bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nerve pathways between the pterygopalatine ganglion and eye in cats
Authors: Lin Ton , Grimes Patricia A. , Stone Richard A. 
Published: February 2005

AbstractBy dissection of thiocholine‐stained orbital preparations, it has been determined that three different nerve pathways link the pterygopalatine ganglion and the eye in cats. (1) Nerves from the proximal half of the ganglion join a plexus of nerves and ganglion cells in the rete mirabile of the maxillary artery. Branches of the internal carotid nerve also supply this plexus. Fine nerves from the plexus travel to the optic nerve and then to the eye, accompanying both the nasociliary nerve that passes through the rete and the ciliary arteries that arise from the rete. (2) One or more nerves from the nerve of the pterygoid canal and from a prominent accessory ganglion near the orbital apex course to the inferior optic nerve surface at the optic foramen; these then run distally along the optic nerve to fuse with ciliary nerves or to accompany ciliary arteries entering the eye. (3) Other nerves from the pterygopalatine ganglion travel medially around the extraocular muscle cone to join the ethmoidal and infratrochlear branches of the nasociliary nerve; some nerves from the ganglion then take a retrograde course to the optic nerve, where they join ciliary nerves or arteries to the eye. All three pathways may transmit sympathetic, parasympathetic and somatic sensory nerve fibers.
An immunohistochemical study of the ontogeny of the horizontal cell in the rat retina using an antiserum against spot 35 protein, a Novel purkinje cell‐specific protein, as a marker
Authors: Kondo Hisatake , Yamamoto Miyuki , Yamakuni Tohru , Takahashi Yasuo 
Published: February 2005

AbstractA sequence of morphological changes during the differentiation of retinal horizontal cells was studied by means of immunohistochemistry for spot 35 protein, a novel Purkinje cell‐specific protein, in the rat retina. Spot 35‐immunoreactive horizontal cell anlagen were first identified at embryonic day 18 (E18) in the outer zone of the neuroblastic cell layer as fusiform cells with slender inner and outer processes. As the development proceeded, the immunoreactive cells increased in number and intensity of the immunostaining, and the outer processes of the immunoreactive cells were often bifurcated close to their origin or at their periphery. At postnatal days 3 and 5 (P3 and P5), a regional difference in morphology of the immunoreactive horizontal cell anlagen was recognized: The immunoreactive cells near the ora serrata still assumed a bipolar shape, and those in the central portion of the retina had multiple processes. At P7 and P10, the immunoreactive cells in the periphery of the retina extended most of their outer processes in the plane of the retina, forming a network together with processes of adjacent immunoreactive horizontal cells. Their internally extending processes during these postnatal stages tended to be present in small numbers and to be short. At P14 all the immunoreactive horizontal cells extended their processes horizontally to form a tight bundle all the way along the outer plexiform layer. These findings indicate that spot 35 protein is a specific marker for the horizontal cells of the rat retina in the developmental process from their bipolar stage at E18 until reaching their mature configuration at P14.
Scanning electron microscope study of the spatial organization of the air and blood conducting components of the avian lung (Gallus Gallus variant domesticus)
Authors: Maina J. N. 
Published: February 2005

AbstractThe lungs of the domestic fowl were prepared for scanning electron microscopy after vascular and airway latex rubber casting to demonstrate the spatial organization of the various structural components that are involved in the gas exchange that takes place in the parabronchial tissue mantle. The bulk of the intrapulmonary air flows through the parabronchial lumen and then centrifugally diffuses into the exchange tissue through the atria, the infundibula, and the air capillaries. The blood flows centripetally from the interparabronchial arteries, then into the intraparabronchial arterioles, and finally into the blood capillaries, which together with the air capillaries constitute the functional terminal gas exchange units. The relationship between the air flow in the parabronchial lumen and the incoming blood (into the exchange tissue) has been shown to be crosscurrent, where the directions of the flow of these two gas exchange media are essentially perpondicularly disposed to each other; whereas the relationship between the blood capillaries and the air capillaries is countercurrent, the blood flowing towards the parabronchial lumen and the air in the opposite direction, i.e., towards its periphery. Both these spatial structural relationships between the air and blood are significant factors that contribute to the remarkable efficiency of the avian lung in gas exchange. The crosscurrent system enhances the duration of interaction between the parabronchial air and the blood, the oxygen being extracted from a parabronchus along its whole length, whereas the overall contribution of the countercurrent relationship, which is superimposed on the crosscurrent system, is not expected to be very high, mainly because of the tortuosity and profuse interlacing of the blood and air capillaries over a relatively short distance, that of approximately the thickness of the parabronchial tissue mantle.
Morphometric and statistical analyses describing the In utero growth of human epidermis
Authors: Foster Carolyn A. , Bertram John F. , Holbrook Karen A. 
Published: February 2005

