bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early ultrastructural changes of developing oocytes in the dog
Authors: Tesoriero John V. 
Published: February 2005

AbstractMany aspects of the developmental stages of the oocyte of the dog resemble those of other mammalian species. The oocyte of the dog, however, contains large amounts of lipid yolk material. A study of the ultrastructural morphology of early growth and maturation of dog oocytes was undertaken to clarify the nature and appearance of this yolk material. The lipid yolk first appears in early primary oocytes as aggregated dense bodies that gradually fill the ooplasm as the oocyte matures. The site of the yolk's initial appearance is consistently related to a single centriole and often to the lamellae of smooth endoplasmic reticulum that surrounds groups of forming lipid yolk bodies. Dense cortical granule‐like vesicles are found to lie deep within the maturing oocyte and often are enclosed within the lamellar yolk space. Granules within this space undergo changes in size, matrix configuration, and vacuolization. These changes suggest a mechanism whereby material is added to the lipid yolk bodies. Light microscope histochemistry for lipid and polysaccharide material is described.
Morphological evidence for probable secreting site for the pheromone “seducin” in males of Nauphoeta cinerea. I. Light microscope studies
Authors: Menon Maya 
Published: February 2005

AbstractMales of the cockroach, Nauphoeta cinerea (Olivier), possess a thickened secretory epithelium limited to the inner surfaces of sternites three to seven and tergites two to eight. The epithelium consists of three cell types: 1. large columnar secretory cells, 2. squamous nonsecretory cells, and 3. duct cells. Type 1 cells constitute the innermost layer and contain large nuclei and vacuoles, which are especially prominent in the epidermis of older males. This cell type may be involved in “seducin” secretion. Type 2 cells lie in the narrow basophilic zone which separates the secretory cells from the cuticle. Here, cellular boundaries are poorly defined. Type 3 cells with condensed nuclei are associated with cuticular ductules leading from the epidermis to the exocuticle. The epidermal height in the secretory zone of the sclerites approaches 40–200 μm depending on the age of the male. The changes in appearance of the secretory cells (increase in height and vacuolation) indicate heightened secretory activity. This is supported by the results obtained when extracts of these regions from different aged males are bioassayed for pheromone (Dimeo et al., '78). A striking difference in the morphology of the cuticle and epidermis of the secretory halves of sternite and tergal integument is noticeable.
A quantitative analysis of mitotic gradients during early development in Calliphora erythrocephala Meig. (Diptera)
Authors: Lundquist Anders 
Published: February 2005

AbstractMitotic waves during superficial cleavage and early gastrulation were analyzed quantitatively in Calliphora. Three consecutive patterns are present: (1) a monotonic anterioposterior mitotic gradient during early superficial cleavage; (2) a double mitotic gradient from the anterior and posterior poles during superficial cleavage, especially toward the end of the period; and (3) more complicated patterns with intermediate mitotic centers during the last superficial cleavage division and during early gastrulation. Mitotic gradients are absent in many eggs during early superficial cleavage, but they then become ubiquitous. The gradients are longitudinal; no transverse component was detected before gastrulation. Anterior and posterior gradient patterns are not mirror images of each other; mitotic activity always starts earlier anteriorly. The gradients are accompanied by a pronounced increase in interphase length. The mitotic gradients are compared with the morphogenetic gradients predicted in a current model for pattern specification in insect eggs.
Microanatomy of the renal cortex in the domestic fowl
Authors: Wideman Robert F. , Braun Eldon J. , Anderson Gary L. 
Published: February 2005

AbstractTwo aspects of the avian renal cortical microanatomy previously were unclear. The precise in situ folding patterns and orientations of the nephrons with respect to the other cortical elements had not been demonstrated. It also was not known whether certain nephron segments are supplied exclusively by either the arterial or the portal blood flow. In the present study, a new casting compound was developed to allow selective examination of the cortical components by light microscopy. Cortical nephrons at the surface of the kidney were serially sectioned and reconstructed in order to determine: (a) their relationships to the vasculature and collecting ducts; (b) the location and characteristics of the tubule segments; and (c) the primary and secondary folding patterns of the tubules. The anatomical findings were documented individually and then summarized in a comprehensive diagram of the superficial cortical microanatomy. In addition, an in vivo method was used to determine the extent of portal blood distribution to the nephron segments. It was demonstrated that renal portal blood suffuses all of the segments except for the loops of Henle.
Sensilla of the antennae and the labial and maxillary palps of Blattella germanica (L.) (Dictyoptera: Blattellidae): Their classification and distribution
Authors: Ramaswamy S. B. , Gupta A. P. 
Published: February 2005

