bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of androgen deprivation and estrogen treatment on the structure and protein expression of the rat coagulating gland
Authors: Holterhus P. M. , Zhao G. Q. , Aumüller G.
Published: February 2005

The effects of androgen deprivation and estrogen stimulation on rat coagulating gland were determined by immunohistochemistry and morphometric quantification of different tissue compartments. In castrated or estrogen‐treated or estrogen‐treated castrated animals, the reduction of the glandular lumen is the most obvious morphological alteration, which is accompanied by an increase in stromal tissue, especially within the lamina propria. Regressive changes occur most rapidly in castrated animals (already by the end of the first week), slower in estrogen‐treated castrated animals, and still slower in estrogen‐treated normal animals. In castrated animals, epithelium shows a reduction of rough endoplasmic reticulum, loss of secretory blebs, and a decrease of cell size and immunoreactivity for secretory transglutaminase. The reduction of glandular lumen results from an impressive increase in connective tissue of the lamina propria. Smooth muscle cells become atrophic in castrated animals, less so in estrogen‐treated animals and in castrated estrogen‐treated animals. A relative increase in thickness of the smooth muscle cell layer occurs in all experimental groups and is most obvious in estrogen‐treated normal animals. The proportion of myofilament and intermediate filament proteins (smooth muscle‐specific actin and desmin immunoreactivities) remains nearly unaltered in these cells after hormonal challenge. A redistribution of intermediate filaments occurs forming thicker bundles within the cells. No indication for increased mitotic activity of estrogenized smooth muscle cells has been found. After castration, and after estrogen treatment, the fibroblasts and the smooth muscle cells, respectively, appear responsible for the architectural changes within the coagulating gland. Reactions of the stroma are differentially regulated after estrogen treatment and androgen deprivation. No indication for increased biosynthetic activities of smooth muscle cells has been observed in any of the experimental conditions. © 1993 Wiley‐Liss, Inc.
Dendritic cell/lymphocyte clustering: Morphologic analysis by transmission electron microscopy and distribution of gold‐labeled MHC class II antigens by high‐resolution scanning electron microscopy
Authors: Setum Cindy M. , Serie Janet R. , Hegre Orion D.
Published: February 2005

Dendritic cells (DCs) are potent antigen‐presenting cells for a variety of immune responses; however, their mechanism of action has not been established. It is known that DCs can cluster with one another and with other cell types during in vitro immune responses, and clustering may be essential for the activation of resting lymphocytes. In this study, ultrastructural examination of clusters that form during extended culture of enriched rat splenic DCs (approximately 70% DCs) is reported. DCs were readily distinguished from other cell types, which inclued lymphocytes and macrophages. DCs displayed characteristic veils and/or dendritic processes that intertwined with processes of other cells within the cluster, or extended from the cluster periphery. Occasional DCs contained large vacuoles lined with small vesicles. A paramount feature of DCs is their constitutive expression of high levels of surface major histocompatibility complex class II antigens. The surface distribution of class II antigens on clustering DCs was examined using 10 nm immunogold labeling techniques and high‐resolution scanning electon microscopy. DCs were readily distinguished by morphologic criteria, and examination of various surface membrane regions revealed a differential distribution of class II antigens. Gold label was frequently distributed in linear arrays and clusters, suggesting a cytoskeletal role in the recycling/redistribution of Class II antigens. These morphologic findings further an understanding of basic DC biology and their mechanism of action as antigen presenting cells. © 1993 Wiley‐Liss, Inc.
Morphometric changes in growth of the rat pelvis after papain administration
Authors: Dixon Andrew D. , Gakunga Peter T.
Published: February 2005

The proteolytic enzyme, papain, was given systematically to evaluate the short‐ and long‐term effects of inhibition of endochondral bone formation on pelvic growth, with emphasis on the innominate bone. Ninety‐eight Lewis‐strain male rats, used concurrently for craniofacial growth studies, were divided into two groups. Thirty rats from Group I (n = 48) received 2% crude papain i.p. daily from 25–40 days‐of‐age and were euthanized at 40, 54, and 70 days‐of‐age. Thirty‐five rats from Group II (n = 50) were given papain at the same dose from 25–70 days‐of‐age and were euthanized at 26, 40, 54, 70, and 120 days. The remaining animals in both groups were the controls. Standardized dorsoventral pelvic radiographs were taken of all 98 animals. Ten linear dimensions were measured on each and the data evaluated statistically. A reduction both in size and rate of growth of the bony pelvis was found. All the anteroposterior and most of the transverse pelvic dimensions were significantly shorter, to a greater extent in the prolonged papain group. Bi‐ischial width was increased, perhaps to compensate for pelvic shortening and to accommodate the pelvic contents. The findings may contribute to our better understanding of abnormal endochondral bone growth in the pelvis. © 1993 Wiley‐Liss, Inc.
Promotion of muscle regeneration in the toad (Bufo viridis) gastrocnemius muscle by low‐energy laser irradiation
Authors: Bibikova Anna , Oron Uri
Published: February 2005

