bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of the development of the atrioventricular conduction system as a consequence of observing an extra atrioventricular node in the normal heart of a human fetus
Authors: Doméanech‐Mateu J. M. , Arnó‐Palau A. , Martíanez‐Pozo A.
Published: February 2005

We have observed an extra atrioventricular node in the normal heart of a human fetus. It is located in the septal wall of the right atrium, subendocardially, and just where Todaro's tendon leaves this wall to go toward the inferior vena cava valve. In its trajectory, this tendon gives way to a remarkable prominence in the cavity of the right atrium: the sinus band. In order to explain the embryogenesis of this extra atrioventricular node, we have studied the normal development of the atrioventricular specific system and have concluded that the atrioventricular node is formed from a growth and displacement toward the atrium of the primitive atrioventricular specific material, which originates from the myocardium of the posterior wall of the atrioventricular canal. Likewise, during its development, the atrioventricular node keeps in close proximity with the Todaro's tendon. In our view, this accounts for the embryogenesis of the extra atrioventricular node, since a fragment of the atrioventricular node can remain cranial to Todaro's tendon and be displaced by it in a craniodorsal direction. This fragment would then lead to the formation of an extra atrioventricular node like the one present in the heart of the fetus we have examined.
Heterogeneity among ovarian blood vessels: Endogenous hepatic lipase is concentrated in blood vessels of rat corpora lutea
Authors: Hixenbaugh Elizabeth A. , Paavola Laurie G.
Published: February 2005

We used indirect immunofluorescence and immunogold light microscopy to examine the distribution of hepatic lipase, an enzyme involved in lipoprotein metabolism, in ovaries of gonadotropin‐treated immature rats. Antibodies utilized were rabbit anti‐rat hepatic lipase IgG, anti‐rat von Willebrand factor (VWF, an endothelial cell marker), and goat anti‐rabbit IgG conjugated to gold particles or rhodamine. Immunoreagents were applied to fresh frozen sections of unfixed ovary or liver (positive control) or were delivered to ovaries by vascular perfusion before fixation in situ and silver‐enhancement of sections. Appropriate controls verified that the immunolocalizations were specific. Immunofluorescence implied that luteal but not stromal blood vessels of ovaries were positive for hepatic lipase, whereas luteal and stromal blood vessels bore VWF. The improved morphology gained by perfusing ovaries with antibodies allowed precise localization of the enzyme. Hepatic lipase was concentrated within thin‐walled vessels of corpora lutea but not those of stroma in ovaries at the time of peak steroidogenic activity. Quantification of hepatic lipase‐labeled vessels in stromal and luteal compartments confirmed our visual impression. Many images suggested that stromal vessels lacking hepatic lipase gained this enzyme upon contact with luteal tissue. Perfusion of ovaries with cationized ferritin labeled all ovarian vessels equally well, ruling out the possibility that the observed distribution of hepatic lipase was artifactual. These findings demonstrate that ovarian blood vessels are heterogeneous for hepatic lipase. Moreover, they imply that luteal tissue, perhaps luteal cells, may influence expression of hepatic lipase binding sites by endothelial cells.
Intracellular variation of rat intestinal mucin granules localized by monoclonal antibodies
Authors: Oliver Mary G. , Specian Robert D.
Published: February 2005

Monoclonal antibodies produced against rat small intestinal mucins were utilized to study variability of stored mucin granules within rat ileal goblet cells. Eleven antibody‐secreting hybridoma cultures were produced; six of these uniformly labeled stored mucin granules in virtually all goblet cells, suggesting that some antigenic features are common to all granules. The other five stained goblet cells in the rat small intestinal epithelium nonuniformly. R803, R805, and R807 localized within almost all goblet cells but revealed differential labeling of centrally and peripherally located mucin granules. R804 uniformly labeled the mucin granules of most villous goblet cells; some of the crypt goblet cells were uniformly labeled, but the majority were only partially labeled, resulting in a mottled staining pattern. R808 stained only a small portion of crypt goblet cells; there is, however, an increase in both number of goblet cells labeled and in uniformity of staining of the stored granule mass from the base of the crypt to the surface, resulting in uniform labeling of virtually all goblet cells at the villus tip. This study demonstrates for the first time that rat small intestinal mucin granules are immunologically heterogeneous and nonuniformly distributed within the epithelium. Additionally, staining patterns within the stored granule mass suggest that structurally distinct subpopulations of mucin granules may exist within a single goblet cell.
Anatomic distribution of autonomic neural tissue in the developing dog heart: II. Nonadrenergic noncholinergic innervation by calcitonin gene‐related peptide‐immunoreactive tissue
Authors: Ursell Philip C. , Ren Chao Ling , Danilo Peter
Published: February 2005

