bluuebunny/crossref_metadata_2025_split huggingface dataset:
Timing of ovulation and early embryonic development in Myotis lucifugus (Chiroptera: Vespertilionidae) from northern central Ontario
Authors: Buchanan G. Dale 
Published: February 2005

AbstractFemale Myotis lucifugus lucifugus, obtained from a hibernaculum in northern central Ontario, were aroused during the week that normal departures from hibernation began, maintained in large cages at 28–30°C, and fed mealworms daily. Some bats ovulated less than 24 hr after arousal, and with one exception, all bats with normal, mature follicles ovulated within 72 hr. Histological examination of reproductive tracts from ovulated bats indicated that oviductal transit was completed in 24–48 hr, and that blastocyst formation and implantation occurred 4 and 10 days, respectively, after fertilization. These time intervals were somewhat shorter than those reported in previous studies; however, the differences appeared to be due to the relative accuracy in determining the time of ovulation, not to differences in rates of development among different populations.
Presence of arginine‐vasopressin in bovine pituitary intraglandular colloid of intermediate lobe origin
Authors: Boyd W. H. , Krogsrud R. , Jichici D. 
Published: February 2005

AbstractIn order to determine whether pituitary intraglandular colloid might contain enough hormonal material to be considered a transport medium for intermediate lobe peptides, arginine‐vasopressin was assayed in three pools of colloid collected from nearly 100 steers. Colloid samples taken from the pituitary glands of freshly slaughtered cattle were pooled, freed of extraneous tissue, and lyophilized. Three such pools were further extracted on octadecylsilyl‐silica and assayed. The radioimmunoassay showed that arginine‐vasopressin was indeed present in the bovine intraglandular colloid at levels ranging from 0.18 to 6.95 ng/mg dry weight. These results indicate that the intraglandular colloid contains a sufficient amount of arginine‐vasopressin to be considered as a transport medium for this and other intermediate lobe peptides.
Mitochondrial migration and Ca‐ATPase modulation in secretory ameloblasts of fasted and calcium‐loaded rats
Authors: Sasaki Takahisa , Garant Philias R. 
Published: February 2005

AbstractMigration of mitochondria and modulation of Ca‐ATPase activity in secretory ameloblasts were investigated ultrastructurally and ultracytochemically by using lower incisors taken from normally fed, 30‐hr‐fasted, and calcium (Ca)‐loaded rats. In normally fed rats, almost all mitochondria were localized in a narrow infranuclear compartment between the nucleus and proximal cell webs of secretory ameloblasts. In 30‐hr‐fasted rats, a prominent migration of many mitochondria into the supranuclear region of the cells was noted. Mitochondria returned to the infranuclear compartment and seldom appeared in the supranuclear region when fasted rats were Ca‐loaded by transcardiac perfusion with physiological Ca solution. Normally, the mitochondria of secretory ameloblast exhibited moderate Ca‐ATPase activity along their inner membranes. This mitochondrial Ca‐ATPase was decreased by a 30‐hr fast and became prominent again after Ca loading. Plasma‐membrane Ca‐ATPase was demonstrated in the entire cell surface of secretory ameloblasts. An especially abundant reaction was found along the invaginated cell surface of the Tomes process. This Ca‐ATPase also became very weak and was almost abolished from the Tomes process after fasting, but Ca loading caused reappearance of an intense Ca‐ATPase activity on the entire cell surface, including along Tomes's processes.These results suggest that (1) mitochondrial localization in secretory ameloblasts is influenced by the Ca concentration of the extracellular milieu, and (2) the level of mitochondrial and cell‐membrane ATPase activity is responsive to the concentration of extracellular calcium.
Posthatching development of the rete ophthalmicum in relation to brain temperature of mallard ducks (Anas platyrhynchos)
Authors: Arad Zeev , Midtgård Uffe , Bernstein Marvin H. 
Published: February 2005

AbstractIn posthatching mallard ducks (Anas platyrhynchos), brain cooling improves with growth. To determine whether this may be correlated with growth‐related changes in morphology of the rete ophthalmicum, we studied the development of this rete in immature mallards from hatching to 29 days of age. We found that the number of arteries and veins was fixed at hatching. The rete continued to grow, however, in length and vessel diameter during body and brain growth. The vascular surface area for heat exchange in the rete therefore also increased with body and brain mass. The increase in retial heat‐exchange area was faster than the simultaneous increase in brain mass. The increase in body‐to‐brain temperature difference (δT) described previously occurred nearly in direct proportion to heat‐exchange area, such that the ratio of δT to exchange area was nearly constant at about 0.1°C per mm2 during growth. It is concluded that the increase in heat‐exchange area of the rete ophthalmicum plays a major role in the development of brain cooling capacity of posthatching ducks.
Nonparenchymal liver cells and granulomas during lamprey biliary atresia
Authors: Youson J. H. , Sargent P. A. , Yamamoto K. , Ogilvie D. , Fisher M. M. 
Published: February 2005

