bluuebunny/crossref_metadata_2025_split huggingface dataset:
Embryonic development of the posterolateral structures of the knee
Authors: Oransky Michel , Canero Gianfranco , Maiotti Marco 
Published: February 2005

AbstractThe development of the structures in the posterolateral corner of the knee was studied in fifteen human embryos and seventeen fetuses by means of serial sections in the coronal and sagittal planes. The attachments of the lateral meniscus and fibular head to the popliteal tendon and muscle are formed during the process of cavitation that forms the bursa. The connection between the tendon and the posterior border of the lateral meniscus forms obliquely to follow the direction of the muscle and tendon. The edge of the bursa is limited by attachments that connect the tendon to the lateral meniscus and fibular head. In this study, no direct ligamentous continuity was found to exist between the posterolateral femur and tibia during development. The only ligament that indirectly connects the lateral femur posteriorly to the proximal segment of the tibia, which has never been reported in human development, is the one that links the popliteal tendon to the fibular head. We have designated this the popliteo fibular ligament which was also found in adult specimens. This ligament should not be confused with the arcuate popliteal ligament.
Ultrastructure of the myocardium of the least shrew, Cryptotis parva say
Authors: Forbes M. S. , Mock O. B. , Van Niel E. E. 
Published: February 2005

AbstractThe heart of the least shrew, Cryptotis parva Say, is an extremely active organ, capable of achieving rates of 800—1,200 beats/minute. The general features of myocardial cell ultrastructure in this insectivore are much like those of other small mammals; no single striking feature of fine structure is present to which the physiological properties of this heart might necessarily be attributed. Still there exist in these myocardial cells a number of atypical properties. These include (1) mitochondria having a wide variety of sizes and internal configurations (2) a pleiomorphic, highly ramified, small‐diameter transverse‐axial tubular system (TATS) (3) numerous “labyrinths,” which are proliferated components of the TATS, and (4) myofibril‐free regions, located both in juxtanuclear and other myoplasmic levels and populated by a concentration of TATS elements and fibrillar structures. Features (2) and (3) are also characteristic of another fast‐beating heart, that of the mouse. The sinoatrial and atrioventricular nodal regions, as well as a Purkinje system, have been identified in the least shrew heart, along with sparsely distributed atrial cells whose myofibrils contain proliferated Z‐band material. A feature frequently encountered in atrial working muscle cells is the occurrence of close appositions between gap junctions and tubules of sarcoplasmic reticulum; such appositions are also present in other regions of the shrew heart, as are complexes composed of gap junctions and mitochondria.
Case with a high‐positioned origin of the testicular artery
Authors: Shinohara Harumichi , Nakatani Toshio , Fukuo Yoshifumi , Morisawa Satoshi , Matsuda Takeshi 
Published: February 2005

AbstractIn a Japanese male, the left testicular artery originated from the aorta as high as 1 cm cranial to the origin of the left inferior phrenic artery. The testicular artery emitted two branches, one to the costal part of the diaphragm and the other to the suprarenal gland. This testicular artery is the most highly positioned one that has ever been reported.
Patterns of skeletal histologic change through time: Comparison of an archaic native american population with modern populations
Authors: Burr David B. , Ruff Christopher B. , Thompson David D. 
Published: February 2005

AbstractThis paper compares patterns of histologic change in an archaic Native American population with those in modern white populations. Histologic sections were removed from core biopsies taken from the anterior femoral cortex of an archeologic sample of Pecos Indians. The data demonstrate many microstructural similarities between the Pecos and modern populations, even though they were genetically and culturally distinct. Pecos women had small Haversian canals and large osteon mean wall thickness, with no clear evidence of an intracortical bone volume deficit even in the older age groups, although significant marrow cavity expansion occurred in both males and females with age. No striking relationships were found between bone tissue changes and gross geometric changes with age. The data suggest that a more active life‐style is associated with greater osteon mean wall thickness or osteon population density, but that it alone does not protect against significant bone loss on the cortical‐endosteal surface.
Neuronal regulation of substrate cycle between glucose 6‐phosphate and glucose in brown adipose tissues of cold‐exposed mice
Authors: Suzuki Hiroshi , Watanabe Jun , Itani Tsuyoshi , Ogawa Ryokei , Kanamura Shinsuke 
Published: February 2005

