bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure of the glomerular capillaries of the domestic chicken and desert quail
Authors: Casotti Giovanni , Braun Eldon J. 
Published: February 2005

AbstractThe glomerular capillary architecture of nephrons that include a loop of Henle (looped) and those that lack the loop (loopless) nephrons was examined qualitatively and quantitatively by electron microscopy in Gallus gallus and Callipepla gambelii. The glomerular capillaries of looped nephrons form a dichotomously branched network, while those of loopless nephrons are arranged loosely, and the majority are unbranched. There was no significant difference in the diameter of the glomerular capillaries between looped and loopless nephrons; however, in all cases the diameter of the afferent arteriole was significantly larger than that of the efferent arteriole. Based on size alone, the predicted blood flow rate in the efferent arteriole in 20% that of the afferent arteriole in G. gallus and 7% that of the afferent arteriole in C. gambelii. There was no significant difference in the volume density (Vv) of the glomerular capillaries between looped and loopless nephrons. However, the surface area density (Sv) of the glomerular capillaries in loopless nephrons of C. gambelii was significantly larger than for the looped nephrons, and for the loopless nephrons in G. gallus. This suggests that there may be a decrease in blood flow rate along the glomerular capillaries of the loopless nephrons in C. gambelii. Overall, the results indicate that the avian glomerular capillaries are less complex than those of mammals. Reasons may be that either avian blood is more viscous than that of mammals or that avian erythrocytes may be unable to fit physically through a tight intertwining network of capillaries due to the presence of a nucleus, which limits the tank‐treading ability of avian erythrocytes. © 1995 Wiley‐Liss, Inc.
Biomechanical adaptation of ulnar cross‐sectional morphology in brachiating primates
Authors: Hallgrimsson Benedikt , Swartz Sharon 
Published: February 2005

AbstractThe forelimbs of hylobatids (gibbons and siamang) are distinctive among tetrapods in that they are loaded in overall tension during normal locomotion. While hylobatid ulnae must also encounter bending stresses in the course of their full range of locomotor behavior, their loading regime differs from that of quadrupedal anthropoids in that these bending stresses are distributed evenly along the bone, are not exerted in a preferred plane, and are probably of generally lower magnitude. This study examines the degree to which hylobatid ulnae are adapted to this suspensory loading regime. We obtained cross‐sections of ulnae at various increments along the length of the bone using CAT scans. The sample comprises 476 cross‐sections representing the ulnae of 25 individuals from five species of comparable body size. We show that in gibbons and siamang, the patterning of ulnar cross‐sectional area and resistance to bending in the dorsoventral plane along the ulnar diaphysis differ from that of similarly sized quadrupedal anthropoids in the manner predicted by a suspensory loading regime. We also find the same pattern for the ulnae of Ateles, whose loading regime may be fairly similar to that of hylobatids. However, we find that the cross‐sectional shape of the ulnar diaphysis in hylobatids and Ateles does not differ from that of quadrupedal monkeys in the manner predicted by a suspensory loading regime. © 1995 Wiley‐Liss, Inc.
Fiber‐type compositions in postnatal chicken muscle spindles with low intrafusal fiber counts and their developmental significance
Authors: Maier Alfred 
Published: February 2005

AbstractThe fiber‐type composition of postnatal chicken leg muscle spindles with from one to four intrafusal fibers was examined in sections incubated with monoclonal antibodies against fast and slow myosin heavy chains. In monofibral spindles the lone intrafusal fiber was almost always fast. In duofibral spindles usually one slow and one fast fiber were present. Trifibral spindles most often displayed two fast and one slow fiber, whereas quadrofibral receptors characteristically contained two slow and two fast fibers. Earlier results showed that the primary intrafusal myotube in nascent spindles has almost always a fast myosin heavy chain profile and that the proportion of slow myotubes and fibers increases as intrafusal fiber bundles grow in size. Data from postnatal chicken leg muscles collected here suggest that up to the first four fibers this proportional increase can be largely accounted for if consecutive intrafusal fibers arise in a fast‐slow‐fast‐slow sequence. The late recognition during myogenesis of primary intrafusal myotubes and their fast myosin heavy chain profiles warrant exploring if nascent chicken muscles spindles are first seeded by fast fetal myoblasts. © 1995 Wiley‐Liss, Inc.
Postembryonic development of the ovary in the penicillate diplopod, Eudigraphis nigricans (Miyosi) (Diplopoda, Penicillata)
Authors: Yahata Kensuka , Makioka Toshiki 
Published: February 2005