AbstractEpidermal development of human embryonic and fetal skin from the lower limb was studied using morphometric and statistical methods. Epidermal grooth, as defined by an increase in epidermal thickness and the number of cell layers, occurred in three distinct stages during the first and second trimesters. The first growth spurt occurred between 5 and 13 weeks estimated gestational age (EGA) and was followed by a plateau phase with little change in epidermal thickness from 14 to 21 weeks, after which the epidermis began to increase in height again. The periderm reached its maximal height by approximately 13 weeks EGA, and by 25 weeks was shed into the amniotic fluid. Thus, within a five‐month period (5 to 25 weeks EGA) the epidermis changed from a single cell layer < 10 μ thick to a 10 to 12‐cell layer, keratinized epithelium >60 μ thick. In contrast, epidermis from adult lower limb consisted of about 25 cell layers and was almost 75 μ in thickness. The age‐related differences in epidermal thickness probably reflect changes in cell size and shape more than changes in the directional movement (apically vs. laterally) of proliferating keratinocytes, because the addition of cell layers throughout development was relatively constant. During the plateau phase, when there is a rapid increase in fetal growth rate, the suprabasal keratinocytes become more flattened, thereby allowing for the addition of new cell layers while maintaining a relatively constant epidermal thickness. The loss of glycogen reserves, along with other intrinsic cellular changes, probably contributes to the flattening effect. However, the internal expansion of growing tissues also may exert a mechanical pressure that could stretch the skin passively and influence epidermal structure.
Effects of long‐term testosterone exposure on ovarian function and morphology in the rhesus monkey
Authors: Faiman C. , Reyes F. I. , Dent D. W. , Fuller G. B. , Hobson W. C. , Thliveris J. A. 
Published: February 2005

AbstractThis study was aimed at developing a model in the rhesus monkey for the human gynecologic disorder termed the polycystic ovary syndrome (PCOS). The effects of chronic constant androgen exposure upon quantitative ovarian morphology and ovulatory function were examined. Twenty‐five normally cycling females, aged 4–12 yr and weighing 3.3–8.2 kg, were enrolled in the study in random fashion. Seventeen animals were implanted subcutaneously (s.c.) with 10 or 25 mg testosterone‐filled silastic tubing so as to maintain steady serum levels of testosterone averaging 80 ng/dl (low‐dose group, n=8) and 115 ng/dl (high‐dose group, n = 9) for 13–16 months. Eight animals served as controls (sham implants); in these, mean serum testosterone levels averaged 24 ng/dl. No effect of androgen treatment was observed on ovulatory function as gauged by periodic luteal phase progesterone determinations and the presence of a fresh corpus luteum at laparoscopy. Menstrual cycle frequency (number of cycles over number of months of observation) was, however, slightly but significantly (P 7lt; 0.05) reduced in the high‐dose (88.9%) vs. the control (96.7%) and low‐dose (95.0%) groups. Quantitative morphology, performed by light microscopy on a single ovary obtained from 16 of the 25 animals and read in a blinded fashion, revealed no differences in ovarian weight, capsular width and numbers, size, or proportion of healthy and atretic follicles among the three groups. Although constant long‐term testosterone exposure failed to result in a picture resembling the human PCOS counterpart, factors such as higher levels, a longer duration of exposure, a different type of androgen used, or a critical peripubertal period of exposure will have to be considered in future experiments.
Effects of diltiazem on isoproterenol‐ or Ca‐induced ventricular myocardial cell injuries in isolated perfused rabbit heart: An electron microscopic study
Authors: Kim Ho‐Dirk , Rah Bong‐Jin 
Published: February 2005