AbstractThe various sensilla on the antennae and on the labial and maxillary palps of Blattella germanica (L.) were studied. Thick‐walled chemoreceptors with fluted shafts and articulated bases are located on the antennae and on the labial and maxillary palps. Thin‐walled chemoreceptors, without fluted shafts or articulated bases, are restricted to the flagellar segments of the antennae and to the distal segments of the palps. Antennae of adult males have more thin‐walled chemoreceptors than do those of females. Hair‐plate sensilla are found at the scape‐head and scape‐pedicel joints, and at the joints of segments on the palps. Campaniform sensilla are concentrated as a ring around the distal margin of the pedicel, and are also scattered singly on the scape, pedicel, and flagellar segments of the antennae, and on the first segment of the maxillary palps. Occasionally, a few sensilla coeloconica and cold receptor sensilla are found on the antennal flagellum.
Observations on preadipocytes and their distribution patterns in rat adipose tissue
Authors: Askew E. W. , Schuschereba S. T. , Brown J. P. , Hecker A. L. 
Published: February 2005

AbstractMicroscopic examination of adipocytes isolated from adult rat epididymal adipose tissue revealed numerous small cells (< 10 μm) morphologically similar to larger adipocytes. These small adipocytes appear identical to a new classification of adipose cells termed preadipocytes. Electron micrographs of these preadipocytes revealed examples of cells < 10 μm in diameter in various stages of maturation and lipid accumulation. The percent distribution pattern of these small adipocytes was not significantly altered by exercise although exercise shifted the distribution patterns of the larger cells (> 30 μm) toward a smaller mean cell size. The quantitative significance of preadipocytes is not established but these preliminary observations indicate that adipocytes < 10 μm in diameter may account for a numerically greater proportion of the total adipocytes observed in collagenase isolated preparations than heretofore recognized, although their contribution to total adipose mass is probably negligible.
Limb regeneration following the discontinuation of growth hormone therapy in the hypophysectomized newt, Notophthalmus viridescens
Authors: Landesman Richard , Hessler Arthur C. 
Published: February 2005

AbstractUntreated adult newts do not undergo normal limb regeneration following hypohysectomy. A fibrocellular dermal barrier (cicatrix) atypically forms between the apical epithelium and the underlying mesenchymal tissues. Historically, continuous administration of growth hormone or of prolactin in combination with thyroxine restored regenerative capacity to these newts. In a previous investigation, we demonstrated that the initial effect of these two hormone treatments, when administered on alternate days to hypophysectomized newts beginning eight days post‐amputation, was to facilitate the erosion of the fibrocellular barrier and establish the epithelial mesenchymal interface that is observed in a regenerating limb.The present investigation was designed to evaluate the necessity of continuous hormone therapy to maintain limb regeneration in hypophysectomized newts. One, two, or three injections of growth hormone or of prolactin in combination with thyroxine was administered on successive alternate days to hypophysectomized newts either immediately following limb amputation (ID) or beginning eight days post‐amputation (DD). The ID and DD newts receiving one, two, or three injections of growth hormone showed evidence of regeneration to the digitiform stage by day 30 post‐amputation, while those receiving prolactin and thyroxine underwent wound healing. While both hormone treatments initially promoted a dermis‐free apical epithelium, only hypophysectomized newts that had received growth hormone were able to continue regenerating.We have, therefore, concluded that discontinuous growth hormone therapy is sufficient to initiate and maintain the conducive environment for limb regeneration to advanced stages in the hypophysectomized newt. While initiating this process, prolactin and thyroxine therapy on a discontinuous regime does not maintain regeneration. The direct and indirect role of growth hormone in supporting limb regeneration in normal and hypophysectomized newts is discussed.
External features of embryonic development of a jumping bristletail, Pedetontus unimaculatus Machida (Insecta, Thysanura, Machilidae)
Authors: Machida Ryuichiro 
Published: February 2005

