bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructure of the reproductive system of the black swamp snake (Seminatrix pygaea). IV. Occurrence of an ampulla ductus deferentis
Authors: Sever David M. 
Published: October 2004

AbstractThe distal end of the ductus deferens of Seminatrix pygaea (Cope) differs from more proximal portions of the tube by possessing a highly fluctuated epithelium. Similar morphology has been reported in this area in one lizard and some mammals and the region has been designated in these taxa as the ampulla ductus deferentis. In this study, light and transmission electron microscopy were used to study the posterior ductus deferens in S. pygaea and compare the histology in this region to more proximal regions of the duct and to descriptions of the ampulla of other species. Seminatrix pygaea stores sperm throughout the ductus deferens during the entire year. The epithelium of the ductus deferens is not secretory, but the presence of numerous small apical vesicles indicates a role in fluid absorption. In addition to the highly folded epithelium, clusters of sperm nuclei are more intimately associated with the apical ampullary epithelium than elsewhere in the ductus deferens. No evidence of phagocytosis of sperm was found. In contrast, the ampulla of mammals and presumably the lizard Calotes versicolor is glandular and phagocytic. The common character shared by the squamates and mammals with specializations in this area is the folded epithelium, and whether this is due to shared ancestry with amniotes or is homoplastic is unresolved. J. Morphol. 262:714–730, 2004. © 2004 Wiley‐Liss, Inc.
Glial fibrillary acidic protein and vimentin immunoreactivity of astroglial cells in the central nervous system of the African lungfish, Protopterus annectens (Dipnoi: Lepidosirenidae)
Authors: Lazzari Maurizio , Franceschini Valeria 
Published: October 2004

AbstractThe distribution of glial intermediate filament molecular markers, glial fibrillary acidic protein (GFAP), and vimentin, in the brain and spinal cord of the African lungfish, Protopterus annectens, was examined by light microscopy immunoperoxidase cytochemistry. Glial fibrillary acidic protein immunoreactivity is clear and is evident in a radial glial system. It consists of fibers of different lengths and thicknesses that are arranged in a regular radial pattern throughout the central nervous system (CNS). They emerge from generally immunopositive radial ependymoglia (tanycytes), lining the ventricular surface, and are directed from the ventricular wall to the meningeal surface. These fibers give rise to endfeet that are apposed to the subpial surface and to blood vessel walls forming the glia limitans externa and the perivascular glial layer, respectively. GFAP‐immunopositive star‐shaped astrocytes were not found in P. annectens CNS. In the gray matter of the spinal cord, cell bodies of immunopositive radial glia are displaced from the ependymal layer. Vimentin‐immunopositive structures are represented by thin fibers mostly localized in the peripheral zones of the brain and the spinal cord. While a few stained fibers appear in the gray matter, the ependymal layer shows no antivimentin immunostaining. In P. annectens the immunocytochemical response of the astroglial intermediate filaments is typical of a mature astroglia cell lineage, since they primarily express GFAP immunoreactivity. This immunocytochemical study shows that the glial pattern of the African lungfish resembles that found in tetrapods such as urodeles and reptiles. The glial pattern of lungfishes is comparable to that of urodeles and reptiles but is not as complex as that of teleosts, birds, and mammals. J. Morphol. 262:741–749, 2004. © 2004 Wiley‐Liss, Inc.
Anatomy of the pharyngeal jaw apparatus of Zenarchopterus (gill) (Teleostei: Beloniformes)
Authors: Tibbetts Ian R. , Carseldine Lee 
Published: October 2004