AbstractThe ultrastructural changes of isoproterenol‐ and those of Ca‐induced ventricular cell injuries were compared in rabbits and the effect of diltiazem on these injuries was studied by electrom microscopy.In comparison with the controls, the isoproterenol‐treated (Group A), the Ca‐treated (Group B), and the diltiazem‐posttreated (Groups E and F) showed severe myocardial cell damage, such as sarcolemmal disruption, mitochondrial swelling, intramitochondrial electron‐dense granules, membranous structures along mitochondrial cristae, thickening or close packing of the Z‐lines, separation of cell junctions, frayed myofibrils, clumping of chromatin, and intracellular fluid accumulation. These ultrastructural changes were more pronounced in the Ca‐treated (Groups B and F) than in the isoproterenol‐treated (Groups A and E) animals. In contrast, the diltiazem‐pretreated groups (Groups C and D) showed relatively intact myocardial ultrastructure. However, intramitochondrial electron‐dense granules could be frequently found, and particularly the diltiazem‐pretreated and Ca‐treated group (Group D) showed intracellular fluid accumulation.The results of this study could suggest the following: (1) isoproterenol‐induced myocardial cell damage is similar to Ca overload, (2) pretreatment with diltiazem could reduce the deleterious effects of isoproterenol‐induced myocardial cell damage, but it could not prevent the effects of Ca overload completely, and (3) posttreatment with diltiazem could not provide any beneficial effect either on the isoproterenol‐induced or on the Ca‐overloaded mycoardial cell damage, and (4) the beneficial effects of diltiazem are probably derived from the enhanced buffering function of mitochondria to cytosolic Ca or from selective inhibition of transsarcolemmal Ca influx.
Cell death in the ventral region of the neural retina during the early development of the chick embryo eye
Authors: Martín‐Partido Gervasio , Rodríguez‐Gallaro Lucía , Alvarez Ignacio S. , Navascués Julio 
Published: February 2005

AbstractThe present study deals with morphologic and quantitative changes that take place in the area of cell death in the ventral part of the presumptive retinal wall of the chick embryo. These changes were followed from the optic vesicle stage until the first optic fiber fascicles leave the neural retina. Our results show that both the volume occupied by the area of cell death and the density of its pyknotic fragments undergo considerable variation during the period between Hamburger and Hamilton's (1951) stages 12 to 20. In the optic vesicle stages, cell death in the ventral wall of the vesicle was observed in 50 to 75% of the embryos studied. During stages 14 and 15, this zone was seen in more than 90%. By the time invagination of the optic cup was complete, the ventral retinal zone of cell death had disappeared entirely in a large proportion of embryos; in all other, it shrank significantly both in volume and density of pyknotic fragments. In stage 19, when the first optic fiber fascicles begin to emerge from the retina, a dramatic increase occurs in the number of pyknotic fragments in the posterior pole of the retina. The appearance of dying cells, in a region shortly to be traversed by developing ganglion cell axons, supports the hypothesis that cell death processes are apparently somehow related to the creation of a suitable environment for the emergence of fibers toward the optic stalk. Densities of mitotic and interphasic cells as well as the mitotic index were determined in both the retinal zone of cell death and in areas devoid of dead cells. In all developmental stages analyzed, the mitotic index was notably lower in the former than in non‐necrotic zones, suggesting that cell proliferation is partially inhibited in retinal areas of cell death.
Familial male pseudohermaphroditism and testicular descent in the racoon dog (Nyctereutes)
Authors: van Vlissingen J. M. Fentener , Blankenstein M. A. , Thijssen J. H. H. , Colenbrander B. , Verbruggen A. J. E. P. , Wensing C. J. G. 
Published: February 2005