The effect of low‐energy laser (He‐Ne) irradiation on the process of skeletal muscle regeneration after cold injury to the gastrocnemius muscle of the toad (Bufo viridis) was studied using quantitative histological and morphometric methods. The injured zones in the experimental toads were subjected to five direct He‐Ne laser (632.8 nm wavelength) irradiations (6.0 mW for 2.3 min) every alternate day starting on the fourth day postinjury. Muscles that were injured as above, and subjected to redlight irradiation, served as a control group. Morphometric analysis was performed on histological sections of injured areas at 9, 14, and 30 days postinjury. At 9 days postinjury, mononucleated cells populated 69.3% ± 16.8% of the total area of injury. Thereafter, their volume fraction (percent of total injured zone) decreased gradually but more rapidly in the laserirradiated muscle than in the control. The volume fraction of the myotubes in the laser‐irradiated muscles at 9 days of muscle regeneration was significantly higher (7.0% ± 2.2%) than in the control muscle (1.2% ± 0.4%). Young myofibers in the laser‐irradiated muscles populated 15.5% ± 7.9% and 65.0% ± 9.5% of the injured area at 9 and 14 days of muscle regeneration, respectively, while in control muscles these structures were not evident at 9 days and made up only 5.3% ± 2.9% of the traumatized area at 14 days postinjury. The volume fraction of the young myofibers further increased by 30 days of muscle regeneration making up 75.7% ± 13.2% of the traumatized area, while in the laser‐irradiated muscles most of the injured zone was filled with mature muscle fibers. It is concluded that He‐Ne laser irradiation during the regeneration process markedly promotes muscle maturation in the injured zone following cold injury to the toad gastrocnemius muscle. © 1993 Wiley‐Liss, Inc.
The physiological cross‐sectional area of motor units in the cat tibialis anterior
Authors: Eldred E. , Garfinkel A. , Hsu E. S. , Ounjian M. , Roy R. R. , Edgerton V. R.
Published: February 2005

The physiological cross‐sectional area (CSA) of a motor unit (MU), taken as the sum of fiber areas measured on a single section through the approximate midlength of the MU, has been compared with the physiological CSA more strictly defined as the sum of the maximal areas to be found anywhere along the length of each of the MU fibers. The CSA at intervals along the fiber length was measured in fibers selected from four glycogen‐depleted, isolated MUs in the cat tibialis anterior (TA), and profiles of the summed areas made. In one MU, measurements were also taken on all the MU's fibers at less frequent intervals. The profiles demonstrate that the summed CSA based on each fiber's maximum CSA may exceed that derived from observation on any single section by as much as 20%. As a consequence, values that have been reported for specific tension (force per unit area) of MUs in the TA and probably other muscles may have been overestimated, especially for those MUs of fast type. Estimates were also made of the share of the MU's total force transmitted directly to the tendons of origin and insertion via endings of the blunt musculotendinous type as distinct from tapering intrafascicular endings acting through in‐series connective tissue and non‐MU fibers. In two MUs of slow type in which most fibers ran from tendon to tendon, “partial tapering” extending over 1 cm of the fiber length accounted for a third of the total physiological CSA, and indicated yet another mode for relay of the MU's force to the tendon. © 1993 Wiley‐Liss, Inc.
Development of the coronary arteries and cardiac veins in the dogfish (Scyliorhinus canicula)
Authors: De Andrés A. V. , Muñoz‐Chápuli R. , Sans‐Coma V.
Published: February 2005

The development of the coronary system in the Dogfish was studied using light microscopy. The sample examined consisted of 44 embryos and four newborns. The chronology of events occurring during the process was referred to the total length (TL) of the specimens. The nourishment of the developing myocardium first takes place by means of intertrabecular sinusoids. This system is later switched to a circulation through coronary vessels. The cardiac veins develop earlier than the coronary arteries. The earliest evidence of development of heart vessels in the present sample was the appearance of a diverticulum from the sinus venosus in three embryos of 31 mm TL. This diverticulum outlined the future coronary sinus. Both the atrioventricular and conoventricular venous rings were completely developed in an embryo of 36 mm TL. Coronary artery vessels appeared for the first time in embryos of 40 mm TL. In these specimens, two arteries arose from the midventral hypobranchial artery and divide to give rise to the four coronary artery conal trunks. In a 51‐mm TL embryo it was already possible to follow the course of the coronary arteries, from the hypobranchial artery to the conoventricular groove. All main coronary vessels were fully developed in embryos of more than 58 mm TL. However, the arteries supplying the atrium were firstly recorded in a newborn of 77 mm TL. Birth usually occurs when the shark reaches about 72–76 mm TL. © 1993 Wiley‐Liss, Inc.
Blood‐urine barrier formation in mouse urinary bladder development
Authors: Jezernik Kristijan , Pipan Nada
Published: February 2005

Formation of the blood‐urine permeability barrier in differentiating mouse transitional urothelium was studied. It was established that the development of superficial cell barrier is a two‐phase process: beginning with formation of the tight junctions, followed by formation of fusiform vesicles and asymmetric apical plasma membranes. Fusiform vesicles differentiate during days 15 and 17 of gestation and fuse with the apical plasmalemma. Thus a thick membrane is formed before the excretion of hypertonic urine into the embryonic bladder. Through some degenerative superficial cells slough between fetal day 17 and the day of birth, the bladder epithelium in mice does not lack an effective permeability barrier. © 1993 Wiley‐Liss, Inc.
Immunohistochemistry of the human ductus epididymis
Authors: Palacios José , Regadera Javier , Paniagua Ricardo , Gamallo Carlos , Nistal Manuel
Published: February 2005

