bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural changes in hamster lung 15 min to 3 hr after exposure to pancreatic elastase
Authors: Morris Shirley M. , Kagan Herbert M. , Stone Phillip J. , Snider Gordon L. , Albright John T. 
Published: February 2005

AbstractA single endotracheal instillation of porcine pancreatic elastase into hamster lungs induces morphological changes that can be detected as early as 15 min after the instillation of enzyme. Lung tissue from animals sacrificed at six time points between 15 min and 3 hr after enzyme instillation was examined for ultrastructural alterations. There were few of these alterations and they were highly focal, but they included damaged epithelial cells and partially digested elastic fibers that occurred both in the parenchyma and the pleura.A cytochemical technique employing N‐t‐Boc‐L‐alanine‐p‐nitrothiophenyl ester as a substrate for elastase‐like enzymes was also used in an effort to locate pancreatic elastase shortly after instillation into the lungs. Reaction product was observed on the alveolar surface and in pinocytotic vesicles of alveolar type I cells, in connective tissue areas, in fibroblasts, and in pinocytotic vesicles of capillary endothelial cells. The location of reaction product coupled with ultrastructural alterations in the tissue suggests that pancreatic elastase instilled into the trachea may reach the interstitium in two ways: First, transport may take place across intact alveolar type I cells via pinocytotic vesicles, and second, a small amount of enzyme may gain access to the connective tissue after the disruption of epithelium in a few highly focal areas.
Differential distribution of lymphocytes and accessory cells in mouse Peyer's patches
Authors: Ermak Thomas H. , Owen Robert L. 
Published: February 2005

AbstractThe aim of this immunohistologic study was to determine how lymphocytes and accessory cells associated with antigen processing are distributed in the domes of Peyer's patches. Monoclonal antibodies against mouse B cells (anti‐B220), T cells (anti‐Thy‐1.2), T helper cells (anti‐L3T4), T cytotoxic/suppressor cells (anti‐Lyt‐2), macrophages (anti‐Mac‐1), and Ia+ cells (anti‐I‐Ad) were applied to cryostat sections of mouse Peyer's patches and visualized with peroxidase‐conjugated avidin‐biotin complexes (ABC). The subepithelial dome, the dome epithelium, and the follicle crypt epithelium were each surveyed for cells labeled with these antibodies. Each region had a characteristic and nonrandom distribution of labeled cells. In the subepithelial dome, B cells, T helper cells, macrophages, and Ia + accessory cells formed a cellular meshwork between follicle and the dome epithelium. T cytotoxic/suppressor cells were sparse beneath the epithelium. In the dome epithelium, solitary and paired lymphocytes occurred both above and below the level of epithelial cell nuclei. B cells predominated, and both T helper cells and T cytotoxic/suppressor cells were present. B cells sometimes aggregated in small clusters. Macrophages were rarely observed in the epithelium. The distribution of cells in the dome epithelium was distinctly different from non–Peyer's patch intestine where T cytotoxic/suppressor cells predominated and B cells were few in number. Although lymphocytes were usually absent in crypts outside Peyer's patches, in follicle crypts B cells and T cells were seen but not Ia + accessory cells or macrophages. Most of the T cells in the crypt epithelium were T cytotoxic/suppressor cells. These characteristic distributions in Peyer's patch domes and crypts are consistent with current hypotheses that antigen processing takes place in follicle domes and that specific lymphocytes may participate in fine regulation of stem cell differentiation in follicle crypts.
Structure of the satellite cell sheath around the cell body, axon hillock, and initial segment of frog dorsal root ganglion cells
Authors: Matsumoto Emiko , Rosenbluth Jack 
Published: February 2005

AbstractThe structure of the satellite cell sheath of frog dorsal root ganglion cells was studied in thin sections and freeze‐fracture replicas. The sheath around the cell body is composed of thin satellite cell lamellae closely applied to the neuronal plasma membrane. At the axon hillock the sheath divides into outer and inner components separated by a broad space containing a distinctive extracellular matrix and occasional flattened satellite cell processes. The sheath around the initial segment is usually multilayered but less compact than that around the cell body, and in some places it exhibits node‐like interruptions. Apart from occasional particle groupings characteristic of tight junctions and gap junctions, the satellite cells display homogeneously distributed intramembranous particles in both fracture faces in all regions of the sheath.
Blood flows in the maxillocarotid anastomoses and internal carotid artery of conscious dogs
Authors: Lee Maw‐Chang , Reid Ian A. , Ramsay David J. 
Published: February 2005

