bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sperm actin and calmodulin during fertilization in the hamster: An immune electron microscopic study
Authors: Fouquet Jean‐Pierre , Fraile Benito , Kann Marie‐Louise 
Published: February 2005

AbstractThe distribution of actin and CaM in hamster spermatozoa was examined during the early events of fertilization using postembedding immunogold procedures. Actin was immunolocalized with a polyclonal antibody and two monoclonal antibodies. CaM was immunodetected with a polyclonal antibody. In epididymal sperm, actin labeling was found solely in the principal piece of the flagellum. CaM labeling was observed in the postacrosomal lamina, subacrosomal ring, and tip of the perforatorium. These distributions were not modified after capacitation and acrosome reaction. During the successive steps of sperm‐egg fusion actin remained undetected in the sperm head whereas its location did not change in the flagellum. CaM distribution remained unmodified until the sperm head begins to decondense. At later stages of sperm head decondensation the postacrosomal lamina and its CaM labeling disappeared, whereas gold particles were still detected in the subacrosomal layer. The predominant location of actin into the egg cortex, particularly the microvillus‐free area was confirmed. Except for the CaM labeling of the meiotic spindle, no special CaM location could be found throughout the egg. Thus, in hamster, a role for sperm actin in sperm‐egg fusion appears unlikely. In contrast the CaM present in the Ca2+‐rich postacrosomal lamina could be involved in the regulation of egg activation.
Thecal and interstitial cells in polycystic ovaries (PCO) in the rat
Authors: Convery Margaret , Brawer James R. 
Published: February 2005

AbstractTwo different types of experimentally‐induced polycystic ovaries (PCO) have been examined. A macrocystic ovarian condition is induced by estradiol valerate (EV) injection, whereas a microcystic ovarian condition is engendered with subcutaneous estradiol implants. In both of these models thecal and secondary interstitial cells were characterized using three functionally significant indices. Expression of alkaline phosphatase was evaluated immunohistochemically, hCG/LH‐binding capacity was assessed by means of EM radioautography, and the size and percent cytoplasmic area of intracytoplasmic lipid were determined, in the same cells, by morphometry. In both types of ovary, thecal cells of healthy and atretic follicles stained heavily for alkaline phosphatase whereas cystic theca exhibited little or no staining. Intermittent faintly stained patches of secondary interstitial cells, as well as intensely stained spheroidal cell clusters, were most numerous in the microcystic ovary and occurred less frequently in the macrocystic ovary. Cystic thecal cells in both conditions exhibited large lipid droplets and minimal hCG binding. Lipid droplet area was minimal and hCG binding maximal in secondary interstitial cells of both types of ovary. It is concluded that specific clusters of secondary interstitial cells are important steroidogenic elements in PCO, whereas cystic theca is relatively inert.
Autotransplantation of the adrenal cortex: A morphological and autoradiographic study
Authors: Vendeira P. , Magalhães M. M. , Magalhães M. C. 
Published: February 2005

AbstractA morphological and autoradiographic study was made of the adrenal gland of adult male rats after autotransplantation. The simple technique involved placement of pieces of the adrenal gland in a dorsal plane between the skin and muscle. Animals for morphological studies were sacrificed at 2, 3, 4, 7, 15, 30, 90, and 180 days after autotransplantation. Those for autoradiographic studies were sacrificed at 2, 3, 7, and 15 days after autotransplantation, with 3H‐thymidine being administered intraperitoneally 2 h before sacrifice. Sham‐operated animals were used as controls. The majority of glandular adrenal cells suffered necrosis in the first days (2 and 3) after autotransplantation. Up until 15 days and after revascularization, morphological features of the cells were compatible with protein synthesis exhibiting a developed RER, scarce SER, and mitochondria with tubular and lamellar cristae. These data may correspond to a proliferative phase of glandular cells. At day 15, cells showed morphological signs of steroidogenic activity (mitochondria with vesicular cristae, increase of SER), and at day 30, an increased number of microvilli were seen. Between 30 and 90 days zonation of the adrenal was evident with glomerulosa, fasciculata, and reticular zones readily apparent. The quantitative analysis showed a significant increase of the volumetric density of mitochondria and microvilli between the days 7 and 30.Autoradiographic studies showed an intense labelling of fibroblast‐like cells at days 2 and 3 and of glandular cells at days 7 and 15, which was confirmed by the quantitative studies.Corticosterone in autotransplanted animals decreased during the first 15 days, but after 30 days the values were similar to controls. The model reported here seems to be good for study of the regeneration of the adrenal gland and can be a simple, useful, and reproducible method for adrenal transplantation.
Multiple glycoproteins localize to a particulate form of extracellular matrix in regions of the embryonic heart where endothelial cells transform into mesenchyme
Authors: Sinning Allan R. , Krug Edward L. , Markwald Roger R. 
Published: February 2005

