bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of compound 48/80 on hepatic glycogen and glucose‐6‐phosphatase early in the diurnal cycle of the rat
Authors: Dimlich Ruth V. W. , Cardell Robert R. 
Published: February 2005

AbstractThe amount and distribution of glycogen as well as the activity of glucose‐6‐phosphatase (G‐6‐Pase) in the livers of rats were analyzed by biochemical and/or histochemical techniques. During the first 5 hr of the light cycle, livers of rats were sampled prior to and 30 min following an injection of compound 48/80 or Ringer's solution. Glycogen decreased significantly in response to sampling; however, treatment with compound 48/80 provoked an additional significant decrease in hepatic glycogen. These differences occurred irrespective of the time during the 5 hr that this was studied. The livers of the majority of the rats treated with compound 48/80 displayed a periportal distribution of glycogen, while those treated with Ringer's showed a more uniform pattern. Hepatic G‐6‐Pase activity was unchanged in either the Ringer's or compound 48/80 treated rats. These results indicated that (1) the significant glycogenolytic response occurs independently of the amount of glycogen present, (2) G‐6‐Pase activity is not affected within 30 min following the stimulation of glycogenolysis, (3) variation in glycogen patterns during depletion depends on the nature of the stimulus and/or degree of response, and (4) the amount of glycogen available for release is limited.
On the functional morphology of the human petrous bone
Authors: Doden E. , Halves R. 
Published: February 2005

AbstractIn this study the human petrous bone was investigated to find out whether and in what way it is adapted to mechanical stress by inner bone structure. Three normally formed petrous bones were cut in serial sections and examined by means of microradiography and circular polarized light with respect to mineralization, distribution of bone structure, and collagen fiber arrangement over the cross section. It has been shown that the human petrous bone can be divided morphologically into four different bony layers: (1) endosteal; (2) enchrondral; (3) inner periosteal layers, which together form the labyrinthine capsule and which are characterized by a higher level of mineralization and show no clear indication of bone remodeling; and (4) outer periosteal layer, in which numerous osteons indicate appositional and resorptional growth processes. The collagen fibers in the labyrinthine capsule are arranged in an irregular web‐like pattern, whereas in the outer periosteal layer they run predominantly parallel to the surfaces of the petrous bone, probably to minimize the mechanical stress in the form of a tension band. These results support the assumption that in the human petrous bone, the outer periosteal layer is adapted to resorb elastic deformation, whereas the brittle labyrinthine capsule is better adapted to the functions of an auditory and vestibular organ.
Fine structure of the glomerular basement membrane and immunolocalization of five basement membrane components to the lamina densa (basal lamina) and its extensions in both glomeruli and tubules of the rat kidney
Authors: Laurie G. W. , Leblond C. P. , Inoue S. , Martin G. R. , Chung A. 
Published: February 2005

AbstractElectron microscopic immunostaining was used to examine the localization of type IV collagen, laminin, entactin, heparan sulfate proteoglycan, and fibronectin within the basement membranes of the rat kidney. In preliminary experiments, various methods of processing formaldehyde‐fixed kidney were compared using antilaminin antiserum and the indirect immunoperoxidase method. Little or no laminin immunostaining of the glomerular basement membrane was present in sections unless they had been frozen‐thawed; and even in this case, the immunostaining was light in comparison to that of basement membranes in adjacent tubules. However, when frozen‐thawed sections were treated with 0.5% sodium borohydride, immunostaining was then as strong in glomerular as in tubular basement membranes. Accordingly, this treatment was applied to frozen‐thawed sections before immunostaining for any of the substances under study.Immunostaining of the glomerular basement membrane for each of the five substances was fairly uniform throughout the lamina densa (also called basal lamina), but uneven in the lamina lucida interna and externa (also called lamina rara interna and externa) in which stained bands extended from the lamina densa. Similarly in the basement membranes of tubules, immunostaining for the five substances was localized to the lamina densa and bands extending into the lamina lucida.When the ultrastructure of the glomerular basement membrane was examined, three structures were found: (1) a network of 4‐nm‐thick “cords,” which seems to be the main component; the cords are closely packed in the lamina densa and more loosely arranged in the lamina lucida interna and externa; (2) straight, hollow 7–10‐nm‐thick structures referred to as “basotubules”; and (3) 3.5‐nm elements composed of minute paired rods, referred to as “double pegs.” The distribution of the cords, but not that of the other two structures, was related to the immunostaining pattern.It is concluded that (1) to fully reveal the antigenicity of the glomerular basement membrane, frozen‐thawed sections must be treated with sodium borohydride prior to immunostaining, possibly because this basement membrane is more compact than the others; and (2) in both glomerular and tubular basement membranes, type IV collagen, laminin, entactin, heparan sulfate proteoglycan and fibronectin are colocalized in the lamina densa and its extensions to the laminae lucidae. Since the distribution of the cords corresponds to that of immunostaining, it is likely that the five substances are present within the cords.
The effect of age on lung structure in male BALB/cNNia inbred mice
Authors: Kawakami Masahiko , Paul J. Lawrence , Thurlbeck William M. 
Published: February 2005

