bluuebunny/crossref_metadata_2025_split huggingface dataset:
Implantation, development of the fetal membranes, and placentation in the captive black mastiff bat, Molossus ater
Authors: Rasweiler John J. 
Published: February 2005

AbstractUterine events during pregnancy were examined histologically in laboratorybred black mastiff bats (Molossus ater) as part of an effort to develop this species as a model for studies of the factors controlling trophoblastic growth.Embryos entered the uterus at the morula stage and in most cases shed their zonae pellucidae reasonably intact, apparently as blastocyst expansion occurred. Implantation was superficial and observed to occur only in the right uterine horn. During implantation the trophoblast was brought into apposition to the endometrium by both blastocyst expansion and closure of the uterine lumen. A decidual reaction was evident at an early stage of uterine epithelial displacement and spread rapidly through the endometrium. Initial trophoblastic proliferation occurred along the uterine lumen and into the glands, while its invasion of the endometrial stroma was delayed.Although one or several primordial cavities have been observed to develop within the epiblast during implantation, these subsequently opened to a trophoepiblastic cavity, and the definitive amnion was formed by folding.A choriovitelline placenta was present briefly at the somite stage, but disappeared as the exocoelom enlarged and the yolk sac collapsed. The latter persisted through pregnancy, however, as a glandular‐appearing body. As the yolk sac retracted from the chorion, it was replaced by allantoic mesoderm, creating a diffuse labyrinthine endotheliodichorial placenta. This was prominent during mid‐gestation, but was supplanted by the discoidal hemochorial placenta as the major site of feto‐maternal exchange during late pregnancy.
Variations in immunoreactivity of angiotensinogen and cathepsins B and H in rat hepatocytes over 24 hours
Authors: Waguri Satoshi , Watanabe Tsuyoshi , Kominami Eiki , Uchiyama Yasuo 
Published: February 2005

AbstractTo examine variations in immunoreactivity of angiotensinogen and cathepsins B and H in hepatocytes over 24 hr, rat liver was examined immunohistochemically. Immunoreactivity of angiotensinogen and cathepsins B and H in periportal and perivenous hepatocytes varied significantly over 24 hr, when analyzed by an image analyzer. In periportal and perivenous hepatocytes, immunoreactivity of angiotensinogen was highest at 0800 hr and lowest at 2000 hr or 0000 hr, whereas that of cathepsins B and H was maximal at 1600 hr and minimal at 0400 hr or 0800 hr. Proteolytic activities of cathepsins B and H in liver extracts varied in parallel to the variations in immunoreactivity of these enzymes. Localization of angiotensinogen in the liver acinus was inversely correlated to that of cathepsins B and H; angiotensinogen was predominantly localized in periportal hepatocytes, but cathepsins B and H were in perivenous hepatocytes at each time point examined. These results suggest that angiotensinogen in hepatocytes is actively synthesized and secreted early in the light period, whereas proteolytic activities in lysosomes of hepatocytes are augmented late in the light period.
Effect of indomethacin and prostaglandin E2 on structural differentiation of rat endometrium during artificially induced decidualization
Authors: Keys J. L. , Kennedy T. G. 
Published: February 2005

AbstractMorphological differentiation of uterine stromal and luminal epithelial cells was studied in steroid‐injected ovariectomized rats following unilateral intrauterine instillation of sesame oil, phosphate‐buffered saline containing gelatin (PBSG), PBSG + indomethacin (IM; an inhibitor of prostaglandin synthesis), or PBSG + IM + prostaglandin E2 (PGE2). The latter two treatments were preceded by a subcutaneous injection of IM. Uteri were examined by light and electron microscopy at intervals between 8 and 120 hr (n = 4/treatment/time). Differentiation began in the periluminal antimesometrial region and progressed peripherally and towards the mesometrial aspect in all groups. Structural features and timing of differentiation were similar for oil‐injected and PBSG‐infused uteri. Administration of IM inhibited the onset of the decidual cell reaction and had deleterious effects on the luminal epithelium. Inclusion of PGE2 in the instillate accelerated stromal cell differentiation and overcame the inhibitory effects of IM. The results implicate prostaglandins, particularly PGE2, in endometrial transformation during decidualization.
N‐cadherin transcripts in Xenopus laevis from early tailbud to tadpole
Authors: Simonneau Lionel , Broders Florence , Thiery Jean‐Paul 
Published: February 2005