AbstractCells derived from an epithelial‐mesenchymal transformation within the atrioventricular canal and outflow tract are involved in the partitioning of the early embryonic heart into a four‐chambered organ. This transformation process has been shown to proceed from an inductive interaction between the myocardium and competent, target endothelial cells within these regions of the heart. Interestingly, immunohistochemistry revealed the presence of fibronectinpositive particulates within the matrix of mesenchyme‐forming regions (Mjaatvedt et al., 1987). This particulate matrix is extractable by EDTA and can elicit the epithelial‐mesenchymal transformation in culture (Mjaatvedt and Markwald, 1989). Analysis of EDTA extracts of embryonic heart tissue revealed the presence of fibronectin and about 40 unidentified proteins, 6 of which appeared to be enriched in the biologically active 100,000g pellet fraction (Mjaatvedt and Markwald, 1989). Based on these and other data we have proposed that the particulate matrix is composed of a multicomponent complex of fibronectin and one or more of the low‐molecular‐weight proteins in this pellet. The purpose of the present study was to begin a biochemical characterization of the nonfibronectin proteins thought to be present in the matrix particulates. Given that many matrix constituents are glycoproteins, lectins were used to initially characterize the particulate constituents. Of the lectins tested, soybean agglutinin (SBA) was found to be specific only for matrix particulates. Histochemical analyses showed that SBA and antibodies against fibronectin colocalized regionally and temporally to the same matrix particulates in embryonic heart tissue. SBA‐agarose affinity chromatography resulted in the isolation of two major (56 and 69 kDa) and six minor (28, 46, 50, 53, 126, 220 kDa) proteins from EDTA extractable heart matrix. Temporal lectin histochemical studies indicate that SBA‐positive particulates are present in the matrix prior to mesenchyme formation, but are absent shortly after the transformation event. These observations support our hypothesis that one or more of these SBA‐positive glycoproteins participate in the endothelial‐mesenchymal transformation of cardiac endothelium.
Zinc iodide‐osmium tetroxide impregnation of the “tubulo‐vesicular system” in Tomes' process of the rat incisor ameloblast
Authors: Uchida T. , Warshawsky H. 
Published: February 2005

AbstractZinc iodide‐osmium tetroxide (ZIO) is a nonspecific but selective impregnation method that visualizes a tubulo‐vesicular system in cells. The detailed structure and three‐dimensional distribution of this ZIO‐impregnated system was studied in the Tomes' process of secretory ameloblasts in the rat incisor. The ZIO‐impregnated system consisted of an extensive array of smooth membranebound thick and thin tubules and vesicles. The interconnected thick and thin tubules formed a complex “core network” in the central cytoplasm of Tomes' process that enmeshed and often surrounded individual secretory granules. From the core network, radial branches extended toward the smooth cell membrane of the interdigitating portion of Tomes' process. Although the core network and branches frequently appeared connected to the secretory granules and the cell membrane, stereo‐pair electron microscopy failed to show conclusive evidence of such continuity. However, many coated vesiclelike structures were attached to the core network and its branches. No special relationship was found between interrod and rod secretory sites and the tubulo‐vesicular network. In thick sections, the ZIO‐impregnated tubulo‐vesicular network occupied a considerable volume of cytoplasm. The vinblastine‐labile nature of this network as demonstrated previously (Nanci et al., 1987) indicated that the system undergoes rapid and extensive turnover. Considering the dynamic nature and sheer volume of the tubulo‐vesicular system, we propose that it be regarded as a major cell organelle.
Anatomy of the bilioduodenal junction of the opossum
Authors: Haley‐Russell D. , Calabuig R. , Moody F. G. 
Published: February 2005