We used immunocytochemical localization of calcitonin gene‐related peptide (CGRP) to trace the ontogenesis and anatomic distribution of this component of nonadrenergic noncholinergic (NANC) innervation in fetal, neonatal, and mature canine hearts and autonomic ganglia which control cardiac function. Rare varicose CGRP‐immunoreactive nerve processes were present in the heart during late gestation. Abundant CGRP‐immunoreactive neural tissue in the neonate suggested a burst of NANC innervation around birth. Neonatal, 1‐, and 2‐month‐old animals all had many varicose individual nerve processes in addition to processes within bundles; however, the density of all CGRP‐immunoreactive tissue appeared to decrease during this stage of development. Similarly, there were relatively more varicose stained nerve processes in the epicardial ganglia and numerous CGRP‐immunoreactive cells and smooth nerve processes in the stellate ganglia of the neonate, as compared with older animals. In the mature animal CGRP‐immunoreactive neural tissue in the heart was more sparse and largely confined to heterogeneous nerve bundles in the epicardium. The extramural coronary arteries were virtually the only site of innervation by individual nerve processes; CGRP‐immunoreactive neural tissue was not found adjacent to working cardiac muscle fibers. At all developmental stages, the area of the sinoatrial node was the primary focus of CGRP innervation, although the atrioventricular nodal region was also preferentially innervated. In general, the atria contained more CGRP‐immunoreactive tissue than the ventricles, which were only sparsely innervated. The perinatal peak in density of CGRP‐immunoreactive neural tissue with subsequent decline to reach the adult pattern suggests a developmental role for NANC innervation in the dog heart.
Further evidence of the presence of rat embryonic hypothalamic factors that induce the differentiation of gonadotrophic hormone‐releasing hormone‐containing secretory neurons
Authors: Daikoku Shigeo , Daikoku‐Ishido Harumi , Okamura Yoshihito , Chikamori‐Aoyama Mika , Yokote Ryoji
Published: February 2005

We examined the presence of factor(s) in the embryonic medial basal hypothalamus (MBH) that may influence nasal placode (NAP)‐derived luteinizing hormone‐releasing hormone (LHRH) neurons in determining their secretory phenotype. In this study, we performed organotypic culture and transplantation of the NAP from 12.5‐day‐old embryos of rats and vomeronasal organ (VNO) from 14.5‐day‐old embryos. Surgical operations, however, were performed on 16.5‐day‐old embryos. The NAP and VNO were cultured singly or with the MBH obtained from the embryos of the same age and, further, in a medium with a nerve growth factor or fibroblast growth factors. Although LHRH neurons were derived from the NAP and VNO in all the cultures, judging from numbers and cellular morphologies, the MBH was most effective. The VNO was transplanted into the third ventricle of adult female rats singly or with the cerebral cortex, the mesencephalon‐myelencephalon complex, or the MBH from 14.5‐day‐old embryos. All the grafts gave rise to LHRH neurons, but the number of the neurons was far greater in the grafts cotransplanted with the MBH, in which the neurons projected long processes to blood capillaries and formed neurovascular complexes, the feature of which may suggest the occurrence of the secretory activity in the fibers. The animals were examined 5 days after the surgical operations. In rhinoectomized embryos, LHRH neurons were distributed throughout the brain in the same pattern as found in intact rats, showing normal cellular morphology. In the encephalectomized rats, immunoreactive LHRH cells were present only in the terminal ganglia. These findings indicate that the embryonal MBH has a factor (s) that is essential to the development of secretory LHRH neurons.
Cervical lymph nodes and mast cells in the marsupial Sminthopsis crassicaudata
Authors: Haynes Julie I.
Published: February 2005

A study of the cervical lymph nodes from the fat‐tailed dunnart, Sminthopsis crassicaudata, revealed the nodes were pigmented with lipofuscin and contained many large cells which were identified as mast cells from their ultrastructure and histochemical staining properties. It is believed that the very high density of mast cells in the cervical lymph nodes contributed to an increase in size of these organs compared to other animals. Very high levels of histamine (90μpg/g)were found in the nodes. Cervical lymph nodes with these unusual features were found not only in healthy, unprimed laboratory bred adults, but also in pouch young, wild caught animals, and adults of the closely related species, Sminthopsis macroura.