AbstractPostembryonic development of the ovary through the larval stages was studied in a penicillate diplopod, Eudigraphis nigricans. In the first instar larva a single young cell cluster, consisting of about 20 spherical gonial cells and some smaller interstitial cells, exists beneath the alimentary canal in the third body segment. The gonadal epithelium encompasses the upper surface of this young cell cluster by the end of the first instar. The epithelium then extends forward and backward to form a single long sac‐like gonad, leaving the young cell cluster on the center of the gonadal floor as a mound‐shaped germarium. In an early second‐instar larva, very early previtellogenic oocytes accompanied by some interstitial cells appear in the front and rear surfaces of the ovarian germarium. During the period from the third through the seventh (the last) larval instar, some cell clusters containing several previtellogenic oocytes and interstitial cells successively separate forward and backward from the germarium to form a series of paired patch‐shaped vitellarial areas on the extending ventral ovarian epithelium. In each vitellarial area, some of the interstitial cells surround the oocytes to form the follicles. In the seventh instar, the ovarian lumen is extremely expanded, and the late previtellogenic oocytes in the vitellarial areas encroach upward into the ovarian lumen. These oocytes floating in the ovarian lumen are still connected with their own vitellarial areas by partial extensions of their follicles.Some phylogenetic implications of the basic characteristics in structure and postembryonic development of the ovary are discussed. © 1995 Wiley‐Liss, Inc.
Cyton II: A subtegumental cell type in the cercaria of Schistosoma mansoni
Authors: Dorsey Charles , Cousin Carolyn 
Published: February 2005

AbstractIn Schistosoma mansoni cercaria, an aggregate of subtegumental cells is found in a small, dorsoanterior area of the body (middivision). These cells are nestled between two laterally positioned flame cells and the muscle that delimits the anterior end of the body, and the anterior end of the central ganglion. This highly amorphous cell type, designated as cyton II, has a heterochromatic nucleus and a cytoplasm that is elaborated into coarse, tortuous processes. Its cytoplasm contains ribosomes, mitochondria, sparse amounts of endoplasmic reticulum, and two types of circular‐to‐oval concentric membranous bodies. One type has an electron‐dense core and measures 200–250 nm on the short axis, and the other is completely membranous and measures 100–125 nm on the short axis. The cell body of cyton II communicates with the tegument that covers a small, dorsoposterior area of the anterior organ (oral sucker); however, we could not confirm a tegumental connection with the body division. When cercariae transform into schistosomules, the concentric membranous bodies of cyton II migrate into the anterior organ's tegument via cytoplasmic processes of the cell. The major function of previously described cells that have similar membranous bodies is to supply additional membranes to the outer tegument during development into an adult worm. A multilaminated outer membrane is an adaptation to the survival of the schistosomule and adult worm in the bloodstream of the vertebrate host (Hockley amd McLaren [′73]). The presence of membranous bodies from cyton II in the tegument does not confirm that this cell type participates in the formation of multilaminated membranes. Its precise function remains to be determined. © 1995 Wiley‐Liss, Inc.
Cranial features of dendrobatid larvae (Amphibia: Anura: Dendrobatidae)
Authors: Haas Alexander 
Published: February 2005

AbstractThe larval neurocranium and visceral arches of seven dendrobatid species representing four genera are described, based on cleared‐and‐stained and serially sectioned specimens. A variety of characters is shared by all seven species. Larval features do not substantiate the assumption of close ranoid affinities of the Dendrobatidae. Instead dendrobatid larvae share features such as the special quadripartite cartilago suprarostralis, the lack of the larval processus oticus, the presence of three foramina acustica, and the lack of a foramen perilymphaticum accessorius with many bufonoid larvae. The first of these characters is unique to bufonids, hylids, dendrobatids, and some New World leptodactylids; the other characters also occur in pelobatids and are presumably plesiomorphic for the Neobatrachia. The free proximal ends of Ceratobranchialia II and III are an autapomorphy of the Dendrobatidae supporting the monophyly of the family. Some features of the cranium are paedomorphic: low cartilago orbitalis, lack of connection between cartilage orbitalis and otic capsule (most species), and vestigal taeniae tecti. New anatomical terms are introduced. © 1995 Wiley‐Liss, Inc.
Sperm storage in the oviduct of the tropical rock lizard, Psammophilus dorsalis
Authors: Srinivas S. R. , Hegde S. N. , Sarkar H. B. D. , Shivanandappa T. 
Published: February 2005