AbstractThe increase in both glucose 6‐phosphatase and hexokinase activities in brown adipose tissues of cold‐exposed mice probably relates to thermogenesis by the substrate cycle between glucose 6‐phosphate and glucose (Watanabe et al.: Anatomical Record 219:39—44, 1987). To clarify the factors causing the simultaneous increase, we examined biochemically the effects of uni‐ or bilateral surgical denervation of brown adipose tissues, of adrenalectomy, or of streptozotocin injection on the increase in the two activities in the tissues of cold‐exposed mice. Further, the effects of denervation on the increase were also examined histochemically. The simultaneous increase in the two activities was inhibited in the denervated tissues of cold‐exposed animals in biochemical and histochemical experiments. However, the increase in the activities was not inhibited in the tissues of animals exposed to cold after adrenalectomy or streptozotocin injection. The results suggest strongly that the activation of the substrate cycle in brown adipose tissues of cold‐exposed mice is caused by a transmitter released from sympathetic nerve endings, probably norepinephrine.
Endorphin suppresses FSH‐stimulated proliferation of isolated neonatal sertoli cells by a pertussis toxin‐sensitive mechanism
Authors: Orth Joanne M. , Boehm Rosemarie 
Published: February 2005

AbstractDuring perinatal development, when the size of the Sertoli cell population is determined, Leydig cells produce β‐endorphin, a peptide which may interact with Sertoli cells to modify their FSH‐responsiveness, as suggested by our previous work. The goal of the present study was first, to test directly the possibility that β‐endorphin modifies the proliferative response of neonatal Sertoli cells to FSH, and second, to gain information on a mechanism(s) involved in any observed effect. We treated isolated 6‐day‐old Sertoli cells with FSH or vehicle in vitro and measured their incorporation of exogenous, radiolabeled thymidine with quantitative autoradiography. After 2 days in culture with FSH, we detected a 10‐fold increase in the rate of Sertoli cell proliferation. The level of cell division in these FSH‐treated cultures was identical to that in other cultures exposed to cAMP under similar conditions. In addition, inclusion of β‐endorphin 3 hr prior to FSH or cAMP decreased the effect of the hormone by 50% but left the cAMP response unchanged. Thus, β‐endorphin acts on isolated, neonatal Sertoli cells at a point prior to intracellular production of cAMP to suppress their response to FSH. When other cultures were treated with pertussis toxin, a blocker of intracellular GTP‐binding proteins such as Gi, before sequential addition of endorphin and FSH, the effect of β‐endorphin on FSH‐responsiveness was abolished. Moreover, when other cultures were exposed to pertussis toxin in the absence of endorphin, followed by FSH, their response to the hormone was unchanged. Thus, β‐endorphin apparently modifies the proliferative response of neonatal Sertoli cells to FSH via a mechanism involving one or more G proteins. These observations, along with our previous data showing enhanced Sertoli cell division in vivo in the presence of an opiate blocker, point to the existence of endorphin‐mediated communication between Leydig and Sertoli cells during perinatal development and provide new evidence suggesting that paracrine mechanisms modify Sertoli cell function during perinatal development, when the size of this population is established.
Impaired elastic matrix development in the great arteries after ablation of the cardiac neural crest
Authors: Rosenquist Thomas H. , Beall Arthur C. , Módis Lászlo , Fishman Richard 
Published: February 2005

AbstractThe cells that form the aorticopulmonary septum in the avian embryo have been shown to be similar to the cells that form the walls of the great vessels in two ways: both are derived from the cardiac neural crest and both are able to synthesize an elastogenic matrix in the early embryo. Because of these similarities, and because ablation of the cardiac neural crest causes congenital defects of the outflow tract that are related to failure of proper septation, it was hypothesized that such an ablation also would cause the walls of the great vessels to be defective. The purpose of this study was to compare the elastic matrix in the mediae of the great vessels of normal embryos with those from which the cardiac neural crest had been ablated.The results show that the elastic matrix in the great vessels of the experimental embryos was impaired (1) in the rate of downstream propagation of the initiation of elastogenesis among younger embryos, incubation days 4–8 and (2) in the spatial configuration of the elastic matrix among the older embryos, incubation days 16–20.These results may provide a biological explanation for the elastin defect that affects the pulmonary artery of many patients with cyanotic congenital heart defects.
Changes in mesenchymal cell and hyaluronate distribution correlate with in vivo elevation of the mouse mesencephalic neural folds
Authors: Morris‐Wiman Joyce , Brinkley Linda L. 
Published: February 2005