AbstractMorphometric examination using light, scanning electron, and transmission electron microscopy was performed on the lungs from 32 inbred male BALB/cNNia mice between 38 days and 28 months of age.Between 38 days and 9 months of age the changes were primarily those of growth. Alveolar multiplication and total elastic‐fiber length appeared complete by 38 days of age. The major increase in the number of interalveolar pores occurred by 68 days, but there was a significant further increase from 68 days to 9 months of age. At 9 months, approximately 10% of the alveolar wall was formed by pores. Alveolar ducts, the cylindrical core of air central to alveolar mouths, increased more in diameter than length.Between 9 and 28 months the changes were attributed to aging and were different from those reported in humans and other species. Lung volume, alveolar surface area, and total volume of alveolar wall increased with age; there was no change in mean linear intercept and volume proportion of alveolar and alveolar duct air. Total area of pores increased with age, but their number and area fraction of the alveolar wall did not change. No transmission electron microscopic changes were seen in the alveolar walls. We speculate that the morphometric differences between our animals and those studied in other reports may reflect the fact that our animals were specific‐pathogen—free animals and kept under protected circumstances.
Morphologic and cytochemical characteristics of amine‐containing globule leukocytes in rat tracheal epithelium
Authors: Pearsall Allan D. , Echt Robert , Ross Lawrence M. , Roth Robert A. , Dinerstein Robert J. 
Published: February 2005

AbstractAmine‐containing cells in the tracheal epithelium are typically of the small‐granule type (diameter approximately 100 nm). However, in the rat, another amine‐containing cell type has been identified that possesses the amine‐handling features of the APUD‐series of cells (amine precursor uptake and decarboxylation) but not the ultrastructural characteristics. It has been postulated that these cells may be related to cutaneous melanocytes. In this study, fluorescent cells were present in the laryngeal and tracheal epithelial lining of adult Sprague‐Dawley rats following freeze‐drying and exposure to formaldehyde vapor (FIF or formaldehyde‐induced fluorescence). Microspectrofluorimetry revealed an emission maximum at 493 nm. The excitation maximum could not be calculated but appeared to be around or below 350 nm (to record spectra below requires the use of quartz optics). Yellow fluorescence also emanated from serotonin‐containing mast cells (excitation and emission maxima: 401/515 nm). Tracheal segments processed according to the aqueous formaldehyde (AFIF) technique, for the demonstration of 5‐hydroxytryptophan (5‐HTP) or serotonin (5‐HT), failed to identify fluorescent cells in the epithelial lining even though connective‐tissue mast cells were evident. Subsequent treatment of AFIF‐fixed sections with formaldehyde and HCl vapors (AFIF‐HCl) resulted in the formation of a fluorogenic compound within numerous cells in the tracheal lining (455/537 nm). This spectral shift and increase in intensity of fluorescence following acidification are characteristic for standards and/or cells that contain tryptamine, tryptophan, or peptides with NH2‐terminal tryptophan and are markedly different from microspectrofluorimetric data reported for the phenylethylamines or serotonin. It is therefore postulated that these cells contain a closely related β‐(3‐indolyl) ethylamine‐like compound, serotonin excluded.The morphology of the fluorescent cells was similar when prepared according to the FIF or AFIF‐HCl techniques. Conjunctive staining, the examination of a single section first by fluorescence microscopy and subsequently by other histochemical and cytochemical methods, demonstrated that the fluorescent granules were also methylene blue, alcian blue, periodic‐acid Schiff, and ferricferricyanide positive. Subsequent correlative electron microscopic examination of Epon‐embedded AFIF‐HCl‐treated tracheal sections demonstrated that these amine‐containing cells were globule leukocytes.
Seasonal variations in pituitary LH‐gonadotropes of the hibernating bat Myotis lucifugus lucifugus: An immunohistochemical study
Authors: Anthony Edythe L. P. , Gustafson Alvar W. 
Published: February 2005

