bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell polarity changes and migration during early development of the avian peripheral auditory system
Authors: Carney Paul R. , Couve Eduardo 
Published: February 2005

AbstractThe intracellular location of organelles was studied in avian embryos immediately before and during the initial detachment of cells from the dorsoanterolateral wall of the otocyst, using light and electron microscopy. The Golgi apparatus was silver‐impregnated, and its location within the otic epithelium was determined quantitatively. The present study demonstrates that a sub‐population of cells of the dorsoanterolateral otic epithelium changes the intracellular location of its organelles, particularly the Golgi apparatus and the centrosome, from an apical to a basal position. Concomitantly, cells lose specializations characteristically present at apical (tight junctions, microvilli) and basal (basal lamina) surfaces. At basolateral cell surfaces, filopodia form ahead of the Golgi apparatus and centrosome and penetrate the previously continuous underlying basal lamina. Thereafter, cells detach from the otocyst and migrate medially toward the hindbrain. Thus, concomitant with changes in surface polarity, the cells that comprise the dorsoanterolateral wall of the otocyst undergo profound changes in the intracellular location of their organelles, especially the Golgi apparatus and the centrosome, so that by the time cells detach from the otic epithelium a reversal in their “normal” internal polarity has occurred. We suggest that the change in cell polarity may be related to the mechanisms that allow cells to leave the otocyst.
Quantitative study of fungiform papillae and taste buds on the cat's tongue
Authors: Robinson P. P. , Winkles P. A. 
Published: February 2005

AbstractThe number of fungiform papillae has been counted on the tongues of six adult cats and of kittens both at birth and aged 2 and 4 months. Papillae were sampled from different regions of the tongue, and their size and the number of taste buds they contained were determined using histological sections taken parallel to the tongue surface. There were approximately 250 fungiform papillae on the tongues of the adult cats, the papillae were most numerous at the tip of the tongue, and there was no significant difference between the number of papillae on each side. The size of the papillae increased from a mean maximum diameter of 0.28 mm at the tip of the tongue to 0.48 mm at the back; the mean number of taste buds increased correspondingly from 6.9 to 16.6. The kitten tongues had a number and distribution of fungiform papillae similar to that found in the adults. In the neonate, papillae were smaller and contained fewer taste buds; these parameters increased with the corresponding increase in tongue size in the 2‐ and 4‐month‐old kittens.
Cross‐sectional internal diameters of human cervical and femoral blood vessels: Relationship to subject's sex, age, body size
Authors: Mortensen JD , Talbot Steven , Burkart John A. 
Published: February 2005

AbstractCross‐sectional internal diameter measurements were made of right and left common carotid and right femoral arteries and right and left internal jugular, superficial femoral, and common femoral veins in 32 normal human subjects utilizing duplex ultrasonography. The relationships of these vessel sizes to the subject's sex, age, height, weight, and body surface area were analyzed statistically; and graphs were constructed, indicating the relationship of blood vessel diameters to the various body size parameters. Findings indicate that (1) for the femoral veins, body surface area had the best correlation with the internal diameter of the vein; (2) for the right internal jugular vein, body weight had the best correlation with the internal diameter of the vein; (3) correlation between vein diameter and body size of the subject is better for the femoral veins than for the internal jugular veins; (4) internal diameter of the femoral and internal jugular veins increases about 20% when they are distended by 15% of positional inclination of the subject's body; (5) neither age nor sex of the subject influences the positional distensibility of the veins examined; (6) the cross‐sectional internal diameter of the femoral and internal jugular veins, as determined by duplex ultrasonography, closely relates to the external diameter of these vessels as measured by direct in vivo application of calipers and to the maximum outside diameter of cannula the vessel will accept.
Embryological development and prevalence of digital flexion creases
Authors: Kimura Sumiko , Schaumann Blanka A. , Plato Chris C. , Kitagawa Tadashi 
Published: February 2005