AbstractCadherins are Ca++ ‐dependent cell adhesion molecules which play a key role in morphogenesis and histogenesis. Two mRNAs clones (8 and 9) corresponding to two N‐cadherin pseudo‐allelic genes are present in Xenopus laevis. We report here that these transcripts share a highly homologous coding region but diverge in the non‐coding region. We have determined the pattern of N‐cadherin expression at the mRNA level by in situ hybridization with a riboprobe complementary to the EC5 domain of Xenopus N‐cadherin clone 8. This part of the sequence is the least conserved in the cadherin gene family, minimizing the risk of cross‐hybridization to other cadherins. N‐cadherin transcripts are not detectable in the first stages of development. Expression first appears in the neural plate and reaches its maximum level in the CNS at tailbud stage. From early tadpole, it diminishes, so that a very weak signal is detected in the premetamorphic frog brain. N‐cadherin expression is not uniform within the CNS, with some areas such as the roof of the rhombencephalon and the olfactory bulbs expressing higher levels of the transcripts. N‐cadherin is present in several mesodermal derivatives such as the notochord, the pronephros, and the heart. It is, however, virtually absent from the myotomes and appears in skeletal muscles at later stages of differentiation. All placodes express high levels of N‐cadherin. The non‐neural ectoderm and the endoderm are always negative. In the brain and the heart, high levels of hybridization are observed with probes corresponding to both copies of the N‐cadherin pseudo‐allelic genes in their 5′ non‐coding region, indicating that both alleles are transcribed. © 1992 Wiley‐Liss, Inc.
Optic chiasm and infundibular decussation sites in the developing rat diencephalon are defined by Glial Raphes expressing p35 (Lipocortin 1, Annexin I)
Authors: McKanna James A. 
Published: February 2005

Abstractp35, a Ca++‐phospholipid‐binding protein that serves as a substrate for the EGF receptor tyrosine kinase, is expressed by primitive glial ependymal cells to define a raphe occupying the ventral midline in the spinal cord and hindbrain of rat embryos (McKanna and Cohen, Science 243:1477–1479, 1989). p35 appears transiently in the median one‐third (80 μ) of the floor plate at precisely the time and place where axons cross to form the ventral commissure. We postulated that if p35 is involved with commissure development, homologous p35 raphes might be found at decussation sites rostral to the floor plate, including the optic chiasm. The present report describes two developmentally regulated p35 raphes in the diencephalon. One raphe is present for 2–3 days at the rostral lip of the nascent infundibulum, the reported decussation site of axons running from the supraoptic nucleus to the neurohypophysis; the other raphe appears in the rostral two‐thirds of the optic chiasm, the site traversed by the optic axons. p35 is never expressed in the caudal one‐third of the chiasm that accommodates non‐retinal axons. To the best of our knowledge, this is the first identification of a specific marker for the retinal component of the optic chiasm. Because the p35 is gone by embryonic day 18.5, it is absent during final stages of chiasm formation when axons from the temporal retina decussate. Thus, p35 also may contribute to the “barrier” perceived by fibers that remain ipsilateral. Our data suggest that the p35 raphe contributes to the midline's role in commisure morphogenesis. Putative lipocortin activities including regulating PLA2, eicosanoids, or intracellular Ca++ could be involved in altering cue specificity as decussating axon growth cones traverse the p35 compartment. © 1992 Wiley‐Liss, Inc.
Chicken tibial dyschondroplasia: A limb mutant with two growth plates and possible defects of collagen crosslinking
Authors: Chen Qian , Gibney Eileen P. , Leach Roland M. , Linsenmayer Thomas F. 
Published: February 2005

