bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence that hepatocytes can phagocytize exogenous substances
Authors: Soji Tsuyoshi , Murata Yoshio , Ohira Akihiro , Nishizono Hisanori , Tanaka Mitsuru , Herbert Damon C. 
Published: February 2005

AbstractAlthough the phagocytic action of Kupffer cells is well known, such a phenomenon has not been well documented for hepatocytes. Follwing the injection of a suspension of egg lecithin‐coated silicon particles (0.5–1.5 μm in diameter) into the portal vein of rats, Kupffer cells showed minimal phagocytotic action, which was in contrast to the hepatocytes which displayed numerous phagocytized silicon particles. By comparison, when noncoated silicon particles of the same diameter as those that were coated were injected into the portal vein, the opposite observation was made. There was no uniformity in the ability of the hepatocytes to phagocytize either coated or noncoated particles from one lobule to another. Some showed active phagocytosis, while in others no evidence of such a process was observed. These data provide strong evidence for the selective phagocytic action of liver hepatocytes. © 1992 Wiley‐Liss, Inc.
Nuclear membrane modifications in polytene nuclei of Drosophila melanogaster. Serial reconstruction and cytochemistry
Authors: Park Paul C. , De Boni Umberto 
Published: February 2005

AbstractThe nuclear envelope of polytene nuclei of salivary glands of Drosophila melanogaster displays modifications consisting of nuclear envelope invaginations (NEI) and evaginations (NEE). Ultrastructural analyses combined with three‐dimensional reconstruction and cytochemistry show that NEI are bounded by a single membrane and that they may arise as invaginations of the inner nuclear membrane. NEI extend deeply into the nucleus. The lumens of NEI may collapse resulting in membranous sheets which may combine with those arising from adjacent NEI to form intranuclear structures resembling annulate lamellae. All NEI are associated with NEE. In contrast to NEI, NEE are enclosed in a double membrane morphologically identical to the nuclear envelope. While NEI and NEE share wheat germ agglutinin binding properties with the nuclear envelope, they differ in their ability to localize lanthanum. Pore annuli of NEI display complete lack of lanthanum binding, while those of NEE exhibit minor deposition of this cation. In contrast, pore annuli of the nuclear envelope are specifically and significantly decorated by lanthanum. A conceptual model based on the results obtained suggests that NEI are formed by invaginations of the inner nuclear membrane, together with accompanying modifications of pore complexes. © 1992 Wiley‐Liss, Inc.
Lymphatic vessels of the human dental pulp in different conditions
Authors: Marchetti C. , Poggi P. , Calligaro A. , Casasco A. 
Published: February 2005

AbstractThe characteristics of the lymphatic vessel endothelial wall have been investigated in human normal and inflamed dental pulps. In normal pulps the endothelial wall is characterized by the presence of micropinocytotic vesicles and intraparietal channels. In the inflamed pulpal tissue, where an increase in interstitial fluid pressure occurs, the distended endothelial wall presents open junctions between endothelial cells and the openings of the intraparietal channels. Moreover the micropinocytotic vesicles disappear. The cytoplasm of the endothelial cells is characterized by the presence of numerous Weibel‐Palade bodies, which increase in number in the dilated vessels. In the fibrillar apparatus surrounding the lymphatic vessel wall collagen fibrils are the prevalent component, while elastic fibers are not present.The different morphological properties of the lymphatic vessels are compared and discussed with regard to the variation of the functional conditions of the tissue. © 1992 Wiley‐Liss, Inc.
Tubule formation and elemental detection in developing opossum enamel
Authors: Stern Doris N. , Song Min J. , Landis William J. 
Published: February 2005