Our objective was to characterize epithelial cells, lamina propria, and sites of estrogen coupling in the caput, corpus, and cauda regions of the human epididymis using antibodies to cytokeratin types; epithelial membrane antigen; laminin; type IV collagen; vimentin; desmin‐, and estradiol‐receptor‐related protein; and immuno‐histochemical techniques. Principal cells immunostain by both AE1/AE3 antibodies (keratins 1–8, 10, 13–15, and 19) and anti‐pan‐keratin antibodies (keratin 5, 6, and 8). Immunoreactions to both anti‐keratin antibodies increase from the caput to the cauda epididymis. The principal cells only immunostained by antikeratin 19 antibodies in the cauda and showed no reaction to keratins 10 and 11. Basal cells and apical cells immunoreact to anti‐AE1/AE3, antipan‐keratin, and antikeratin 19 antibodies, but not to antikeratin 10 and 11 antibodies, in all three epididymal regions. The principal cells immunoreact with epithelial membrane antigen antibodies in the stereocilia and subjacent cytoplasm. This immunostaining decreased from the caput to the cauda. Antivimentin antibodies stained the apical cytoplasm of principal cells and limited areas of both principal cells and basal cells. This immunoreaction decreased from the caput to cauda. Apical cells immunostained in the three regions. Immunoreaction to ER‐D5 was moderate in the principal cells, basal cells, apical cells, and muscular coat cells in the cauda. The apical cells immunostained in the three regions. Antilaminin antibodies stained the epithelial basement membrane in the three regions. Type IV collagen was detected in the basement membrane as well as around the muscular coat cells in the three regions. Immunoreaction to desmin was intense in the muscular coat cells in the three regions. Thickness of the immunostained area for both type IV collagen and desmin increases from the caput to the cauda. The differences in immunostain pattern along the epididymis length seem to be related to regional differences in function. © 1993 Wiley‐Liss, Inc.
Pulmonary neuroendocrine cells in species at high altitude
Authors: Gosney John Roy
Published: February 2005

Ever since pulmonary neuroendocrine cells were first described, a chemoreceptor function has been attributed to them. This hypothesis proposes that the innervated clusters of these cells, which are known to degranulate when the oxygen tension around them is reduced, respond to hypoxia to initiate activity in a reflex arc and ultimately adjust some aspect of pulmonary function. If this were true, one might expect to see changes in the pulmonary neuroendocrine system in species exposed to the unremitting hypoxia at natural high altitude. Whilst evidence from some studies suggests that such changes do occur, others have been unable to demonstrate any effect. To some extent this may be attributable to species variability, but might also reflect whether the organism is genetically adapted or merely acclimatized to life in an oxygen‐poor environment. © 1993 Wiley‐Liss, Inc.
Pulmonary neuroendocrine cells in pediatric lung disease: Alterations in airway structure in infants with bronchopulmonary dysplasia
Authors: Johnson Dana E. , Anderson W. Robert , Burke Barbara A.
Published: February 2005

Despite four decades of investigation, the function of pulmonary neuroendocrine cells (NEC) remains unclear. Since NEC secretory products may influence airway growth or differentiation or alter airway smooth muscle tone, increased numbers of NEC seen in bronchopulmonary dysplasia (BPD) may be partially responsible for the genesis of the structural and pathophysiological alterations seen in this disease state. Changes in airway structure were studied in six infants dying with BPD and six conceptional age‐matched control infants dying of noncardiopulmonary disease. Changes in bombesin‐, calcitonin‐, and serotonin‐immunoreactive NEC were quantified in lung specimens from three infants who died at 2 months of age with severe BPD and three conceptional age‐matched controls. There were no differences in either bronchiolar or bronchial airway epithelial areas, but significant increases in bronchiolar (1.8‐fold) (P < 0.001) and especially bronchial smooth muscle (2.5‐fold) (P < 0.001) were documented in infants with BPD. Few bombesin‐, calcitonin‐, and serotonin‐immunoreactive cells were identified in cartilaginous airways; however, there was a clear increase in the total number of bronchiolar immunoreactive cells in infants with severe BPD (28.5 ± 11.2 cells/mm airway epithelium) compared to control infants (4.5 ± 4.9) (P < 0.05). Our results confirm that airway wall composition does change in BPD, but there is either no or an inverse correlation between NEC number and airway epithelial and smooth muscle areas and cell numbers. The role of NEC secretory products in airway smooth muscle growth and function requires further investigation. © 1993 Wiley‐Liss, Inc.
Cholinergic‐nicotinic control of growth and secretion of cultured pulmonary neuroendocrine cells
Authors: Nylen Eric S. , Becker Kenneth L. , Snider Richard H. , Tabassian Ali R. , Cassidy Marie M. , Linnoila R. Ilona
Published: February 2005

