bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neuroepithelial endocrine cells in the lung of Ambystoma mexicanum
Authors: Scheuermann Dietrich W. , Adriaensen Dirk , Timmermans Jean‐Pierre , De Groodt‐Lasseel Marie H. A. 
Published: February 2005

AbstractNeuroepithelial endocrine (NEE) cells were for the first time identified in the lung of the entirely aquatic urodele, Ambystoma mexicanum, by using light and electron microscopy, histochemistry, and immunocytochemistry. In the basal part of the ciliated epithelium and, less often, in the respiratory portion of the lung, NEE cells were found to occur both solitarily and in small clusters. No typical neuroepithelial bodies could be found. Using the method of Fernandez Pascual, some NEE cells were found to be argyrophilic. Microspectrofluorimetric analysis of formaldehyde‐induced fluorescence and immunocytochemistry revealed the presence of 5‐hydroxytryptamine. With antibodies to neuron‐specific enolase only a few NEE cells exhibited a faint immunostaining. Electron‐microscopically, the NEE cells are provided with distinctive cytoplasmic membranebound dense granules of variable size, which gave a positive argentaffin reaction. The images of emiocytotic granule release are indicative of a secretory function. In the tracheal epithelium, NEE cells seem to occur only solitarily. They bear the same ultrastructural characteristics as the intrapulmonary NEE cells but here, the dense granules are larger and associated with numerous bundles of microfilaments. Intraepithelial nerve endings were observed near the airway lumen. Between nerve terminals and NEE cells, synaptic complexes with aggregations of clear‐centered vesicles close to the presynaptic membrane thickenings were observed. In addition, some nerve endings from “reciprocal synapses” with NEE cells. A receptosecretory function for NEE cells in the lung of A. mexicanum is supposed.
Differentiation of trophoblast of the baboon blastocyst
Authors: Enders Allen C. , Lantz Katherine C. , Schlafke Sandra 
Published: February 2005

AbstractThe structure of trophoblast of the baboon blastocyst undergoes a number of maturational changes from the early blastocyst to the late blastocyst stage. The striking expansion of the blastocyst that occurs during the preimplan tation period is accompanied by the development of an extensive endocytic apparatus. Cationized ferritin labels coated depressions and vesicles near the apical cell surface, numerous uncoated tubules and larger apical vesicles, and multivesicular bodies within trophoblast cells. Basally and laterally the labeled components are primarily small uncoated vesicles and tubules. Small, discrete clusters of ferritin particles were seen within the basolateral compartment between trophoblast and its basal lamina and beneath trophoblast cells that do not have a basal lamina. The results indicate that ingested materials may be directed in two pathways, one involving breakdown within the lysosomal system and one involving transcytosis. The zona pellucida is a trilaminar structure consisting of a fibrillar outer layer that often contains spermatozoa, an intermediate zone, and an inner layer containing columns of dense zonal material. Loss of the zona occurs after expansion of the blastocyst and development of the endocytic organelles. During the late blastocyst stage, syncytial trophoblast differentiates at the margin of the polar trophoblast. Because blastocysts were flushed from the uterus, it could not be determined whether azonal blastocysts had been adherent to the uterine surface prior to collection.
Formation of multinucleated cells with osteoclast precursor features in human cord monocytes cultures
Authors: Orcel Philippe , Bielakoff Josette , De Vernejoul Marie Christine 
Published: February 2005