AbstractMost marsupials and some placental mammals possess enamel characterized by the presence of tubules, and the cellular origin of these structures has been the subject of a number of previous studies (See, for example, Lester, 1970; Azevedo and Goldberg, 1987). In the present report, tooth germs of the American opossum were examined to determine the structure and composition of enamel tubules during development and to analyze the enamel matrix relative to that of placental mammals with atubular enamel. For this purpose, tissues prepared by aqueous (decalcified and undecalcified) and anhydrous (undecalcified) methods were investigated by conventional transmission (TEM) and high voltage electron microscopy (HVEM), as well as by electron probe x‐ray microanalysis (EPMA), selected‐area electron diffraction (SAED), and electron spectroscopic imaging (ESI).Results indicate that most enamel tubules in the opossum begin as cytoplasmic remnants of Tomes' processes of ameloblasts. During development of the matrix, some of the tubules do not appear to be continuous throughout the prismatic layer. Sulfur is detectable around the lumen of the tubule in decalcified sections by EPMA and in and around the tubule by ESI. Calcium/phosphorus (Ca/P) molar ratios of the mineralizing matrix are generally higher than those found in enamel of other mammals and appear to decrease rather than increase with enamel maturation. The summary of data indicates the presence of sulfated glycoproteins or proteoglycans in this tissue, specifically around enamel tubules. Calcium and phosphorus are also present within the tubules, with the sulfated groups possibly binding calcium to prevent mineralization of the enamel tubules themselves. © 1992 Wiley‐Liss, Inc.
Reproduction in a South American mouse, Abrothrix longipilis
Authors: Pearson Oliver P. 
Published: February 2005

AbstractApproximately 700 Abrothrix longipilis were trapped in Argentina, and their reproductive organs were studied. Some were kept briefly in captivity. Males have the same body length as females but are 8% heavier. Sexually immature males are shorter and lighter than breeding males of the same age. Few individuals in the wild live as long as two years. All overwintering males come into breeding condition in the spring and become infertile in the autumn. All overwintering females have open vaginas in the spring, and most undergo several infertile ovulatory cyles, probably without copulating, before they become pregnant. Corpora lutea of the sterile cycles accumulate; there may be as many as 28 in a pair of ovaries. The average number of ova shed per cycle is 4.66; average litter size is 3.85. Ovulation is spontaneous. There is postpartum ovulation and fertilization without intervening sterile cycles but with maintenance of old corpora lutea.Unusual architecture of the penis and vagina may result from unusual timing of hormone production during development, and the disjunction of ovulation and fertilization may similarly result from hormonal heterochrony at the beginning of the breeding season. The apparently nonadaptive wastage of ova in sterile cycles may be a novel example of kin selection. © 1992 Wiley‐Liss, Inc.
Anatomy and developmental chronology of the rat inferior alveolar nerve
Authors: Johansson Carina S. , Hildebrand Claes , Povlsen Bo 
Published: February 2005

AbstractThis report describes the anatomy of the inferior alveolar neuroascular bundle in the adult rat and provides a quantitative analysis of the developing inferior alveolar nerve (IAN). Soon after its entrance in the mandibular canal, the IAN splits into a mental nerve (MN) and an inferior dental nerve (IDN), which course in separate bony compartments. The MN passes unbranched through the mandibular canal. The IDN sends branches to the incisor, the first molar, and the second molar. The third molar (M3) is supplied by a separate IAN branch. The adult rat IAN contains 8,000–10,000 axons, 70% of which are myelinated. The MN accounts for 70% of all IAN axons, the IDN 26%, and 4% form the M3 branch. The proportion of large myelinated axons is lower in the MN than in the IDN. Following chemical sympathectomy, the IAN axon number does not change in a statistically sigificant way. The total number of IAN axons, which is high prenatally and neonatally, has decreased to the adult level about 1 week after birth. De novo myelination commences at birth and is complete 3–4 weeks later. The size spectrum of the myelinated fibres is narrow and unimodal during the first postnatal weeks. By 1 month, the largest fibres reach diameters of ∼6 μm, and a bimodal pattern is emerging. From 3 months and on, the size range reaches up to 10–12 μm, and the distribution is bimodal. These data provide a basis for further studies on developmental tooth‐nerve interactions. © 1992 Wiley‐Liss, Inc.
Comparative study of sexual dimorphism of the innominate bone in rodents and amphibians
Authors: Uesugi Yasuo , Ohta Yasuhiko , Asashima Makoto , Iguchi Taisen 
Published: February 2005

AbstractSexual dimorphism in the shape of the innominate bone was demonstrated in the rat, mouse, Chinese hamster (Cricetulus griseus), frog (Ranna nigromaculata), and newt (Cynops pyrrhogaster) with a computer‐assisted morphometric technique. In the rat, mouse, and hamster, ratios of ischium and pubis widths to the innominate bone lenght (INL) were larger in the males than in the females; however, the ratio of pubis length to INL was larger in the females than in the males. In the frog, the ratio of distance between the upper edge of the acetabulum and the lower edge of the pubis to INL was larger in males than in females. In the newt, ratios of width of ischiopubis and the longitudinal length of the ischiopubis to INL were larger in females than in males.© Willey‐Liss, Inc.
Presence of pulmonary intravascular macrophages in the equine lung: Some structuro‐functional properties
Authors: Atwal Onkar S. , Singh Baljit , Staempfli Henry , Minhas Kanwaljit 
Published: February 2005