AbstractAlthough the external carotid artery is known to contribute to the cerebral blood flow in anesthetized dogs, quantitative information on the anastomoses and their role in conscious dogs is lacking. This study was carried out to determine blood flows in these anastomoses and the internal carotid artery, and also to examine the functional significance of the anastomoses in conscious dogs. Fifteenmicron radioactive microspheres were injected into common and external carotid arteries of four conscious dogs through chronically implanted catheters. Blood flows were determined by the reference sample method and by comparing microsphere distributions in the brain and the masseter muscle. Blood flows were estimated to be 140 ± 32, 7.7 ± 1.4, and 3.3 ± 1.1 ml/minute (mean ± SD) in the common carotid artery, internal carotid artery, and anastomoses on each side, respectively. Additional evidence indicated that the anastomotic flow so determined was primarily the flow in the anastomotic artery. Humoral responses to angiotensin II infusions were also studied in conscious dogs. External carotid angiotensin increased plasma 11‐hydroxycorticosteroid concentration (used as an index of ACTH secretion) but did not increase plasma vasopressin concentration to the same extent as common carotid infusion. Therefore, the external carotid artery is functionally important in perfusing the brain in conscious dogs.
Scanning electron microscopical studies of the arterial terminals in the red pulp of the rat spleen
Authors: Satodate R. , Tanaka H. , Sasou S. , Sakuma T. , Kaizuka H. 
Published: February 2005

AbstractThe arterial terminals in the red pulp of the perfused rat spleen were studied by scanning electron microscopy. The arterial terminals were tubular or funnel‐shaped and ended openly in the splenic cord. No continuity was observed between the arteries and the sinuses. The endothelial cells of the arterial terminals extended their processes at the fringe of the terminal ends, and these endothelial processes were connected to the processes of the reticular cells of the splenic cord. In addition, large pores, measuring 0.5–8 μm in size, were found in the wall of the terminals adjacent to their end.
Lectin binding sites on human endocervix: A comparison with secretory and proliferative endometrium
Authors: Yen Yun , Lee Mao‐Chi , Salzmann Martina , Damjanov Ivan 
Published: February 2005

AbstractEndocervix and corresponding endometrium of women of reproductive age were studied histochemically with 13 fluorescein isothiocyanate‐labeled lectins to delineate the differences between the epithelial cells in two anatomical sites. Lectin from Maclura pomifera (MPA), Ulex europaeus (UEA‐I), Glycine max (SBA), and Vicia villosa (VVA) bound only to endocervical epithelium and were the only four lectins that distinguished endocervical from endometrial epithelium. These differences were independent of menstrual cyclic changes and blood group antigen secretion. These data show that lectins can be used to histochemically distinguish endocervical from endometrial glands.
Ultrastructural immunocytochemistry of somatotrophs and mammotrophs in embryos of the dwarf mutant mouse
Authors: Wilson Doris B. , Wyatt Darlene P. 
Published: February 2005

AbstractThe embryonic development of somatotrophs and mammotrophs in the adenohypophysis in dwarf (dw) mutant mice was studied by means of ultrastructural immunocytochemistry. Embryos at 16–18 days of gestation were removed from litters consisting entirely of dwarf homozygotes obtained from homozygous matings of adult dwarfs in which reproductivity was induced by means of hormone supplementation and renal capsule implants of normal pituitaries. Litters from normal (−/+) matings served as controls. Pituitaries from adult normal and dwarf mice also were removed and processed with the embryonic material. Thin sections were exposed to anti‐growth‐hormone serum (anti‐GH) or to antiprolactin serum (anti‐PRL) and processed immunocytochemically with the colloidal gold procedure. In the normal pituitaries, a strong positive reaction to anti‐GH occurred in the adult and in embryos as early as 16 days, whereas the reaction to anti‐PRL was strong in the adults but relatively weak in the embryos. In dwarf embryonic and adult pituitaries, ambiguous cells showing combinations of features characteristic of somatotrophs and mammotrophs were present. However, neither these cells nor other granulated cells reacted to anti‐GH or to anti‐PRL, except for a questionable reaction to the latter at 18 days and in the adult. Thus, the dwarf pituitary shows functional as well as morphological abnormalities as early as 16 days of gestation.
Distribution of actin in sertoli cell ectoplasmic specializations and associated spermatids in the ground squirrel testis
Authors: Vogl A. W. , Grove B. D. , Lew G. J. 
Published: February 2005