AbstractPituitary gonadotropes were identified throughout the year in the seasonally breeding, hibernating bat Myotis lucifugus lucifugus by means of light microscopic immunohistochemistry. In both male and female bats, these cells were immunoreactive with an antiserum directed to the β subunit of luteinizing hormone. Some gonadotropes were aggregated near a portion of the infundibular stalk which crosses the anterior lobe, while most were scattered singly in a uniform manner throughout the rest of the pars distalis. This cell population exhibited seasonal variations in both sexes. In males, the proportional volume of the pars distalis occupied by immunoreactive gonadotropes (volume fraction) was significantly reduced in late July, when plasma testosterone levels were approaching their seasonal peak. In females, the volume fraction declined in April, following ovulation, and remained low during pregnancy and lactation. The size and shape of gonadotropes appeared relatively constant throughout the annual reproductive cycle in male bats; the immunoreactive cells were irregular in shape, with cytoplasmic extensions insinuating between and often “cupping” other secretory cell types. In females, the gonadotropes resembled those of males throughout most of the year, except during pregnancy, when these cells became enlarged and ovoid. No evidence of involution was observed in these anterior pituitary cells in either males or females during hibernation.
The double cascade of lymphoid proliferation: Current challenges and problem areas
Authors: Nossal G. J. V. 
Published: February 2005

AbstractTwo largely but not entirely separate cascades of proliferation and differentiation are involved in immunity. First, processes that are mainly independent of the entry of antigen into the body generate the two types of lymphocytes, T cells and B cells. This lymphoneogenesis proceeds in the thymus and the bone marrow, respectively. It creates families and subfamilies of nondividing cells that do nothing but patrol the body until antigen enters. Each lymphocyte set represents a repertoire of recognition units preequipped with receptors for antigen, and each individual lymphocyte carries its own particular specificity as a result of a somatic rearrangement of genes. When an antigenic stimulus is given, the second and antigen‐dependent wave of proliferation and differentiation occurs. This involves clonal selection of particular lymphocytes within the repertoire with specificity for the antigen, and the generation of both immunologic effector cells and memory cells. This second cellular cascade takes place chiefly in the secondary lymphoid tissues, e.g., lymph nodes or spleen. The developing immune system learns to discriminate self from not‐self. The paper outlines the chief mechanisms operative in immunologic tolerance and also briefly addresses the fact that T lymphocytes must learn to “see” antigens in association with a “self” major‐histocompatibility‐complex antigen. Both proliferative cascades depend on intercellular interactions, but much more is known about those operative in antigen‐driven lymphocyte activation. Here there is a cyclical process in which antigen‐trapping cells stimulate helper/inducer T cells, which in turn stimulate cytotoxic/suppressor T cells or B cells. Some T‐cell products can augment the antigen‐trapping cells' inductive role. The structure of some of the molecules involved is rapidly being revealed by gene cloning and expression, but the anatomic basis of cell interactions within the lymphoid system is not being addressed as fully as it might be.
Ontogeny of primary lymphoid organs and lymphoid stem cells
Authors: Le Douarin Nicole M. , Dieterlen‐Lièvre Françoise , Oliver Peter D. 
Published: February 2005

