bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of heterologous antisera on embryonic development. XIII. Lack of effect of antisera to alpha fetoprotein
Authors: Leung Christopher C. K. , Watabe Hiroyuki , Brent Robert L. 
Published: February 2005

AbstractThis investigation was carried out to determine whether heterologous antisera to alpha fetoprotein (AFP) are embryotoxic to developing rat embryos. Homogeneous rat AFP was isolated and antisera directed against this glycoprotein were produced in rabbits, horse and goat. The effect of the antisera on embryonic development was examined by injecting the antisera intraperitoneally into pregnant rats on the ninth, eleventh and thirteenth days of gestation. The results demonstrated that there was no evidence of increased incidence of fetal abnormalities in 472 surviving fetuses of 42 injected rats. There was no evidence of increase embryonic death or retardation of intrauterine growth following administration of the antisera on the ninth, eleventh and thirteenth days of gestation. The localization of the injected antisera was examined by the indirect immunofluorescent method. The results showed that the heterologous AFP antibodies localized specifically in the visceral yolk sac placenta. No antibody localization was observed in the embryo proper or the chorioallantoic placenta. It is speculated that the localization of AFP antibodies in the visceral yolk sac does not interfere with the embryotrophic function of the visceral yolk sac placenta.
Fine structural features of adrenergic nerve fibers and endings in the pineal gland of the rat, ground squirrel and chinchilla
Authors: Matsushima Shoji , Reiter Russel J. 
Published: February 2005

AbstractThe ultrastructural features of the adrenergic nerve fibers in the pineal glands of the rat, ground squirrel and chinchilla are described. Frequencydistribution histograms of diameters of granulated and non‐granulated vesicles in the adrenergic nerve endings demonstrate that the pineal nerve endings in the chinchilla contain a considerable number of large granulated and non‐granulated vesicles, in contrast to those in the rat and ground squirrel. Synaptic ribbons seen in the pinealocytes of the ground squirrel were often localized near that plasma membrane which lay in close proximity to the axolemma of adrenergic nerve fibers. This observation may indicate that the synaptic ribbons are involved in the functional interconnection between pinealocytes and adrenergic nerve fibers. Localized dilations of the adrenergic nerve fibers were commonly observed in the pineal glands of all species examined. In addition to a variety of axonal constituents, various forms of inclusion bodies were tightly packed within these axonal dilations. The accumulation of the inclusion bodies may represent degenerative changes which occur in the pineal adrenergic nerve fibers in relation to the functional activity of the pineal gland.
The thyroid in the spontaneously hypertensive rat: A light and electron microscopic study
Authors: Krupp P. P. , Thomas L. L. , Alpert N. R. , Frink R. 
Published: February 2005

AbstractThe present study was undertaken to seek ultrastructural changes in the thyroid gland of the spontaneously hypertensive rat which would contribute to the understanding of previously reported abnormalities in thyroid function. Light and electron microscopic observations and measurements of plasma T3 and systolic blood pressure were recorded from a colony of Wistar‐Kyoto rats (WKY) and of spontaneously hypertensive rats (SHR). The systolic blood pressure of SHR was significantly higher than that of WKY but the plasma T3 levels of the two groups did not differ significantly. After administration of propylthiouracil (PTU), serum T3 levels and systolic pressure of both groups decreased. The size of the thyroid follicles in SHR was highly variable throughout the gland, and the colloid contained unevenly dense areas and cell debris. The follicular cells contained slightly dilated rough surfaced endoplasmic reticulum (ER) and numerous pleomorphic bodies of uneven density. After treatment with PTU, the vessels between the follicles of SHR did not become as dilated as those in WKY but the fine structure of follicular cells in SHR was similar to that of WKY and was characteristic of the typical thyroid response to PTU administration. We suggest that the thyroid in SHR does not respond adequately to the elevated TSH levels reported to be present in these animals, although it can respond to the highly elevated TSH levels which occur with PTU administration. This impairment most probably involves defects in synthesis and/or secretion of thyroid hormones in response to TSH stimulation.
Precocious induction of secretory granules by hormones in convoluted tubules of mouse submandibular glands
Authors: Kumegawa Masayoshi , Takuma Taishin , Takagi Yoshihiko 
Published: February 2005