AbstractWe have investigated the possibility that the complex patterns of fluorescence associated with spermatids of the ground squirrel labeled with 7‐nitro‐benz‐2‐oxa‐1,3‐diazole‐phallacidin (NBD‐phallacidin) are due to the presence of filamentous actin within the spermatids themselves rather than to actin in attached Sertoli cell ectoplasmic specializations, as previously reported (J. Cell Biol., 100:814–825). Enzymatic treatments (trypsin, DNAase 1) freed Sertoli cell ectoplasmic specializations from spermatids and resulted in a loss, from the spermatids, of the complex fluorescence patterns, suggesting that the latter were generated by labeled actin in ectoplasmic specializations. Moreover, ectoplasmic specializations that were detached enzymatically from spermatids demonstrated the same fluorescence patterns as those emitted from spermatids in the intact or mechanically fragmented seminiferous epithelium. Most spermatids, however, do display a weak and diffuse pattern of fluorescence that changes during spermatogenesis and that is localized between the acrosomal cap and nucleus. S‐1 decoration confirmed this subacrosomal localization and further demonstrated that the actin in adjacent Sertoli cell ectoplasmic specializations is arranged in a unipolar fashion. We conclude that the complex patterns of actin fluorescence associated with mechanically isolated spermatids are a superimposition of both Sertoli cell and germ cell actin; however, the latter is either poorly detected or not detected at all when Sertoli cell ectoplasmic specializations overlie the germ cells.
Developmental changes in the astrocytic response to lateral olfactory tract section
Authors: Sijbesma Hans , Leonard Christiana M. 
Published: February 2005

AbstractWhen the lateral olfactory tract (LOT) of the golden hamster, Meso cricetus auratus, is transected in the first week of postnatal life, axons can grow back past the lesion and achieve functional reinnervation of caudal projection regions. In contrast, when the tract is sectioned after postnatal day 7 (P7), axons do not reinnervate regions caudal to the cut. The experiments reported here investigated whether regenerative failure after tract section in pups older than P7 is accompanied by developmental changes in the astrocytic response. LOT transections were performed at P3 and P9 and the glial reaction was observed at survival times ranging from 12 hr to 2 weeks. Immunocytochemistry with glial fibrillary acidic protein (GFAP) was employed for histological visualization of astrocytic reactivity.Staining for GFAP immunoreactivity showed an appreciable glial reaction after tract section at both P3 and P9, but the extent of astrocytic hypertrophy and proliferation of glial processes was considerably greater and more extensive after tract section at P9. Radial glial cells were observed 2 weeks after LOT transection at P3 but were absent after lesions made at P9.The results from this study suggest that the developmental loss of regenerative capacity after LOT transection may be related to maturational changes in the glial response. In particular, the presence of radial glial elements after P3 lesions could serve to establish a more favorable microenvironment for axonal elongation.
Dexamethasone induces proliferation and terminal differentiation of osteogenic cells in tissue culture
Authors: McCulloch C. A. G. , Tenenbaum H. C. 
Published: February 2005

AbstractDexamethasone is an important regulator of cellular proliferation and differentiation, but paradoxical effects have been noted in a variety of culture systems. The purpose of this study was to determine whether dexamethasone induces proliferation and differentiation of osteogenic precursor cells. Periosteal explants from embryonic chicks were grown in culture for 3 or 4 days, treated continuously with dexamethasone or ethanol vehicle, and then either pulse‐labeled with 3H‐thymidine at 3 days or labeled for 24 hr between day 3 and day 4. Histochemical and autoradiographic procedures were used to assess the proliferation and differentiation of osteogenic cells. At 3 days, the area of bone, the percentage of alkaline phosphatase‐positive cells, the percentage of 3H‐thymidine‐labeled cells, and the percentage of cells labeled with both markers were significantly higher in dexamethasone‐treated cultures. Between day 3 and day 4 no significant changes in these parameters were observed in the dexamethasone‐treated cultures. In comparison, control cultures exhibited significant increases in the percentage of 3H‐thymi‐dine‐labeled cells after 24 hr of continuous labeling. The data show that dexamethasone induces a burst of proliferation in a cohort of cells that undergo differentiation. Once these cells have divided, further proliferation within the culture is limited. Finally, it is apparent that the timing of experiments may be critical in determining whether dexamethasone will inhibit or stimulate proliferation.
Attraction of chick primordial germ cells by gonadal anlage in vitro
Authors: Kuwana Takashi , Maeda‐Suga Hitomi , Fujimoto Toyoaki 
Published: February 2005