AbstractThe external features of the embryo and the first instar larva of Pedetontus unimaculatus are described. Blastokinesis of P. unimaculatus is very similar to that of Petrobius brevistylis (Larink, '69), but differs from that of Machilis alternata (Heymons and Heymons, '05). The superficial structures of three pairs of protocerebral lobes are present. The terga of the mandibular, maxillary, and labial segments take part in the formation of the head capsule. In the maxilla and labium, the palpi are homologous with the telopodites of the legs; the other parts proximal to the palpi are homologous with the coxopodites. No sternal element contributes to the postmentum. Both glossa and paraglossa consist of two lobes. The pleuropodium, stylus and ventral sac are derived from distal parts of appendage anlagen. The pleuropodium of the first abdominal segment is homologous with the styli of the successive abdominal segments; the ventral sacs of succeeding segments are serially homologous. The basal parts of appendage anlagen cover each sternum in the first to ninth abdominal segments to form coxites, which are therefore appendicular in origin. The basal part of the cercus also covers the ventral and lateral surfaces of the eleventh abdominal segment.
The embryonic development of the primitive moth, Neomicropteryx nipponensis Issiki (lepidoptera, micropterygidae): Morphogenesis of the embryo by external observation
Authors: Kobayashi Yukimasa , Ando Hiroshi 
Published: February 2005

AbstractThe micropterygid moth Neomicropteryx nipponensis belongs to the most primitive suborder Zeugloptera of the Lepidoptera. During embryogenesis the small circular germ disk formed on the ventral egg surface invaginates deeply into the yolk. It finally separates from the egg periphery or rudimentary serosa, and becomes a sac‐shaped germ rudiment. Its anterior part later develops into the germ band, while its posterior part is the future amnion. Just before revolution of the embryo, the embryo assumes a completely superficial position beneath the yolk. Neither amnion nor serosa rupture during revolution; by completion of dorsal closure they have been incorporated into the yolk to form the secondary dorsal organ.The formation of the germ rudiment and embryonic membranes in N. nipponensis resembles those of swift moths, Endoclyta (suborder Monotrysia) and of the caddisflies, Stenopsyche (Trichoptera), but differs from those of ditrysian Lepidoptera. The secondary dorsal organ has never been found in any other lepidopteran embryos; however, it is formed in N. nipponensis and in the Trichoptera. The results of the present study strongly support the general phylogenetic views that the Zeugloptera have a close affinity to the Trichoptera.
Olfactory bulb efferents in the channel catfish, Ictalurus punctatus
Authors: Bass Andrew H. 
Published: February 2005

AbstractAutoradiographic, HRP, and Fink‐Heimer techniques define olfactory bulb efferents in the channel catfish. The olfactory bulb projects bilaterally to eight targets in the area ventralis telencephali including the preoptic area, five targets in area dorsalis telencephali, and the posterior tuber of the diencephalon. There is additional input to the peripheral margin of the internal cell layer of the contralateral olfactory bulb. Fibers cross in rostral (nervus terminalis and commissure of Goldstein) and caudal components of the anterior commissure and the habenular commissure. HRP techniques reveal the origin of bulb efferents from the internal and mitral cell layers of the olfactory bulb. The olfactory tract is divided into five major components, each with a unique subset of ipsilateral and commissural pathways.
The cytoarchitecture of the torus semicircularis in the red‐eared turtle
Authors: Browner Robert H. , Kennedy Michael C. , Facelle Thomas 
Published: February 2005