AbstractIn the cartilaginous epiphyseal growth plate, extracellular matrix molecules such as collagens are believed to play important roles during both normal and abnormal development. One defect of the epiphyseal plate occurs in chickens with a condition termed tibial dyschondroplasia (TD). This abnormality occurs in certain strains of juvenile chickens and other rapidly developing animals. It is characterized by the presence of a mass of avascular, uncalcified cartilage which is retained in the proximal metaphysis of the tibiotarsus. To elucidate the developmental events which may be involved in this lesion, we have performed both immunohistochemistry and in situ hybridizations for collagen types II and X, known components of the extracellular matrix of the growth plate. By immunohistochemical analyses, the TD lesion contains both of these collagen types; therefore, the presence of these molecules per se is not sufficient for calcification of vascularization to occur. Since type X collagen is expressed exclusively in hypertrophic cartilage, the chondrocytes in the lesion must have undergone hypertrophy before their developmental arrest. The matrix of the lesion also reacted with a monoclonal antibody which is directed against an epitope in the NH2‐terminal telopeptide of the α1(II) chain. Our previous data suggest that this epitope is rendered unavailable in type II collagen which has undergone crosslink formation; its availability in the lesion suggests that crosslinking may be abnormal. Lastly, analyses by in situ hybridization failed to detect mRNA for either type II or type X collagen within the lesion, but chondrocytes distal to the lesion do contain mRNAs for these collagens in a spatial pattern suggesting the presence of a second growth plate. © 1993 wiley‐Liss, Inc.
Molecular markers of differentiation in Caenorhabditis elegans obtained by promoter trapping
Authors: Young Jane M. , Hope Ian A. 
Published: February 2005

AbstractDifferentiation of specific cell types during animal development can be detected by monitoring expression of appropriate genes. For this study, six different β‐galactosidase expression patterns which can be used as differentiation markers in the nematode Caenorhabditis elegans are described. An earlier promoter trap screen identified pools of recombinant plasmids which gave patterns of β‐galactosidase expression when used to transform C. elegans. Each recombinant plasmid contained a random fragment of C. elegans genomic DNA fused upstream of a promoterless lacZ gene. Six of these pools were chosen, and individual pattern‐producing plasmids within these pools were identified. The expression patterns have been characterized more thoroughly than in the original screen, thereby providing molecular markers for differentiation of several cell types. Many of the expression patterns involve more than one cell type. The genomic origin of the inserts of active plasmids were determined through localization on the physical genome map. © 1993 wiley‐Liss, Inc.
Localisation of transforming growth factor beta 1 in developing muscles: Implications for connective tissue and fiber type pattern formation
Authors: McLennan Ian S. 
Published: February 2005

AbstractSkeletal muscles are highly ordered mixtures of cell types, with each muscle having its own characteristic pattern of fiber types, connective tissues, and vasculature. The precursors of the myogenic and connective elements of a muscle are initially intermixed and are proliferating and differentiating together in a manner that generates an ordered array of mature cells. The molecular basis of myogenesis is unknown, although in vitro studies have revealed numerous putative regulators. The results obtained from in vitro studies are not easily related to in vivo myogenesis because of a lack of information about the localisation of the putative regulators in developing muscles. The objective of this paper was therefore to describe the spatial and temporal distribution of transforming growth factor beta 1 (TGF‐β1), a small peptide that affects cultured fibroblasts, myoblasts, and vascular endothelial cells. TGF‐β1‐immunoreactivity was associated with the epimysia, perimysia, and vasculature of the developing muscles. The expression of TGF‐β1 within developing muscles had a distinct spatial and temporal pattern that correlated with the fate of adjacent myotubes. Myotubes which formed prior to the expression of TGF‐β1 developed into slow fibers whereas those which formed adjacent to TGF‐β1‐containing connective tissue matured into fast fibers. The possibility that TGF‐β1 is involved in the generation of the pattern of epi‐ and perimysia and/or fiber types is discussed. © 1993 Wiley‐Liss, Inc.
Second messenger regulation of occlusion of the spinal neurocoel in the chick embryo
Authors: Desmond Mary E. , Duzy Michael J. , Federici Benigno D. 
Published: February 2005