AbstractThe structure of the pharyngeal jaw apparatus (PJA) of Zenarchopterus dispar and Z. buffonis, carnivorous estuarine and freshwater West‐Pacific halfbeaks, was investigated using dissection, light, and scanning electron microscopy as part of a comparison with estuarine and marine herbivorous confamilials. The Zenarchopterus PJA differs from published descriptions of hemiramphid PJAs in that the otic capsules are less pronounced; the pharyngocranial articulation facet is trough‐like; the third pharyngobranchials are ankylosed; the second pharyngobranchial anterior processes are relatively hypotrophied; all pharyngeal teeth except the posterior teeth in the fifth ceratobranchial face posteriorly; the muscularis craniopharyngobranchialis 2 posterior is short; the muscularis craniopharyngobranchialis 2 anterior is lacking, as is its insertion site, the inferior parasphenoid apophysis; the protractor pectoralis is well developed; the pharyngocleithralis internus originates dorsal to the level of the fifth ceratobranchial bony process; the fifth ceratobranchial bony processes are directed ventrolaterally; the opposing upper and lower tooth fields appear not to occlude erosively; and the muscular portion of the pharyngohyoideus is well developed anteriorly. The extent of these differences and their implications for the function of the PJA support recent molecular studies that suggest that the Hemiramphidae is polyphyletic. J. Morphol. 262:750–759, 2004. © 2004 Wiley‐Liss, Inc.
Functional morphology of the ear in fossorial rodents, Microtus arvalis and Arvicola terrestris
Authors: Lange Simone , Stalleicken Julia , Burda Hynek 
Published: October 2004

AbstractFunctionally relevant features and parameters of the outer, middle, and inner ear were studied morphologically and morphometrically in two species of voles, smaller Microtus arvalis and larger Arvicola terrestris. The findings in these fossorial (i.e., burrowing) rodents with components of surface activity were compared with respective findings reported for taxonomically related muroid rodents representing the same size classes but different eco‐morphotypes: obligate subterranean rodents (Ellobius talpinus and Spalax ehrenbergi superspecies) and generalized rodents (Mus domesticus and Rattus norvegicus). The ear in voles was characterized by traits reported for subterranean rodents. The eardrum was round, without a distinct pars flaccida, and had an area of 5.4 mm2 in M. arvalis and 9 mm2 in A. terrestris. The middle ear exhibited reduced goniale, enlarged incus nearly parallel to the manubrium of the malleus. The malleus‐incus lever ratio amounted to 2.1 (M. arvalis) and 2.0 (A. terrestris). The malleus‐incus complex weighed about 0.8 mg in both vole species. The stapedial footplate had an area of 0.3 mm2 in M. arvalis and 0.4 mm2 in A. terrestris. The cochlea had 2.3 coils in both vole species; the basilar membrane was 8.5 mm and 10.5 mm long in M. arvalis and A. terrestris, respectively. There were on average 1,030 (M. arvalis) and 1,220 (A. terrestris) inner hair cells, and 3,760 (M. arvalis) and 4,250 (A. terrestris) outer hair cells in the organ of Corti. In quantitative terms, all these (as well as some further) traits and parameters were intermediate (related to body size) between those reported for generalized rodents on the one hand and subterranean ones on the other. The sound transmission system of the ear seems to be best tuned to frequencies of about 8–16 kHz with a high‐frequency cut‐off at about 50–60 kHz. The ear of A. terrestris seems to be tuned to somewhat lower frequencies than that in M. arvalis. In this aspect as well as regarding hearing sensitivity (as judged from the mechanical transmission parameters), voles can be considered intermediate not only in their lifestyle but also in their hearing abilities between the subterranean rodents (mole‐vole and blind mole‐rat) and the surface dwellers (house mouse and Norway rat). J. Morphol. 262:770–779, 2004. © 2004 Wiley‐Liss, Inc.
Avian fissura prima: Differential accumulation of extracellular matrix at a fold
Authors: Bowers Doria F. , Atkins David L. 
Published: October 2004