AbstractThe embryological development and morphology of digital flexion creases were studied in 178 human embryos and fetuses 6‐20 weeks of gestational age. The results suggest the existence of two types of digital flexion creases, that differ from each other in their development. The regular creases, with the exception of the distal crease of the proximal interphalangeal creases, and the oblique and extra creases of the irregular creases, develop concurrently with the appearance of the digital pads by about 11 weeks of gestation. The remaining creases, i.e., the distal crease of the proximal interphalangeal creases and the accessory crease develop later unrelated to the pads but, apparently, secondary to the flexion movements of the hand. Our observations further suggest that, because of their high frequencies, the oblique creases on the ulnar side of digits I and II and on the radial side of digit V and the extra creases on the proximal phalanx of digits I, III, and IV should be considered as “regular” creases.Previously unreported pads were also found on the middle phalanges at about 11 weeks of gestation. Unlike the single, large pads with high elevation, typically found on the distal phalanges, those on the middle phalanges are multiple, small, and only slightly elevated. This observation provides further support to the concept of the relationship between the fetal digital pads and the development of the epidermal ridge patterns.
SEM and TEM analyses of isolated human retinal microvessel basement membranes in diabetic retinopathy
Authors: Carlson Edward C. , Bjork Nancy J. 
Published: February 2005

AbstractHuman retinas from persons with diabetic retinopathy and agematched controls were rendered acellular by sequential detergent treatment. The resulting network of microvascular extracellular matrix (ECM) materials, including basement membranes (BMs), was compared by TEM and, following cryofracture, by SEM. Our study demonstrates that in diabetics, retinal capillary BM complexes are generally thickened and that their ECM subcomponents, including BM leaflets and BM‐like pericytic matrix (PCM), are differentially altered. Two diabetic microvessel types were identified. In type A vessels, ECM expansion is manifested by loosely arranged combinations of concentric PCM layers and collagen fibrils with thickened subendothelial (EBM) and pericyte (PBM) BM leaflets. Type B vessels show densely compact central PCM masses and poorly recognizable EBMs and PBMs. In both types, Müller cell BMs (MBMs) are relatively unaffected. High‐resolution SEM shows tissue‐specific features in normal EBM and MBM surfaces, but disease‐related topographic changes are not evident. It is possible that the ECM arrangements identified in our study relate to different microvessel domains and that their specific morphological features may play important roles in the pathogenesis of diabetic retinopathy including capillary closure and neovascularization.
Intercellular communication within the rat anterior pituitary Gland. II. castration effects and changes after injection of luteinizing hormone‐releasing hormone (LH‐RH) or testosterone
Authors: Soji Tsuyoshi , Herbert Damon C. 
Published: February 2005

AbstractThis study investigated the relationship between gap junction formation and sex steroids in the male rat anterior pituitary gland. Animals were castrated at 5 days of age and separated into the following three groups: (1) oiltreated controls, (2) those injected with LH‐RH, and (3) those given testosterone. On days 10, 20, 30, and 40, five rats in each group were sacrificed and their hypophyses removed for ultrastructural examination. When compared with age‐matched, intact animals, there was a marked suppression in follicular development and in the number of gap junctions present in the pituitary glands of both the castrated controls as well as the castrates given luteinizing hormone releasing hormone (LH‐RH). In contrast, the morphology of these structures in the animals given testosterone was indistinguishable from that observed in the intact controls. These observations provide more definitive evidence that in the male rat pituitary gland maturation of the structural organization of the follicles, including gap junction formation, requires an intact hypophyseal‐gonadal axis and is highly dependent on the hormone testosterone.
Skeletal structural adaptations to mechanical usage (SATMU): 2. Redefining Wolff's Law: The remodeling problem
Authors: Frost H. M. 
Published: February 2005

