bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphological and biochemical changes in the adult male rat reproductive system following long‐term treatment with 1,2‐dibromo‐3‐chloropropane
Authors: Ahmad N. , Wisner J. R. , Warren D. W. 
Published: February 2005

AbstractAdult Long‐Evans male rats were treated with various dosages of pure or technical grade 1,2‐dibromo‐3‐chloropropane (DBCP), epichlorohydrin (Epi), or allyl chloride (AC) for 1, 3, or 6 months on a daily basis. AC, which is the substrate for the production of DBCP, and Epi, which is a contaminant and/or metabolite of DBCP, had no effect on any of the parameters of the male reproductive system studied. The deleterious effects on male reproduction are therefore attributable specifically to DBCP. The effects of DBCP were dose and duration dependent. At the lowest dose (1 mg/kg) DBCP did not have any discernible effects on the male reproductive system. By 3 months of treatment at the intermediate dose of 5 mg/kg, the morphology of the testis ranged from normally appearing seminiferous tubules to ones which contained Sertoli cells only. At 6 months of treatment there was a reduction in the weights of the testes and sexual accessory glands. At the highest dose, the majority of the rats showed advanced testicular regression by 1 month of treatment. The most extreme testicular regression was observed in the 6‐month treatment group. Almost all of the seminiferous tubules of all of the rats were composed of Sertoli cells only. In some of the animals, a few isolated seminiferous tubules contained an occasional spermatogonium or primary spermatocyte. Some of the Leydig cells of the rats in this group showed morphological evidence of atrophy as evidenced by the clumping of chromatin and paucity of stainable cytoplasm. This was confirmed by lower levels of intratesticular testosterone, a significant reduction in the number of luteinizing hormone (LH) receptors and increased serum levels of LH and follicle‐stimulating hormone (FSH). From these results we conclude that DBCP is a specific male gonadotoxin and that the effects are not a result of contamination or metabolism. The effects appear to be a direct action at the testicular level because feedback inhibition to the pituitary gland was adversely affected.
Thy‐1 positive tingible body macrophages (TBM) in mouse lymph nodes
Authors: Smith John P. , Kosco Marie H. , Tew John G. , Szakal Andras K. 
Published: February 2005

AbstractThis study was prompted by the observation that cells in mouse lymph nodes (LN) with cytological characteristics of tingible body macrophages (TBM) appeared to be Thy‐1 positive. The objective of this study was to determine if these large cells were TBM and to conclusively demonstrate their reactivity for Thy‐1. The cells were studied using monoclonal antibodies (MoAb) against Thy‐1 and macrophage markers including F4/80 and Ia antigens at both light microscopic (LM) and electron microscopic (EM) levels. Immunocytochemical reactivity by TBM for Thy‐1 antigen specific MoAb was demonstrated by LM in both in situ and in vitro LN preparations. Furthermore, ultrastructural examination of these germinal center cells in situ demonstrated that the Thy‐1 reactivity visualized at the LM level was associated with ribosomes and endoplasmic reticulum as well as their plasma membrane. Similarly, these cells expressed intracytoplasmic and membrane reactivity for Ia antigens and also for the macrophage specific antigen F4/80. This indicates that the reactivity is due to active synthesis of the Thy‐1 antigen and not attributable to reactivity of any phagocytosed Thy‐1 positive cells. As defined by their germinal center location and morphological characteristics, these Thy‐1 reactive macrophages were identified as TBM. Germinal center TBM thus represent a unique, vigorously phagocytic subset of mature macrophages which express both macrophage and thymocyte markers.
Nonimmune‐mediated phagocytosis by “premedullary” lung macrophages: Effects of concanavalin A, tuftsin, and macrophage‐inhibitory peptide
Authors: Sorokin Sergei P. , Hoyt Richard F. , McNelly Nancy A. 
Published: February 2005

