bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cruciate ligaments of the avian knee: Insight into a complex system
Authors: Fuss Franz K. , Gasser Chris R. 
Published: February 2005

AbstractThe avian cruciate ligaments were examined in Gallus domesticus, Anas platyrhynchos, Meleagris gallopavo, and Struthio camelus australis. The ligaments proved to be deviated around the intercondylar groove (cranial cruciate) and around the medial femoral condyle (caudal cruciate). Four functionally different fiber groups could be differentiated: fibers taut only in maximal extension, fibers taut only in maximal flexion, fibers taut in ranges from an intermediate position to an extreme position, and fibers taut throughout the entire range of motion (guiding bundles). Hence the cruciates serve the guiding of the joint and the restriction of motion, whereby the majority of the cranial cruciate fibers are taut in extension while those of the caudal cruciate are in flexion. No differences were found between the species examined with respect to fiber arrangement and function. The avian mechanical model proved to be more complex than the relatively simple mammalian four‐bar link model as the avian guiding bundles change their shape due to deflection during motion. © 1992 Wiley‐Liss, Inc.
Renal haemopoietic tissue of the mudskipper Periopthalmus koelreuteri (Pallas)
Authors: El‐Sayed N. K. , Safer A. M. 
Published: February 2005

AbstractThe renal haemopoietic tissue of the mudskipper Periophthalmus koelreuteri was examined by light and electron microscopy. Leukopoietic zone surrounding melanomacrophage center and erythropoietic zone were differentiated. The ultrastructural features of the cellular components of the haemopoietic compartments are similar to those described in other fishes. Despite the presence of lymphoid cells, this tissue is mainly myeloid, and active granulopoiesis and erythropoiesis occur, as in the red bone marrow of higher vertebrates. © 1992 Wiley‐Liss, Inc.
Comparative skeletogenesis of the forearm of the little brown bat (Myotis lucifugus) and the norway rat (Rattus norvegicus)
Authors: Adams Rick A. 
Published: February 2005

AbstractThis study describes, quantifies, and compares the growth and development of the volant forelimb morphology of Myotis lucifugus with that of the terretrial forelimb morphology of Rattus norvegicus. In M. lucifugus there is (1) accelerated growth in forearm length after parturition, (2) cessation in growth of the midshaft diameter of the ulna just after the onset of osteogenesis, (3) proximal fusion of the radius and ulna, which results in the radius occupying 97% of the articular surface of the elbow joint in adults, (4) fusion between the cartilaginous distal epiphyses of the radius and ulna which results in formation of a radioulnar bridge that becomes fully ossified in adults, and (5) incomplete ossification of the ulna with a section of the diaphysis becoming ligamentous. None of these events occurs during development in R. norvegicus. © 1992 Wiley‐Liss, Inc.
Specialized veins in the submucosa of the equine lleocecal junction
Authors: Kotzé Sanet H. , Soley J. T. 
Published: February 2005

AbstractSpirally arranged bundles of sub‐endothelial smooth muscle enfold the small to medium‐sized submucosal veins in the equine ileocecal junction. The muscle bundles, accompanied by the endothelial lining, bulge into the lumen of the vessels, partly occluding the latter. Transmission electron microscopy of the muscle cells reveals features consistent with vascular smooth muscle ultrastructure. It is proposed that the throttling effect of the muscle bundles causes engorgement of the submucosal venous plexus, which then assists in the closing of the ileocecal orifice. © 1992 Wiley‐Liss, Inc.
Configurations of the rectus abdominis muscle of anuran tadpoles
Authors: Carr Karen M. , Altig Ronald 
Published: February 2005

AbstractConfigurations of the rectus abdominis in tadpoles of 60 anuran species in 13 families were examined. This muscle is present by Gosner stage 25 and does not change until late in metamorphosis. The anterior terminus of the r. abdominis usually is a straight, transverse front or fan‐shaped array only loosely associated with the rectus cervicis. In some suspension feeders (Rhinophrynus, Xenopus, but not microhylids), macrophagous suction feeders (Lepidobatrachus) and bromeliad inhabitants (Hyla bromeliacia) the r. abdominis is contigous with the r. cervicis which continues anterolaterally and dorsally from the wall of the spiracular cavity. Suctorial forms (Scutiger), those that live in confined spaces (burrowers, Centrolenella; bromeliad inhabitants, Hyla bromeliacia), and the taxa that have the r. cervicis and r. abdominis contiguous all have closed myosepta; the myosepta of other taxa; except for ones with large tadpoles (e.g., Rana catesbeiana), have large gaps between at least anterior myotomes. These initial data suggest that the configurations of the r. abdominis have responded to selection based on ecomorphological function and convergence among lineages are noted. © 1992 Wiley‐Liss, Inc.
Cranial osteogenesis in Monodelphis domestica (Didelphidae) and Macropus eugenii (Macropodidae)
Authors: Clark Christopher T. , Smith Kathleen K. 
Published: February 2005