AbstractTransmission (thin sections and freeze‐fracture replicas) and scanning electron microscopy were used to describe the nonparenchymal liver cells during the seven (1–7) stages of metamorphosis in the sea lamprey, Petromyzon marinus L., when bile ducts and canaliculi degenerate. The biliary atresia is accompanied by an increased diameter of fenestrae in the endothelium, an active phagocytosis by Kupffer cells in the sinusoids, and large lipid inclusions in perisinusoidal lipocytes (fat‐storing or Ito cells). Plasma‐like cells and foci of nonparenchymal cells (granulomas) are present in the liver interstitium during at least four stages of metamorphosis. The fenestrae in the sinusoidal wall are wider (up to 2.8‐μm diameter) than normally reported for vertebrate livers but are likely a reflection of the morphogenetic and physiological events and consequences of the biliary atresia. Kupffer cells are involved in an extensive erythrophagocytosis, the storage of iron, and perhaps the incorporation of cellular components from hepatocytes. Lipocytes are the vitamin A‐storing cells of the transforming liver and may be responsible for some perisinusoidal fibrosis. Granulomas are present during stages 3–6 and are focal areas where mononuclear leukocytes (lymphocytes and plasmalike cells), macrophages, and neutrophils have infiltrated the hepatic parenchyma. The function of the granulomas is not known; but their presence may be related to the porous nature of the sinusoidal wall, the tissue degeneration, and/or the physiological change (e.g, bile stasis) during biliary atresia.
Passive Heymann nephritis induced by rabbit antiserum to membrane antigens isolated from rat visceral yolk‐sac microvilli
Authors: Leung Christopher C. K. , Cheewatrakoolpong Boonlert , O'Mara Tom , Black Mercedes 
Published: February 2005

AbstractPassive Heymann nephritis (PHN) is an animal model of immune‐complex‐induced renal disease resembling human membranous glomerulonephritis. It was induced in rats by injecting rabbit antiserum directed against glycoprotein antigens isolated from rat embryonic visceral yolk‐sac microvilli (VYS‐MV). The glycoprotein antigens were isolated by extracting the VYS‐MV with detergent Nonidet P‐40 followed by gel filtration in Sephacryl S‐300 and finally by lectin affinity chromatography with Ricinus communis agglutinin I. In vitro immunofluorescent localization studies demonstrated that the nephritogenic antibodies were localized along the apical region of the visceral yolk‐sac endodermal cells and the brush border of the proximal tubular cells of the kidney. Rats injected with a single dose of the antiserum manifested proteinuria. Indirect immunofluorescent studies showed that the injected rabbit IgG was localized in vivo along the capillary walls of the glomerulus in a granular fashion. Electron microscopic examination of the same kidney glomeruli revealed numerous electron‐dense deposits along the lamina rara externa of the glomerular basement membrane. Fusion of the epithelial foot processes was also present. These findings represent the typical immuno‐pathological characteristics of Heymann nephritis. Furthermore, with the aid of Ouchterlony analysis, the antiserum against the isolated VYS antigens exhibited an immunoprecipitin band which was in common with that formed by the antiserum against the homogeneous nephritogenic antigen (gp330) of renal brush border origin. Thus, the nephritogenic antigens which have been found to be associated with the brush border of the renal proximal tubules may also be present or cross‐reacted in the microvilli of the rat embryonic visceral yolk‐sac.
Innervation of mouse lymph nodes: Nerve endings on muscular vessels and reticular cells
Authors: Villaro A. C. , Sesma M. P. , Vazquez J. J. 
Published: February 2005