AbstractExtracellular matrix components that flank the fissura prima, a primary surface infolding of the cerebellum in birds and mammals, were examined in the embryonic chick using light and transmission electron microscopy. Cerebella dissected from Day 10 embryos were perfused with a paraformaldehyde‐glutaraldehyde‐tannic acid primary fixative and sectioned in the sagittal plane through the mid‐vermis. Ultrastructural analysis revealed a distinct, continuous basal lamina separating the organ parenchyma (epithelia) from pia mater (mesenchyme) at the fissure surface (arbitrarily labeled; fissure floor, folia wall, and folia apex). The basal lamina was significantly thicker (P < 0.001) at the fissure floor compared to that found at the folia wall, which was significantly thicker (P < 0.001) than that observed at the folia apex. Folds in the basal lamina were observed exclusively at the fissure floor. Surface‐associated collagen fibrils were distributed in an aligned, relatively dense manner at the fissure floor, compared with fibrils observed in various orientations and widely separated or absent at the folia wall and folia apex. Metachromasia was more pronounced in the fissure floor than in either the folia wall or folia apex in methylene blue‐stained tissue sections. Together, the thicker, folded basal lamina and densely aligned collagen fibrils at the fissure floor provide a chemical rationale for this color change. These findings suggest that the differential accumulation of extracellular matrix at the fissura prima is positioned to play a structural and/or biochemical role in the maintenance of this fold. J. Morphol. 262:780–790, 2004. © 2004 Wiley‐Liss, Inc.
Development of the genital ducts in Telmatodrilinae (Tubificidae, Clitellata)
Authors: Gustavsson Lena M. 
Published: October 2004

AbstractIn Tubificidae, the male genital duct comprises a funnel in the testes segment, followed by a vas deferens, an atrium, and, frequently, a copulatory structure in the adjacent ovarian segment. There may also be a diffuse or compact prostate gland in association with the duct. The morphology and position of the genital ducts are important for the classification of the oligochaetous Clitellata. Different parts of the male duct, however, have been named without regard to whether they are homologous or not. One way to establish better hypotheses of homology is to study the detailed morphology and/or the development of the genital ducts. The morphogenesis of the genital ducts in Alexandrovia onegensis (Telmatodrilinae) is described. The male funnel originates by multiplication of peritoneal (mesodermal) cells in the posterior septum in the testes segment. A cord of these cells breaks through the septum and grows backwards into the next segment, where it connects to the epidermis. This cord gives rise to the vas deferens, and is therefore mesodermal in origin. The atrium in A. onegensis develops from a primary epidermal (ectodermal) invagination. The vas deferens and atrium connect and a continuous duct from the testes segment to the exterior is formed. Several compact prostate glands develop along the atrium, each being formed from cells in the atrial epithelium. The spermatheca develops from an invagination of the epidermis in the testes segment. The female duct is formed from peritoneal (mesodermal) cells in the posterior septum in the ovarian segment. These developmental findings strengthen the hypothesis about a closer relationship between the Telmatodrilinae and Tubificinae (both Tubificidae). J. Morphol. 262:791–799, 2004. © 2004 Wiley‐Liss, Inc.
Ontogeny of tracheal system structure: A light and electron‐microscopy study of the metathoracic femur of the American locust, Schistocerca americana
Authors: Hartung DeeAnn K. , Kirkton Scott D. , Harrison Jon F. 
Published: October 2004