AbstractPrevention of reflux is a major function of the terminal biliary duct system at its junction with the duodenum. We examined this area via scanning electron microscopy and light microscopy to explore anatomic features that might play such a role in the Virginia opossum, a species with a highly developed sphincter of Oddi (SO). The terminal apparatus, most of which consists of a dilated extramural ampulla, has a lumen with abundant folds. Mucus is produced by the lining epithelium and by a plethora of glands. Three muscle layers constitute the SO: an inner longitudinal, an outer circular, and a less consistent, outermost longitudinal. The terminal apparatus forms an acute angle and narrows as it enters the duodenum; at this point, the SO becomes continuous with the muscularis externa of the intestine. Four anatomical features with potential antireflux properties may be identified: mucus production, luminal folds, and the narrow opening and oblique course of the intramural duct.
Topographical mapping of GnRH receptors on dispersed mouse pituitary cells by backscattered electron imaging
Authors: Pal Dhananjay , Miller Brian T. , Parkening Terry A. 
Published: February 2005

AbstractMouse anterior pituitary cells cultured for 2 days were stimulated with one of three biotinylated‐GnRH probes ([biotinyl‐Lys6]‐[D‐Lys6]GnRH, [biotinyl‐Ser4]‐[D‐Lys6]GnRH, [biotinyl‐Ser4]‐[D‐Trp6, des‐Gly10]GnRH) in the cold (4°C) for 1 hr. These cells were subsequently fixed and an avidin‐gold complex was conjugated to the bound GnRH. After a second fixation, the gold label was silver‐enhanced for viewing with a scanning electron microscope. Gonadotropes were identified as a result of the labeling procedure, measured for size, and the number of GnRH receptor sites counted. Gonadotropes ranged from 3 to 13 μm in diameter and contained from 23.2 ± 3.3 to 338.4 ± 25.2 sites per cell depending upon the size of the cell and the ligand employed. The methods described should be applicable for studying the topographical distribution of a variety of cellular receptors. © 1992 Wiley‐Liss, Inc.
Mammotropes and somatotropes in the adenohypophysis of androgenized female mice: Morphological and immunohistochemical studies by light microscopy correlated with routine electron microscopy
Authors: Yamaji Akiko , Sasaki Fumihiko , Iwama Yoshie , Yamauchi Shoji 
Published: February 2005

AbstractFemale mice were divided into androgenized (AF) and control (CF) groups. The AF mice were injected subcutaneously with testosterone propionate (Tp) and the CF mice with sesame oil at 5 days of age. Mammotropes (PRL cells) and somatotropes (GH cells) in the adenohypophyses of these mice when they became adults were studied with immunohistochemistry and morphometry by light microscopy correlated with routine electron microscopy. In CF mice, almost all of the PRL‐immunoreactive cells (about 43% of all parenchymal cells) were type I (classical) PRL cells, and almost all of the GH‐immunoreactive cells (about 30% of all parenchymal cells) were type I (classical) GH cells. Type II PRL cells accounted for about 0.4% of parenchymal cells, and type II GH cells were about 2.5% of all parenchymal cells. In AF mice, the percentages of PRL and GH cells were not significantly different from those of CF mice. Mammosomatotropes (Ms cells) in both groups were less than 1% of all parenchymal cells. Numbers of all parenchymal, PRL and GH cells, however, were increased significantly in AF mice when compared to those in CF, because the adenohypophysis was increased in volume in AF mice. Type I PRL cells were larger in AF than in CF. The ultrastructure suggested that type I PRL cells may show increased PRL synthesis and secretion in AF mice. Furthermore, AF mice, in which the hypothalamus is masculinized by the neonatal treatment with Tp, retained feminine characteristics in the population and size of PRL cells and GH cells in the adenohypophysis. © 1992 Wiley‐Liss, Inc.
Muscle atrophy continues after early cast removal following tendon repair
Authors: Maxwell L. C. , Moody M. R. , Enwemeka C. S. 
Published: February 2005