AbstractThe mesenchyme of the elevating mesencephalic neural folds of the mouse is composed primarily of mesenchymal cells embedded in an hyaluronate‐rich extracellular matrix. In this study we provide evidence that hyaluronate and mesenchymal expansion may play a role in neural fold elevation and closure. Spatial and temporal patterns of mesenchymal cell and hyaluronate distribution were analyzed during neural fold elevation and closure using the computer‐assisted method of smoothed spatial averaging and established methods of image processing. Degree of fold elevation and fold shape changes were analyzed using standard morphometric measures. The results of these analyses defined five distinct stages in mesencephalic neural fold elevation and closure. Mesenchymal cells and hyaluronate were found in a non‐random distribution within the neural fold and showed distinct patterns of distribution which could be correlated with specific stages in neural fold elevation. The results of these analyses suggested that the elevation of the mesencephalic neural folds is produced by the expansion of an hyaluronate‐rich extracellular matrix in the central mesenchyme which under the direction of surrounding tissues pushes the folds mediad towards the dorsal midline.
Skeletal structural adaptations to mechanical usage (SATMU): 3. The hyaline cartilage modeling problem
Authors: Frost H. M. 
Published: February 2005

AbstractA chondral growth/force response curve predicts how intact hyaline cartilage plates grow in vivo under typical peak mechanical unit loads and gradients thereof in healthy immature mammals. Growth under tension would increase as tension rises from zero to a level that damages the tissue. Under compression, growth would increase as the load rises from zero to a level at which growth becomes maximal (the growth‐ascending limb of the curve). Further increases in compression loads retard growth and large enough increases can stop it entirely (the growth‐descending limb of the curve). For equal changes in loads, the smallest growth change would occur under tension; the largest change would occur on the growth‐descending part of the curve. Under zero load a respectable “baseline growth” still occurs. Those effects are superimposed on inherent differences in growth potential of different chondral plates, differences that are determined partly in utero and by the genome.The curve's features can explain many anatomical facts, including the ball‐and‐socket ankle, joint alignment in the valgus‐varus sense, hip dislocations in spasticity, different epiphyseal heights, short bones in paralysed limbs, long bone overgrowth after fractures, why some joint surfaces remain concave and others convex throughout growth, and why some growth plates are domed instead of flat. The above phenomena can be expressed mathematically, and a phenomenologic basic logical framework for doing that is suggested.
Melano‐macrophage centers in the aglomerular kidney of the sea horse (Teleosts): Morphologic studies on its formation and possible function
Authors: Tsujii Tadashi , Seno Satimaru 
Published: February 2005

AbstractIn order to elucidate the process of the formation and possible function of the renal “melano‐macrophage centers (MMC)” of fish, light and electron microscopic observations were carried out on the aglomerular kidney of the sea horse, Hippocampus kuda BLEEKER, injected with antigenic horse‐spleen ferritin (AF) and nonantigenic carbon particles (CP). Kidneys of the sea horse have well‐developed hemopoietic foci in the interstitial tissues surrounding the bundles of renal tubules. Each hemopoietic focus has a small artery in the central area and is framed with the densely arranged sinusoids lined with monolayered macrophages which have no melanin pigments. In the hemopoietic foci free macrophages (Mϕ) were hardly found, but large clusters or MMC filled with densely packed masses of cell debris with some melanin pigments were encountered. Some of them had degenerated Mϕ with fibrotic change surrounded by fibroblasts. AF and CP injected intraperitoneally entered quickly into blood vessels and were taken up actively by the sinusoidal Mϕ. The Mϕ full of AF or CP left the sinusoidal wall and moved gradually into hemopoietic foci to form the MMC or to fuse with the preexisting MMC. The melanophores in the interstitial connective tissue joined to form the MMC. No specific histologic change suggestive of immune response to the AF was present in and around the MMC. The results indicate that the MMC of fish should be only the aggregates of Mϕ to digest the ingested materials effectively. The process of formation of MMC and their possible function is discussed.
Sites of endometrial vascular leakage during implantation in the rabbit
Authors: Hoffman Loren H. , Winfrey Virginia P. , Hoos Paula C. 
Published: February 2005