AbstractDoes oxygen delivery become more challenging for insects as they increase in size? To partially test this hypothesis, we used quantitative light and electron microscopy to estimate the oxygen delivery capacity for two steps of tracheal oxygen delivery within the metathoracic femur (jumping leg) for 2nd instar (about 47 mg) and adult (about 1.7 g) locusts, Schistocerca americana. The fractional cross‐sectional areas of the major tracheae running longitudinally along the leg were similar in adults and 2nd instars; however, since the legs of adults are longer, the mass‐specific diffusive conductances of these tracheae were 4‐fold greater in 2nd instars. Diffusive gas exchange longitudinally along the leg is easily possible for 2nd instars but not adults, who have many air sacs within the femur. Mitochondrial content fell proximally to distally within the femur in 2nd instars but not adults, supporting the hypothesis that diffusion was more important for the former. Lateral diffusing capacities of the tracheal walls were 12‐fold greater in adults than 2nd instars. This was primarily due to differences in the smallest tracheal class (tracheoles), which had thinner epidermal and cuticular layers, greater surface to volume ratios, and greater mass‐specific surface areas in adults. Adults also had greater mitochondrial contents, larger cell sizes and more intracellular tracheae. Thus, larger insects do not necessarily face greater problems with oxygen delivery; adult grasshoppers have superior oxygen delivery systems and greater mass‐specific aerobic capacities in their legs than smaller/younger insects. J. Morphol. 262:800–812, 2004. © 2004 Wiley‐Liss, Inc.
Soluble KDI domain of γ1 laminin protects adult hippocampus from excitotoxicity of kainic acid
Authors: Wiksten Markus , Väänänen Antti , Liebkind Ron , Rauhala Pekka , Liesi Päivi 
Published: October 2004

AbstractRecent data indicate that the soluble KDI domain of γ1 laminin promotes survival and neurite outgrowth of human central neurons in vitro (Liebkind et al.[2003] J Neurosci Res 73:637–643), and seems to neutralize both glia‐ and myelin‐derived signals that hamper regeneration in the central nervous system (CNS) of adult mammals. We show that damage of adult rat neocortical and hippocampal areas by a stereotaxic injection of kainic acid (KA) is prevented by a preceding injection of the soluble KDI domain. In the presence of the KDI domain, both neocortical and hippocampal areas show extensive gliosis but have viable neurons and glial cells, which are absent and the areas fully destroyed after injection of KA alone. This result indicates that the KDI domain of the γ1 laminin protects the CNS against excitotoxic insults and promotes survival of both neurons and glial cells. The KDI domain may thus be a potential drug to prevent CNS damage induced by neurodegenerative disorders, mechanical injury, or ischemia. © 2004 Wiley‐Liss, Inc.
A Study on Biomineralization Behavior of N‐Methylene Phosphochitosan Scaffolds
Authors: Yin Yu Ji , Luo Xiao Yan , Cui Jun Feng , Wang Chang Yong , Guo Xi Min , Yao Kang De 
Published: October 2004

AbstractSummary: Biomimetic growth of calcium phosphate over natural polymer may be an effective approach to constituting an organic/inorganic composite scaffold for bone tissue engineering. In this work, N‐methylene phosphochitosan (NMPCS) was prepared via formaldehyde addition and condensation with phosphoric acid in a step that allowed homogeneous modification without obvious deterioration in chitosan (CS) properties. The NMPCS obtained was characterized by using FT‐IR and elemental analysis. The macroporous scaffolds were fabricated through a freeze‐drying technique. A comparative study on NMPCS and CS scaffold biomimetic mineralization was carried out in different media, i.e, a simulated body fluid (SBF) or alternative CaCl2 and Na2HPO4 solutions respectively. Apatite formation within NMPCS and CS scaffolds was identified with FT‐IR, scanning electron microscopy (SEM), energy‐dispersive X‐ray (EDX) and X‐ray diffractometery (XRD). The results revealed alternate soaking of the scaffolds in CaCl2 and Na2HPO4 solutions was better than soaking in SBF solution alone in relation to apatite deposition on the scaffold pore walls. Biomineralization provides an approach to improve nature derived materials, e.g., chitosan derivative NMPCS properties e.g., compressive modulus, etc.SEM image of a NMPCS/apatite composite scaffold.magnified imageSEM image of a NMPCS/apatite composite scaffold.
Controlling Degradation of Acid‐Hydrolyzable Pluronic Hydrogels by Physical Entrapment of Poly(lactic acid‐co‐glycolic acid) Microspheres
Authors: Lee Jun Bae , Chun Ki Woo , Yoon Jun Jin , Park Tae Gwan 
Published: October 2004