AbstractLymph node nerve endings have been studied in 1‐ to 48‐day‐old mice. Serial sections of Epon‐embedded lymph nodes were observed under the electron microscope to find the nerve endings. Most lymph node nerve fibers finally reach the smooth muscle cells of arterioles and muscular venules. Both kinds of vascular endings are similar, although endings are less numerous on venules. Nerve endings consist of one or more nerve processes surrounded by a usually incomplete Schwann cell sheath; frequently, axons show wide areas directly facing the muscle cells. The distance between such a naked axon and a myocyte ranges from 100 to 800 nm. Small granulated and clear vesicles are especially abundant in varicosities of nerve processes that are located very close to muscle cells. Nerve endings of lymph node vasculature probably correspond to vasomotor sympathetic adrenergic endings, regulating the degree of contraction of vessels which have a muscular layer. Other kinds of nerve endings also exist in lymph nodes: some axons appear free in the stroma and contact the surfaces of reticular cells; the latter also extend delicate cytoplasmic processes that surround the axons. The functional significance of nerve cell–reticular cell contacts is unknown.
Quantitative morphology of the primate peripheral retina (Macaca irus)
Authors: Krebs Wolf , Krebs Ingeborg P. 
Published: February 2005

AbstractBy using electron microscopy to study the quantitative morphology of the retina, it was possible to determine the spatial density of all principal retinal cells at a defined retinal location. In two retinas of cynomolgus monkeys at a position of 30° nasal of the fovea centralis, the following cell densities were determined from composite electron micrographs: retinal pigment epithelium: 3,400 cell/mm2; rod cells: 115,000 and 168,000 cells/ mm2; cone cells: 8,200/mm2; horizontal cells: 7,000/mm2; bipolar cells: 50,000/mm2; amacrine cells: 11,500/mm2; Müller cells: 16,000/mm2; and ganglion cells: 5,350 and 6,750/mm2.
Opossum adrenal medulla: I. Postnatal development and normal anatomy
Authors: Carmichael Stephen W. , Spagnoli Daniel B. , Frederickson Richard G. , Krause William J. , Culberson James L. 
Published: February 2005

AbstractThe anatomy and histology of the adrenal gland in the adult opossum were found to be typical for mammals. The development of the adrenal medulla was also found to follow the typical mammalian pattern. Primitive sympathetic cells were found in both intra‐ and extra‐adrenal locations in the newborn at a time when chromaffin precursor cells were migrating to the adrenal anlage. Pheochromoblasts first appeared within the forming medulla where at a later stage chromaffin cells could be observed forming columns of cells between adjacent sinusoids. Unlike in other mammals, much of this development takes place postnatally when the neonate is in the mother's marsupium. The value of the developing opossum adrenal medulla as an experimental model is stressed, since a significant amount of development takes place in an environment that is accessible to experimental manipulation.
Paracervical ganglia of the female rat: Histochemistry and immunohistochemistry of neurons, SIF cells, and nerve terminals
Authors: Papka R. E. , Traurig H. H. , Klenn P. 
Published: February 2005

AbstractThe paracervical ganglia of the female rat were studied to elucidate the variety of neural elements in the ganglia. Light and electron microscopy, histochemistry, and immunohistochemistry were employed to reveal subtypes of neurons; small, intensely fluorescent (SIF) cells; and nerve terminals and to examine the relationships between these elements. On the basis of their histochemical markers, four subtypes of principal neurons were identified: acetylcholinesterase (ACHE)‐positive, noradrenergic, neuropeptide tyrosine‐immunoreactive (NPY‐I), and vasoactive intestinal polypeptide‐immunoreactive (VIP‐I). The NPY‐I neurons appeared to be the most numerous and the noradrenergic the least common type of neuron. Four subtypes of chemically coded SIF cells were revealed: catecholamine‐containing, NPY‐I, and those immunoreactive for calcitonin‐gene‐related peptide (CGRP‐I) and cholecystokinin‐octapeptide (CCK‐8‐I). The SIF cells were present (1) as single cells among and adjacent to principal neurons and (2) as large clusters near the edges of the ganglia or in nearby nerve trunks. Synaptic contacts on SIF cells, or between SIF‐cell processes and neurons, were not observed. Seven subtypes of nerve terminals were stained: ACHE‐positive, CGRP‐I, CCK‐8‐I, VIP‐I, substance P‐I, enkephalin‐I, and atrial na‐triuretic factor‐I. Nerve terminals enwrapped the neurons as perineuronal plexuses in synaptic‐like relationships.These results demonstrate that the paracervical ganglia of the female rat are a complex system of neural elements. For example, several classes of chemically coded neurons, SIF cells, and terminals exist in the ganglia. Each of these components contains a number of substances, some of which are putative neurotrans‐mitters, which could influence activity in the ganglia or in the effector organs innervated by the ganglia.
Ultrastructural, histochemical, and freeze‐fracture evaluation of multilamellated structures in human pulmonary alveolar proteinosis
Authors: Takemura Tamiko , Fukuda Yuh , Harrison Maria , Ferrans Victor J. 
Published: February 2005