AbstractCells of the immune system go through a series of important developmental steps that begin early in embryonic life and include, first, the various waves of hemopoietic‐cell production in the embryo and, second, the homing of these cells to the hemopoietic organs, which are the sites of hemopoiesis and lymphopoiesis in embryonic and adult life. The avian embryo is an important model for investigating these early steps; and this paper presents a comprehensive review of the work done on the early ontogeny of the avian immune system.
Early events in T lymphocyte genesis in the fetal thymus
Authors: Owen John J. T. , Jenkinson Eric J. 
Published: February 2005

AbstractThere is considerable uncertainty about the nature and level of maturation of the stem cells which colonize the thymus. Arguments are presented here which raise doubts about the claims that these cells have undergone substantial maturation along the T‐lineage pathway prior to migration to the thymus. Instead, emphasis is placed on the role of thymic stromal cells in T‐lymphocyte maturation. The heterogeneous nature of these cells is well established, but progress is described in analyzing the various cell types and their embryological origins. In particular, the expression of the major histocompatibility complex (MHC) antigens on thymic stromal cells might be relevant to the understanding of restriction and tolerance. The early phases of thymus lymphocyte differentiation are described; but no clear account of the generation of T‐cell subsets from immature cells can, as yet, be offered.
Immunohistology of lymphoid and non‐lymphoid cells in the thymus in relation to T lymphocyte differentiation
Authors: Van Ewijk W. 
Published: February 2005

AbstractThe present paper reports the distribution of lymphoid and non‐lymphoid cell types in the thymus of mice. To this purpose, we employed scanning electron microscopy and immunohistology. For immunohistology we used the immunoperoxidase method and incubated frozen sections of the thymus with (1) monoclonal antibodies detecting cell‐surface‐differentiation antigens on lymphoid cells, such as Thy‐1, T‐200, Lyt‐1, Lyt‐2, and MEL‐14; (2) Mococlonal antibodies detecting the major histocompatibility (MHC) antigens, H‐2K, I‐A, I‐E, and H‐2D; and (3) monoclonal antibodies directed against cell‐surface antigens associated with cells of the mononuclear phagocyte system, such as Mac‐1, Mac‐2, and Mac‐3. The results of this study indicate that subsets of T lymphocytes are not randomly distributed throughout the thymic parenchyma; rather they are localized in discrete domains.Two major and four minor subpopulations of thymocytes can be detected in frozen sections of the thymus: (1) the majority of cortical thymocytes are strongly Thy‐1+ (positive), strongly T‐200+, variable in Lyt‐1 expression, and strongly Lyt‐2+; (2) the majority of medullary thymocytes are weakly Thy‐1+, strongly T‐200+, strongly Lyt‐1+, and Lyt‐2− (negative); (3) a minority of medullary cells are weakly Thy‐1+, T‐200+, strongly Lyt‐1+, and strongly Lyt‐2+; (4) a small subpopulation of subcapsular lymphoblasts is Thy‐1+, T‐200+, and negative for the expression of Lyt‐1 and Lyt‐2 antigens; (5) a small subpopulation of subcapsular lymphoblasts is only Thy‐1+ but T‐200− and Lyt−; and (6) a small subpopulation of subcapsular lymphoblasts is negative for all antisera tested. Surprisingly, a few individual cells in the thymic cortex, but not in the medulla, react with antibodies directed to MEL‐14, a receptor involved in the homing of lymphocytes in peripheral lymphoid organs. MHC antigens (I‐A, I‐E, H‐2K) are mainly expressed on stromal cells in the thymus, as well as on medullary thymocytes. H‐2D is also expressed at a low density on cortical thymocytes. In general, anti‐MHC antibodies reveal epithelial‐reticular cells in the thymic cortex, in a fine dendritic staining pattern. In the medulla, the labeling pattern is more confluent and most probably associated with bone‐marrow‐derived interdigitating reticular cells and medullary thymocytes. We discuss the distribution of the various lymphoid and non‐lymphoid subpopulations within the thymic parenchyma in relation to recently published data on the differentiation of T lymphocytes.
Contribution of thymus lymphocytes to the peripheral lymphoid tissues and the effect of antigen on the rate of cell exit from the thymus
Authors: Scollay Roland , Shortman Ken 
Published: February 2005