AbstractSummary: Chemically crosslinked biodegradable hydrogels based on di‐acrylated Pluronic F‐127 tri‐block copolymer were prepared by a photopolymerization method. Poly(lactic acid‐co‐glycolic acid) (PLGA) microspheres were physically entrapped within the Pluronic hydrogel in order to modulate the local pH environment by acidic degradation by‐products of PLGA microspheres. The PLGA microspheres were slowly degraded to create an acidic microenvironment, which facilitated the cleavage of an acid‐labile ester‐linkage in the biodegradable Pluronic hydrogel network. The presence of PLGA microspheres accelerated the degradation of the Pluronic hydrogel and enhanced the protein release rate when protein was loaded in the hydrogel.SEM image of photo‐crosslinked Pluronic hydrogel entrapping PLGA microspheres.magnified imageSEM image of photo‐crosslinked Pluronic hydrogel entrapping PLGA microspheres.
Synthesis and Functionalization of Isotactic Poly(propylene) Containing Pendant Styrene Groups
Authors: Zou Junfeng , Cao Chengang , Dong Jin‐Yong , Hu Youliang , Chung Tze‐Chiang 
Published: October 2004

AbstractSummary: Copolymerization of propylene and 1,4‐divinylbenzene was successfully performed by a MgCl2‐supported TiCl4 catalyst, yielding isotactic poly(propylene) (i‐PP) polymers containing a few pendant styrene groups. With a metalation reaction with butyllithium and a hydrochlorination reaction with dry hydrogen chloride, the pendant styrene groups were quantitatively transformed into benzyllithium and 1‐chloroethylbenzene groups, respectively, which allowed the synthesis of i‐PP‐based graft copolymers by living anionic and atom transfer radical (ATRP) polymerization mechanisms.The incorporation of styrene pendant groups into isotactic poly(propylene) using a Zeigler–Natta catalyst gave functionalized polymers able to undergo living anionic and atom transfer radical (ATRP) polymerizations.imageThe incorporation of styrene pendant groups into isotactic poly(propylene) using a Zeigler–Natta catalyst gave functionalized polymers able to undergo living anionic and atom transfer radical (ATRP) polymerizations.
Abnormalities of sensory processing and sensorimotor interactions in secondary dystonia: A neurophysiological study in two patients
Authors: Tamburin Stefano , Zanette Giampietro 
Published: October 2004

AbstractExperimental data suggest that abnormalities of sensory processing and sensorimotor integration may play a role in the genesis of symptoms in primary dystonia. We studied 2 patients with dystonia secondary to lesions in the somatosensory pathways. We documented sensorimotor alterations in these patients that strongly resemble those found in primary dystonia. Our data are consistent with the hypothesis that abnormalities in sensorimotor processing may contribute to the pathogenesis of dystonic conditions. © 2004 Movement Disorder Society
Repeated visual hallucinations in Parkinson's disease as disturbed external/internal perceptions: Focused review and a new integrative model
Authors: Diederich Nico J. , Goetz Christopher G. , Stebbins Glenn T. 
Published: October 2004