AbstractFree cells arising in organ‐cultured embryonic rat and hamster lungs share ultrastructural, lysosomal enzyme, and cell membrane properties with typical alveolar macrophages, expressing the developmental potential of the earliestmacrophage precursors resident in the lungs. In the lung culture environment cell proliferation is supported and macrophage attributes are developed despite absence of lymphocytes from the system. We have shown previously that among these attributs, the cells respond with increased phagocytosis of erythrocytes if these are opsonized with immunoglobulin G. Attention has now been turned to the question of nonimmune‐mediated phagocytosis by the same population. Living macrophages that emerged from lung cultures bound rhodamine‐coupled soybean and wheat germ agglutinins to a greater degree than concanavalin A (Con A), which nevertheless promoted lateral translocation of occupied receptors in the cell membrane. Emerged cells also phagocytosed living bacteria and native yeast cells (Y). The percentage of macrophages ingesting 3 or more yeast cells increased 400 (hamsters) to 500% (rats) when yeast was preincubated with Con A (200 μg/ml). Pretreatment of macrophages with Tuftsin (100 μM) enhanced uptake of Y by 100 (hamster) to 200% (rat). Pretreatment of macrophages with macrophage‐inhibitory peptide (500 μM) appeared to inhibit phagocytosis of Y by 60% in hamsters but had no significant effect on cells from rat lung cultures.
Co‐localization pattern of growth hormone (GH) and prolactin (PRL) within the anterior pituitary cells in the female rat and female musk shrew
Authors: Ishibashi Toshiko , Shino Masataka 
Published: February 2005

AbstractBy a double immunocytochemical labeling procedure, using the protein A‐gold method combined with electron microscopy, the co‐localization pattern of growth hormone (GH) and prolactin (PRL) was detected in the anterior pituitary cells of female rats and female musk shrews. Two types of co‐localization of GH and PRL were demonstrated. First, GH‐ and PRL‐containing secretory granules were intermixed within closely aggregated and interdigitated cell clusters that were composed of GH and PRL cells. This phenomenon was characteristically seen in pregnant rats and pregnant musk shrews. Therefore, the occurrence of an inter‐mixture of GH and PRL granules might be related to an enhanced cellular function for PRL synthesis.In another pattern of co‐localization of GH and PRL, both hormones were co‐packaged in the same secretory granules within a single cell. Such cells were scarce, small, irregularly shaped, and observed only in pregnant rats. These mixed GH‐PRL cells contained not only mixed GH‐PRL granules but also granules containing only GH or PRL. This suggests that these bihormonal cells are able to synthesize, synchronously or asynchronously, GH and PRL. Furthermore, granule extrusion from the mixed cells was clearly shown in this study. It seems likely that the mixed GH‐PRL cells reveal active cellular function in the pituitary gland of the pregnant rat.
Neurulation in the mouse: Manner and timing of neural tube closure
Authors: Sakai Yoshio 
Published: February 2005

AbstractThe manner and timing of neural fold fusion in primary neurulation were studied in 1,575 normal ICR mouse embryos by using binocular dissecting, light, and scanning electron microscopy.The initial fusion of apposing neural folds occurred at the level of the intermediate point between the third and fourth somites (i.e., in the caudal myelencephalon) and proceeded both rostrally and caudally. A second fusion occurred at what was originally the rostral end of the neural plate and proceeded rostrodorsally. A third fusion occurred in the caudal diencephalon and proceeded both rostrally and caudally. This was followed by complete closure of the telencephalic neuropore at the midpoint of the telencephalic roof and then complete closure of the metencephalic neuropore at the rostral part of the metencephalic roof. A fourth fusion occurred at what was originally the caudal end of the neural plate and proceeded rostrally. Finally, the caudal neuropore completely closed at the level of the caudal end of the future 33rd somite.
Neural crest ablation does not alter pulmonary vein development in the chick embryo
Authors: Phillips Marvin T. , Waldo Karen , Kirby Margaret L. 
Published: February 2005

AbstractCranial neural crest, which extends from the mid‐diencephalon to somite five, plays an integral role in development of pharyngeal arch derivatives and supplies mesenchyme to the aortic arch arteries. Neural crest cells in pharyngeal arches three, four, and six migrate to the heart and are involved in aorticopul monary and conotruncal septation. Ablation of the “cardiac” neural crest cells in chick embryos results in a variety of outflow tract anomalies, including persistent truncus arteriosus. Although other studies have shown the importance of the neural crest in the development of the cardiac outflow tract, the role of neural crest in venous development has not been established. This investigation evaluates the effect of cardiac neural crest ablation on the morphological development of the pulmonary vein. The presence of the pulmonary vein was confirmed initially at early stage 15 using histological sections and computer reconstructions of serially sectioned, normal embryos. India ink injections demonstrated a complete, patent pulmonary circuit at stage 18. Cardiac neural crest was ablated at stages 8–10. Operated, sham‐operated, and control embryos were sacrificed at incubation day 11, and acrylic plastic casts prepared of the intravascular compartment. In experimental embryos with persistent truncus arteriosus, there were no morphological differences in the pulmonary veins, compared with shams and controls. These data indicate that the lesions of the cardiac neural crest have little morphological impact on pulmonary vein development. It is concluded that alterations in the cardiac neural crest are not involved in venous anomalies such as cor triatriatum and total or partial anomalous pulmonary venous return.
Teratogenic antibodies are directed against a coated‐pit glycoprotein
Authors: Leung Christopher C. K. , Cheewatrakoolpong Boonlert , Yan Cai‐Lou 
Published: February 2005