Dispersed newborn hamster lung cells were established in vitro in a defined, low‐serum growth medium. Neuroendocrine markers (immunohistochemistry for bombesin/gastrin‐releasing peptide and calcitonin) revealed a cellular predominance of pulmonary neuroendocrine (PNE) cells. While the supernatant concentration remained stable, the concentration of PNE cell immunoreactive calcitonin (iCT) gradually declined over 4 weeks. Supplementation of the medium with nicotine for 3 weeks prevented this decline in cellular iCT. Concurrently, the number of cells and [3H]thymidine incorporation were significantly increased. The stimulatory effect of chronic nicotine was reversed by the coadministration of the nicotinic antagonist hexamethonium. In another set of experiments, prior multiple transplacental nicotine pretreatments resulted in a significant increase in iCT in the lungs of newborns; when these lungs were subsequently placed in cell culture without nicotine, despite the higher concentration of iCT, there was a drop in iCT similar to that observed in the control culture. In contrast, in vivo, the lung iCT remained significantly elevated at 1 week postparturition. Cell culture supernatants were analyzed at week 4 for the evoked release of iCT; cholinergic‐nicotinic agonists promptly increased the supernatant iCT, which was blocked by nicotinic but not by muscarinic antagonists. We suggest that this in vitro system provides a useful tool to study directly the PNE cell. The acute and chronic effects of nicotine are most likely related to stimulation of cholinergic‐nicotinic receptors on iCT‐containing PNE cells. © 1993 Wiley‐Liss, Inc.
Colocalization of peptide hormones in neuroendocrine cells of human fetal and newborn lungs: An electron microscopic study
Authors: Stahlman Mildred T. , Gray Mary E.
Published: February 2005

This study investigated the colocalization of the peptide hormones bombesin or calcitonin with calcitonin gene related peptide (CGRP) in neuroendocrine cells (NE) in the lungs of human fetuses of varying gestational ages and in the lungs of newborn infants who died with acute or chronic lung disease in the first weeks or months after birth. Double immunolabeling of dense core granules for these peptides was also studied in this same patient population. On‐grid double gold immunolabeling was carried out on 29 subjects using anti‐bombesin and anti‐CGRP and on 22 subjects using anti‐calcitonin and anti‐CGRP as primary antibodies, the secondary antibodies being labeled with different‐size gold spheres. Colocalization of both bombesin and calcitonin with CGRP was demonstrated, not only in the same NE cell, but also on the same dense core granule. Colocalization was rarely found in normal fetuses, and most frequently found in newborn infants with acute lung disease, usually hyaline membrane disease (HMD), or with the development of chronic lung disease in the first weeks or months after birth. Double labeling of the same dense core granules might imply action of peptides in concert, or perhaps one peptide acting in a paracrine role (e.g., on bronchial or bronchiolar smooth muscle) and the second peptide acting in an autocrine fashion on the parent cell (e.g., in the regulation of granule production or release). © 1993 Wiley‐Liss, Inc.
BMPs induce direct bone formation in ectopic sites independent of the endochondral ossification in vivo
Authors: Sasano Yasuyuki , Ohtani Eriko , Narita Kenji , Kagayama Manabu , Murata Masaru , Saito Takashi , Shigenobu Keiichi , Takita Hiroko , Mizuno Morimichi , Kuboki Yoshinori
Published: February 2005

Bone formation in vivo occurs via two major processes, one of which depends on pre‐existing cartilage, and the other does not. Bone morphogenetic proteins (BMPs) have been suggested to induce cartilage formation from non‐skeletogenic mesenchymal cell population, which results in osteogenesis through the endochondral sequence. In the present study we examined if BMPs could cause direct bone formation independent of pre‐existing cartilage using bovine fibrous collagen membrane (FCM) as a carrier for BMPs. Bovine metatarsal bone was extracted in 4 M guanidine HCl and BMPs were partially purified through the hydroxyapatite chromatography and the Heparin‐Sepharose CL6B chromatography. The carrier was loaded with BMPs and then implanted in Wistar rats subcutaneously. The implants were fixed together with surrounding tissue every week after implantation and processed for von Kossa stain, immunohistochemistry, and electron microscopy. The phenotypes of bone and cartilage were identified histologically and immunohistochemically using antibodies against type I and type II collagen. Cartilage and bone were independently induced by 2 weeks. The bone formed directly on the collagen substrate of FCM without pre‐existing cartilage. Calcification occurred in the carrier as well as the cartilage and bone matrix. The present study suggests that the BMPs induce osteogenesis in vivo independent of the endochondral sequence. © 1993 Wiley‐Liss, Inc.
Perinatal development of gubernacular cones in rats and rabbits: Effect of exposure to anti‐androgens
Authors: Van Der Schoot P. , Elger W.
Published: February 2005

In male rats gubernacular cones develop during the latter half of prenatal life. Inversion of these papilla‐like organs after birth is the first step to postnatal growth of the muscular cremaster sacs. The factors regulating prenatal growth and differentiation or postnatal inversion of these gubernacular cones are unknown. The lack of a detailed and unequivocal description of the normal gubernacular cone growth is judged at least partially responsible for this ignorance. The present study therefore describes the normal development of the gubernacular cones in male and female rats from day 14 of fetal life.

Androgens are hypothesized to control male gubernacular cone development but recent evidence throws doubt upon this proposal. Therefore, the second part of this study describes perinatal development of gubernacular cones in male rat foetuses exposed to the anti‐androgen flutamide from day 10 after conception. Quantitatively normal growth occurred prior to birth, indicating no role of androgen in this process. Excessive growth in length was noticed during the neonatal period together with delay of gubernacular cone inversion. These developmental alterations did not represent direct anti‐androgen–induced modifications of gubernacular cones development as the alterations were not observed in flutamide‐exposed neonatally castrated animals.

Failure of androgens to affect directly perinatal gubernacular cone growth could represent a rat‐specific feature. Fetal rabbits show the development of similar structures during the second half of fetal life. The third part of this study examined the effect on the development of these structures of exposure of male and female foetuses to the anti‐androgen cyproterone acetate. The latter compound inhibited male internal and external genital development but allowed unaltered gubernacular cone growth.