AbstractThe pattern of onset and general rate of cranial ossification are compared in two marsupials, Monodelphis domestica (Didelphidae) and Macropus eugenii (Macropodidae). In both species a similar suite of bones is present at birth, specifically those surrounding the oral cavity and the exoccipital, and in both postnatal events follow a similar course. The facial skeleton matures more rapidly than the neurocranium, which is characterized by an extended period of ossification. Most dermal bones begin ossification before most endochondral bones. Endochondral bones of the neurocranium are particularly extended in both the period of onset of ossification and the rate of ossification. These data confirm suggestions that morphology at birth is conservative in marsupials and we hypothesize that the pattern of cranial osteogenesis is related to two distinct demands. Bones that are accelerated in marsupials are correlated with a number of functional adaptations including head movements during migration, attachment to the teat, and suckling. However, the very slow osteogenesis of the neurocranium is probably correlated with the very extended period of neurogenesis. Marsupials appear to be derived relative to both monotreme and placental mammals in the precocious ossification of the bones surrounding the oral cavity, but share with monotremes an extended period of neurocranial osteogenesis. © 1993 Wiley‐Liss, Inc.
Falciparum malaria in naturally infected human patients: I. Ultrastructural differences between malaria pigments in intraerythrocytic asexual and sexual forms
Authors: El‐Shoura Samir M. , Al‐Amari Omar M. 
Published: February 2005

AbstractVenous blood samples were taken from patients naturally infected with the human malaria parasite Plasmodium falciparum. Two types of malaria pigment (MP) particles have been demonstrated in intraerythrocytic asexual forms (trophozoites and schizonts), while a single type was detected in gametocytes. Type I MP particles, found in both asexual and sexual forms, are electron‐dense. It is suggested that these are proteinaceous and may be intermediate, utilizable metabolic products that serve as a food reserve during development of the parasite in the human host and also during the growth cycle of the sexual form in the mosquito. In asexual forms, type I particles occur within food vacuoles (FV) containing semidigested hemoglobin (Hg), while they are unenveloped in the cytoplasm of the sexual forms. Type II MP particles, found in electron‐lucent residual bodies, are crystalloid and of low electron density. It is suggested that these are the final, waste product of Hg digestion in the asexual forms. © 1993 Wiley‐Liss, Inc.
Falciparum malaria in naturally infected human patients: II. Ultrastructural alterations to erythrocytes infected with asexual forms
Authors: El‐Shoura Samir M. , Al‐Amari Omar M. 
Published: February 2005

AbstractUltrastructural alterations of human erythrocytes infected with asexual forms of Plasmodium falciparum were studied in naturally infected Saudi patients. These included surface knobs and nodules as well as invaginations associated with cytopasmic vesicles observed in erythrocytes infected with asexual forms of the parasites. Such nodules and surface invaginations have been previously described only in erythrocytes infected with P. ovale and P. vivax, respectively. Within the cytoplasm of infected erythrocytes were membrane‐bound clefts, similar to those that appear to be a common characteristic in all red cells infected with malaria parasites. Vacuolations were often seen in the peripheral cytoplasm and may represent hemolyzed areas. Collapsed cells with an internal‐lucent interior and surrounded by an irregularly folded membrane may represent completely hemolyzed erythrocytes. © 1993 Wiley‐Liss, Inc.
A microscopic investigation of the lymphoid organs of the beluga, Delphinapterus leucas
Authors: Romano Tracy A. , Felten Suzanne Y. , Olschowka John A. , Felten David L. 
Published: February 2005