AbstractBasic multicellular unit (BMU)‐based remodeling of lamellar bone causes bone turnover, net gains and losses of bone on some bone surfaces or “envelopes,” and a remodeling space comprising bone temporarily absent due to evolving resorption spaces and incomplete refilling of them by new bone. Those features depend (a) on how many new BMU arise annually, (b) on how much bone each BMU has resorbed and (c) formed upon its completion, and (d) on how long the typical BMU takes to become completed. Because a, b, and c have limiting or maximal values in life that direct and/or indirect effects of mechanical usage of the skeleton can change, the theory presented here derives mechanical usage functions that express what fractions of those maxima a given mechanical usage history allows to happen. The theory predicts some changes in bone formation, resorption, balance, turnover, and remodeling space that depend on how remodeling responds to the vigor of a subject's mechanical usage. The theory can predict specific effects of specific mechanical challenges that experiments can test, and it fits abundant published evidence. As the kernel of a new approach to the problem it awaits critique and refinement by others. It plus the 3‐way rule can redefine Wolff's law conceptually and also in mathematical and quantifiable form.
Cellular regulation of basal and FSH‐stimulated cyclic AMP production in irradiated rat testes
Authors: Kangasniemi Marko , Kaipia Antti , Toppari Jorma , Mali Pekka , Huhtaniemi Ilpo , Parvinen Martti 
Published: February 2005

AbstractBasal and follicle‐stimulating hormone (FSH)‐stimulated cyclic AMP (cAMP) productions by seminiferous tubular segments from irradiated adult rats were investigated at defined stages of the epithelial cycle when specific spermatogenic cells were low in number.Seven days post‐irradiation, depletion of spermatogonia did not influence the basal cAMP production, but FSH response increased in stages II‐VIII. Seventeen days post‐irradiation when spermatocytes were low in number, there was a small increase in basal cAMP level in stages VII‐VIII and FSH‐stimulated cAMP production increased in stages VII‐XII and XIII‐I. At 38 days when pachytene spermatocytes and round spermatids (steps 1‐6) were low in number, a decreased basal cAMP production was measured in stages II‐VI and IX‐XII. FSH‐stimulated cAMP output increased in stages VII‐XII but decreased in stages II‐VI. At 52 days when all spermatids were low in number, basal cAMP levels decreased in all stages of the cycle, whereas FSH response was elevated only in stages VII‐XII.All spermatogenic cell types seem to have an effect on cAMP production by the seminiferous tubule in a stage‐specific fashion. Germ cells appear to regulate Sertoli cell FSH response in a paracrine way, and a part of cAMP may originate from spermatids stimulated by an unknown FSH‐dependent Sertoli cell factor. The FSH‐dependent fuctions may control such phenomena as spermatogonial proliferation, final maturation of spermatids, and onset of meiosis.
Ultrastructure of the pituitary intermediate lobe in aging rats
Authors: Saland L. C. , Samora A. , Desai S. 
Published: February 2005

AbstractThe pituitary intermediate lobe, a source of pro‐opiomelanocortin (POMC) peptides, was examined with light and electron microscopic techniques in Sprague‐Dawley rats aged 5–18 months and Zucker rats aged 18 months. Cysts were common in the intermediate lobe in the Zucker animals, a finding also noted in human pituitary glands by other investigations. The nuclear envelopes were often indented in cells of aging rats, while those of young animals were generally smooth. Lipid droplets and lysosomes, rarely seen in tissue from young animals, were frequently observed in endocrine cells of older rats. Most cells had an abundance of secretory granules, suggestive of enhanced storage of peptides in the cytoplasm. Nerve terminals which were present among endocrine cells contained myelin figures in some of the old rats, and may indicate degenerative changes, while other terminals appeared normal. These morphologic findings suggest that the aging phenomena in intermediate lobe tissue have characteristics in common with nervous tissue, and may also reflect a diminished inhibitory neuroregulation.
Lympho‐epithelial interactions in the turtle Chrysemys scrypta elegans
Authors: Bianchi F. , Giannessi F. , Dolfi A. , Lupetti M. 
Published: February 2005