AbstractThe pulmonary intravascular macrophages (PIMs) have been described in several species of animals. This study demonstrates for the first time that the equine lung has PIMs as resident phagocytes in its microvasculature. Their salient features such as globular surface coat, structures of the endocytic pathway, and related cell organelles closely resemble those of the calf, goat, and sheep. The exquisite organization of the coat globules in the form of a linear chain was structurally similar to the lipolytic lipase and the heparin‐sensitive globular coat from PIMs of calf, goat, and sheep. Monastral blue (MB) when employed as a tracer to assess the phagocytic properties of equine PIMs induced similar modification of the globules of the coat into lipid droplets, reminiscent of neutral lipids. Lipid droplets (modified coat globules) were delivered into acid phosphatase‐positive endosomes and lysosomes. Concurrently, the unaltered globules of the coat, probably internalized via fluid‐phase constitutive pinocytoses, followed a different endocytic pathway. Large‐scale platelet uptake by the PIMs was observed with thrombocytopenia in MB‐treated ponies. The possible significance of hypothetical LDL‐coat and the endocytic organelles as equivalents of synthetic apparatus of vasoactive lipids in the PIMs of horse needs to be assessed in future studies.© Willey‐Liss, Inc.
Growth of the normal human lower urinary tract from 12 to 21 weeks gestation
Authors: Cutner Alfred , Moscoso Gonzalo , Cardozo Linda , Driver Marie , Cooper Derek 
Published: February 2005

AbstractNormal development of the human lower urinary tract was studied between the 14th and 20th week of gestation using 3 modes of fixation. Fixation by direct distension provides a high degree of reproducibility of parameters used to study the growth of the fetal bladder. Using this method, fetuses ranging from 12 to 21 weeks gestation were studied. Results obtained demonstrate that the length of the bladder, the inter‐ureteric distance, and the distance between the apex of the trigone and the distal tip of the urethra occur in a linear mode. Furthermore, the rate of growth of the male urethra was evidently higher when compared to that of the female from the 12th week of gestation.Data from this work can be used for a more accurate assessment of cases with abnormal lower urinary tract development.© Willey‐Liss, Inc.
Regulation of the 12‐o‐tetradecanoyl‐phorbol‐13‐acetate‐induced inhibition of intercellular communication
Authors: Murray Sandra A. , Plummer Howard K. , Leonard Edward E. , Deshmukh Pushpa 
Published: February 2005

AbstractEffects of the tumor promoter 12‐O‐tetradecanoyl‐phorbol‐13‐acetate (TPA) and protein kinase C (PKC) inhibitors on cell‐cell communication were studied in a normal rat liver cell line, clone 9. Communication was observed and quantitated with microspectrofluorometric and image analysis techniques following scrape‐loading of the cells with lucifer yellow. Lucifer yellow migrated as far as ten cells away from the scraped edge in control populations. Two minute TPA (25–50 μg/ml) treatment inhibited dye movement such that the dye remained mainly in the cells at the cut edge. The TPA‐induced inhibition of cell‐cell communication could be partially blocked by 15 min treatment of the cell populations with the PKC inhibitors trifluoperazine (30 μg/ml), staurosporine (2 × 10−8 or 2 × 10−6 M), sangivamycin (15 or 200 μM), or a PKC inhibitor peptide (20 μg/ml) scraped in at the same time as lucifer yellow. Normal communication was observed in cultures treated only with PKC inhibitors. Lower concentrations of TPA (50 ng/ml‐1 μg/ml) used for 2 min did not inhibit dye communication. Our results demonstrate the phorbol ester‐induced interruption of cell‐cell communication. The inhibition of PKC by inhibitors eliminates the effect of TPA on communication. Our data are consistent with a role of PKC in the control of junctional communication. © 1993 Wiley‐Liss, Inc.
Ectoplasmic (“junotional”) specializations in sertoli cells of the rooster and turtle: Evolutionary implications
Authors: Pfeiffer D. C. , Vogl A. W. 
Published: February 2005