AbstractThe attraction of primordial germ cells (PGCs) by the gonadal anlage (germinal ridge; GR) in vitro has been demonstrated in the chick. PGCs were isolated from circulating blood of stage 13 embryos (Hamburger and Hamilton, 1951), placed between the GR and other embryonic tissues (neural tube, heart, allantois, liver) as controls separated by a distance of 170 μm on collagen‐coated substrate, and cultured with modified medium 199 (Kuwana and Fujimoto, Anat. Rec., 209:337–343, 1984) containing 10% fetal calf serum (pH 7.3). The behavior of PGCs was observed for 3 hr by 16‐mm time‐lapse microcinematography.PGCs showed directional movement toward GR. Also, there was a stronger attractive effect on the PGCs by GR from stage 13 embryos than by GR from later stage embryos. These results suggest that PGCs are attracted by some factor emitted from GR.
Axoglial contacts in the area postrema of the cat: An ultrastructural study
Authors: D'Amelio Fernando E. , Gibbs Michael A. , Mehler William R. , Philpott Delbert E. , Savage Wayne 
Published: February 2005

AbstractAxoglial contacts were observed in an ultrastructural study of the area postrema of the cat. According to the disposition of the electron‐dense projections attached to the adjoining membranes these contacts were classified as symmetrical or asymmetrical. The axon profiles contained aggregations of clear vesicles randomly distributed or grouped in clusters adjacent to the electron‐dense projections. Dense core vesicles were occasionally seen. The neuroglial profiles were either astrocytic or ependymoglial in nature. The astrocytes showed a clear cytoplasm, polymorphous vesicles, mitochondria, glycogen granules, and bundles of filaments. The ependymal cells, in contrast, had a more electron‐dense and granular appearance, tubular structures, irregular vesicular formations, profiles of smooth reticuloendoplasm, and filaments grouped in bundles or isolated in the cytoplasm. The possibility that these contacts might play a role in the chemical transfer from neurons to glial cells is discussed on the basis of existing biochemical data.
Ultracytochemistry of ouabain‐sensitive K+‐dependent p‐nitrophenyl phosphatase in rat incisor enamel organ
Authors: Garant Philias R. , Sasaki Takahisa 
Published: February 2005

AbstractSprague‐Dawley strain rats of 4–5 weeks old were perfusion‐fixed with either a mixture containing 0.1 or 0.25% glutaraldehyde and 2% formaldehyde, or a 2% formaldehyde in 0.1 M sodium cacodylate buffer for 10 minutes. Non‐decalcified 30–50‐μm sections of the enamel organ taken from lower incisors were then processed for ultracytochemical demonstration of ouabain‐sensitive, K+‐dependent, p‐nitrophenyl phosphatase, by use of the one‐step lead method, representing the second dephosphorylative step of Na+‐K+‐ATPase. Throughout the secretory, transition, and maturation stages of amelogenesis, the enzymatic activity was demonstrated along the cytoplasmic side of the plasma membranes of the stratum intermedium and the papillary layer cells, especially along their numerous micro‐villi. The plasma membranes forming gap junctions and desmosomes were free of reaction or showed slight focal precipitates of reaction products. The stellate reticulum and the outer enamel epithelium exhibited either a weak reaction or were reaction negative. Secretory ameloblasts showed a weak trace‐like reaction along the basal and lateral cell surfaces; however, the latter surfaces were sometimes completely free of reaction. Tomes' processes were usually reaction negative. Ameloblasts in the transition and maturation stages were devoid of enzymatic activity, except for a slight reaction along the plasma membranes of the basal cell surfaces of transition ameloblasts facing the papillary layer. The enzymatic activity described above was completely dependent on the presence of potassium and substrate in the incubation media and was almost completely inhibited by an addition of 10 mM ouabain to the incubation media.
Differential distribution of brush cells in the rat lung
Authors: Chang Ling‐Yi , Mercer Robert R. , Crapo James D. 
Published: February 2005