AbstractVisual hallucinations (VH) in Parkinson's disease (PD) are a chronic complication in 30 to 60% of treated patients and have a multifaceted phenomenology. Flickering, faultive impressions, and illusionary misperceptions precede the core syndrome of stereotyped, colorful images. The patient variably recognizes these images as hallucinations, being rarely irritated or frightened and more often amused as a bystander. Although studies on VH in PD focus on several research domains, no comprehensive, unified theory has been developed to study their pathophysiology. We have adapted Hobson's work on the states of consciousness and propose a model integrating seemingly disparate data on VH. We suggest that VH should be considered as a dysregulation of the gating and filtering of external perception and internal image production. Contributive elements and anatomical links for the model include poor primary vision, reduced activation of primary visual cortex, aberrant activation of associative visual and frontal cortex, lack of suppression or spontaneous emergence of internally generated imagery through the ponto‐geniculo‐occipital system, intrusion of rapid eye movement dreaming imagery into wakefulness, errative changes of the brainstem filtering capacities through fluctuating vigilance, and medication‐related overactivation of mesolimbic systems. Different etiologies likely produce different phenomenologies and the prognosis may not be uniform. This new conceptual framework permits an anatomical view of VH and suggests new, testable hypotheses regarding their pathophysiology and therapy. © 2004 Movement Disorder Society
Sacsin‐related autosomal recessive ataxia without prominent retinal myelinated fibers in Japan
Authors: Hara Kenju , Onodera Osamu , Endo Minoru , Kondo Hiroshi , Shiota Hiroshi , Miki Kenji , Tanimoto Naoyuki , Kimura Tetsuya , Nishizawa Masatoyo 
Published: October 2004

AbstractAutosomal recessive spastic ataxia of Charlevoix–Saguenay (ARSACS) has been described in the Quebec region and in Tunisia. We report on two Japanese siblings with a new homozygous mutation (6543 del A) of the SACS gene. Compared with previously reported ARSACS patients, both of these patients had a unique phenotype characterized by dementia, ophthalmoplegia, and the absence of prominent retinal myelinated fibers. © 2004 Movement Disorder Society
Panconnectivity, fault‐tolerant hamiltonicity and hamiltonian‐connectivity in alternating group graphs
Authors: Chang Jou‐Ming , Yang Jinn‐Shyong , Wang Yue‐Li , Cheng Yuwen 
Published: October 2004

AbstractJwo et al. [Networks 23 (1993) 315–326] introduced the alternating group graph as an interconnection network topology for computing systems. They showed that the proposed structure has many advantages over n‐cubes and star graphs. For example, all alternating group graphs are hamiltonian‐connected (i.e., every pair of vertices in the graph are connected by a hamiltonian path) and pancyclic (i.e., the graph can embed cycles with arbitrary length with dilation 1). In this article, we give a stronger result: all alternating group graphs are panconnected, that is, every two vertices x and y in the graph are connected by a path of length k for each k satisfying d(x, y) ≤ k ≤ |V| − 1, where d(x, y) denotes the distance between x and y, and |V| is the number of vertices in the graph. Moreover, we show that the r‐dimensional alternating group graph AGr, r ≥ 4, is (r − 3)‐vertex fault‐tolerant Hamiltonian‐connected and (r − 2)‐vertex fault‐tolerant hamiltonian. The latter result can be viewed as complementary to the recent work of Lo and Chen [IEEE Trans. Parallel and Distributed Systems 12 (2001) 209–222], which studies the fault‐tolerant hamiltonicity in faulty arrangement graphs. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44(4), 302–310 2004
Pentacyclic triterpene 5‐phenylpenta‐2,4‐dienoyl esters from Peltastes peltatus (Vell.) Woodson
Authors: Humberto Margarida M. S. , Nascimento Maria Cleonice B. S. , Sant'Ana Antônio E. G. 
Published: October 2004

AbstractTwo new pentacyclic triterpene esters, peltastine A {3β‐[5‐phenyl‐(2E,4E)‐penta‐2,4‐dienoyloxy]‐urs‐12‐ene} and peltastine B {3β‐[5‐phenyl‐(2E,4E)‐penta‐2,4‐dienoyloxy}‐lup‐20(29)‐ene}, have been isolated from the stem of Peltastes peltatus (Vell.) Woodson along with the previously reported β‐amyrin juarezate {3β‐[5‐phenyl‐(2E,4E)‐penta‐2,4‐dienoyloxy]‐olean‐12‐ene}. The structures of these compounds were established by MS, 1D‐ and 2D‐NMR experiments as well as by chemical degradation. Copyright © 2004 John Wiley & Sons, Ltd.