AbstractA common lineage between monocytes and osteoclasts has been suggested but not yet proved, and an osteoclast precursor might be an immature cell of the monocyte‐macrophage family. We therefore compared the ability of cord blood and adult monocytes in long‐term culture to differentiate toward osteoclasts. Both adult and cord monocytes were cultured for 3 weeks in the presence of 20% horse serum. The proportion of multinucleated cells formed was influenced by 1,25(OH)2D3 in cord, but not in adult monocyte cultures: 10−9M 1,25(OH)2D3 increased multinucleated cells from 13 ± 2 to 26 ± 1% of total cells in cord monocyte cultures. The formation of multinucleated cells in cord monocyte cultures, in the presence of 10−9 M 1,25(OH)2D, was decreased by salmon calcitonin (dose dependently from 10−8 to 10−6 M) and increased by 1—34 parathormone (100 ng/ml). None of these hormones induced any modification of the proportion of multinucleated cells formed in adult monocytes culture. Specific antigens on the membrane of the cells obtained after 3 weeks culture in the presence of 10−9 M 1,25(OH)2D3 were assessed by immunocytochemistry. The respective proportion of adult and cord labeled cells was 64 ± 11 vs. 63 ± 6% with Leu M5 (specific for monocyte) and 68 ± 7 vs. 30 ± 10% (P<0.05) with the anti‐HLA DR antibody. The monoclonal antibody 23C6 is specific to the vitronectin receptor, which is highly expressed by osteoclasts–41 ± 2% of the cells in cord monocyte cultures–but none in the adult monocytes culture were labeled with 23C6 at the end of the culture period. The ability of cells formed in cord monocyte culture to resorb devitalized bone on which they were cultured was investigated after 3 weeks culture. These cells did not release 45Ca from devitalized 45Ca‐prelabeled rat calvaria; they did not form an acidic extracellular compartment, as assessed by acridine orange fluorescence, and there was no ultrastructural evidence of a brush border at the interface with bone. In conclusion, cord blood monocytes in long‐term culture do not form mature osteoclasts. However, in contrast to adult monocytes, some acquire, in culture, characteristics of osteoclast precursors: sensitivity to osteotropic hormones and expression of an osteoclast membrane‐specific antigen.
Characterization of the synthetic capacities of isolated placental binucleate cells from sheep and goats
Authors: Morgan G. , Whyte A. , Wooding F. B. P. 
Published: February 2005

AbstractSheep and goat binucleate cells (BNC) play a central role in placental growth and development. This study reports a simple method for isolating 60‐70% pure populations of BNC of high viability. After incubation of the isolated BNC with a brief pulse of 14C‐leucine or 3H‐fucose or 3H‐galactose, electron microscope autoradiography showed that label was eventually incorporated into the characteristic BNC granules via the Golgi body. Fucose and galactose initially showed a much higher Golgi body label than leucine, which was at first predominantly localised in the endoplasmic reticulum. 35S‐methionine incorporation by BNC suspensions was extensive enough to allow an immunoprecipitation investigation which demonstrated that the protein hormone ovine placental lactogen and the SBU‐3 antigen were synthesised de novo. Previous studies with isolated BNC have shown a remarkable range of substances to be released into the incubation medium but not necessarily synthesised during the incubation. The results demonstrate unequivocally that isolated BNC's are capable of total synthesis in vitro of two of the proteins that these same cells are known to secrete in vivo.
Developmental morphology of vascular and lymphatic capillaries in the working myocardium and purkinje bundle of the sheep septomarginal band
Authors: Smolich Joseph J. , Shimada Tatsuo , Canale Enrico , Campbell Gordon R. 
Published: February 2005

AbstractThe normal development of vascular and lymphatic capillaries in the right ventricular septomarginal band of the sheep heart was studied in 9 fetuses aged 60—143 days (term = 147 days), 14 lambs aged 1 day to 16 weeks, and 3 adults. Tissue was fixed by perfusion and examined with light and transmission electron microscopy.The septomarginal band is composed of working myocardium and a well‐defined peripheral bundle of Purkinje cells. Vascular capillaries of the working myocardium were closely apposed to myocardial cells. By contrast, vascular capillaries of the Purkinje bundle were situated within the connective tissue sheath and septa, at variable distances from the Purkinje cells. After birth, the capillaries of the Purkinje bundle were also found in grooves and tunnels within the Purkinje strands. The ultrastructure of fetal vascular capillaries associated with myocardial and Purkinje cells was initially similar, and characterized by an abundance of synthetic organelles in endothelial cells and pericytes. However, after 115 days in utero, capillary endothelium with diaphragmed fenestrae, 40—60 nm in width, were observed within the Purkinje bundle. The fenestrae attained an average frequency of 1 per 11 capillary cross sections just before term, and this was maintained in lambs and adults. The ultrastructure of lymphatic capillaries, which were not observed in the septomarginal band until just before term, changed little during development.
Androgen‐induced changes in nuclear pore number and in tight junctions in rat seminal vesicle epithelium
Authors: Ortiz Hector E. , Cavicchia Juan Carlos 
Published: February 2005