AbstractSome of the important questions concerning the development of T cells in the thymus can be answered by a study of the different thymocyte subpopulations and a comparison of their properties with those of the cells exported to the peripheral lymphoid tissues. What is the relationship between cortical and medullary thymocytes? Why do most cortical cells die? Which subpopulation gives rise to thymus migrants? How many cells are exported from the thymus? Are the exported cells fully mature? Are any of these functions affected by antigen stimulation or other peripheral events? In this paper we review the background to some of these questions and focus on the effect of peripherally administered antigen on the export of cells from the thymus. Experimental data are presented which suggest that the overall rate of emigration is not grossly affected by large doses of intravenous protein antigens. Nor is there any obvious qualitative change, at least in terms of the size of the cells released. The possibility of changes in the specificity of the exported cells is discussed, but as yet there are no data which throw light on this point.
T‐Cell development in the absence of a thymus: The number, the phenotype, and the functional capacity of T lymphocytes in nude mice
Authors: Chen Wei‐Feng , Scollay Roland , Shortman Ken , Skinner Margot , Marbrook John 
Published: February 2005

AbstractA small but definite proportion of T‐lymphocyte‐like cells have been reported in nu/nu (nude) mouse spleen despite the congenital absence of a thymus in these animals. We have determined the number and the characteristics of such cells using flow cytometry. The level of T‐like cells increased with age. In 4‐month‐old nu/nu CBA spleen, 14% of all cells expressed some Thy 1 antigen. However, only 4% expressed mature T‐cell levels, and only the 2% with the highest Thy 1 also showed a normal distribution of Ly 1 and Ly 2 antigens. These T‐like cells were slightly larger than normal nondividing T lymphocytes.We have assessed the total functional capacity of T‐like cells in nu/nu CBA spleen using a high‐cloning‐efficiency limit‐dilution culture system. Almost all precursor cells capable of forming clones when stimulated with concanavalin A in the presence of irradiated spleen cells and growth factors, and almost all precursors of those clones that were cytolytic in a lectin‐mediated tumor‐cell‐lysis assay, were within this 2% subpopulaton of nu/nu spleen cells with mature T‐cell markers. Increased levels of purified interleukin 2 failed to induce further precursor function, indicating that maturation of pre‐T cells was not obtained. However the nu/nu spleen cells bearing mature T‐cell markers displayed only 10‐30% of the cloning efficiency of normal splenic T cells. The majority of nu/nu spleen T‐like cells, even within this phenotypically “normal” subset, appeared to be nonfunctional.We conclude that the absence of a thymus leads to qualitative, as well as quantitative, deficiencies in the T‐cell population, and various interpretations are discussed.
The migration of lymphocytes across specialized vascular endothelium: VIII. Physical and chemical conditions influencing the surface morphology of lymphocytes and their ability to enter lymph nodes
Authors: Ford W. L. , Allen T. D. , Pitt M. A. , Smith M. E. , Stoddart R. W. 
Published: February 2005

AbstractThe introductory review amplifies the finding that simply holding lymphocytes in vitro reversibly compromises their ability to enter lymph nodes from the blood, although entry into the spleen is unaffected. The differential migration of T and B lymphocytes from the blood, lymphocyte traffic in athymic rats, and the secretion of a sulphated glycoconjugate by high endothelial cells in lymph nodes are also discussed.Original data are presented concerning the effects of varying the conditions under which lymphocytes are held in vitro (time, temperature, medium, centrifugation) on their ability to enter lymph nodes and also on their surface morphology. In general, conditions that reduced the number of microvilli and induced surface blebbing also tended to affect the delicate function of crossing specialized vascular endothelium; but there was no simple relationship between morphology and migratory behavior. The localization of lymphocytes to the bone marrow was augmented by holding them in vitro, and this effect was greater after holding at room temperature (RT) than at 0°C, in contrast to impaired entry into lymph nodes. Small amounts of heparin (10 units) injected along with lymphocytes significantly reduced early localization in lymph nodes. These findings have practical implications for the design of lymphocyte traffic experiments and are relevant to the mechanism of lymphocyte attachment to vascular endothelium, since the well‐known effect of trypsinizing lymphocytes can be reproduced by maintenance in vitro.