimulated the proliferation of a small proportion of the convoluted tubular cells in the submandibular glands. We investigated the effects of DHT and thyroxine (T4) on the maintenance of these proliferated convoluted tubular cells. For this, castrated adult female mice that had been treated daily with DHT for 3 days and then once with [3H]thymidine, received a first series of daily injections of DHT for various periods or T4 for 10 days, and then a second series of injections of treatment with DHT or T4, or no further treatment. The second series of treatments with DHT or T4 maintained the percentages of 3H‐labeled convoluted tubular cells at similar or slightly lower levels than those at the end of the first series of treatments. In mice that did not receive the second series of treatments, the percentages of 3H‐labeled convoluted tubular cells decreased markedly, becoming significantly lower than those at the end of the second series of treatment with DHT or T4. We also examined the effect of DHT on the proliferation of convoluted tubular cells of castrated adult female mice that had received 10 daily injections of DHT and then no treatment for 28 days. In these mice, the cells did not proliferate markedly on stimulation with DHT. These results suggest that androgen and thyroid hormone maintain convoluted tubular cells that have proliferated in response to androgen, and that the convoluted tubular cells may become unresponsive to androgen in terms of proliferation after their exposure to androgen.
Determination of relative fiber orientation in heart muscle: Methodological problems
Authors: McLean Miriam , Prothero John 
Published: February 2005

AbstractKnowledge of the muscle pattern in the heart is important to understanding cardiac contraction and propagation of the electrical stimulus. Most work on this pattern has been carried out by blunt gross dissection, whereby fiber bundles are easily visible on the peeled heart wall. However, it has never been shown, to our knowledge, that the orientation of macroscopic fiber bundles seen in a peeled heart corresponds to that of the constituent myofibers (muscle cells). For this purpose, one needs to carry out a three‐dimensional microscopic reconstruction within a documented macroscopic reference frame. To draw valid conclusions in such a coordinated macroscopic and microscopic study, one must estimate the (slice) angle between the long axis of a muscle cell and the plane of section. Otherwise any alleged differences between the macroscopic and microscopic orientations may be just an artifact of sectioning. In this study we have shown that, provided the images of the myofibers meet simple criteria, one can be reasonably confident that the potential error incurred by sectioning is small. On this basis, we demonstrated that while there is a general correspondence between the macroscopic fiber and the microscopic myofiber orientations, there are significant differences in detail.
Correlation of the arrangement pattern of enamel rods and secretory ameloblasts in pig and monkey teeth: A possible role of the terminal webs in ameloblast movement during secretion
Authors: Nishikawa Sumio 
Published: February 2005

AbstractEnamel rod architecture and ameloblast arrangement were examined in pig and monkey teeth using light microscopy and scanning and transmission electron microscopy. Enamel rods in the pig teeth were arranged in longitudinal straight rows in the initial enamel layer, in longitudinal wavy rows in the inner enamel layer, and in a staggered pattern in the outer enamel layer. Rod decussation was seen only in the inner layer. Cross‐sectined enamel rods in the pig were arcade‐shaped in the initial and inner layers, and mostly round in shape with circular boundaries in the outer layer. Arrangement of secretory ameloblasts at the level of the distal terminal web and Tomes' processes, and shape of Tomes' processes, corresponded to those of the enamel rod in the enamel layers. Distal terminal webs were well developed between straight rows of the ameloblasts forming the initial layer and between wavy rows of the ameloblasts forming the inner layer, and less developed within a row. The filament bundles in the distal terminal webs were also oriented along the rows. However, in the ameloblasts forming the outer layer, which lost their row pattern, distal terminal web filaments were distributed uniformly at the cell periphery. A similar arrangement of wavy rows of ameloblasts at the level of distal terminal web and Tomes' processes was also seen in monkey teeth.
Immunolocalization of laminin, heparan‐sulfate proteoglycan, entactin, and type IV collagen in the rat anterior pituitary. I. An in vivo study
Authors: Vila‐Porcile E. , Picart R. , Vigny M. , Tixier‐Vidal A. , Tougard C. 
Published: February 2005

AbstractThe distribution of three components of basement membranes (BM): heparan‐sulfate proteoglycan (HSPG), entactin (ENT), and type IV collagen (Coll. IV), was studied in the adult rat anterior pituitary and compared to the distribution of laminin (LAM) described in an earlier report (Vila‐Porcile et al., 1987, J. Histochem. Cytochem., 35, 287). Several immunocytochemical methods were applied at both light and electron microscope levels.The three components were detected in all the pituitary BM and in endothelial and perivascular connective cells, as previously observed for LAM within epithelial cells, however, only a faint immunoreaction could be detected for the other components, with nonetheless a discrete signal for Coll. IV.These findings indicate that (1) the four studied components are present in all the BM of the rat anterior pituitary; (2) pituitary endocrine cells contain LAM, and to a lesser extent Coll. IV, and thus could participate to the elaboration of the BM; and (3) the presence of the four components in non‐epithelial cells also suggests their cooperation in BM building. The questions of the turnover and intracellular pathways of each of these components were addressed but remain unanswered.