AbstractThe numbers of nuclear pore complexes and tight junctions were quantified in the seminal vesicle epithelial cells of castrated and castrated‐plus‐androgen‐treated male rats, which received subcutaneous pellets of testosterone propionate (1 mg/kg body weight) for 1 week. Seminal vesicle weights were 0.284 ± 0.02 g for castrated, 1.006 ± 0.006 g for androgen‐treated, and 0.918 ± 0.04 g for untreated groups. Tissue samples were processed for light or electron microscopy and for freeze‐fracture techniques. Nuclear areas were measured: controls were 279.34 ± 8 m̈m2; these increased significantly (P < .001) in castrated‐plus‐androgen‐treated rats (324.66 ± 11 m̈m2) and decreased (P < .001) in castrated animals (173.14 ± 6.3 m̈m2). Nuclear pore density increased (P < .001) in castrated‐plus‐androgen‐stimulated rats (5.38 ± 0.24 pores/ m̈m2) (control: 4.78 ± 0.14 pores/m̈m2), and decreased (P < .001) in castrated rats (3.16 ± 0.14 pores/m̈m2). A significant (P < .001) increase in numbers of tight junction strands that extended in the lateral cell membranes was detected in castrated‐plus‐androgen‐treated rats vs. controls or castrated‐only animals.
Microanatomy of the lung of the bowhead whale balaena mysticetus
Authors: Henk William G. , Haldiman Jerrold T. 
Published: February 2005

AbstractThe lungs from six bowhead whales harvested by Alaskan Eskimos have been examined with light and electron microscopes. Airways ranging from 1 to 40 mm in luminal diameter are lined by a pseudostratified ciliated epithelium containing numerous mucus‐secreting cells. The underlying lamina propria‐tela submucosa of these airways contains tubuloalveolar glands, plasma cells, and lymphatic accumulations in addition to both elastic and collagenous fibrillar elements. Cartilage extends to the level of the respiratory airways, but smooth muscle is absent from airways larger than 3 mm, and tubuloalveolar glands are absent from airways smaller than 3 mm. Respiratory airways are lined by pseudostratified, simple cuboidal, and simple squamous epithelia. Alveolar ducts are lined by simple squamous epithelium exclusively. A connective tissue core composed mostly of elastic fibers supports the walls of the alveolar ducts. Neither smooth muscle nor cartilage has been observed in these structures. Alveoli contain the typical cetacean double capillary bed separated by a thick septum composed mainly of collagenous connective tissue. Alveoli are lined by a simple squamous epithelium similar to that encountered in alveolar ducts and respiratory airways. This epithelium is composed of type I and II pneumocytes closely appressed to an underlying capillary network. The type II pneumocytes contain typical lamellar bodies and tubular myelin can be seen in the air spaces. The lung is surrounded by a thick (X = 2.5 mm) visceral pleura rich in blood vessels and elastic fibers.
Influence of age, growth, and sex on cardiac myocyte size and number in rats
Authors: Bai Shuling , Campbell Scott E. , Moore Jo Ann , Morales Martha C. , Martin Gerdes A. 
Published: February 2005

AbstractThe effects of altered neonatal nutrition on cardiac myocyte size and number was examined in 21‐day‐old and 3‐month‐old rats. Nutritional differences in growth rate were produced in newborns by adjusting litter size to four (fast‐growing), eight (normally growing), or 16 (slow‐growing) pups per litter. Isolated myocytes were prepared from animals in each group to evaluate changes in cell size and number. Heart weight (mg ± S.D.), at 21 days of age, was 398 ± 51 for “fast‐growing” rats, 329 ± 43 for “normally growing” rats, and 228 ± 24 for “slow‐growing” rats. Body weights showed a comparable decline with reduced nutrition. In adults, treatment‐related differences in body and heart weight were present in males but not females.“Slow‐growing” rats had 21% fewer myocytes than “fast‐growing” rats at 21 days of age, a change that persisted in adults. Values for myocyte number from “normally growing” rats were intermediate between those of “fast and slow‐growing” rats at both 21 days and 3 months of age. In each heart region of weanling rats, myocyte length and volume were smallest in 16 per litter rats. Cellular dimensions increased progressively with better nutrition. In adults, differences in myocyte size as a function of altered neonatal nutrition were not statistically significant.Sex‐related differences in myocyte size or number were not found in males and females from any group at the time of weaning. In adults, it was also noted that males and females have a similar number of cardiac myocytes, but the larger heart weight found in males was primarily due to increased myocyte size. Myocyte size and number were also examined in 2‐year‐old female rats. There were no differences in cardiac myocyte size or number between 2‐year‐old females and 8‐month‐old weight‐matched females.
Differentiation of the inner cell mass of the baboon blastocyst
Authors: Enders Allen C. , Lantz Katherine C. , Schlafke Sandra 
Published: February 2005