AbstractThe female rock lizard, Psammophilus dorsalis (Agamidae), lays multiple clutches of eggs over a period of 6 months (June–December). The later clutches of eggs are presumably fertilized by sperm stored from earlier matings, since testes and epididymides are regressed after August. Sperm storage is seen in pockets of the anterior vaginal region of the oviduct. Sperm recovered from the uterovaginal region are intact and motile. Discrete granules resembling the secretory granules present in the vas deferens also occur along with sperm in the vaginal sperm storage structures. The PAS‐positive granules and acid phosphatase form important components of the secretions present along with sperm in the vaginal sperm storage pockets. The epithelium of the vaginal sperm storage pockets is PAS‐positive and contains lipid. Several enzymes, including hydroxysteroid dehydrogenases and hydrolases, are localized histochemically in the epithelium of the vaginal sperm storage pockets. A possible role is suggested for the secretions from the male reproductive tract during sperm storage in the oviduct, in which physiological “dormancy” of the sperm during their storage may be maintained by the metabolic “milieu” in the vaginal sperm storage pockets by a mechanism similar to that effecting dormancy of the epididymal sperm in the male. © 1995 Wiley‐Liss, Inc.
Convergent evolution of the vestibular organ in the subterranean mole‐rats, Cryptomys and Spalax, as compared with the aboveground rat, Rattus
Authors: Lindenlaub Thies , Burda Hynek , Nevo Eviatar 
Published: February 2005

AbstractThe membranous labyrinth of the vestibular organ (examined in toto) in two unrelated species of subterranean rodents, Cryptomys sp. from Zambia and Spalax ehrenbergi from Israel, was in many parameters (streamline length, curvature radius, and cross‐sectional area of the lumen) relatively or even absolutely (especially the cross‐sectional area) larger than in the laboratory Norway rat. The mechanical sensitivity of the vestibular organ (estimated according to the mathematical model of Oman et al., [1987] Acta. Otolaryngol (Stockh.) 103:1–13) was similar in both subterranean rodent species and significantly higher than that in the laboratory rat. The most pronounced differences in morphometry and the resulting mechanical sensitivity between the subterranean forms and the rat occurred in the lateral (i.e., phylogenetically and ontogenetically most recent and presumably most plastic) semicircular duct. The area of the sensory epithelia, and density and total numbers of vestibular receptors, were estimated on surface specimens for both maculae and for all three cristae for all three species. While the density of hair cells in comparable sensory epithelia was similar in all three species, the sensory area and thus, also, the total receptor counts were significantly larger in both subterranean forms. The peripheral vestibular organ in subterranean rodents is, in comparison to a generalized aboveground dwelling form, i.e., the rat, progressively specialized, and in any case cannot be denoted as degenerate. © 1995 Wiley‐Liss, Inc.
Lectin histochemical identification of carbohydrate moieties in opossum chemosensory systems during development, with special emphasis on VVA‐identified subdivisions in the accessory olfactory bulb
Authors: Shapiro Lena Shnayder , Halpern Mimi , Ee Pei‐Lee 
Published: February 2005