AbstractLymphoid organs from belugas, Delphinapterus leucas, ranging in age from less than one to 16 years, were harvested during a sanctioned hunt to investigate morphology. The spleen is divisible into red and white pulp and a stroma consisting of a reticular network, a collagenous capsule, and trabeculae containing smooth muscle bundles. White pulp areas appear to be devoid of follicles and consist mainly of periarteriolar lymphatic sheaths (PALS), that are larger in younger than in older belugas. Definitive marginal zones between red and white pulp are difficult to discern in older belugas. Lymph nodes are similar to those of other mammals; they possess a follicular cortex surrounding a vascular medulla composed of lymphatic cords and sinuses. Smooth muscle is abundant in the medullary region, usually in close proximity to sinuses. The expansive nodular mass at the root of the mesentery, often referred to as the “pseudopancreas,” is similar to lymph nodes in microscopic architecture. Pharyngeal tonsils and gut‐associated lymphoid tissue (GALT) are found along the digestive tract and display an “active” morphology. Tonsils are comprised of lobules of follicles separated by vascular connective tissue. Epithelial‐lined crypts communicate with the pharyngeal lumen. GALT consists of diffuse and follicular lymphocytes within the intestinal mucosa and submucosa. The thymus is well developed in the younger belugas, with lobules divisible into densely packed cortical zones of thymocytes and more loosely arranged medullary lymphocytes. Hassall's corpuscles are occasionally visible within the medulla. Cetaceans diverged evolutionarily from other mammals over 55 million years ago. This study investigates changes in lymphoid organ morphology in a species that now inhabits a unique ecological niche. This study also lays the groundwork for functional investigation of the beluga immune system, particularly as it relates to differences between healthy and stranded animals. © 1993 Wiley‐Liss, Inc.
Evolution and functional significance of tendon ossification in woodcreepers (Aves: Passeriformes: Dendrocolaptinae)
Authors: Bledsoe Anthony H. , Raikow Robert J. , Glasgow Angela G. 
Published: February 2005

AbstractThe woodcreepers, a clade of scansorial, neotropical birds, are distinctive among passerines in having extensive tendon ossification. Dissection of 42 of the 50 species indicates that such ossification in the hindlimb is limited almost entirely to tendons of insertion of the crural muscles. Most crural muscles have ossifications, and in all but one the ossified tendons are long and thin. Preliminary dissection revealed a similar pattern among ossified wing tendons. Phylogenetic analysis suggests that extensive tendon ossification is a synapomorphy of the woodcreepers. The species ofDendrocincla, which form a clade, show secondary reduction of ossification in some tendons, which may be correlated with increased intraspecific variation and with an expansion of foraging habits and postures to include nonscansorial behaviors. In contrast, the larger woodcreepers, other thanDrymornis bridgesiiandNasica longirostris, form a clade with virtually no loss in ossification or evidence of intraspecific variation, even in large series of two species. Phylogenetic losses do not occur for the primary flexor of the ankle (M. tibialis cranialis), whereas two extensors (Mm. fibularis longus and gastrocnemius pars lateralis) show a complex pattern of derivation and loss. Previous biomechanical studies demonstrate that ossification increases the stiffness of tendons, making them stretch less under a given force. These structural and phylogenetic patterns are consistent with the view that hindlimb tendon ossification in woodcreepers is an adaptation to resist increased forces that act to extend the limb during vertical climbing. © 1993 Wiley‐Liss, Inc.
In‐series fiber architecture in long human muscles
Authors: Heron Marcia I. , Richmond Frances J. R. 
Published: February 2005

AbstractThe fiber architecture of adult human sartorius and gracilis muscles was examined using a combination of fiber microdissections and histological methods. Intact fibers were dissected from fascicles of muscle strips that were digested in nitric acid. All of these fibers terminate intrafascicularly by tapering to a fine strand at one or both ends. They measure 4–20 cm after correction for shrinkage. Systematic dissections of 1 cm long blocks sampled at intervals along the muscle length suggest that tapered fiber endings occur at all locations along the muscle but are most common centrally; here they accounted for up to 14% of dissected fibers in each block. Transverse sections of muscle confirm that fiber profiles with small diameters occur at all levels of the muscle but are especially common in sections more than 5 cm from its origin or insertion. The architectural arrangement demonstrated here suggests that long human muscles, like muscles in other species, are composed of relatively short, in‐series fibers. This has many implications for the neural activation and force‐developing behavior of these muscles that must be considered when paralyzed muscles are reanimated using electrical stimulation. Further, it may predispose long muscles to certain types of neuromuscular damage and dysfunction. © 1993 Wiley‐Liss, Inc.
Structure and histochemical organization of the spleen of Agama stellio (Sauria: Agamidae) and Chalcides ocellatus (Sauria: Scincidae)
Authors: Saad A.‐H. , Bassiouni W. M. 
Published: February 2005