AbstractUltrastructural, histochemical, and freeze‐fracture studies of material recovered by bron‐choalveolar lavage from patients with pulmonary alveolar proteinosis revealed four types (A, B, C, and D) of multilamellated structures (MS). Type A, the major component, consisted of concentric, trilaminar structures which were composed of two electron‐dense layers and a central lucent layer (5.7–7.5 nm in overall width) alternating with wider (25–30 nm) electron‐lucent intervening layers. Type B MS were formed by concentric lamellae with a 5–5.3‐nm periodicity. Type C MS were composed of wavy, electron‐dense lamellae with a 4–4.5‐nm periodicity. Type D MS were conglomerated masses of intricately arranged double or triple electron‐dense layers (7.5–13.5 nm wide) alternating with wider (30–40‐nm) electron‐lucent layers. The electron‐dense lamellae of type A, type C, and type D MS were stained with ruthenium red, the Thiéry method, and concanavalin A, indicating the presence of carbohydrate components. Freeze‐fracture studies revealed smooth inner and outer surfaces in type A MS, with the fracture planes passing through the central parts of the trilaminar structures; the intervening layers contained 10‐nm particles, which probably are proteins. Type B MS had smooth surfaces, and type C MS had slightly particulate surfaces; while type D MS showed tubular or polygonal structures, 350 nm wide, with rows of particles 7–8 nm in diameter. It is concluded that type A and type D MS contain proteins and carbohydrates, probably in the form of glycoproteins, as well as phos‐pholipids, and are related to tubular myelin. Type B and type C MS are considered to contain mainly phos‐pholipids; type C MS are also considered to contain carbohydrates and to be related to lamellar bodies of type II alveolar epithelial cells.
Neuropeptides in sensory perikarya projecting to the rat ovary
Authors: McNeill Daniel L. , Burden Hubert W. 
Published: February 2005

AbstractAfferent perikarya in dorsal root ganglia (DRG) at the T13 and L1 segmental levels projecting to the rat ovary were identified by utilizing the fluorescent retrograde tracer true blue (TB). Subsequently, TB‐labeled ovarian afferent perikarya in DRG were examined for vasoactive intestinal polypeptide (VIP), substance P (SP), cholecystokinin‐8 (CCK‐8), neuropeptide Y (NPY), and somatostatin (SOM) immunoreactivity and for the presence of fluoride‐resistant acid phosphatase (FRAP) enzyme activity. Of the ovarian afferent perikarya at the T13 and L1 segmental levels, 20.5% displayed VIP immunoreactivity, 23.8% displayed SP immunoreactivity, and 43.1% were immunoreactive for CCK‐8. No ovarian afferent perikarya contained SOM or NYP immunoreactivity or FRAP activity. It is suggested that different neuropeptides may participate in modulation of specific ovarian functions.
Changes in binucleation and cellular dimensions of rat left atrial myocytes after induced left ventricular infarction
Authors: Oberpriller John O. , Oberpriller Jean C. , Aafedt Bradley C. 
Published: February 2005

AbstractThe left atrium of young rats has previously been demonstrated to respond with DNA synthesis and binucleation 11 days after left ventricular infarction. This investigation was designed to examine the hypertrophic response of the left atrial myocyte of the rat at 20 and 60 days after ventricular infarction. Male Sprague‐Dawley rats were subjected to left coronary artery ligation (CAL) or sham operation. Following enzymatic separation, left atrial myocytes were examined at 20 and 60 days postoperation for number of nuclei and cellular dimensions (cell length, width and area, and nuclear area). Results demonstrated that the level of binucleation at 20 days (77.3%) and 60 days (71.3%) was nearly twice that observed in sham‐operated animals, which were 33.1% binucleated at 20 days and 43.5% binucleated at 60 days. In both mononu‐cleated and binucleated myocytes, the mean lengths, widths, and cell areas from CAL hearts were significantly greater than those of corresponding sham‐operated animals. In all cases, these values were larger in binucleated myocytes than in mononucleated cells. The mean area of CAL cells was approximately twice that of sham‐operated myocytes. With regard to mean lengths and widths, although both were greater in the CAL animals, there was a decrease in length and increase in width between 20 and 60 days in the CAL group. Mean nuclear areas were significantly greater in CAL myocytes than in those from the sham‐operated group. These increases in nuclear number and cellular dimensions of the atrial myocyte are prominent features of the response to the stress imposed by left ventricular infarction.
Luteal morphology, atresia, and plasma progesterone concentrations during the reproductive cycle of two oviparous lizards, Crotaphytus collaris and Eumeces obsoletus
Authors: Fox Sandra L. , Guillette Louis J. 
Published: February 2005