AbstractWe studied soleus (SOL), plantaris (PLN), and gastrocnemius (GST) muscles to determine whether early cast removal minimizes muscle atrophy or permits recovery from atrophy after tendon repair. After right tendocalcaneus (Achilles tendon) was transected and repaired, rabbit right hindlimbs were immobilized with the ankle plantar flexed and the knee flexed to 90°, Rabbits were maintained in the cast and sacrificed at 5, 15, or 21 days postoperatively or the cast was removed on day 5 and the animals sacrificed at day 15 or 21. SOL, PLN, and GST muscles of both limbs were removed and weights, mean fiber cross‐sectional area, and percentage of Type I fibers and increased the percentage of Type IIc fibers. Ten days after cast removal (i. e., postoperative day 15), SOL muscle atrophy and fiber composition did not differ significantly from continuously immobilized controls. However, 16 days after cast removal (i. e., postoperative day 21), SOL muscle fiber cross‐sectional area and fiber composition were near normal, differing significantly from continuously casted controls. At each of the time intervals studied, PLN (containing many glycolytic fibers) did not atrophy as much as SOL (containing mainly oxidative fibers). Our results indicate that (1) early cast removal prevents atrophy of PLN glycolytic fibers, but not oxidative fibers in either PLN or SOL, and (2) early cast removal promotes recovery from atrophy of both oxidative and glycolytic fibers. In spite of the many differences between rabbits and humans, these findings suggest that, although early cast removal may not prevent oxidative muscle fiber atrophy after postoperative immobilization, it may facilitate recovery from atrophy. © 1992 Wiley‐Liss, Inc.
Protein‐gold transport in the endocytic complex of trophotaenial absorptive cells in the embryos of a goodeid teleost
Authors: Schindler Joachim F. , Greven Hartmut 
Published: February 2005

AbstractThis paper reports adsorptive endocytosis of exogenous proteins by the trophotaenial absorptive cells (TACs) in the viviparous goodeid teleost, Ameca splendens. In vitro incubations were performed with gold conjugated to bovine serum albumin (Au‐BSA), human transferrin (Au‐HTf), fetuin (Au‐Fet), and asialofetuin (Au‐ASFet). Localization of gold label on the TAC surface was nearly exclusive to patches of an amorphous coat associated with part of the intermicrovillous plasma membrane. On addition of excess BSA, HTf, Fet, or ASFet to incubation media containing, respectively, Au‐BSA, Au‐HTf, Au‐Fet, or AuASFet, the density of gold particles adsorbed on the TAC surface decreased drastically. Moreover, attachment of the four protein‐gold complexes to the same plasma membrane sites was suggested by reciprocal inhibitory effects. Further proteins such as hemoglobin, myoglobin, and cytochrome c were as well potent inhibitors of Au‐BSA and Au‐HTf binding and uptake.Binding to TACs of native BSA or HTf was visualized by immunogold labeling. The interactions between proteins and binding sites required both the presence of Ca2+ and appropriate pH>6.6. Analyses of the concentration‐dependent BSA and HTf binding curves, plotted from morphometric data, resulted in apparent dissociation constants, Kds, of approximately 5 × 10−7 M and 4 × 10−7 M, respectively.Following binding at the TAC surface and internalization via clathrin‐coated pits and vesicles the several ligands were routed along the lysosomal pathway with transit through the endosomal compartment. Prolonged incubation periods led to massive intracellular accumulation of tracer proteins. The effects of NH4Cl (10 mM) treatment on TACs included enormous cytoplasmic vacuolation, a reversible loss of protein binding sites on the plasma membrane, and a block in the transport of protein‐gold complexes to lysosomes. © 1992 Wiley‐Liss, Inc.
Changes in the apical microfilaments of rat uterine epithelial cells in response to estradiol and progesterone
Authors: Luxford Karen A. , Murphy Christopher R. 
Published: February 2005

AbstractThis study investigates the interaction of hormones and the cytoskeleton within the apical cytoplasm of uterine epithelial cells of the rat. The effects of the hormones estradiol‐17β and progesterone on the microfilament configuration were studied using myosin subfragment 1 (S1) decoration of actin microfilaments (MF) and transmission electron microscopy. In control ovariectomized animals, a sparse MF distribution was found in the apical cytoplasm underlying short microvilli with S1‐decorated core MF. Hormone treatment experiments consisted of injecting ovariectomized rats with either progesterone or estradiol‐17β. For the study of the MF configuration accompanying an apical surface primed for blastocyst receptivity, progesterone treatment was immediately followed by a single dose of estradiol‐17β. The long, regular microvilli associated with estradiol only treatment contained bundled, decorated MF with tightly bundled rootlets. Progesterone alone produced numerous short microvilli with decorated core bundle MF and pronounced rootlets that frequently appeared splayed. The irregular microvilli and luminal surface of the uterine epithelial cells associated with the receptivity hormone sequence contained variable MF configurations, including MF bundles, networks, and areas with a “felted” appearnce. The results show that the various hormone regimes produce characteristically different MF configurations and that this component of the cytoskeleton appears to be under the control of a delicate hormone balance within these uterine cells. The responses of uterine MF to specific regimes of steroid hormones used in this study are not only important for the understanding of the mechanisms at work during early pregnancy, but also contribute to the body of knowledge concerning the ways in which hormones in general effect the cytoskeleton of target cells. © 1992 Wiley‐Liss, Inc.
Inhibition of epibranchial placode‐derived ganglia in the developing rat by bisdiamine
Authors: Kuratani Shigeru C. , Bockman Dale E. 
Published: February 2005