AbstractThe spleen of Agama stellio is composed mainly of red pulp; the white pulp is poorly developed, and its clusters are scattered throughout the organ and contain lymphocytes, reticular cells, and some plasma cells. The red pulp consists of clear reticular cells intermingled with blood cells, sinusoids, and pigment cells. The spleen of Chalcides ocellatus is encapsulated by connective tissue and is composed of white and red pulp. The white pulp consists of lymphoid tissue that surrounds the central arterioles, forming the periarteriolar lymphocyte sheath (PALS). The red pulp is composed of a system of venous sinuses and cords. The results of various histochemical procedures designed to demonstrate mucosubstances, proteins, and nucleic acids indicate that the spleen in these species resembles the mammalian spleen. © 1993 Wiley‐Liss, Inc.
Histology of the late‐stage placentae in the matrotrophic skink Chalcides chalcides (Lacertilia; Scincidae)
Authors: Blackburn Daniel G. 
Published: February 2005

AbstractExamination of late‐stage placental material of the lizard Chalcides chalcides from the Hubrecht Laboratorium (Utrecht, The Netherlands) reveals several cytological and histological specializations that appear to have been superimposed over a morphological pattern that is typical for squamates. The chorioallantoic placenta is highly vascularized and consists of a single mesometrial placentome and a generalized paraplacentomal region, both of which are epitheliochorial. The placentome is deciduate, and contains deeply interdigitating folds of hypertrophied uterine and chorioallantoic tissue. Chorionic epithelium lining the placentome comprises enlarged, microvilliated cells, a small proportion of which are diplokaryocytes. The placentomal uterine epithelium is not syncytial and consists of enlarged cells bearing microvilli. The yolk sac placenta is a true omphaloplacenta (sensu stricto), being formed by juxtaposition of uterine tissues to an avascular, bilaminar omphalopleure. Epithelium of the omphalopleure is stratified and is hypertrophied into papillae that project into detritus of the uterine lumen. The omphalopleure is separated from the yolk sac proper by a yolk cleft that is not confluent with the exocoelom and is not invaded by the allantois. Neither an omphalallantoic placenta nor a true choriovitelline placenta is present in late gestation. Morphologically, the mature placentae of C. chalcides are among the most specialized to have been described in reptiles, reflecting the substantial maternal‐fetal nutrient transfer that occurs in this species. © 1993 Wiley‐Liss, Inc.
Androgen effects on vocal muscle structure in a teleost fish with inter‐ and intra‐sexual dimorphism
Authors: Brantley Richard K. , Marchaterre Margaret A. , Bass Andrew H. 
Published: February 2005

AbstractThe plainfin midshipman fish Porichthys notatus has both interand intra‐sexual dimorphism in the sound‐producing (vocal or sonic) muscles attached to the swimbladder wall. The “Type I” and “Type II” male morphs differ in that dramatic structural changes related to sexual maturity occur in the mass, the area of mitochondria‐filled sarcoplasm, and the myofiber number of the sonic muscles of Type I males, but not in those of Type II males (nor of females). Androgen implantation for 9 weeks markedly increased the relative sonic muscle size in juvenile males, juvenile females, and Type II males, whereas estradiol or cholesterol treatment did not. The principal androgen effect on myofiber structure was an increase in the area of mitochondria‐filled sarcoplasm. The ratio of sarcoplasm area to myofibril area (Sr/Mf) increased by 1.4‐ to 2‐fold in myofibers of all androgen‐treated groups, with the greatest structural change occurring in juvenile males. When androgen implants were removed from juvenile males, the muscle mass and Sr/Mf ratio reverted toward the unimplanted juvenile phenotype. Total fiber number in sonic muscle increased significantly in juvenile males following androgen implantation but did not detectably change in juvenile females or Type II males. These results suggest: (1) sonic muscle in Porichthys notatus is an androgen target tissue, (2) fiber structure and fiber number are androgen‐sensitive features, and (3) there exist sex‐ and morph‐specific patterns of sonic muscle responsiveness to androgen implants. © 1993 Wiley‐Liss, Inc.
Muco‐follicle cells of the jelly coat in the oocyte envelope of the sheatfish (Silurus glanis L.)
Authors: Abaham Mordechai , Hilge Volker , Riehl Rüdiger , Iger Yoni 
Published: February 2005