AbstractLectins, sugar‐binding molecules of nonimmune origin, were used in this study to describe the development of the main olfactory and vomeronasal systems in the Brazilian gray short‐tailed opossum, Monodelphis domestica. A battery of seven lectins of the N‐acetylgalactosamine/galactosebinding group was used. Of the seven lectins, only two, Vicia villosa agglutinin (VVA) and Griffonia (Bandeiraea) simplicifolia lectin I‐isolectin B4 (GS I‐B4), were specific to the vomeronasal system. The other five lectins recognized carbohydrates in both chemosensory systems, although the binding was more intense in the accessory olfactory system. Furthermore, whereas six of the lectins stained the adult opossum accessory olfactory bulb (AOB) homogeneously, the VVA lectin distinguished two regions of the AOB. Similar to the expression of olfactory marker protein (OMP) (Shnayder et al. [1993] Neuroreport 5:193–196), the rostral half of the AOB stained much darker with VVA than the caudal half, and the onset of the restricted pattern of staining at age 45 days also coincided. We conclude that (1) GS I‐B4 and VVA recognize cell surface carbohydrate moieties specific to the vomeronasal, but not to the main olfactory, system, and (2) the carbohydrate moiety that is recognized by the VVA lectin, presumably terminal N‐acetyl‐galactosamine, is both temporally and spatially restricted in the opossum AOB. These results are discussed in the framework of other known spatially restricted molecules of the two major nasal chemosensory systems. © 1995 Wiley‐Liss, Inc.
Structure of the extraembryonic matrices around the benthic embryos of Patiriella exigua (Asteroidea) and their roles in benthic development: Comparison with the planktonic embryos of Patiriella regularis
Authors: Cerra Anna , Byrne Maria 
Published: February 2005

AbstractThe extracellular matrices (ECMs) surrounding the benthic embryos and larvae of the seastar Patiriella exigua and the planktonic embryos of Patiriella regularis were examined by transmission and scanning electron microscopy. Three ECMs surround unhatched embryos: An outer jelly coat, a fertilization envelope, and an inner hyaline layer. The ECMs of P. exigua are modified for supporting benthic development. The dense jelly coat attaches the embryo to the substratum, and the fertilization envelope forms a though protective case. In comparison, P. regularis has a less dense jelly coat and a thinner fertilization envelope. The hyaline layer of both species is comprised of three main regions: An intervillous layer overlying the epithelium, a supporting layer, and a coarse meshwork layer. Unhatched P. exigua have an additional outer amorphous layer that adheres to the fertilization envelope. As a result, the hyaline layer forms a continuous ECM that unites the embryonic surface with the fertilization envelope. Embryos of P. exigua removed from their fertilization envelopes lack the outer amorphous region, have a poorly developed hyaline layer, and do not develop beyond gastrulation. It appears that the substantial hyaline layer of P. exigua and its attachment to the fertilization envelope are essential for early development and that this ECM may function as a gelatinous cushioning layer around the benthic embryos. At hatching, the amorphous layer is discarded with the envelope. In contrast, an amorphous layer is absent from the hyaline layer of P. regularis. The demembranated embryos of this species have an ECM similar to that of controls and develop normally to the larval stage. © 1995 Wiley‐Liss, Inc.
Scanning electron microscopic study of intestinal mucosa of the Nile crocodile (Crocodylus niloticus)
Authors: Kotzé Sanet H. , Soley John T. 
Published: February 2005

AbstractAs part of an ongoing study of the intestinal tract of the Nile crocodile Crocodylus niloticus, the appearance of the small intestinal mucosa was examined using a scanning electron microscope (SEM). The duodenum displayed ridge‐like and complex primary folds, both of which were arranged in a longitudinally directed zigzag pattern. The two types of folds alternated with each other, with the second type following the zigzag contours of the first. The folds were covered with polygonal‐ and dome‐shaped epithelial cells. The latter cell type was less common and was restricted in location to the proximal two thirds of the mucosal folds. Both types of epithelial cells were covered with stubby microvilli which displayed a distinct linear arrangement. Goblet cells were present between the absorptive cells. In the jejunum the basic pattern of the folds persisted except that both types of primary folds became tall and leaf‐like. The angle of the zigzag pattern was less acute than in the duodenum. In the ileum the two types of alternating folds decreased in height and were arranged in a longitudinally directed wave‐like fashion. The zigzag mucosal folds of the small intestine ended abruptly at the ileorectal junction. The rectum displayed low, irregular folds which formed occasional large, puckered, rosette‐shaped structures. The particular arrangement of the intestinal folds fulfills the dual function of promoting the absorptive process and facilitating the smooth passage of the intestinal contents. © 1995 Wiley‐Liss, Inc.
A commentary on the segmental motor system of the turtle: Implications for the study of its cellular mechanisms and interactions
Authors: Callister Robert J. , Laidlaw Douglass H. , Stuart Douglas G. 
Published: February 2005