AbstractEctoplasmic specializations are complex actin‐containing structures found at certain sites of intercellular attachment in Sertoli cells. Current evidence indicates that these structures are a form of actin‐associated adhesion junction. In the turtle (Pseudemys script) and rooster (Gallus domesticus)ectoplasmic specializations are known to occur adjacent to sites of attachment to elongate spermatids and are characterized by a layer of “loosely” cross‐linked actin filaments that lies next to the plasma membrane. In the turtle, a cistern of endoplasmic reticulum is associated with the cytoplasmic face of the filament layer. We have found that, in fixed frozen sections of turtle and rooster testes, immunological probes for myosin II react with epithelial regions that also stain with probes for filamentous actin and that are known to be sites at which ectoplasmic specializations occur. Furthermore, when exposed to standard contraction buffers, the diameters of glycerinated ectoplasmic specializations of the turtle are statistically smaller than those of the same structures exposed to control buffers. We interpret these smaller diameters as being produced by the contraction of actin bundles within the ectoplasmic specializations.Our results indicate that ectoplasmic speializations in the rooster and turtle, unlike those in mammals, possess contractile properties. We speculate that ectoplasmic specializations in eutherian mammals may have evolved from actin‐associated adhesion junctions in which the actin bundles were initially contractile and from which myosin II was secondarily lost. © 1993 Wiley‐Liss, Inc.
Rabbit ductus arteriosus during development: Anatomical structure and smooth muscle cell composition
Authors: Giuriato L. , Scatena M. , Chiavegato A. , Guidolin D. , Pauletto P. , Sartore S. 
Published: February 2005

AbstractThe anatomical structure as well as the smooth muscle cell (SMC1) composition of the ductus arteriosus (DA) were studied in rabbits ranging in age from 29 days of gestation to 20 days after birth. Computerassisted, three‐dimensional reconstructions of hematoxylin‐eosin stained serial cryosections from ductus arteriosus‐aorta (DA‐AO) junctures revealed that DA in animals near term is separated from the aorta by a “septumlike” structure that is continuous with the aortic wall. Two days after birth, obliteration of DA is almost complete, and a small “pocketlike” cavity appears in the pre‐existing site in which DA merged into the aorta. This small cavity in the aortic arch was still evident in the large majority of animals examined even 20 days after birth, as also demonstrated by scanning electron microscopy. At this time period DA consisted of a central, fibrotic region surrounded by several layers of SMC (the ligamentum arteriosum, LA) and ended within the aortic media just above the small cavity, forming a round “scar.”Vascular SMC composition of DA during closure was examined by means of indirect and double immunofluorescence procedures, using a panel of monoclonal antibodies against some cytoskeletal and cytocontractile proteins (vimentin, desmin, smooth muscle (SM), and nonmuscle (NM) myosinisoforms). “Intimal cushions” were particularly evident from 5 hr after birth and were found to be desmin‐negative, homogenously reactive for vimentin and NM myosin, and heterogeneously stained with anti‐SM myosin antibody. In SMC subjacent to the “intimal cushions,” distribution of vimentin and SM myosin was homogeneous, whereas the one of desmin and NM myosin content was heterogeneous. The cytoskeletal and cytocontractile protein content displayed by SMC during the closure of DA is similar to that of “intimal thickening” found in some pathological conditions of the arterial wall in adult rabbits. Completation of DA closure (day 2) was accompanied by the disappearance of cellular heterogeneity in myosin isoform distribution in both the “intimal cushions” and the underlying media. These results give new insights into: (1) the structure of DA‐AO juncture, which can be relevant to the physiology of blood circulation in the fetus, and (2) the phenotypic similarity of vascular SMC populations involved in the formation of “intimal cushions” and “intimal thickening”.
Morphometric analysis of the pelvis in mice treated neonatally with tamoxifen
Authors: Uesugi Yasuo , Sato Tomomi , Iguchi Taisen 
Published: February 2005