AbstractThe distribution of brush cells in the rat lung was studied using electron microscopic morphometry. Samples were taken from six distinctive anatomical regions. Tissue from the trachea, lobar bronchi, terminal bronchioles, first alveolar duct bifurcations, proximal alveolar regions, and the distal alveolar region were isolated and embedded in Epox 812. Aside from the trachea and the lobar bronchi, the other four regions were isolated from embedded tissue using microdis‐section techniques. Electron micrographs taken from thin sections of these samples were analyzed. It was found that brush cells made up 10% of the volume of epithelium covering the first alveolar duct bifurcation. Approximately 2% of the proximal alveolar epithelium, 1.4% of the terminal bronchiolar epithelium, and 3% of the tracheal epithelium were made up of brush cells. No brush‐bordered epithelium was found in the lobar bronchi or in the distal alveolar walls. We conclude that brush cells have a distinct spatial location in the lung, being in high concentration in the trachea and in areas where first generation alveolar duets bifurcate. The highest density was on the bifurcation of the first alveolar ducts, and their density decreased radially from this region.
An HRP study of the motoneurons supplying the rat hypobranchial muscles: Central localization, peripheral axon course and soma size
Authors: Kitamura Seiichiro , Nishiguchi Takahiko , Okubo Johji , Chen Kai‐Li , Sakai Akira 
Published: February 2005

AbstractThe locations of motoneurons (MNs) supplying the rat hypobranchial muscles (lingual, geniohyoid, and infrahyoid) and the peripheral courses of axons of these MNs were investigated by using a method of HRP injection into the hypoglossal nerve or these muscles in combination with severing of the hypoglossal and/or cervical components of the plexus hypoglossocervicalis. Moreover, soma sizes of the MNs were investigated in both transverse and horizontal sections. The hypobranchial MNs formed a sequence of cell columns extending caudally from the hypoglossal nucleus, via the supraspinal nucleus, to the medial and then the ventrolateral subnuclei of the ventral horn of C1 to C3. The lingual and geniohyoid MNs were located in the hypoglossal nucleus. The majority of their axons passed solely through the hypoglossal nerve, whereas a small number of axons, whose somata lay in the caudal hypoglossal nucleus, passed through the first cervical nerve and then through the ansa cervicalis to reach the hypoglossal nerve. The infrahyoid MNs were located in the supraspinal nucleus and the ventral horn, and their axons passed through the first to third cervical nerves. The hypobranchial MNs were divided into three groups according to their size: the lingual, the geniohyoid and thyrohyoid, and lastly the other infrahyoid MNs, in order of smaller to larger size. The sizes of lingual, geniohyoid, and thyrohyoid MNs displayed a unimodal distribution both in transverse and horizontal sections, whereas the other infrahyoid MNs showed a bimodal distribution.
The nucleus of Darkschewitsch in the cat: A Nissl, Golgi, and electron microscope analysis
Authors: Bianchi Rossella , Gioia Magda 
Published: February 2005

AbstractA light and electron microscope study was carried out to elucidate the cytoarchitectural organization of the nucleus of Darkschewitsch (ND) in the cat. From the anatomical staining methods, including Nissl and Golgi‐Cox, it appears that the ND shows a clear heterogeneity of shape and size of the neuronal population. The small or medium‐sized neurons show a high nuclear/cytoplasmic ratio and a modest basophilia. Spiny extrusions are present on many of the neurons, arranged either as varicosities giving a rosary feature or clumped in small groups over the dendritic processes; these are absent at the level of the soma. From the electron microscope analysis it appears that the neuropil is not very extensive because the neuronal bodies are numerous and compact. The synaptic complex is extensive both at the level of the nerve cell bodies and at the level of the neuropil. Since many of the synapses display the features typical of the inhibitory synapses, it is possible that they represent the anatomical basis of an inhibitory integrative function.
Preparation of flexible models of hollow gastrointestinal organs
Authors: Updike Susan J. , Holladay Steven D. 
Published: February 2005

AbstractFlexible models of hollow gastrointestinal organs can be easily prepared by coating air‐dried organs with a commercially available clear plastic compound. The plastic infiltrates the full thickness of organ walls to support and protect internal as well as external structures. Models are flexible, resistant to fluids, and lightweight. This plasticizing technique is particularly useful for the preservation and study of large animal gastrointestinal tracts.