The observations in this report thus present the normal pattern of perinatal gubernacular cone growth in rats together with evidence that these organs show male‐specific growth independent of androgen. Further work should reveal the testicular or other factors responsible for this part of male bodily sexual differentiation processes. © 1993 Wiley‐Liss, Inc.
Seasonal changes of the blood‐testis barrier in viscacha (Lagostomus maximus maximus): A freeze‐fracture and lanthanum tracer study
Authors: Morales Alfonsina , Cavicchia Juan C.
Published: February 2005

Adult male viscachas (Lagostomus maximus maximus) were gathered from their natural habitat during the period of complete spermatogenesis (June) and during the month of maximum testicular regression (August). The testes were processed by conventional electron microscopic technique using lanthanum nitrate (electron‐dense intercellular tracer) to define the intercellular spaces below the inter‐Sertoli tight junctions and by freeze‐fracture techniques.

During complete spermatogenesis the tracer surrounds spermatogonia, preleptotene, and leptotene spermatocytes and stops at the level of the inter‐Sertoli tight junctions below all germ cells displaying synaptonemal complexes (zygotene‐pachytene spermatocytes) and germ cells in more advanced stages of differentiation. Conversely, during testicular regression the tracer percolates all intercellular spaces between Sertoli cells and the remaining germ cells (spermatogonia and few preleptotene and leptotene spermatocytes.) During complete spermatogenesis, freeze‐fracture replicas exhibit numerous inter‐Sertoli tight junction strands parallel to each other and to the basal lamina. During spermatogenesis decay, the inter‐Sertoli tight junctions are found to be short, tortuous, frequently interrupted, and often associated with extented membranous areas of gap junctions. © 1993 Wiley‐Liss, Inc.
Expression and accumulation of interstitial collagen in the neonatal rat heart
Authors: Carver Wayne , Terracio Louis , Borg Thomas K.
Published: February 2005

Significant physiological changes occur in the heart following birth including increased arterial blood pressure and heart rate. Concurrently, biochemical and structural alterations are evident in the neonatal heart in response to these dynamic physiological properties. Prominent among these is the elaborate development of the cardiac extracellular matrix, composed primarily of interstitial collagen. The collagenous fibers, together with other matrix components, form and elastic, stress‐tolerant network which functions in the dissipation of force throughout the heart wall. The present studies have used biochemical and molecular techniques to show the temporal and spatial patterns of interstitial collagen accumulation expression during late fetal and neonatal development of the rat heart. The use of biochemical and particularly molecular methodologies allows the analysis of the expression of matrix components at a resolution previously not attained by structural studies alone. These data show relative increases in interstitial collagen immediately following birth as well as spatial differences in collagen mRNAs within the heart. The data presented provide further evidence for a role of mechanical stimulation in the regulation of collagen gene expression during this period of heart development. © 1993 Wiley‐Liss, Inc.
Quantitative ultrastructural analysis of the periaqueductal gray in the rabbit
Authors: Meller S. T. , Dennis B. J.
Published: February 2005

The fine structure of the periaqueductal gray (PAG) of the rabbit was examined using the transmission electron microscope. On the basis of synaptic polarity, vesicle size, and the nature of the pre‐ and postsynaptic elements, 10 essentially different synaptic types could be discerned (6 axo‐dendritic, 2 axo‐somatic, 1 axo‐axonic, and 1 dendro‐dendritic). Synaptic contact on the soma of PAG neurons were small and covered, on average, only 1.6% of the soma surface. The most striking feature of the synaptic structure of the PAG was that more than 94.1% of all synapses were axo‐dendritic. Of these, 83.5% were of the symmetrical type. Most of these contacts occurred on buttons of small to medium size, and contained either round vesicles of medium size or pleomorphic vesicles of medium size. Boutons containing only flattened vesicles were quite rare. Boutons contacting larger dendrites were generally small‐to‐medium in size, made asymmetric‐type synaptic contacts, and contained pleomorphic vesicles of medium‐to‐large size. Medium‐sized dendrites were contacted principally by small boutons exhibiting either symmetrical or asymmetrical junctions containing medium‐sized pleomorphic vesicles, and in addition a few of these boutons contained both large, and small, round vesicles. Dendritic spines were generally provided with only one synaptic contact, stretching the entire width of the spinous process. Boutons and the spines on dendrites were approximately the same size. Synapses between two vesicle‐containing structures (axo‐axonic or dendro‐dendritic synapses) were rare (1.4%). They were generally asymmetric and contained round vesicles of medium size. Complex synapses, where a glial sheet enclosed the synapse, were occasionally observed. Also seen were multiple synapses, with up to 11 contacts on a single dendritic profile. Large dense‐core vesicle were seen in approximately 40% of all synapses, whereas small dense‐core vesicles were only found in about 3%. Data is provided on how different synaptic features relate to ventral, lateral, dorsal, and medial PAG. Principally this is in relation to neuron size, glia cell content, axonal characterization, and vesicular type. © 1993 Wiley‐Liss, Inc.
Incidence and histology of human accessory parotid glands
Authors: Toh Hidetoshi , Kodama Jun , Fukuda Jinichi , Rittman Barry , Mackenzie Ian
Published: February 2005