AbstractIt has been well established that heterologous antibodies against certain tissue components may cause congenital abnormalities when injected into pregnant rats during the critical period of organogenesis. A glycoprotein antigen (gp340) of rat renal proximal tubules was isolated (C.C.K. Leung: (J. Exp. Med., 156:372–384, 1982); antibodies against gp340 were teratogenic.Indirect colloidal gold immunocytochemical method was utilized to study the ultrastructural localization of gp340. For comparative studies, both preembedding and postembedding immunostaining procedures were used. The results indicate that gp340 is a resident of coated pits and possibly also of coated vesicles of the rat renal proximal tubules and visceral yolk‐sac (VYS) endodermal cells. It appears that gp340 may also be associated with the microvilli and some as‐yet‐unidentified cytoplasmic structures of the same tissues. However, gp340 is absent on the epithelium of the small intestine.It is hypothesized that the teratogenic antibodies may interact with gp340 on the coated pits and interfere with receptor‐mediated endocytosis, causing yolk‐sac placenta dysfunction which in turn causes abnormal embryonic development.
Scanning and transmission electron microscopic study of the tracheal air sac system in a grasshopper Chrotogonus senegalensis (Kraus)—Orthoptera: Acrididae: Pyrogomorphinae
Authors: Maina J. N. 
Published: February 2005

AbstractThe morphology of the trachea‐air sac system in a species of grasshopper Chrotogonus senegalensis has been studied by using scanning and transmission electron microscopes. Capacious air sacs were formed as dilatations along the primary tracheal trunks. Narrower secondary trachea arose either directly from the primary trachea that bypassed the air sacs or from the air sacs themselves. At or close to the organ or tissue supplied with air, the secondary trachea gave rise to the notably smaller tertiary trachea that penetrated the tissue, giving rise terminally to the extremely small tracheoles that indent some cells. The trachea and the air sacs were basically made up of an inner cuticular lining, helical taenidial rings, and an overlying epithelial cell cover. The air sacs may be important in efficient ventilation of the respiratory system. The supply of air directly to the tissue cells was viewed as an exemplary efficient design when compared to that prevailing in the nontracheate air‐breathing animals, where the vascular system is interposed between the respiratory organ and the target tissue cells. A similarity in the general morphological design of the insect and avian respiratory systems has been observed, mainly in respect to the presence of the air sacs and that of the respiratory shunts. This, together with the reported functional features like the unidirectional mode of ventilation, has been interpreted as a classic case of structural and functional convergent evolution leading to the evolution of similar and comparably efficient respiratory systems capable of providing the large amount of oxygen demanded by flight.
Immunofluorescent localization of desmin and vimentin in developing cardiac muscle of Syrian hamster
Authors: Osinska Hanna E. , Lemanski Larry F. 
Published: February 2005

AbstractThe distributions of desmin and vimentin were examined in frozen sections of cardiac muscle from embryonic, newborn, and adult Syrian hamster by using immunofluorescent methods. Frozen sections of newborn and adult skeletal muscle were used for comparison. Cardiac myocytes from day 9 in utero embryos already show a clear association of desmin with the sarcomeric myofibrils. In newborn hearts, desmin is localized in the myofibrillar Z‐line areas as well as in the peripheral cytoplasm of the cell. Three days after birth, desmin is associated with the intercalated discs. Thus, in adult cardiac muscle, desmin is present in both Z‐bands and intercalated discs. Skeletal muscle of newborn and adult hamster also contains desmin associated with the Z‐lines of myofibrils. Vimentin is associated with the myofibrils of day 9 in utero cardiac muscle cells. The protein remains associated with the myofibrillar Z‐lines in the newborns and adults. No detectable staining for vimentin was observed in newborn or adult hamster skeletal muscle. The existence of vimentin as well as desmin in differentiated cardiac muscle may be a consequence of the somewhat more epithelial‐like nature of cardiac cells as compared to skeletal muscle syncitia.
Pathways between lymph vessels and sinuses in lymph nodes: A study in horses
Authors: Heath Trevor J. , Perkins Nigel R. 
Published: February 2005