AbstractVascular labelling with carbon suspension was used to identify endometrial vessels demonstrating macromolecular leakage at implantation sites in the rabbit. Extravasation was seen first in venous components of the deep endometrial stroma on the mesometrial aspect of implantation sites. Carbon labelling was apparent in such vessels at 7 d, 0 hr post coitum, (p.c.), and was attributed to gap formation between endothelial cells. Later in the implantation process, leakage was seen as microextravasations of carbon in the lateral and antimesometrial walls of implantation chambers. Here, penetration of vessels by trophoblast was apparent and membranous processes from the trophoblast projected into vessel lumina. Extravasated material (carbon, platelets) was localized to a labyrinthine system of membranes within the trophoblast, and a potential role for the labyrinth in handling of ingested plasma constituents is discussed. A similar process of trophoblastic penetration of vessels occurred on the mesometrial aspect of implantation sites several hours later. Systemic administration of the anti‐inflammatory agent indomethacin blocked vascular leakage due to endothelial gap formation but had little or no effect on trophoblast knob penetration of vessels. This observation may explain the results of previous studies in which treatment with anti‐inflammatory agents reduced, but could not inhibit completely, the vascular permeability changes at implantation sites.
Development of the conducting airway epithelium in fetal Syrian golden hamsters during normal and diabetic pregancies
Authors: McDowell Elizabeth M. , Coleman William P. , De Santi Andrea M. , Newkirk Carnell , Strum Judy M. 
Published: February 2005

AbstractThe conducting airway epithelium of fetal Syrian golden hamsters was studied from gestational day 12 to day 15, during normal and uncontrolled diabetic pregnancies. Diabetes was induced in the pregnant hamsters by injecting streptozotocin at 60 mg/kg body weight, subcutaneously, early on gestational day 10. Cells in S‐phase were labelled immunochemically with bromodeoxyuridine (BrdU), and the day on which endocrine cells and ciliated cells first appeared was determined.In control fetuses, the BrdU‐labelling indices (LI's) of different anatomical airway levels were significantly different from one gestational day to the next. For example, the LI of the lobar bronchus was significantly different on each gestational day (P.0001), and the same was true of the bronchioles. Moreover, the difference between LI's of the lobar bronchus and bronchioles‐terminal buds was highly significant on day 12 (P <.0001), and on day 13 the differences between lobar bronchus and bronchioles, lobar bronchus and terminal buds, and bronchioles and terminal buds were also highly significant (P .0001). However, on gestational days 14 and 15, the LI's were reduced and were comparable at different airway levels. The BrdU‐labelling indices were very consistent among fetuses of the same age, and the differences between the average LI's for pups of different litters was numerically very small.Hyperglycemia (mild, moderate, severe) did not alter LI's in the fetal airway epithelial cells. Furthermore, although glycogen was not depleted from the airway epithelium of the hyperglycemic fetuses as it was in the controls, the endocrine cells first appeared on gestational days 12, 13, and 14, respectively, in the trachea, lobar bronchus and bronchioles, followed 1 day later by the ciliated cells, in the fetuses of control and diabetic mothers. In our experimental model, induction of diabetes in the pregnant hamsters on gestational day 10 did not appear to alter development or diferentiation of the fetal conducting airway epithelium.
Polar trophoblast (Rauber's layer) of the rabbit blastocyst
Authors: Williams Betsey S. , Biggers John D. 
Published: February 2005