A comparison of the histochemical and ultrastructural characteristics of mast cells from various organs of adult S. crassicaudata was also made. Mast cells from lymph node, skin, tongue, salivary glands, intestinal mucosa, and spleen showed slight variations in staining and structure.
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

The 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

Two 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

A 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

Cells 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

Zinc 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

Prevention 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

Mouse 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

Female 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

We 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

This 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

This 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

Although 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

The 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

The 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

A 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.
Changes in histochemical distribution of cell surface heparan sulfate proteoglycan in mouse uterus during the estrous cycle and early pregnancy
Authors: Potter Sandra W. , Morris John E.
Published: February 2005

We have investigated the changes in immunolocalization of a cell surface heparan sulfate proteoglycan (HSPG) in the mouse uterus during the estrous cycle and at the time of implantation in early pregnancy. A monoclonal antibody prepared against syndecan, a cell surface HSPG from mouse mammary epithelium (gift of Dr. M. Bernfield), was reacted with unfixed and fixed frozen sections of uteri from normally cycling, 3.5 and 4.5 days pregnant, and estradiol‐treated immature and ovariectomized mature mice. A polyclonal antibody prepared against basal lamina HSPG from Engelbreth‐Holm‐Swarm (EHS) tumor cells (gift of Dr. John Hassell) was used as a positive control. The latter showed no variation during the estrous cycle or early pregnancy. Localization of syndecan in uterine epithelium changed from basolateral to predominantly basal as the cycle progressed from metestrus toward estrus. A similar pattern was seen in immature and ovariectomized mature females that had received estradiol injections. With the onset of pregnancy, the basolateral localization became progressively less intense from 3.5 days through 4.5 days of pregnancy. Thus, cell surface HSPG distribution is modulated by hormonally dependent changes in cycling and pregnant mice, supporting previous suggestions that early pregnancy in mice is accompanied by a turnover and rearrangement of uterine epithelial cell surface.© Willey‐Liss, Inc.
Scanning electron microscopy of developing primary endoderm during first 6 hours of incubation in the chick
Authors: Low Frank N. , McClugage Sam G.
Published: February 2005

Development of primary endoderm in the domestic fowl (Gallus domesticus) is described in scanning electron microscopy (SEM) supplemented by transmission electron microscopy (TEM). Although complicated by great variability, the ventral surface of the blastoderm reveals this process during the first 6 hours of incubation. Primary endoderm arises (1) from the hypoblast, (2) from the margin of the area pellucida, and (3) from intervening protions of the area pellucida. The early hypoblast becomes several cells thick while individual cells are still spherical. TEM reveals a variety of immature cell junctions. During subsequent flattening of these cells into primary endodermal epithelium, numerous filopodia arise from their surfaces. These are 0.20–0.25 μm in diameter. They become long and branched, attaching to each other and to other cell bodies. Similar filopodial processes are present less conspicuously among cells in the margin of the area pellucida. Here, there is pseudopodial evidence that cells or cell sheets creep along the ventral surface of the epiblast. The filopodia disappear as cell flattening proceeds. The ventral surface of the exposed epiblast delaminates cells that become free after their exploratory filopodia and lamellipodia are put forth. Lateral contacts among cell bodies from the above three sources increase until a continuous epithelium is formed. The primary endoderm of the embryo, a simple squamous epithelium that separates the connective tissue space above from the gastrocoele below, is generated by these developmental events. © Wiley‐Liss, Inc.
Vasocontractions of the in‐vitro toad aortas induced by endothelin‐1 and sarafotoxin‐S6b
Authors: Doi Yoshiaki , Fujimoto Sunao
Published: February 2005

Dose‐dependent tension curves were recorded from the in vitro toad aortas by administration of endothelin‐1 and sarafotoxin‐S6b. The maximal contractile tensions by both drugs were evoked at a 10−8 M concentration. By a single dose application (10−8 M) of endothelin‐1 and sarafotoxin‐S6b to both endothelium‐preserved and denuded vessels, the induction of the endothelium‐dependent vasocontraction occurs after 2 min of administration.