The parotid glands of 228 Japanese human cadavers were examined to determine the incidence and histological features of accessory parotid glands. The incidence was found to be 56% with no differences between right and left sides or between sexes. Thirty parotid glands and their associated accessory glands were examined histologically: eight of these accessory glands were found to be mixed secretory glands (i.e., containing both serous and mucous acini). Thus, the pattern of differentiation of a significant fraction of accessory glands differs from that of the main parotid gland: it appears that mixed acini, present in the early stages of development, persist into later life, and their presence may be related to tumors developing at these sites. © 1993 Wiley‐Liss, Inc.
Immunocytochemistry of ambiguous cells in adult and embryonic dwarf (dw) mouse pituitaries
Authors: Wilson Doris B. , Wyatt Darlene P.
Published: February 2005

In the pars distalis of the pituitary gland in adult and embryonic dwarf (dw/dw) mutant mice, ambiguous cells exhibiting ultrastructural features common to growth hormone (GH) cells and prolactin (Prl) cells were analyzed by means of colloidal gold ultrastructural immunocytochemistry in order to define the functional nature of these peculiar cells. Adult and 18‐day embryonic pituitaries from normal (+/+; dw/+) and dwarf (dw/dw) mice were processed with antibodies to GH, Prl, TSH (thyroid‐stimulating hormone), ACTH (adrenocorticotropic hormone), LH (luteinizing hormone), FSH (follicle‐stimulating hormone), and HCG (chorionic gonadotropic hormone). In the adult and embryonic dwarf pituitaries, the ambiguous cells reacted negatively to all of the antibodies except for anti‐ACTH, which labeled them well. In addition, the ACTH‐positive cells showed a much wider variety of shapes and granule size and distribution, as compared with normal adults. In the embryos, this variability in ACTH cell morphology occurred not only in dwarf embryos, but in their normal counterparts as well. The results thus suggest that adult dwarf pituitaries may retain an embryonic or incompletely differentiated form of ACTH cells. © 1993 Wiley‐Liss, Inc.
Aging and the Meynert cells in rhesus monkey primary visual cortex
Authors: Peters Alan , Sethares Claire
Published: February 2005

We have assessed the effects of aging on the cell bodies of the large Meynert cells in layers V and VI of the rhesus monkey primary visual cortex by comparing the frequency, size, and cytology of these neurons in three young (5–6 years of age), one middle‐aged (12 years of age), and four old monkeys (25–35 years of age). In the young monkeys there is an average of 20.8 Meynert cells beneath 1 mm2 of cortical surface, and in the old monkeys the value is 22.3 cells. The cell bodies of these large pyramidal cells do not become smaller with age, and surprisingly they accumulate only small amounts of lipofuscin. The conclusion is that in the rhesus monkey there is no loss of Meynert cells with age and that aging has little effect on the morphology of the cell bodies of these neurons. © 1993 Wiley‐Liss, Inc.
Ultrastructural characteristics of in vivo and in vitro fertilization in the grey short‐tailed opossum, Monodelphis domestica
Authors: Taggart D. A. , O'Brien H. P. , Moore H. D. M.
Published: February 2005

To establish the mode of fertilization in a marsupial, a morphological investigation was made of the gametes of the South American grey short‐tailed opossum, Monodelphis domestica, at the time of fertilization in vivo and in vitro. Oestrus was induced in females by the introduction of an unfamiliar male. To obtain oocytes recently fertilized in vivo, females were killed 18–24 hours after the first mating and the region of the oviduct containing eggs excised and fixed. Unfertilized mature oocytes were recovered from ovarian follicles 15–18 hours after first mating and fertilized in vitro with cauda epididymal spermatozoa in a modified MEM medium supplemented with bovine serum albumin at 37°C in 5% CO2 in air. Following sperm‐egg binding and fertilization, oocytes were fixed and prepared for light and electron microscopy.

Spermatozoa unpaired prior to fertilization in vivo and in vitro and single spermatozoa bound to the zona surface by their plasmalemma overlying the acrosome on the dorsal face of the sperm head. The acrosome reaction was only observed at the zona surface (suggesting that it may be induced by zona components) and involved a vesiculation of sperm plasma and acrosomal membranes over the main body of the acrosome but not over the narrow, marginal region which persisted after the acrosome reaction was complete. Sperm penetration of the zona pellucida caused a large breach in the zona and the dispersal of perivitelline material. The fusion of the spermatozoon with the oolemma occurred first over the marginal acrosomal region and was accompanied by a fertilization cone which protruded through the zona penetration hole. Activation of the egg was characterized by the release of material from vesicles in the peripheral cytoplasm and extrusion of the second polar body.

The mode of fertilization in Monodelphis was compared with what is known in other marsupials (New World and Australian) and eutherian (placental) mammals. It was concluded that the general features of the acrosome reaction and sperm‐egg fusion may be essentially similar in both groups and that an evolutionary schism did not occur following the development of the eutherian mode of fertilization. © 1993 Wiley‐Liss, Inc.
Cell behaviors underlying notochord formation and extension in avian embryos: Quantitative and immunocytochemical studies
Authors: Sausedo Roger A. , Schoenwolf Gary C.
Published: February 2005