AbstractThe pathways through which lymph flows from terminal afferent lymphatics to the lymph sinuses, and from the sinuses to initial efferent lymphatics, were studied in horse lymph nodes by using Microfil casts and electron microscopy.Terminal afferent lymphatics are continuous with the subcapsular sinus through oval holes, about 3 μm wide, along their length, and through larger openings near their end. Other terminal afferents penetrate into the node within trabeculae and are supported by processes across the lumen. They connect with trabecular and medullary sinuses through oval or round holes, generally 20–30 μm across. Some of these have processes, similar to the luminal strands of the adjacent sinuses, extending across them, apparently providing reinforcement.Initial efferent lymphatics receive lymph from medullary sinuses through holes which are similar to those in afferent lymphatics, though more common, especially near the origin of the vessel. Initial efferents within the medulla appear to be supported by the luminal strands of the surrounding medullary sinuses. It seems likely that these strands, like the trabeculae which surround the penetrating afferent lymphatics, may help to keep the lymphatic vessels open as the node swells while draining an area of infection.
Muscle receptors: Content of some of the extrinsic and intrinsic muscles of the larynx in the bonnet monkey (Macaca radiata)
Authors: Raman R. , Devanandan M. S. 
Published: February 2005

AbstractThe number of muscle receptors and in particular the muscle spindle content of some of the intrinsic and extrinsic laryngeal muscles was evaluated, using bonnet monkeys (Macaca radiata). The technique of Barker and Ip [J. Physiol. (Lond) 169:73–74, 1963] was used to stain the muscle receptors. The results indicate that the intrinsic laryngeal muscles were devoid of muscle spindles. The extrinsic laryngeal muscles that were examined contain muscle spindles, though their density is less than that reported in the spindle‐rich muscles like the rotators of the head and some of the intrinsic muscles of the hand (Cooper in: Structure and Function of Muscle, Vol. I, G.H. Bourne, ed, Academic Press, New York and London, 1960).
Mechanism of calcification: Role of collagen fibrils and collagen‐phosphoprotein complexes in vitro and in vivo
Authors: Glimcher Melvin J. 
Published: February 2005

AbstractSamples of decalcified chicken bone together with varying concentrations of phosphoproteins from bone or egg yolk (phosvitin) were used in vitro as heterogenous nucleators for the induction of Ca‐P apatite crystals. The lag time between exposure of the collagen‐phosphoprotein complexes and the time nucleation of crystals occurred decreased as the concentration of Ser(P) and Thr(P) increased. Enzymatic cleavage of the phosphate groups by wheat germ and phosphatase reversed this effort, indicating that the phosphate group per se principally facilitated the nucleation of Ca‐P crystals by the phosphoprotein complex and collagen.
Structure and function of enamel gene products
Authors: Deutsch Dan 
Published: February 2005

AbstractThe present paper reviews the main features of amelogenin and enamelin biochemistry, molecular biology, structural and ultrastructural localization, and immunology. It also examines recent studies concerning the origin, chemical characterization, suggested role, and participation of these two major classes of extracellular developing enamel matrix proteins in the complex process of “matrix‐mediated” mineralization.
Isomyosin expression patterns during rat heart morphogenesis: An immunohistochemical study
Authors: De Groot Imelda J. M. , Lamers Wouter H. , Moorman Antoon F. M. 
Published: February 2005