AbstractSexual differentiation was investigated in familial male pseudohermaphroditism in Nyctereutes procyonoides (Canidae). In intersex males, development of external genital organs and prostate glandular tissue was severely disturbed; Wolffian (mesonephric) duct derivatives developed prepubertally but were absent in some adults. Müllerian (paramesonephric) duct regression was complete. Testicular descent was undisturbed. Male/female sex differences in plasma testosterone, 5α‐dihydrotestosterone, and luteinizing hormone concentrations were present. Intersex plasma hormone concentrations were within the normal male range. The concentration of androgen receptors in pubic skin was similar in male, female, and intersex animals and no significant differences in affinity for the ligand were detected.It was concluded that in intersex animals androgen‐dependent virilisation was deficient despite the presence of androgens and androgen receptors and that this condition had not affected gubernaculum development and testicular descent.
Stereological study on the mode of optic cup expansion and the accumulation of mitoses in the early stages of chick embryo development
Authors: Calvente Ruth , Carmona Ramón , Abadí‐Molina Francisco , Abadía‐Fenoll Francisco 
Published: February 2005

AbstractThe present study was designed to contribute to our understanding of the factors that take part in the development transformation of the optic vesicle into the optic cup. The expansion and formation of this structure are dependent upon factors such as cellular proliferation, the space or zone occupied by the growing optic cup, and environmental influences. Our investigation in the chick embryo analyzes the relationship between retinal thickness and ventricular mitotic density. This relationship is shown in the study as PEI (proliferation‐expansion index). That index varies in the superior, medial and inferior regions of the retina when the zones of the same stage are compared, as well as in the comparisons of values between the 13–14 stage and the 17–18 stage. These differences indicate a different behavior of the cells constituting the retinal regions. Also discussed is the influence of the retinal fissure on the morphological changes observed during optic cup development.
Suppression of erythroid cell differentiation in mouse embryos exposed to retinoic acid in utero
Authors: Yasuda Yoshiko , Konishi Hiroyoshi , Matsuo Takuya , Tanimura Takashi 
Published: February 2005

AbstractDifferentiation of circulating erythrocytes was inhibited by all‐trans‐retinoic acid in 8‐ and 9‐day‐old mouse embryos exposed in utero on day 8 of gestation. Histochemical, light, and electron microscopic examinations revealed that all‐trans‐retinoic acid first decreased the numbers of polychromatic erythroblasts and then increased them. Simultaneously, immature erythroblasts proliferated, and differentiation of mature primitive erythrocytes was suppressed. Electron microscopy of these immature erythroblasts revealed monosomes rather than the usual polyribosomes in the cytoplasm. RNA histochemistry revealed a greater number of intermediate differentiating erythroblasts with pyronin‐positive cytoplasm than those in the controls and revealed also a dose‐dependent relationship between the number of polychromatic erythroblasts with positive pyronin staining and the controls. These findings suggest that all‐trans‐retinoic acid destroys the messenger RNA system, resulting in an inability to produce hemoglobin.
Mechanism for the removal of residual cytoplasm from spermatids during mouse spermiogenesis
Authors: Sakai Yasuhiro , Yamashina Shohei 
Published: February 2005