AbstractThe cytoarchitecture and neuronal morphology of the torus semicircularis in the red‐eared turtle, Chrysemys scripta elegans, were examined in Nissl‐stained and Golgi‐impregnated material. The torus semicircularis begins in the caudodorsal mesencephalon and extends rostrally and laterally to end ventrally to the tectal ventricle. The torus semicircularis consists of a central nucleus and a laminar nucleus, which is interposed between the central nucleus and the ventricle.The central nucleus can be divided into two regions, a small, large‐celled area, located dorsally, and a larger area of small spherical (6–17 μm), large spherical (18–25 μm), triangular (15–27 μm) and fusiform (10–26 μm) neurons. The small spherical cells have two dendritic patterns: “radiate” and “single.” The radiate pattern has a dorsoventral orientation, several secondary branches and few dendritic spines. These cells are usually located in the center of the central nucleus. The single pattern is oriented mediolaterally. This cell type is most often observed at the periphery of the central nucleus. These neurons have few secondary branches and dendritic spines. The large spherical neurons display two dendritic orientations: dorsoventral and mediolateral. All dendritic trees have numerous secondary branches and few dendritic spines. The triangular neurons exhibit primary dendrites projecting from the corners of the somata and have few secondary branches and dendritic spines.The fusiform neurons have a majority of their dendrites oriented mediolaterally, few secondary branches and a small number of dendritic spines.The laminar nucleus consists of several layers and three cell types: ovoid (9–15 μm), triangular (20–40 μm), and fusiform (20–40 μm). All neurons have few secondary dendritic branches and few dendritic spines. The dendrites of many neurons course perpendicularly to the long axis of the brainstem and encapsulate the central nucleus. Some ovoid and fusiform neurons display dendrites that enter the central nucleus.
The torus semicircularis in a gekkonid lizard
Authors: Kennedy Michael C. , Browner Robert H. 
Published: February 2005

AbstractThe cytoarchitecture and neuromorphology of the torus semicircularis in the tokay gecko, Gekko gecko, were examined in Nissl‐stained, fiber‐stained, and Golgi‐impregnated tissues.From a superficial position, the torus semicircularis extends rostrally under the caudal half of the optic tectum. Caudally, the two tori abut upon one another; rostrally, they diverge. The torus semicircularis consists of central, laminar, and superficial nuclei.The central nucleus consists of fusiform, spherical and triangular neurons. Their dendrites are highly branched, with numerous dendritic spines, and are oriented mediolaterally, dorsoventrally, and rostrocaudally. Fusiform and spherical neurons display two dendritic patterns: “single axis,” ramifying in one axis, and “dual axis,” exhibiting higher‐order branches perpendicular to the primary dendrites. Triangular neurons exhibit a “radiate” dendritic pattern.In the rostral half of the torus semicircularis, the laminar nucleus caps the central nucleus. The laminar nucleus encircles the central nucleus in the caudal torus semicircularis. The neurons of the laminar nucleus have dendritic arrays oriented parallel to the border of the central nucleus. These dendrites exhibit a paucity of dendritic spines and higher‐order branches. Fusiform and spherical neurons exhibit “single axis” and “dual axis” dendritic patterns. Triangular neurons display “radiate” patterns.The caudal superficial nucleus lies dorsal and dorsolateral to the central nucleus. The superficial nucleus is sparsely populated by small fusiform and spherical neurons with moderately branched dendrites and moderate numbers of dendritic spines. These neurons display “single axis” (fusiform neurons) as well as “dual axis” and “radiate” (spherical neurons) dendritic patterns. They are oriented either parallel to or perpendicular to the boundary of the laminar nucleus.
A Study of the influence of the ambient microflora on the structure of lung alveolar macrophages and an ultrastructural comparison of lung and peritoneal macrophages in germ‐free and conventionally reared mice
Authors: Woodward B. 
Published: February 2005