AbstractWe know that, once rostral neurulation is completed in the neuroaxis of the chick embryo, the caudal neurocoel becomes occluded and the brain rapidly expands. However, very little is known about the mechanisms maintaining occlusion. Studies had shown that occluded neurocoels reopened in embryos treated with chelators of cations, but the reasons remained unclear and the cations unidentified. To begin defining the role of cations, this study explored the effect of Ca2+, calmodulin, and cAMP on maintaining the occluded neurocoel. Chick embryos during the natural phase of neurocoel occlusion (stage 12) were cultured in vitro with drugs known to modulate Ca2+ transport, to inhibit calmodulin activity, or to elevate cAMP levels. To test if occlusion is a Ca2+ ‐dependent process, embryos were treated with verapamil and ionophore A23187. To test if occlusion requires calmodulin, embryos were treated with antipsychotic agents. To test if occlusion is cAMP dependent, embryos were treated with methylisobutylxanthine (MIX), forskolin (FOR), or dibutyl cyclic adenosine (DbC). Following each treatment, occlusion of the neurocoel was tested by injecting dye into the midbrain. All treatments resulted in a predominant number of precocious reopenings of the occluded neurocoels. MIX‐treated, naked neural tubes had a fourfold increase in cAMP, whereas FOR‐ and DbC‐treated neural tubes showed ten‐ and 14‐fold increases, respectively. The presence of calmodulin in the cells of the neural tube was confirmed by fluorescent tagging and 3H‐chlorpromazine labelling. The combined results of this study show that occlusion of the spinal neurocoel depends on exogenous Ca2+, requires calmodulin, and is cAMP sensitive. © 1993 Wiley‐Liss, Inc.
Raphe of the posterior neural tube in the chick embryo: Its closure and reopening as studied in living embryos with a high definition light microscope
Authors: van Straaten H. W. M. , Jaskoll T. , Rousseau A. M. J. , Terwindt‐Rouwenhorst E. A. W. , Greenberg G. , Shankar K. , Melnick M. 
Published: February 2005

AbstractChick embryos cultured on a curved substratum show a transient enlargement of the posterior neuropore (PN), mimicking the temporary delay of PN closure as seen in the curly tail (ct) mouse mutant (van Straaten et al. [1993] Development 117:1163–1172). In the present study the PN enlargement in the chick embryo was investigated further with a high definition light microscope (HDmic), allowing high resolution viewing of living embryos in vitro. The temporary PN enlargement appeared due to considerable reopening of the raphe of the posterior neural tube, which was followed by reclosure after several hours. The raphe was subsequently studied in detail. It appeared very irregular, with small zones of apposed, open and fused neural folds. During closure, these raphe features shifted posteriorly. A distinct fusion sequence between surface epithelium and neuroepithelium was not seen. During experimental reopeining of the raphe in vitro, small bridges temporarily arose, broke and disapeared quickly; they likely represented the first adhesion sites between the neural folds. More prominent adhesion sites partly detached, resulting in bridging filopodia‐like connections; they probably represented the first anteroposterior locations of neural fold fusion. Our observations in the living chick embryo in vitro thus show that the caudal neural tube has an irregular raphe with few adhesion sites, which can be readily reopened. As a result of the irregularity, the PN does not close zipper‐like, but button‐like by forming multiple closure sites. © 1993 Wiley‐Liss, Inc.
Retinoic acid induced heparin‐binding protein expression and localization during gastrulation, neurulation, and organogenesis
Authors: Cockshutt Amanda M. , Jonet Laurent , Jeanny Jean‐Claude , Vigny Marc , Raulais Daniel 
Published: February 2005

AbstractRetinoic acid induced heparin‐binding protein (RIHB) is a highly basic, soluble polypeptide of the chick embryonic extracellular matrix. We have examined the expression and localization of RIHB during very early embryogenesis by in situ hybridization and immunohistochemistry. RIHB mRNA is very weakly detectable above background in the blastodiscs of unincubated eggs. The expression increases greatly over the first 24 hours of incubation, and is observed throughout the blastodisc in all three of the germ layers following gastrulation. As neurulation occurs, the expression becomes more restricted to certain areas, notably the ectoderm, the neural folds, and especially the notochord. After the neural tube has formed the expression in the tube itself decreases dramatically, whereas the expression in the head ectoderm and the notochord persists. After 72 hours of incubation expression remains relatively high throughout most of the embryo, with higher levels of expression in regions undergoing organogenesis and lower levels in organs which have already differentiated. RIHB protein is also weakly detectable in unincubated eggs as patches of immunoreactive material between the blastodisc and the vitelline. After 6 hours of incubation small regions of basement membrane are immunoreactive. RIHB is detected in this matrix, apparently before even fibronectin. The amount of RIHB protein increases dramatically over the first 24 hours of incubation. It is found in basement membrane separating the epiblast from the hypoblast, then later in that separating the ectoderm from the mesoderm. It is also detected surrounding individual cells, especially of the ectodermal layer. During neurulation RIHB is observed in the basement membrane surrounding the neural fold and the notochord, and in the lamina separating the ectodermal, mesodermal, and endodermal layers. Later in development, RIHB is detected in the basement membrane under the epidermis, throughout the developing limbs, and in the lamina of various developing organs, such as the eye, the pulmonary bud, the intestine, and the mesonephros. These results demonstrate that RIHB is highly expressed during the early embryonic period, by all three germ layers, and is an important and very early component of the embryonic extracellular matrix. Its very broad expression and localization argue for a more general role in development than its demonstrated weak neurotrophic activity. © 1994 Wiley‐Liss, Inc.
The arterial supply and venous drainage of the bones of the human knee joint
Authors: Crock Henry V. 
Published: February 2005