Formation and extension of the notochord is one of the earliest and most obvious events of axis development in vertebrate embryos. In birds, prospective notochord cells arise from Hensen's node and come to lie beneath the midline of the neural plate, where they assist in the process of neurulation and initiate the dorsoventral patterning of the neural tube through sequential inductive interactions. In the present study, we examined notochord development in avian embryos with quantitative and immunological procedures. Extension of the notochord occurs principally through accretion, that is, the addition of cells to its caudal end, a process that involves considerable cell rearrangement at the notochord‐Hensen's node interface. In addition, cell division and cell rearrangement within the notochord proper contribute to notochord extension. Thus, extension of the notochord occurs in a manner that is significantly different from that of the adjacent, overlying, midline region of the neural plate (i.e., the median hinge‐point region or future floor plate of the neural tube), which as shown in one of the previous studies from our laboratory (Schoenwolf and Alvarez: Development 106:427–439, 1989), extends caudally as its cells undergo two rounds of mediolateral cell‐cell intercalation and two‐three rounds of cell division. © 1993 Wiley‐Liss, Inc.
Organization of the extraocular and preganglionic motoneurons supplying the orbit in the lesser galago
Authors: Sun Wensi , May Paul J.
Published: February 2005

The retrograde tracer wheat germ agglutinin‐conjugated horseradish peroxidase was used to establish the organization of the extraocular muscle motoneuron pools in a prosimian, Galago senegalensis, for comparison with the organization in monkeys and non‐primates. Medial rectus motoneurons were distributed in three subgroups in the ipsilateral oculomotor nucleus, a pattern similar to that of the monkey. Furthermore, the other component of the near response system, the preganglionic parasympathetic motoneurons, were confined within the Edinger‐Westphal nucleus, as in the monkey. In contrast, the distribution of the levator palpebrae and superior rectus motoneurons was similar to that of the cat. Specifically, the majority of levator palpebrae motoneurons were located contralaterally, in the caudal central subdivision of the oculomotor nucleus, and the superior rectus motoneurons had a dorsocaudal location in the contralateral oculomotor nucleus. The distributions of motoneurons supplying the superior oblique and lateral rectus muscles were similar to those of other mammals. Unlike previously studied species, the galago was found to have two accessory muscles, that lie beneath the medial and lateral rectus muscles. Motoneurons supplying the accessory rectus muscles were found ventrolateral to the main abducens nucleus, in a position similar to that occupied by the cat accessory abducens nucleus; although others may be present in the main nuclei. Taken together, these results suggest that the organization of extraocular and preganglionic motoneurons in the galago exhibits both monkey and non‐primate features. These observations are consistent with the notion that the galago is a primate species whose oculomotor organization is more similar to the general mammalian scheme. © 1993 Wiley‐Liss, Inc.
Ultrastructure of the glomus cells in the carotid body of chronically hypoxic rats: With special reference to the similarity of amphibian glomus cells
Authors: Kusakabe Tatsumi , Powell Frank L. , Ellisman Mark H.
Published: February 2005

The ultrastructural characteristics of the glomus cells in the rat carotid body exposed to extremely long‐term hypoxia (10–12 weeks) were investigated. The glomus cells could be classified into four distinct types according to the shape of dense‐cored vesicles in the glomus cell cytoplasm: (1) small vesicle cells (SVCs, 50 nm in mean diameter), (2) large vesicle cells (LVCs, 80 nm in mean diameter), (3) dilated eccentric vesicle cells (EVCs, 400–800 nm in diameter), and (4) mixed vesicle cells (MVCs, large and eccentric vesicles). Many clusters of glomus cells were found to contain all four categories of cell types. The appearance of EVCs was a unique and common characteristic of glomus cells in this long‐term hypoxia model. We also noted other ultrastructural features with chronic hypoxia which are characteristic of the amphibian carotid labyrinth glomus cells: (1) incomplete covering of glomus cells with the supporting cell missing over a wide area, (2) long thin cytoplasmic projections in the intervascular stroma, and (3) intimate apposition of the glomus cells and pericytes (g‐p connection), endothelial cells (g‐e connection), plasma cells, and fibrocytes. Because arterial PO2 is generally low in amphibia, these may be general features of hypoxic adaptation and facilitate both uptake of oxygen from blood and release of catecholamine into the blood. The g‐p and g‐e connections may take part in the regulation of the microcirculation in the enlarged carotid body. © 1993 Wiley‐Liss Inc.
Posterior pituitary of the newborn marsupial possum, Trichosurus vulpecula
Authors: Gemmell R. T. , Chua T. , Bathgate R. A. D. , Sernia C.
Published: February 2005

The fetal anterior pituitary‐adrenal axis is thought to be involved in the initiation of birth in both eutherian and marsupial mammals. Little is known about the structure and function of the posterior pituitary at birth in the marsupial. Immunocytochemistry, high pressure liquid chromatography, and radioimmunoassay were used to identify vasopressin and mesotocin in the posterior pituitary of a newborn marsupial, the brushtail possum, Trichosurus vulpecula. The concentrations of vasopressin and mesotocin in the head of the newborn possum were 0.34 and 0.28 ng, respectively. The concentration of vasopressin was always greater than that of mesotocin, and the amounts of neuropeptides present in the head increased as the possum developed. © 1993 Wiley‐Liss Inc.
Unique features of the cauda epididymidal epithelium of hibernating bats may promote sperm longevity
Authors: Crichton Elizabeth G. , Suzuki Fumie , Krutzsch Philip H. , Hammerstedt Roy H.
Published: February 2005