AbstractIn order to investigate quantitatively and objectively the influence of the normal microbial flora on the ultrastructure of the alveolar macrophage, three groups of mice were studied stereologically: germ‐free (GF), conventionally reared under non sterile isolation conditions (IC), and conventionally reared in an open environment (OC). The alveolar macrophages of GF mice possess a smaller mitochondrial compartment, possibly with fewer organelles, than the macrophages of conventional mice. Other influences of the normal microflora on alveolar macrophage substructure are obscured by the effects of nonmicrobial stimuli such as droplets of lung surfactant.No previous comparison exists of alveolar and peritoneal macrophage ultrastructure. Lung macrophages are larger than the phagocytes of the peritoneum, but the difference in size is much less than is commonly believed. Alveolar macrophages are rounder than peritoneal macrophages, and exhibit much less rough endoplasmic reticulum (RER) as well as differences in mitochondrial morphometry. No difference in mitochondrial volume fraction exists between the two types of macrophage even though alveolar macrophages represent the extreme of aerobic adaptation in the mononuclear phagocyte system. Phagosomes occupy a significant fraction of cellular volume only in the alveolar macrophages. Moreover alveolar phagocytes contain fewer but larger lysosome‐like granules than are found in peritoneal macrophages. The results represent the first objective, quantitative structural evidence confirming the common belief that alveolar macrophages experience greater physiological stimulation than peritoneal macrophages. The normal microflora accounts for only a small proportion of the differing degree of stimulation exerted on the two types of macrophage.
An electron microscopic study on the innervation of the gill filaments of a lamprey, Lampetra japonica
Authors: Nakao Taisuke 
Published: February 2005

AbstractThis paper reports observations on the innervation of gill filaments of the lamprey, Lampetra japonica. Nerve fibers run on each side of the afferent filament artery (AFA nerve) and in the connective tissue compartment along the efferent filament artery (EFA nerve). The AFA nerve supplies vasomotor fibers to the afferent filament artery and arteriovenous anastomoses and special visceral motor fibers to branchial muscle fibers (musculus compressor branchialis circularis). Nerve endings of the vasomotor fibers contain large, cored vesicles (60–180 nm in diameter) with a variable number of small, clear vesicles (30–70 μm in diameter), whereas those of the visceral motor fibers have many small, clear vesicles with few large, cored vesicles. The EFA nerve supplies vasomotor fibers to the efferent filament artery. Their endings, containing mixtures of predominantly large, cored vesicles and small, clear vesicles make close synaptic contacts with reticular cells. The latter in turn are connected with each other or with smooth muscle cells in the wall of the efferent filament artery by nexuses. No nerves are found in the axial plate between the afferent and efferent filament arteries nor in the secondary lamellae of individual gill filaments. No afferent nerve supply to the gill filament has been found.
Retinal afferents and efferents of an infrared sensitive snake, Crotalus viridis
Authors: Schroeder Dolores M. 
Published: February 2005

AbstractThe retinal afferents and efferents were examined in Crotalus viridis. Retinofugal fibers were traced by injecting horseradish peroxidase (HRP) or tritiated leucine into the eye, or by removing the eye and staining degenerating axons with silver methods. Terminations were seen contralaterally in the suprachiasmatic nucleus, the dorsal and ventral lateral geniculate nuclei (extensive), the pretectal nuclei, including the nucleus posterodorsalis (a very heavy input), the nucleus lentiformis mesencephali, nucleus geniculatus pretectalis, and nucleus pretectalis, the superficial layers of the optic tectum, including the stratum zonale, the stratum opticum, the stratum griseum et fibrosum centrale and the upper portion of stratum griseum centrale, and the basal optic nucleus. Ipsilateral input reaches the intermediate portion of the dorsal lateral geniculate nucleus, a small portion of the pretectal nucleus and nucleus posterodorsalis, and the basal optic nucleus (very minimally). Retinopedal fibers were traced with the HRP method. The cell bodies lie in the ventral thalamus within the nucleus of the ventral supraoptic decussation. These neurons project primarily to the contralateral retina, but some more rostrally located neurons project to the ipsilateral retina.
The fully formed chondrocranium of the agamid lizard, Agama pallida
Authors: Zada Suher 
Published: February 2005

AbstractMajor features of interest in the mature chondrocranium of Agama pallida are striking curvature of the nasal region, lack of the paranasal cartilage and concha nasalis, and presence of a cartilaginous roof over Jacobson's organ. In addition, the course of the ethmoid nerve deviates from the normal lacertilian pattern; there is no foramen epiphaniale, and the temporal region is reduced. The prefacial commissure and facial foramen lie in front of the cochlear portion of the auditory capsule, whereas the prominentia semicircularis anterior is separated from the rest of the otic capsule. Several chondrocranial characters are suggested to be unique to the agamids.