AbstractDuring the blastocyst stage of development in the baboon, the inner cell mass changes from an irregular accumulation of cells within the cavity of the blastocyst to a disk at one side of the blastocyst and finally to a spherial mass of epiblast cells exhibiting a distinct polarity. The cells that will become the primitive endoderm are first seen as flattened but undifferentiated cells on the cavity side of the disk‐shaped inner cell mass. After endoderm cells develop their typical cytological characteristics, they extend well beyond the inner cell mass to form parietal endoderm. A basal lamina develops associated with the epiblast cells and mural trophoblast, but not with either parietal or visceral endoderm. Cytological differentiation of inner cell mass cells includes increased numbers of polyribosomes and a change in mitochondria from long, convoluted structures to short, more typical shapes. Evidence that epiblast is polarized is seen by the late zonal blastocyst stage. Apical junctional complexes develop within the center of the epiblast. These junctions presage the development of the potential amniotic cavity. Large vacuoles containing cell debris, some of which contain nuclear fragments, are present at all stages. Extensive cell death occurs during growth of the blastocyst, but the pattern appears to be random and products of cell death are readily phagocytized by adjacent cells.
Smooth muscle cells of neural crest origin form the aorticopulmonary septum in the avian embryo
Authors: Beall Arthur C. , Rosenquist Thomas H. 
Published: February 2005

AbstractPrevious studies have shown that the cells of the aorticopulmonary (AP) septum are similar to the smooth muscle cells of the mediae of the great vessels in their common origin from the cardiac neural crest and in their common expression of an elastic extracellular matrix. The purpose of this study was to test the cells of the AP septum for the presence of certain cytoplasmic proteins, especially smooth muscle alpha‐actin (SMAA) whose presence is definitive of smooth muscle.A monoclonal antibody against SMAA was applied to normal chicken embryos at 3.5–8 days of incubation and to age‐matched embryos from which the cardiac neural crest had been ablated surgically. Antibodies against the intermediate filaments desmin, cytokeratin, and vimentin also were applied.The results showed that the AP septal cells expressed SMAA during the process of septation, days 5–8; but when the cardiac neural crest was ablated and septation was defective, no cells in the conotruncal connective tissue expressed SMAA. None of the intermediate filament proteins were detected in the septum.These results indicate that the AP septal cells are smooth muscle and therefore may be hypothesized to have an active role in septation.
Skeletal structural adaptations to mechanical usage (SATMU): 4. Mechanical influences on intact fibrous tissues
Authors: Frost H. M. 
Published: February 2005

AbstractThis paper proposes that the growth in length of living fibrous tissue structures (tendon, ligament, fascia) responds primarily to circulating systemic rather than mechanical factors. However, growth of the thickness of those structures responds primarily to their mechanical tension loads in the special sense that, when the tissue's typical peak mechanical strains exceed a threshold value, its cells begin to add new collagen to increase its thickness, strength, and tension stiffness. When subsequent peak strains reduce to the threshold value, then further additions of collagen stop. That process defines mechanically controlled modeling of fibrous tissues. The collagen in these tissues can also develop mechanical microdamage (MDx) under repeated tension load‐deload cycles. Special maintenance mechanisms normally repair that MDx to prevent accumulations that would threaten structural integrity. As a result, spontaneous complete ruptures of these structures can happen when MDx production exceeds its repair. These maintenance mechanisms also prevent gradual stretching under continuous tension loads, a process the author suggests calling creep compensation. When the creep compensation mechanism becomes incompetent, structures can stretch under continuous loads; when it becomes overactive, contractures can occur. The above meld of fact and inference provides the kernel of a general theory for the responses of the architecture and mechanical competence of intact fibrous tissues to mechanical usage.
Three‐dimensional reconstruction of adult female mouse submandibular gland secretory structures
Authors: Denny Paul C. , Chai Yang , Pimprapaiporn Watchara , Denny Patricia A. 
Published: February 2005