Measurements of extremely high osmolalities in cauda epididymidal fluids of hibernating bat species led to an investigation of the junctional complex morphology of the epithelium of this sperm storage site. Freeze fracture replicas revealed the presence, at certain times of the year, of a tight junction architecture that resembled that traditionally thought to be exclusive to the blood‐testis barrier, the strongest permeability barrier in the body. It is hypothesized that seasonal establishment of these specialized Sertoli cell‐like tight junctions is necessary to the maintenance of the high osmotic state of the luminal environment, allowing for the prevention of dilution of its contents by paracellular routes and its protection from bursting under the osmotic pressure contained within. © 1993 Wiley‐Liss, Inc.
Immunoelectron microscopy on the localization of endothelin in the umbilical vein of perinatal rabbits
Authors: Sakamoto Yoshitaka , Doi Yoshiaki , Ohsato Keiichi , Fujimoto Sunao
Published: February 2005

Immunoelectron microscopic localization of endothelin (ET) using the mouse monoclonal anti‐ET sera was performed on the pre‐and postnatal rabbit umbilical vein during stages when Weibel‐Palade (WP) bodies increase in number in the endothelial cells.

The immunoreactions are localized in the rough endoplasmic reticulum, Golgi cisterns, and WP bodies that are actively segregated from the Golgi apparatus. After degranulation and extracellular release of WP bodies was induced by compound 48/80, heavy immunoreactions were seen in both vascular lumen and cytoplasm near the degranulated WP bodies. These results indicate that ET is stored in WP bodies after segregation from the Golgi apparatus and released from the endothelial cells concomitantly with other components of these granules by exocytosis.

Because the immunoreactions are also seen in pinocytotic vesicles that are occasionally in contact with WP bodies, it seems likely that WP bodies are also involved in the uptake and storage of ET from blood plasma. © 1993 Wiley‐Liss, Inc.
Morphologic basis for loss of regulated insulin secretion by isolated rat pancreatic islets
Authors: Pai Gokul M. , Slavin Bernard G. , Tung Paul , Volk Bruno W. , Johnson Daisie G. , Anderson Deborah G. , Levin Seymour R.
Published: February 2005

Laboratories engaged in secretory studies of rat pancreatic islets often encounter high baseline insulin secretion with poor secretory response to secretagogues, such as glucose. The specific morphologic abnormalities that accompany this unregulated release have not been described. We isolated islets comparing two approaches. Both used stationary digestion with collagenase. In method I, we distended the biliary duct extracorporeally with collagenase and minced the pancreas after a 28 min digestion (37°C). In method II, we distended the pancreas intracorporeally and digested for 40 min without mincing. Both methods utilized a similar collagenase concentration (2 μg/ml in Hank's balanced salt solution (HBSS)). Both methods yielded over 300 islets/rat. Islets from both methods appeared intact, when viewed under the dissecting microscope. We found that adequate secretion from incubated islets was evoked with method I, i.e., low basal insulin levels at low glucose (3.3 mM), tripling at 11.0 mM glucose, and nearly quadrupling in response to higher glucose (16.7 mM). In contrast, method II was characterized by high basal levels without response to higher glucose. Ultramicroscopic examination of islet B cells in method I revealed normal cytological features, while B cells in method II showed marked degranulation, profiles of swollen endoplasmic reticulum, and swollen mitochondria. Morphometric analysis of B cells confirmed quantitatively a decrease in secretory granule density and mitochondrial enlargement in method II compared to method I. Anatomic changes, largely confined to the B cells of islets may account for functional alterations of responses. Defects cannot be predicted from gross appearance of islets. © 1993 Wiley‐Liss, Inc.
Further studies on the kidney of the hook‐lipped African rhinoceros, Diceros bicornis
Authors: Maluf N. S. R.
Published: February 2005

A healthy, pregnant Diceros bicornis (No. 29455), with histologically normal but relatively large kidneys containing a correspondingly large number of nephrons, died suddenly from an injury. Renal lobation was studied partly from serial transverse cuts across the kidney. The fibromuscular pelvic conduits, which are a craniocaudal bifurcation of the ureter, are associated with prominent longitudinally disposed paraconduital veins which anastomose with the interlobar veins. The arcuate veins open widely into the paraconduital veins. The latter drain into the major tributaries of the renal vein at the renal sinus. The interlobar arteries enter the parenchyma through the interlobar septa. These arteries release internal perforator branches, through the septa, which pass to the corticomedullary border, branch along that border as arcuate arteris, and release cortical branches centrifugally. All these branches give off twigs to the glomeruli.

Relative renal mass of mammals is inversely proportional to their adult body mass. This is indicated by a regression line which includes rhinoceroses. D. bicornis No. 29455, accordingly, has exceptionally large kidneys.

The mesonephros of the 75 mm fetus of D. bicornis has mature glomeruli and tubules. The metanephros has pelvic conduits, paraconduital veins, but, as yet, no medullary loops. © 1994 Wiley‐Liss, Inc.
Arrangement and innervation of the glutei medius and minimus and the piriformis: A morphological analysis
Authors: Akita Keiichi , Sakamoto Hirokazu , Sato Tatsuo
Published: February 2005

In order to examine the relationships between the positional arrangement and supplying nerves of the glutei medius and minimus and the piriformis, we investigated 49 pelvic halves of 28 cadavers. The superior gluteal nerve ran on the ventral surface of the piriformis in 44 cases (89.8%) (Type A), and some branches of the nerve perforated the piriformis in five cases (10.2%) (Type B). Based on the detailed findings of the innervation of the three muscles, the piriformis is chiefly composed of the caudal element of the gluteus medius (Type A) and in some cases the caudal element of the gluteus minimus as well (Type B). © 1994 Wiley‐Liss, Inc.