AbstractFrom ovulation to oviposition, the corpora lutea of the oviparous lizards Crotaphytus collaris and Eumeces obsoletus exhibit three stages of luteal development: (1) luteogenesis, (2) luteal maturity, and (3) luteal regression. Each stage exhibits distinct characteristics, involving changes in: (1) luteal volume, (2) nuclear diameter of cells within the luteal cell mass, and (3) thecal development. Plasma progesterone concentration is greatest during luteogenesis and is positively correlated with ovarian atresia, although atresia occurred throughout the period of gravidity. These data suggest that in these two species, the corpora lutea secrete high amounts of progesterone immediately following ovulation and exhibit morphologically distinct stages of growth and regression.
In vitro behavior of thymic nurse cell‐like complexes from mechanically and enzymatically dissociated frog tadpole thymuses
Authors: Holtfreter Hiroko B. , Cohen Nicholas 
Published: February 2005

AbstractCellular complexes, analogous by virtue of their external appearance, size, and number of seemingly internalized thymocytes to thymic nurse cells (TNCs) of endothermic vertebrates, were seen in short‐term cultures (6–8 days) of mechanically and enzymatically dissociated thymuses of leopard frog tadpoles. Most TNC‐like complexes from mechanically disrupted thymuses were covered with many thymocytes that morphologically resembled the “internalized” thymocytes. With time in culture, most complexes remained spherical and lost their externally adherent and “internalized” thymocytes. Some complexes, however, adhered to the glass substratum by means of macrophage‐like cells. After one typically appearing TNC from a mechanically dissociated thymus had released its “internalized” thymocytes and spread completely over the glass substratum, it could be seen to consist actually of 9–10 stromal cells with the appearance of epithelial cells, macrophages, and dendritic cells. TNC‐like structures from enzymatically dissociated thymuses had few, if any, attached thymocytes. Although these structures closely resembled murine TNCs initially, they displayed abnormal transformations within a few days of culture. Our observations led us to question the assumption that all TNCs from mechanically as well as enzymatically isolated TNCs from vertebrate thymuses are single cells. Rather, some if not all of the so‐called TNC may actually be entities composed of several stromal cell types that enclose thymocytes. We suggest that this configuration seen in vitro may reflect the architecture of the compartmentalized reticular stromal cell meshwork that characterizes the intact thymus.
Histological, histochemical, and fine structural observations on the spleen of seals
Authors: Schumacher Udo , Welsch Ulrich 
Published: February 2005

AbstractSpleens of three species of Antarctic seals with different diving habits (Weddell seal, crabeater seal, and fur seal) have been studied with histological, histochemical, and electron microscopic methods. The spleens can be classified as nonsinusoidal, with capsule and trabeculae rich in innervated smooth muscle cells. The trabecular system is particularly well developed in the deep‐ and long‐diving Weddell seal. As in other mammals the pulp can be divided into white and red pulp. In the white pulp, periarteriolar lymphatic sheaths and secondary lymphatic nodules occur; both are surrounded by a marginal zone rich in macro‐phages and eosinophils. The nodules can be observed frequently, which is in accordance with abundance of plasma cells in the red pulp. Well‐developed white pulp and numerous plasma cells and eosinophils obviously reflect a high load of nematodes, which have mainly been found in lung and stomach. Additionally, in the red pulp morphological evidence for the following functions has been found: destruction of erythrocytes, erythropoiesis, and thrombopoiesis. In respect to blood flow through the red pulp, we interpret our observations in the following way: terminal branches of arterioles open into the space between the fibroblastic reticulum cells; blood draining from here is collected into pulp veins, which are mainly found near the trabeculae. Thus, the seals have an open vascular compartment in their spleens, as also occurs in the cat. The red pulp is innervated by numerous nerve fibers that seem to include both cholinergic and adrenergic ones. The target cells of these fibers seem to be the fibroblastic reticulum cells, whose state of contraction may influence the direction of blood flow through the red pulp.