AbstractComputer‐assisted reconstructions of adult female mouse submandibular gland have been used to positionally characterize within the three‐dimensional structure likely intermediates in secretory cell replacement. The locations of striated granular duct cells and granular intercalated duct cells are consistent with a role as intermediates between intercalated duct cells and granular duct cells or acinar cells, respectively. Average volumes of the two putative intermediate cell types are also consistent with this role. The reconstructions suggest that, in addition to a “streaming” mechanism for secretory cell replacement, formation of new secretory structures composed of multiple acini and second‐order intercalated ducts may also contribute to the cell replacement process.
Peripubertal human breast development
Authors: Monaghan Paul , Perusinghe Nina P. , Cowen Philip , Gusterson Barry A. 
Published: February 2005

AbstractThe microanatomical and histological appearance of the human breast has been studied during puberty. The macroscopic architecture of the mammary epithelial tree was identified and correlated with the histological appearance of material excised from defined regions of the breast preparations. Between ages 13 yrs and 15 yrs the human breast shows evidence of ductal elongation and branching, with lobules formed by lateral and dichotomous branching. The majority of ducts are lined by a two‐layered epithelium consisting of recognisable myoepithelial and luminal cells. Less‐well‐defined multilayered regions were also observed in some areas, apparently at the site of lateral branching or early lobular development.
Adaptation of cancellous bone to aging and immobilization in the rat: A single photon absorptiometry and histomorphometry study
Authors: Li Xiao Jian , Jee Webster S. S. , Chow Sien‐Yao , Woodbury Dixon M. 
Published: February 2005

AbstractNine‐month‐old female rats were double‐labled with bone markers and subjected to right hindlimb immobilization or served as control for 0, 2, 10, 18, or 26 weeks. The right limb was immobilized against the abdomen, thus unloading it, while the left limb was overloaded during ambulation. Single photon absorptiometry and cancellous bone histomorphometry were performed on dissected intact femur and 20‐m̈m‐thick undecalcified specimens of the proximal tibial metaphysis. In the unloaded limb, immobilization‐induced muscle and cancellous bone loss occurred rapidly before 10 weeks and stabilized at 50% less bone mass after 18 weeks. Unloading caused a negative bone balance from a combination of elevated bone resorption and depressed bone formation. At 2, 10, and 18 weeks of immobilization, the ratios of bone resorption to bone formation surfaces were 1.6, 1.5, and 1.3, respectively; at 26 weeks, the ratio was 1. The bone loss was accompanied by poorer trabecular architecture (trabecular number decreased and trabecular separation increased), reaching the maximum at 18 weeks and stabilizing thereafter. These observations are in general agreement with Frost's postulate for mechanical effects on lamellar bone remodeling, and the findings on disuse osteoporosis in man. Therefore, the one‐legged immobilization model can be useful in studies of the mechanisms of structural adaptation to mechanical usage.
Elastic and collagenous fibers in the temporomandibular joint capsule of the rabbit and their functional relevance
Authors: Savalle Willem P. M. , Weijs Wim A. , James Jan , Everts Vincent 
Published: February 2005

AbstractThis study deals with the form and function of the temporomandibular joint capsule and compares the histogical structure of the capsule and kinetics of condylar and disc movement in rabbit and man.The morphology of the capsule of the jaw joint of the rabbit was studied by means of histological sections of isolated capsules, cellodin sections of decalcified heads, and cryostat sections containing the joint, fixed in jaw open and closed positions. General staining methods and selective methods for elastin and collagen were used. The volume density of the elastic fibers was determined morphometrically. The capsule consists of a portion connecting disc and skull and a portion connecting disc and mandible. The former portion has a fibrous outer layer of dense connective tissue. It contains numerous bundles of specifically oriented collagen but hardly any elastic fibers. Few irregularly arranged elastic fibers are present in the lateral and medial areas of the capsule. In contrast, the portion connecting disc and condylar process contains not only oriented collagen but also large amounts of elastic fibers. Anteriorly, there is a thin elastic band that is streched greatly at jaw opening. Posteriorly, the capsule takes the appearance of a large fibro‐elastic pad that covers the posterior extension of the condyle. This part is somewhat stretched when the jaw is closed. The findings correlate well with the results of jaw movement studies, showing a remarkable capability for condylar protrusion and retrusion. In contrast to the situation in humans, this movement occurs mainly between condyle and disc. It is made possible by the rather tight connections between skull and disc and flexible ones between disc and condyle.