AbstractThe pelves of male and female C57BL/Tw mice given five daily injections of 100 μg tamoxifen, 50 μg dihydrotestosterone (DHT), or 2 μg diethylstibestrol (DES) from the day of birth were examined morphometrically and histomorphometrically. Total areas of the pelvis, ilium, ischium, and pubis were significantly smaller in neonatally tamoxifentreated mice than in the controls. There was no significant difference in length of the ischium between tamoxifen‐treated and control mice of both sexes. However, lengths of ilium and pubis, and widths of ilium, pubis, and ischium in tamoxifen‐treated male and female mice were significantly smaller than in the respective controls. In contrast, neonatal treatment with DHT or DES did not affect the shape of the pelvis of either sex. In the neonatally tamoxifen‐treated females, the number of osteoblasts and osteoclasts per 200 μm trabecular surface length and per 10,000 μm2 subperiosteal area of pubic bone section was smaller than in the controls. Inhibition of ossification persisted in the junction of the pubis and ischium of pelves treated with tamoxifen in vitro. These results suggest that neonatally administered tamoxifen mainly retards the growth of the ilium and pubis in mice by changing the activities of osteoclasts and osteoblasts, and that tamoxifen acts directly on the neonatal mouse pubis to inhibit its ossification. © 1993 Wiley‐Liss, Inc.
Sites of renin production in fetal, neonatal, and postnatal syrian hamster kidneys
Authors: Dodge Alice H. 
Published: February 2005

AbstractRenin is first observed in the 14‐day fetal kidney. There is a sharp increase in the number of renin positive cells in the 15‐day fetal kidney. Renin is located in the smooth muscle cells of arteriols, interlobular arteries, and branches of the renal artery. In the neonatal kidney, the amount of renin appears to be equal to that observed in the 15‐day fetal kidney and is still located in the same blood vessels. In the 24‐hour postnatal kidney, there is a sharp decrease in the total amount of renin. Renin positive cells are now observed at the vascular pole. In the 48‐hour postnatal kidney, there is a sharp increase in the total amount of renin. Most of the renin positive cells are located at the vascular poles; however, a few renin positive cells are seen in the interlobular arteries. © 1993 Wiley‐Liss, Inc.
Reduced surface area in mitotic rounding of human chang liver cells
Authors: Sit K. H. , Bay B. H. , Wong K. P. 
Published: February 2005

AbstractThe rounding up of mitotic human Chang liver cells in monolayer culture was studied quantitatively. It was surprising to find significant reduction in cell surface area considering that endocytosis has been demonstrated to be at a complete standstill in M phase. Uptake studies using impermeant BCECF (2′,7′‐bis(2‐carboxyethyl)‐4(5)‐carboxyfluorescein free acid) pH indicator and particulate neutral red dye in aqueous buffer showed preferential internalization into mitotic cells in direct contrast to expectation since interphase cells do not have arrested endocytosis. However, infolded plasma membrane ruffles and internalized extracellular material were demonstrated in prophase cells, much like those seen in interphase rounding via the induction of intracellular alkalinizations. Raised intracellular pH (pHi) is a universal and consistent finding in M phase cells. Despite cessation of small pit endocytosis, it remains possible for plasma membrane internalization to be a causal factor in the observed surface area reduction in mitotic rounding. © 1993 Wiley‐Liss, Inc.
Morphogenesis in the fetal rat proximal colon: Effects of cytochalasin D
Authors: Colony Pamela C. , Conforti Jeff C. 
Published: February 2005

AbstractTwo major morphogenetic events, epithelial conversion and fold formation, occur in the proximal rat colon during the last week of gestation. To evaluate the role of actin microfilaments in these two developmental processes, explants from the proximal colon of 19 day fetal rats were cultured in the presence of vehicle (0.1% dimethylsulfoxide), 0.1, 1.0, or 10 μg/ml of cytochalasin D (CD) for 24–48 hr. Explants as well as 19, 20, and 21 day in vivo controls were prepared for light, fluorescence, and electron microscopy. The distribution of actin filaments was determined by rhodamine‐conjugated phalloidin binding and ultrastructural analysis of tissue fixed in the presence of tannic acid. Prior to fold formation, phalloidin binding was enhanced along the entire epithelial‐mesenchymal interface. At the onset of fold formation, focal areas of intense fluorescence appeared at irregular intervals along the base of the stratified epithelium. Within 1 day, these focal intensities were localized at the apex of small forming folds. Additional changes occurring at the epithelial‐mesenchymal interface in association with fold formation included: (1) ruffling of the previously smooth basal lamina, (2) a shape change in the subjacent mesenchymal cells from elongate to cuboidal along with the appearance of numerous processes abutting the basal lamina, and (3) a unique orientation of the associated collagen fibrils in some presumptive folds. Fold formation was inhibited in > 93% of explants cultured in the presence of 1.0 μ g/ml CD. These explants appeared to be arrested precisely at the onset of fold formation. Epithelial conversion was also incomplete in these explants. These findings indicate an active role for actin in both fold formation and epithelial conversion. © 1993 Wiley‐Liss, Inc.