AbstractA commentary is provided on the segmental motor system of the turtle Pseudemys (Trachemys) scripta elegans with an emphasis on neuronal, neuromuscular, and muscular mechanisms that control the development of force under normal, fatiguing, and pathophysiological conditions. For the central neuronal component of the segmental motor system, it has recently been shown that intracellular analysis of the firing properties of motoneurons and interneurons can be undertaken for relatively long periods of time in in vitro slices of the lumbosacral spinal cord of the adult turtle. In other less reduced in vitro preparations, analyses are available on complex motor behaviors generated by the isolated spinal cord. These behaviors of spinal neuronal networks are analogous in key aspects to those generated by the isolated in vivo cord, and by the cord in intact preparations. These results suggest that the neuronal components of the segmental motor system can now be studied from the cellular/molecular level of analysis in in vitro slice preparations to the systems level in conscious, freely moving animals. The in vitro approach can also be used for the analysis of cellular mechanisms in suprasegmental brain structures, which contribute to the control of voluntary movement. For the peripheral neuromuscular component of the segmental motor system, information is now available on muscle fiber types and selected aspects of sensory innervation, and it is feasible to study the mechanical and biochemical properties of motor units. As such, the turtle presents a valuable model for exploring interrelations between the neuronal and mechanical components of the segmental motor system of the generalized tetrapod. A prominent feature of these recent developments is the extent to which they have been deriven by findings that have emphasized an evolutionary conservation of motor‐control mechanisms extending from ion channels, at the cellular level, to the control of multijointed movements at the systems level of analysis. © 1995 Wiley‐Liss, Inc.
Isolated cell type corpora allata in adults of the loreyi leafworm, Leucania loreyi duponchel (Lepidoptera: Noctuidae)
Authors: Kou R. , Tu M. P. , Chang C. Y. , Yin C.‐M. 
Published: February 2005

AbstractThe corpora allata in adult Loreyi leafworms Leucania loreyi (Lepidoptera: Noctuidae) exhibit sexual dimorphism. The male possesses right and left corpora allata of about the same size. Each gland is composed of a cluster of approximately 40 semi‐transparent, spherical, isolated cells held together by fine tracheae and nerve fibers. The largest cell diameter found in male glands was 203 pm. In contrast, the female gland cells and clusters are much smaller. The largest dimensions of one whole female gland cluster were 452 μm in length and 280 μm in width. Using bilateral and unilateral larval allatectomy, we confirmed that the adult isolated cell type glands develop ontogenetically from larval capsular type glands. Ultrastructural study re‐ vealed many similarities between the subcellular structures of the isolated cell type glands of L. loreyi and the more common capsular gland reported by others. These similarities include very large numbers of mitochondria, abun‐ dant whorled smooth endoplasmic reticulum, irregularly shaped nuclei, Golgi bodies, and free ribosomes. Compared with the corpora allata of 3‐ to 9‐day‐old adults, the glands of 1‐day‐old adults possessed much less smooth endoplasmic reticulum. The gland cells in females usually have more neurosecretory nerve endings, less‐abundant stacked smooth endoplasmic reticulum, and less‐ defined interdigitations than the gland cells in males. © 1995 Wiley‐Liss, Inc.
Functional anatomy of the pigeon hand (Columba livia): A muscle stimulation study
Authors: Vazquez Rick J. 
Published: February 2005

AbstractThe morphology and function of all muscles controlling the pigeon hand were analyzed. Muscle action was determined in situ by inducing contraction via silver wire electrodes in anesthetized birds. EMG electrodes were implanted in the test muscle and an adjacent muscle to monitor contraction and volume conduction respectively. Results indicate that pigeons have fine control of hand and digit movements. However, the directions of movement are restricted. Movements have been eliminated or severely limited in those directions that experience strong stress during flight. Such restrictions may reduce the amount of muscular activity required for stabilization of the hand and its components. Mobility is retained in directions not subject to large stresses and where movement is essential for the kinematics of flight to be executed properly. © 1995 Wiley‐Liss, Inc.