AbstractThis paper is based on a study of bones from fifty‐five (55) knee joints, ages ranging from newborn to ninety (90) years. Full details of techniques of specimen injection and preparation are given.The gross arterial and venous patterns in adult bones are identical with the patterns present within these structures which are largely cartilaginous at birth.The lower end of the femur is penetrated by radiate epiphyseal arteries around its circumference. These terminate in sinusoidal capillaries within the cartilage, the corresponding veins leaving along the lines of entry of the radiate arteries. No anastomoses exist between adjacent intracartilaginous vessels, their distribution in the epiphysis being segmental. The lateral superior genicular radiate epiphyseal arteries, for example, supply a relatively fixed segment of the lateral femoral condyle. This arrangement no longer exists when the ossific center extends to involve the sinusoidal tips of more and more vessels, effective anastomoses eventually developing between all vessels supplying the lower end of the femur.Analagous findings are reported in the tibia.The patella is penetrated at its center and lower pole by nutrient arteries.In adult bones a subarticular collecting vein system is orientated parallel to articular surfaces. Short venous stems of subchondral capillary loops drain into these subarticular collecting veins which then drain off at articular margins into tributaries of the main veins. These are original findings.
Effects of testosterone on histochemical reactions of epithelium of hamster ductus epididymidis and seminal vesicle
Authors: Gohary M. El , Cavazos L. F. , Manning J. P. 
Published: February 2005

AbstractHistochemical changes in hamster epididymides and seminal vesicles were studied in non‐treated controls; non‐treated castrates allowed to live for 2, 5, 10 and 20 days after gonadectomy; castrates injected daily with graded doses of testosterone propionate for 20 days (0, 50, 100, 150, 300 and 400 μg); and castrates receiving 150 μg testosterone propionate for 2, 5, 10 and 20 days. Histochemical procedures included the periodic acid‐Schiff method, toluidine blue, Sudan black B and oil red O techniques and a phospholipid procedure. In addition, statistical methods were used to evaluate seminal vesicle response.The histochemistry of the hamster epididymis and seminal vesicle is similar to that described for the rat, mouse and rabbit. The rapid regression of the epididymal epithelium is also comparable to that reported in the rat. In contrast, the major alteration in the seminal vesicle following castration is associated with loss of secretion and not epithelial involution. Increased cellular pigmentation in the gonadectomized hamster seminal vesicle rather than cellular atrophy may be a more accurate index of the level of circulating androgen.
The brachiocephalic artery in the dog with special reference to the arterial supply of the esophagus
Authors: Jarvis J. F. , Nell Annette M. H. 
Published: February 2005

AbstractTwo direct branches of the brachiocephalic artery are frequently present in the dog. These are described in 33 dogs and their incidence recorded. One supplies the lower cervical trachea and esophagus and the other the thymus gland and sometimes the pericardium. Suggested names are “Tracheoesophageal” and “Thymopericardial” branches of the brachiocephalic. The embryology of the blood vessels of the esophagus is discussed and the identification of the tracheoesophageal with a secondary anastomotic vessel is considered most likely. Occasional branches from the brachiocephalic artery in man are reviewed. The Arteria Thyroidea Ima seems to bear the closest relationship to this vessel described in the dog. The value of this study in relation to heart‐lung preparations and to experimental surgery of the esophagus is suggested.