AbstractAlthough bisdiamine has been shown to affect the development of mammals, its effect on the nervous system has gone largely unrecognized. In the present study, rats were given bisdiamine by gavage on days 9 and 10 of pregnancy. They were sacrificed at intervals and the fetuses were prepared for study of serial sections stained with hematoxylin and eosin, or by immunohistochemical reaction with HNK‐1 monoclonal antibody. HNK‐1 reacted strongly with the nervous system, allowing precise analysis of the components and their relationships. Controls receiving no bisdiamine were prepared and studied in parallel with the experimental fetuses. Administration of bisdiamine inhibited development of the petrosal and nodose ganglia, altered associations of the glossopharyngeal, vagus, and hypoglossal nerves, and inhibited contributions of vagal nerve fibers to the developing enteric system. The proximal ganglia of the glossopharyngeal and vagus nerves developed normally. It is concluded that bisdiamine affects, directly or indirectly, the differentiation of nervous components derived from the epibranchial placodes. It seems likely that these placode‐derived components serve as pioneer neurons in establishing the pathway for the posteriorly extending trunks of the glossopharyngeal and vagus nerves. The early changes in congenital conditions such as the DiGeorge syndrome may not be limited to alterations in neural crest derivatives. It may be worthwhile to investigate more closely whether there are alterations in the nervous system associated with these syndromes. © 1992 Wiley‐Liss, Inc.
Blood cells of the gilthead seabream (Sparus aurata L.): Light and electron microscopic studies
Authors: López‐Ruiz Antonio , Esteban M. Angeles , Meseguer José 
Published: February 2005

AbstractThe peripheral blood cells of the gilthead seabream (Sparus aurata L.) were studied by light and transmission and scanning electron microscopic methods. Acidophilic erythroblasts and mature erythrocytes, round, oval, and fusiform thrombocytes, neutrophils, acidophils and basophils, lymphocytes, plasma cells, and monocyte‐macrophages were characterized. A comparison of our light and electron microscopic results was carried out. The results were discussed with those for other fish species and the main modifications from the common vertebrate haematological pattern observed being considered.© Willey‐Liss, Inc.
Anatomical study of the bronchial system and major blood vessels of the chicken lung (Gallus gallus) by means of a three‐dimensional scale model
Authors: Del Corral J. López Diez , Gómez E. , Sesma P. 
Published: February 2005

AbstractThe bronchial and vascular patterns of the chicken lung, from specimens age 8–10 days, have been studied by serial, paraffin sections of the whole organ. According to the histological structure, the bronchial system consists of three airway types: primary bronchus or mesobronchus, secondary bronchi, and tertiary bronchi or parabronchi. The mesobronchus gives rise to three sets of secondary bronchi: four dorsomedial, four dorsal, and three lateral ones. The total number of secondary bronchi is 11, which is less than the number reported in adult birds by other authors until now. Nevertheless, the number and distribution of the major vessels, arteries and veins are in basic agreement with previous descriptions.© Willey‐Liss, Inc.
Expression of α‐tropomyosin during cardiac development in the chick embryo
Authors: Prados José , Fernández Juan E. , Garrido Federico , Alvarez Luis , Hidalgo Roque , Muros María A. , Aránega Antonia 
Published: February 2005

AbstractA new monoclonal antibody (mAb) that recognizes α‐tropomyosin in cardiac muscle cells was used in a qualitative (polyacrylamide gel electrophoresis and indirect immunofluorescence) and quantitative (fluorescence‐activated cell sorting) study of the expression of this protein during heart development. α‐Tropomyosin expression was weak in early stages of chick embryo development (Hamburger and Hamilton stage 18), and increased steadily until Hamburger Hamilton stage 40. In early stages, the protein was found mainly in cytoplasm, whereas by the final stages, it was more abundant in the cytoskeletal compartment. The mAb cross‐reacted with α‐tropomyosin in smooth and striated muscle cells from chickens, mice, and humans, but did not cross‐react with nonmuscle tropomyosin.© Willey‐Liss, Inc.