AbstractThe germinal area of the rabbit blastocyst between 108 h postcoitum (pc) and 168 h pc has been examined by scanning electron and transmission electron microscopy. At 108 h and 120 h pc the polar trophoblast (Rauber's layer) is an intact epithelium overlying the epiblast of the inner cell mass. By 132 h pc the polar trophoblast cells begin to separate at multiple foci, exposing the underlying epiblast. Most of the polar trophoblast cells have become individually separated at 144 h pc. The villous, electron‐dense polar trophoblast cells can be easily distinguished from cells for the epiblast, which have smooth apical surface. By 162 h pc the polar trophoblast cells have disappeared from the germinal area.Before the polar trophoblast breaks up, the underlying epiblast cells are only loosely attached to one another. Concurrent with the disintegration of the trophoblast epithelium, the epiblast cells change in shape so that their lateral borders become closely apposed, and juctions develop to form a new epithelium. The epiblast becomes contiguous with the mural trophoblast, and thus the blastocyst does not lose its turgidity as the permeability sea is maintained.There are two classical theories on the fate of the polar trophoblast: the cells die, or they become incorporated into the epiblast as living cells. In newly exposed epiblast the presence of very large phagosomes, which are not found when the polar trophoblast is still intact, favors the first hypothesis and indicates that in the rabbit the epiblast is involved in the phagocytosis of the polar trophoblast.
Glycogen metabolism in cultured chick hepatocytes: A morphological study
Authors: Parkes Joan Lee , Cardell Emma Lou , Grieninger Gerd , Cardell Robert R. 
Published: February 2005

AbstractUltrastructural and autoradiographic observations of cultured chick hepatocytes under the following conditins are described: Induction of glycogen synthesis with glucose alone and glucose plus insulin, and glucagon‐induced glucogen glucogen breakdown. Profiles of hepatocytes cultured in medium containig 10 mM glucose showed typical cellular organelles and occasionally a few glycogen granules. After incubation of hepatocytes with 3H‐glucose, silver grains were found over these sparse glycogen granules, indicating a low level of glycogen synthesis by a few cells. After addition of 75 mM glucose for 1 hr about 3% of the profiles of cells showed glycogen, and by 24 hr half of the hepatocytes had glycogen. Addition ofinsulin plus glucose induced glycogen synthesis in 82% of the cells after 6 hr. and by 24 hr almost every cellular profile showed glyocgen particles. Morphologically, glycogen accumulation was similar whether the cells were stimulated by high glucose or by glucose plus insulin: glycogen granules appeared in restricted regions of the cytoplasm, which were rich in smooth endoplasmic reticulum (SER), and peroxisomes were found close to the newly deposited glycogen particles. At maximum glycogen accumulation the association of SER and peroxisomes with glycogen was less obvious. Glycogenolysis induced by incubation of glycogen‐rich hepatocytes with glucagon resulted in proliferation of SER in the glycogen regions of the cells. These observations are compatible with the concept of regions in the hepatocyte cytoplasm specialized for glycogen metabolism. Possible roles for SER and peroxisomes found near glycogen particles and other organelles in hepatic glycogen metabolism are discussed.
Taste bud distribution in the rat pharynx and larynx
Authors: Travers Susan P. , Nicklas Kent 
Published: February 2005

AbstractThe present study evaluated the number and distribution of taste buds in the rat pharynx and larynx using light microscopic techniques. The average number of taste buds in this region was 141.9 (S.D. = 29.4, n = 10). Pharyngeal and laryngeal taste buds could be grouped into three subpopulations: those associated with laryngeal structures (LA), the nasopharynx (NP), or the palatopharyngeal eminence (PE). Laryngeal taste buds were most numerous (X = 103.2, S.D. =23.6). They were observed on the laryngeal surface of the epiglottis and extended caudally along the aryepiglottic folds, reaching peak density at the caudal extreme of the folds. Further caudally, when the larynx and rostral esophagus separated, taste bud density decreased sharply. Fewer taste buds were associated with the NP (X = 31.9, S.D. = 13.7) or PE (X = 6.8, S.D. =4.0) and taste bud density in these subpopulations peaked at the anterior border of the nasopharyngeal hiatus. Taste buds in the rat larynx and pharynx account for 10% all taste buds in this species, a proportion similar to that accounted for by taste buds on the soft palate. Taste buds in this region appear to be ideally situated for protecting the airway during accidental aspiration of food or fluids. Most pharyngeal and laryngeal taste buds are unlikely to be involved in triggering normally occurring swallows, although they could be stimulated as the bolus is propelled from the oral cavity to the esophagus.