AbstractAn immunohistochemical study of cardiac alpha and beta myosin heavy chain (MHC) expression during rat heart morphogenesis was performed. In tubular hearts (embryonic days, ED10–11) coexpression of both cardiac alpha and beta MHC was found throughout the heart, except for the left free wall of the atrium, where only cardiac alpha MHC is detected. A transition of coexpression to single expression of either cardiac alpha or beta MHC begins at the same time in both atria and ventricles but requires a longer time for completion in the ventricules; in the atria transition takes place during the period ED 12–13 and in the ventricles during ED12–15. Furthermore, expression of cardiac alpha and beta MHC was detected in the sinus venosus, and cardiac alpha MHC expression was detected in the pulmonary veins.A comparison of the results obtained in chicken embryos revealed that in tubular hearts the expression pattern is similar, whereas in later developmental stages two major differences were observed: (1) transition of coexpression to single expression in rat ventricles appears to take a longer developmental period; (2) the persistence of areas of coexpression in the sinoatrial junction, dorsal mesocardium, atrioventricular junction, and outflow tract, as found in the chicken embryo in later developmental stages, is not found in the rat heart.
Catecholamine‐containing, dopamine‐beta‐hydroxylase‐immunoreactive perivascular nerve specializations in the rat kidney
Authors: Knight D. S. , Beal J. A. , Fabre R. D. , Henderson R. J. 
Published: February 2005

AbstractFluorescence histochemical visualization of catecholamines and immunolabeling of dopamine beta hydroxylase (DBH) were employed to study noradrenergic nerve terminals and perivascular nerve specializations in the rat kidney. Plexuses of catecholamine‐containing and dopamine‐beta‐hydroxylase‐immunoreactive nerves innervate the intrarenal arterial tree and larger intrarenal veins. Some perivascular nerve bundles have specialized segments composed of clusters of axonal enlargements that are immunoreactive for DBH and fluoresce intensely in ultraviolet light after fixation in a solution of formaldehyde and glutaraldehyde or treatment with glyoxylic acid. No fluorescent neural structures were found in denervated rat kidney sections treated with glyoxylic acid. Many such structures are associated with arteriolar branches of interlobar, arcuate, and interlobular arteries and are composed, in part, of axonal enlargements that contain mitochondria, microtubules, and one or more clusters of synaptic vesicles. These perivascular nerve specializations may be sites of axoaxonal interactions between noradrenergic axons or between these axons and other types of autonomic or sensory axons. The synaptic vesicles evidently store large amounts of catecholamine, but there is no evidence whether it is released into the surrounding tissue. These structures may be involved in changes in intrarenal innervation patterns which may occur as the rat ages. Regardless of the autonomic or sensory nature of intrarenal neural structures, close association of most such structures with arterioles suggests some neurovascular interaction.
Effects of indomethacin on spacing of conceptuses within the uterine horn and on fetal and placental growth in the rat
Authors: Wellstead Jennifer R. , Bruce Neville W. , Rahima Ali 
Published: February 2005

AbstractIn the rat, as in most other polytocous species, fetuses tend to be relatively evenly spaced along the uterine horn, porhaps to minimize possible effects of local overcrowding on placental function and fetal growth. Here we administered 2 mg of indomethacin, in split doses on day 5 of gestation, in an attempt to disturb evenness of spacing and so reveal local overcrowding effects, if any. The effects on spacing, expressed as the coefficient of deviation of distances between neighboring implants (CVd%) and correlations between fetal and placental weights and distance to neighbors, was examined on day 16 and day 22 of gestation to cover the period of rapid fetal growth. Indomethacin markedly affected evenness of spacing; at day 16, CVd% increased from a control value of 19.2 to 50.8% and at day 22 from 27.5 to 41.2%. Despite the increased variability of spacing and consequent local crowding, including examples of conjoined placentas in the treated rats, there was no evidence that these local factors affected placental growth or weight of individual fetuses. Indomethacin, however, had a general effect on placental and fetal growth. At day 16, mean fetal weights were retarded but by day 22 had caught up to those of control litters, and this was accompanied by significant placental hypertrophy. Collectively, these results show that the uterus has sufficient reserve to cope with relatively uneven spacing of fetuses and have provided a model for examining catch‐up growth of fetuses and accompanying placental changes.
Developmental competency in spinal nerve fiber extension on a reconstituted basement‐membrane‐like matrix
Authors: Liebig Veronica , Pollack Emanuel D. 
Published: February 2005

AbstractNerve fibers readily extend from larval frog spinal cord explants when cultured on a commercially available reconstituted basement‐membrane‐like matrix derived from the EHS mouse sarcoma. This superior, naturally derived substratum enables the in vitro development of complex neuritic arrays with long survival times in a defined medium, thus permitting the detailed analysis of spontaneous and target‐mediated neuritogenesis.