AbstractThe morphological relationships present in the areas of lymphoid infiltration found in the esophagus in Chrysemys scripta elegans were studied by the use of light and transmission electron microscopy. These infiltrations are wide‐spread and can be observed in the lamina propria and the covering epithelium. Electron microscopy reveals the presence of epithelial cells with differing characteristics at the apex of the lymphoid infiltrations. The introduction of horseradish peroxidase (HRP) into the esophageal lumen revealed that these cells possess a micropinocytotic activity. On the basis of the morphological and experimental results obtained, a hypothesis is advanced of the existence, also in the turtle, of a local system of uptake of extraneous material, which induces local and systemic immunological processes.
Effects of chronic corticostorone treatment on the morphology of rat neuromuscular junctions
Authors: Fahim Mohamed A. , Andonian Marc H. 
Published: February 2005

AbstractThis study examined the effects of chronic corticosterone (CORT) treatment on the morphology of two physiologically different muscles. Nerve terminals from the slow twitch soleus (SOL) and fast twitch extensor digitorum longus (EDL) of Fischer 344 rats were stained using the zinc iodide osmium (ZIO) technique. Nerve terminal area, perimeter, and logitudinal extent legth were measured using computer‐aided morphometry.Slow and fast muscle fibers from animals which received 5–10 mg CORT per day for 3 months were atrophied compared with controls. Treated animals failed to gain weight during the study, while controls gained 37%. Adrenal weights in treated animals were 30% less than controls, after correction for body weight.Morphological parameters for SOL nerve terminals were generally larger in the CORT group, while EDL nerve terminals from the CORT group did not differ significantly from controls. Soleus nerve terminal area was 43% greater, perimeter 14% longer, and logitudinal extent length 18% longer than the control nerve terminals. This study demonstrates a greater effect of CORT treatment on slow twitch muscle than has been demonstrated in previous studies. Changes in the nerve terminal morphology of the SOL were also greater than in previous studies and suggest that a functional adaptation or remodelling may occur following CORT treatment to maintain the neuromuscular interface during the enhanced catabolic effects of the steroid.These steroid‐induced stress changes are similar in some respects to those observed in aging and disuse studies of the vertebrate neuromuscular junction. This suggests that glucocorticoid hormones may play an etiological role in the homeostasis of the neuromuscular junction in response to various stimuli.
Adaptation of cancellous bone to overloading in the adult rat: A single photon absorptiometry and histomorphometry study
Authors: Jee Webster S. S. , Li Xiao Jian 
Published: February 2005

AbstractNine‐month‐old female rats were subjected to right hindlimb immobilization or served as controls for 0, 2, 10, 18, and 26 weeks and were double‐labeled with bone markers. The right limb was immobilized against the abdomen and considered unloaded, while the left limb was overloaded during ambulation. Single‐photon absorptiometry was performed on intact femur; static and dynamic histomorphometry were performed on 20 μm thick undecalcified frontal sections of the proximal tibial metaphysis. Changes in the continuously overloaded limb was compared to that in both limbs of age‐matched control animals.Single‐photon absorptiometry detected increases of bone mineral density of +6%, +6%, and +5% in the proximal and +9%, +7%, and +10% in the distal femoral metaphyses after 10, 18, and 26 weeks of continuous overloading. Morphometrically, significant changes occurred in proximal tibial metaphyses compared to age‐matched controls; trabecular area increased +41% and +45%, trabecular number increased +31% and +32%, and trabecular separation decreased −30% and −31% after 18 and 26 weeks of overloading. A significant increase in mineral apposition rate (+38%) was found only at 26 weeks of overloading. Insignificant decreases in both eroded and labeled bone surfaces occurred at all time periods. The histomorphometric changes indicated that increased cancellous bone mass was caused by an increase in bone formation activity (i.e., increases in mineral apposition and bone formation rates) and a decrease in remodeling space (i.e., decrease in bone eroded surface). These findings indicate that the adult skeleton can quickly adapt to the increased biomechanical needs by increasing its cancellous bone mass with an adequate structural pattern. It further support Frost's postulate that increasing skeletal mechanical usage stimulates bone modeling and depresses bone remodeling to increase and maintain bone mass.
Kinetics of germinal center development in lymph nodes of young and aging immune mice
Authors: Szakal Andras K. , Taylor Janet Kurowski , Smith John P. , Kosco Marie H. , Burton Greg F. , Tew John J. 
Published: February 2005