Ultrastructural changes of Weibel‐Palade bodies such as decrease in electron density, swelling with a wide peripheral halo, and expulsion of their contents in a manner of exocytosis become evident within 2 min after administration of these drugs. These findings indicate that some vasocontractile substances in Weibel‐Palade bodies are extracellularly discharged by endothelin‐1 and sarafotoxin‐S6b. © 1993 Wiley‐Liss, Inc.
A study of the chick thymus microenvironment during development: Analysis by monoclonal antibodies against thymic epithelium
Authors: Paz P. , Sánchez A. , Melcóan C. , Fernández J. G. , Chamorro C. A.
Published: February 2005

The process of T‐lymphocyte differentiation within the thymus involves a series of molecular interactions. In this work we have carried out an analysis of the chick thymus microenvironment in order to evaluate its heterogeneity during development. We have produced 11 monoclonal antibodies whose staining patterns detected by the immunoperoxidase technique allowed us to divide them into five groups. A first group (E19‐E2, P0‐E5, and P15‐T1) binds to thymic medullary stroma showing a reticular pattern on medullary epithelial cells and whose significance would be related to thymic stromal secretion. The second group of monoclonal antibodies (P15‐T3) stains thymic corpuscles of 10‐ and 15‐day chicks. The third group of antibodies includes P0‐E1, P0‐E3, P5‐A6, and P15‐T2 whose staining pattern is both medullary and cortical. The fourth group (P10‐HB1 and P10‐HB2) binds to thymic stromal and cortical thymocytes, and the fifth group (P5‐A1) is characterized by the staining of medullary vessels of 5‐day chicks. These five groups of monoclonal antibodies corroborate the existence of an antigenic diversity of the chick thymus microenvironment. Their possible relationships with T‐cell differentiation and stromal‐thymocyte interactions are discussed. © 1993 Wiley‐Liss, Inc.
An electron microscopic study of the harderian gland of the Syrian hamster with particular reference to the processes of formation and discharge of the secretory vacuoles
Authors: Lóapez J. M. , Tolivia J. , Alvarez‐Uría M. , Payne A. P. , McGadey J. , Moore M. R.
Published: February 2005

The lipid‐secreting cells of the Harderian gland of the Syrian hamster were studied using light, transmission, and scanning electron microscopy. Three morphologically different secretory cell types are identified in the gland: type I and II cells of the male gland and, distinct from either, the female gland cell. In all secretory cell types, lipid droplets in the cytoplasm were surrounded by unit membranes. Ultrastructural evidence of the involvement of the Golgi apparatus in the formation of the secretory vacuoles was obtained. The process of secretion involved the fusion of the boundary unit membrane of the vacuole with the plasma membrane and the release of the vacuolar content alone into the lumen. No evidence of holocrine processes was observed in this study. In addition to lipids, vacuoles contained materials whose solubility properties clearly differed from those of lipids. There appear to be variations in the ultrastructural characteristics of the vacuole content of the different types of secretory cell. © 1993 Wiley‐Liss, Inc.
Distribution of dystrophin and neurofilament protein in muscle spindles of normal and mdx‐dystrophic mice: An immunocytochemical study
Authors: Nahirney Patrick C. , Ovalle William K.
Published: February 2005

Dystrophin is a high molecular weight protein localized under the sarcolemma of normal extrafusal muscle fibers but absent in skeletal muscle of Duchenne muscular dystrophy patients and mdx mice. Muscle spindles in the soleus of 32‐week‐old normal and age‐matched mdx mice were examined by immunocytochemical methods to determine the localization of dystrophin in polar and equatorial regions of the intrafusal fibers. Spindles were serially sectioned in transverse and longitudinal planes, and were double‐labelled with an antibody to dystrophin and with an antibody to a 200 kD neurofilament protein, which revealed their sensory innervation. By fluorescence microscopy, intrafusal fibers in the soleus of mdx mice were deficient in dystrophin throughout their lengths, whereas their sensory nerve terminals stained intensely with the nerve‐specific antibody and appeared unaltered in dystrophy. In the normal soleus, intrafusal fibers displayed a regional variability in the distribution of dystrophin. Polar regions of bag and chain fibers exhibited a peripheral rim of sarcolemmal staining equivalent to that seen in the neighboring extrafusal fibers. Dystrophin labelling in equatorial regions of normal intrafusal fibers, however, showed dystrophin‐deficient segments alternating in a spiral fashion with positive‐staining domains along the sarcolemma. Double‐labelling for dystrophin and neurofilament protein showed that these dystrophin‐deficient sites were subjacent to the annulospiral sensory nerve wrappings terminating on the intrafusal fibers. These findings suggest that dystrophin is not an integral part of the subsynaptic sensory membrane in equatorial regions of normal intrafusal fibers and thus is not directly related to sensory signal transduction. The complete absence of this protein in mdx intrafusal fibers indicates that these fibers exhibit the same primary defect in muscular dystrophy as seen in the extrafusal fibers. However, because of their small diameters, capsular investment, and relatively low tension outputs, dystrophic intrafusal fibers may be less prone to the sarcolemmal membrane disruption that is characteristic of extrafusal fibers in this disorder. © 1993 Wiley‐Liss, Inc.
Morphometric analysis of intact sperm heads and of sperm nuclei in the mouse
Authors: Pogany Gilbert C. , Linder Kathleen A.
Published: February 2005