AbstractDuring spermiogenesis, cytoplasmic processes of Sertoli cells invade spermatid cytoplasm to form a canal complex (Sakai et al., 1988). Thin tubules are formed from the canal complex and intertwine with each other to give rise to the “mixed body.” In the present study, analysis of the changes undergone by the intertwining thin tubules indicated that they contribute to the removal of cell organelles from spermatid cytoplasm.Intertwining thin tubules were first detected at step 13. By step 15, their number had greatly increased. In the present study, the membranes of the intertwinging thin tubules were clearly observed to be continuous with the spermatid plasma membranes. Thus, the mixed body possibly may be formed as a long pit of the spermatid plasma membrane situated close to the invading Sertoli cell process. With the progress of spermiogenesis, the lumens of the intertwining thin tubules gradually became swollen, and the intertwining swollen tubules fused with each other so that the spermatid cytoplasm enclosed by the intertwining swollen tubules isolated into fragments. This fragmented cytoplasm, which contained a large amount of endoplasmic reticulum, became spherical. Small branches of the invading Sertoli cell processes entered into the lumens of the intertwining swollen tubules and occupied their interior to the point that, finally, they completely engulfed the fragmented spermatid cytoplasm. Because the invading Sertoli cell processes were continuous with Sertoli cell bodies surrounding a spermatid at this step, it is possible for the fragmented cytoplasm to be transported into the latter by way of the invading Sertoli cell processes.
Embedding prolene for the development of fiducial markers
Authors: Johnson Carole L. , Underwood Robert A. , Holbrook Karen A. 
Published: February 2005

AbstractA simple, inexpensive method is described for embedding Prolene with tissue samples to provide landmarks for fiducial points to align serial sections in tissue reconstructions. Prolene is a monofilament suture material that can be easily sectioned with diamond knives to provide circular markers in each section. The sections are photographed, the negatives are projected through an enlarger and the contours, Prolene circles, and scratches from the diamond knife are traced onto paper. These landmarks establish a framework for assigning fiducial points that are necessary for the correct alignment of the contours. No special equipment is needed for embedding the Prolene and the method is adaptable for both automated and nonautomated computer systems. An example of this method for tissue alignment is given using embryonic limb tissue to determine the spatial organization of developing blood vessels as demonstrated by computer reconstruction.
Radioautographic study of [3H]mannose utilization during cementoblast differentiation, formation of acellular cementuum, and development of periodontal ligament principal fibers
Authors: Cho Moon‐Il , Garant Philias R. 
Published: February 2005

AbstractThe formation of acellular cementum and the deposition of [3H]mannose‐labeled extracellular matrix were studied in 14‐day‐old Sprague‐Dawley rats. The sequential events of cementogenesis and periodontal ligament formation observed by light and electron microscopy were described from the stage of an intact root sheath to postcementogenesis. Ultrastructural examination of cementoblasts and periodontal ligament fibroblasts revealed [3H]mannose labeling of the Golgi apparatus at 10 minutes, collagen secretion granules at 30 minutes, and the extracellular matrix beginning at 30 minutes. The extracellular matrix between cementoblasts and dentin was heavily labeled at 1 and 4 hours. Newly formed principal fibers of the periodontal ligament were also heavily labeled at 4 hours. Fully differentiated cementoblasts exhibited the largest sectional profiles and the highest number of silver grains per unit area of cytoplasm. The morphologic and radioautographic data suggest that during the formation of acellular cementum, the cementoblast phenotype is expressed for a short period of time, after which cementoblasts appear to mix with the fibroblasts of the periodontal ligament.
Development of spermatozoa in the rhea
Authors: Phillips David M. , Asa Cheryl S. 
Published: February 2005

AbstractWe have examined the ultrastructural changes that take place during spermiogenesis in the rhea. Spermatozoa are characterized by a curved head a midpiece. A thin rod extends from the anterior tip of the spermatozoon through the center of the nucleus. A 3‐μ‐long distal centriole occupies the entire midpiece. The principal piece is characterized by a small fibrous sheath and tiny dense fibers that are only observed in the region of the principal piece, which is immediatley behind the annulus. During development a circular manchette surrounds the nucleus of young spermatids. Later the microtubules of the circular manchette become reoganized into a longitudinal manchette. A long distal and short proximal centriole are observed in early round spermatids. The distal centriole becomes associated with the plasma membrane. Later the proximal centriole is observed in association with the nucleus. The area around the centriole pair then accumulates dense material, which is associated with either the centrioles or the circular manchette. The longitudinal manchette forms and then dissappears and mitochondria subsequently associate with the distal centriole. The long centriole of the rhea enables this species to develop a midpiece similar to the midpiece of mammalian sperm without the complex intercellular movements that characterize mammalian spermiogenesis.