AbstractDuring early vitellogenesis of the oocytes of Silurus glanis, the follicular cells proliferate, their epithelial organization becomes disrupted, and they transform into an irregularly structured large mass of cells engaged in intensive secretory activity. They contain nuclei, rough endoplasmic reticulum, Golgi bodies, and secretory inclusions termed “acorn bodies,” which are synthesized in the cytoplasm. The acorn bodies have two components: an electron‐dense cap and a moderately electron‐dense body. As development proceeds, the acorn bodies become modified into spherules of mucous material, the mucosomes. The electron‐dense part persists as a small calotte or crescent often irregularly structured at the periphery of the mucosome, and fragments of it are dispersed into the interior of the mucosomal body. The mucosomes are membrane‐bound and contain small granules, 55 nm in diameter.At the end of vitellogenesis, the follicle cells are filled with mucosomes, and cytoplasmic residua can only sparingly be observed among them. Oocytic microvilli extend through the zona radiata and intermingle with follicular cell processes in the cleft between the zona radiata and the belt of mucosomes during growth of the oocyte. Capillaries develop in connective tissue of the theca layer as vitellogenesis proceeds. © 1993 Wiley‐Liss, Inc.
Fine structure of the nephridial muscle layer cells of Phascolosoma granulatum (Sipuncula)
Authors: Serrano Teresa , Angulo Eduardo , Mateo Antonio , Moya Jesus 
Published: February 2005

AbstractThe nephridial muscle layer of Phascolosoma granulatum consists of a network of longitudinal and circular cells separated by connective tissue matrix. The muscle fibers are densely packed with thick and thin myofilaments, among which are scattered cytoplasmic dense bodies. The nucleus and noncontractile cytoplasmic organelles occupy a lateral projection from the contractile portion of the fiber. Cytoplasmic dense bodies are the result of a clustering of an indeterminate number of the thin actin filaments that fill the cytoplasm between thick filaments. Attached to the cytoplasmic face of the cell membrane are membrane‐associated electron‐dense plaques. These sites are linked to the contractile myofilaments by narrow filamentous bridges. Extracellular narrow filaments extend from these plaques to collagen fibers of the connective tissue matrix. Differences in length of the dense plaques may be related to differences in thick myofilament diameter in three types of muscle fiber, types A, B and C, statistically distinguished by mean fiber size differences. The plaques may serve as connecting links for the transmission of tension from contractile units to the connective tissue of the muscle layer. © 1993 Wiley‐Liss, Inc.
Turkey embryo staging from cleavage through hypoblast formation
Authors: Gupta S. K. , Bakst M. R. 
Published: February 2005

AbstractThe progressive development of the turkey embryo from first cleavage through hypoblast formation was examined in order to determine the applicability of a chicken embryo staging procedure. It was concluded that the temporal and spatial events associated with the development of the early turkey embryo are sufficiently different from those of the chicken embryo to warrant a separate staging procedure. Cleavage is asynchronous and often results in asymmetrical segmentation. Unlike the chicken embryo, which at oviposition has already formed the area pellucida and area opaca and is classified as a Stage X embryo, the turkey embryo at oviposition is only at the beginning of area pellucida formation and is classified as a Stage VII embryo. After about 3 hr of incubation and prior to completion of the area pellucida, hypoblast formation begins at the posterior end, thereby establishing the bilaterally symmetrical pattern of the embryo. When viewed from the dorsal surface, an opaque region is observed at the center of the area pellucida. This opacity is unique to the turkey embryo and is referred to as the area alba. When viewed from the ventral surface, the area alba appears to be composed of large whitish cells. To conclude, the rate of turkey embryo development through the completion of hypoblast formation, which consists of 11 stages, lags behind that of the chicken. Furthermore, the organization as well as origin of the area pellucida and hypoblast observed in the turkey embryo differ from that of the chicken embryo. © 1993 Wiley‐Liss, Inc.