AbstractRecent findings imply that germinal center paucity in old mice, at least in part, results from a defect in the mechanisms responsible for the transport of antigens to lymphoid nodules (follicles) and the consequent impairment of the antigen retaining reticulum (ARR) of follicular dendritic cells (FDCs). The present objective was to observe the kinetics of lymph node germinal center development in old mice having antigen transport and ARR deficits. Germinal center development was monitored in popliteal (PLN) and axillary (AXLN) lymph nodes of 6–;8 wk and 23‐mo‐old horseradish peroxidase (HRP) immune C57BL/6 mice. Using the selective binding of germinal center B cells for peanut agglutinin (PNA), germinal centers were identified in serial vibratome sections following histochemical labeling with PNA‐peroxidase conjugates at times 0, 15 min, 1, 3, 5, and 10 days after footpad challenge with 8 μg HRP. To follow the fate of preexisting (environmental antigen‐induced) germinal centers and the development of de novo (HRP‐induced) germinal centers, it was essential to distinguish between these germinal centers. Accordingly, PNA positive germinal centers associated with HRP‐retaining (peroxidase positive) ARR were identified as de novo germinal centers and germinal centers not associated with a peroxidase positive ARR were classified as preexisting germinal centers. Kinetic analysis of PNA positive germinal centers showed the following: (1) Preexisting, environmentally‐induced germinal centers dissociated and disappeared by day 3 as indicated by a decline in their numbers after antigen injection; the process of germinal center dissociation remained unaffected by aging. (2) The latency of de novo germinal center appearance was approximately equal in duration (∼3 days) to the disappearance of preexisting germinal centers. (3) The number and size of de novo HRP‐induced germinal centers increased through the experimental period in young lymph nodes, but in old mice these parameters were depressed, resulting in a significant germinal center deficit. (4) The ratio of HRP‐retaining ARR to de novo induced germinal centers was 1:1 in young and responder old mice. This ratio was not affected by aging. This finding favored the concept that antigen retention in ARR is a requirement of germinal center development. The observations supported our hypothesis that germinal center development, at least in part, depends on a normal antigen transport by showing that in aged mice with defective antigen transport‐related ARR and iccosome deficits there is an impaired development of germinal centers.
Increased density of glutamic acid decarboxylase—containing terminals in the medial preoptic nucleus and the area surrounding the paraventricular hypothalamic nucleus is associated with deoxycorticosterone acetate (DOCA)‐salt hypertension
Authors: Zappia Anthony , Hwang Bang H. , Wu J.‐ Y. 
Published: February 2005

Abstractγ‐Aminobutyric acid (GABA) is a major inhibitory neurotrans‐mitter and has been shown to exert considerable influence on the neural control of the cardiovascular function. It is not clear, however, which GABAergic systems are involved in salt‐induced hypertension. This study was designed to investigate the GABAergic neurons in specific regions of the brain possibly linked to salt‐induced hypertension. After 4 weeks of deoxycorticosterone acetate (DOCA) and salt treatments, the rats developed cardiac hypertrophy. All of the animals were sacrificed for immunocytochemical localization of GABAergic terminals using specific antibodies to glutamic acid decarboxylase (GAD). GAD‐positive GABAergic terminal densities in discrete regions of the brain were determined by using morphometric quantitation. Results showed that GABAergic terminal densities in the medial preoptic nucleus and the area lateral to the paraventricular hypothalamic nucleus were significantly increased in DOCA‐salt‐treated rats 4 weeks after the experiment as compared with 4 week controls. This study provides new evidence to support further the idea that central GABAergic neurons are closely associated with pathogenesis of salt‐induced hypertension. Different hypertensive mechanisms between salt‐induced hypertension and genetic hypertension are also discussed.