A morphometric analysis of mouse sperm and of their nuclei was undertaken to investigate their respective post‐testicular maturation. Sperm were collected from the testis, caput and cauda epididymidis, and their corresponding nuclei were isolated. Results indicate that the post‐testicular maturation of sperm is distinct from that of nuclei. The size of intact sperm heads increases in the caput followed by a subsequent decrease in the cauda. In contrast, sperm nuclei decrease progressively in size. In general, a greater magnitude and number of alterations in intact heads and nuclei occur while in transit from the testis to the caput than during passage to the cauda epididymis. These results suggest that the period immediately following their release from the testis is crucial to the complete morphological maturation of sperm heads and nuclei. © 1993 Wiley‐Liss, Inc.
Neuropeptide distributions in the colon, cecum, and jejunum of the horse
Authors: Burns Gilbert A. , Cummings John F.
Published: February 2005

The pelvic flexure portion of the equine large colon is the proposed location of a pacemaker mechanism. This study was conducted to ascertain whether the distribution of certain putative neurotransmitters differs at the pelvic flexure compared to other sampling sites. Tissue samples were collected from the intestinal tracts of six horses. Serial sections from these samples were reacted with primary antisera specific for substance P, vasoactive intestinal polypeptide (VIP), methionine‐Enkephalin, and calcitonin gene‐related peptide (CGRP).

The regional distribution of immunoreactive neuronal elements was uniform for each of the neuropeptides except VIP. Although neurons exhibiting VIP‐like immunoreactivity were abundant throughout the colon, they were somewhat more plentiful near the apex of the pelvic flexure and the left dorsal colon. These neurons may participate in the initiation and propagation of the propulsive/retropulsive contraction waves, which emanate from this location and are believed to lend a sphincter‐like capacity to the pelvic flexure. The submucosal plexus was replete with neurons with intense substance P and VIP‐like reactivity. Reactive fibers left submucosal ganglia to project to the intestinal mucosa, reflecting a possible secretogogic role for these neurons. This role may be especially important for the horse as a hindgut fermenter. There were abundant methionine‐Enkephalin and substance P‐like reactive varicosities throughout the myenteric plexus, many of which established a pericellular plexus of varicose fibers. The abundance of these varicosities, which may correlate with a high degree of neuronal integration, did not vary regionally. These data may enhance our understanding of both normal colonic peristalsis and motility disorders caused by a depletion of these neuropeptides. © 1993 Wiley‐Liss, Inc.
Changes of lectin staining pattern of the Golgi stack during differentiation of the ameloblast in developing rat molar tooth germs
Authors: Matsuo Saburou , Ichikawa Hiroyuki , Kurisu Kojiro , Wakisaka Satoshi , Kiyomiya Ken‐Ichi , Kurebe Masaru
Published: February 2005

Changes of lectin staining patterns in the Golgi stack during cell differentiation were examined in the ameloblasts of developing rat molar tooth germs, using HRP‐labeled lectins: Canavalia ensiformis (Con A), Griffonia simplicifolia I (GS‐I), Glycine max (SBA), Ulex europeus I (UEA‐I), Triticum vulgaris (WGA), and Arachis hypogaea (PNA). The Golgi stacks of the inner enamel epithelial cells and the presecretory ameloblasts were stained with the lectins, although the staining strength and pattern varied among the stacks with each lectin. In some cases, the reaction products for the lectins were observed in most or all saccules of the Golgi stack. In the secretory ameloblasts, however, discrete staining patterns of the Golgi stack were found for each lectin. The reaction products deposited in definite saccules of the Golgi stack of the secretory ameloblast, especially for UEA‐I and PNA which stained only the trans Golgi saccules of the stack. The reaction‐positive saccules distributed more extensively in the Golgi stack of the inner enamel epithelial cell and the presecretory ameloblast than in the secretory ameloblast. These findings suggest that the Golgi stack is not fully compartmentalized in the inner enamel epithelial cell and the presecretory ameloblast. It is proposed that, in the differentiating ameloblast, various glycosyltransferases may coexist in most saccules of the Golgi stack. © 1993 Wiley‐Liss, Inc.