AbstractPrecocious differentiation of convoluted tubules of the submandibular glands of mice was induced by daily injection of thyroxine, insulin, hydrocortisone and 5α‐dihydrotestosterone from day 4 after birth. This treatment induced enlargement of the tubules and synthesis of secretory granules in the tubules. Treatment with 5α‐dihydrotestosterone alone had no effect on enlargement of the tubules or synthesis of the granules. These findings suggest that, besides androgenic hormones, these three hormones are also involved in synthesis of granules in developing mice.
The interaction of clomiphene, estradiol, and progesterone in the control of rat uterine glycogen metabolism
Authors: Poteat William L. , Bo Walter J. 
Published: February 2005

AbstractUterine glycogen accumulation was studied in ovariectomized rats treated with all combinations of clomiphene citrate (0.25 mg/kg) estradiol (1.0 μg) and progesterone (5.0 mg). The rats were given three consecutive daily dosages and killed 24 hours after the final dosage. Based on biochemical data, either estradiol or clomiphene increased uterine glycogen concentration and total glycogen, but progesterone did not. Progesterone significantly suppressed both the estradiol and clomiphene‐induced glycogen increases. Based on the histochemical results, progesterone also suppressed the estradiol and clomiphene‐induced glycogen responses, but the tissue affected differed. Clomiphene markedly increased luminal epithelial glycogen whereas estradiol induced primarily myometrial glycogenesis. Progesterone completely suppressed the clomiphene‐induced epithelial effect and partially suppressed the estradiol‐induced myometrial effect. Clomiphene also suppressed the estradiol induced myometrial response. The results indicate that progesterone does have a significant interaction with clomiphene in the control of uterine morphology and biochemistry. The results also stress the importance of correlated histochemical and biochemical studies in the study of clomiphene‐induced uterine glycogenesis.
Osteopetrosis in the toothless (tl) rat: Presence of osteoclasts but failure to respond to parathyroid extract or to be cured by infusion of spleen or bone marrow cells from normal littermates
Authors: Marks Sandy C. 
Published: February 2005

AbstractOsteoclasts have been observed for the first time in toothless (tl) rats, a mutation which inherits osteopetrosis as an autosomal recessive. The ability of tl rats to raise the serum calcium concentration after injection of parathyroid extract was severely limited when compared with normal littermates. In addition, osteopetrosis in tl rats is not cured by radiation and infusion of normal spleen or bone marrow cells from normal littermates, a method known to cure osteopetrosis in mutants of this and other species. This indirect evidence for a reduction in bone resorption as a cause of osteopetrosis in this mutation and the failure of transplanted cells to cure the disease are discussed in relation to the development and function of osteoclasts.
Initial intramembraneous osteogenesis in vitro
Authors: Marvaso Vicki , Bernard George W. 
Published: February 2005

AbstractCalvariae of fetal mice 12 to 13 days in utero were placed in Rose chambers and cultured in BGJb medium supplemented with 20% fetal calf serum and antibiotics. After periods of 7 and 12 days, the explants were harvested and processed for light and electron microscopy. The mesenchymal cells, after a brief lag time, differentiated into osteoblasts which produced woven bone. Light and electron microscopic observations showed that in vitro, as well as in vivo, growth and development share all of the same characteristics of initial intramembraneous osteogenesis: (1) migration and differentiation of mesenchymal cells into osteoblasts, (2) the subsequent appearance of matrix vesicles in the extra‐cellular space, (3) crystallization of hydroxyapatite within and about these vesicles, (4) growth of hydroxyapatite crystals into spheroidal nodules of bone, and (5) the subsequent fusion of these nodules into seams of woven bone. Thus cellular involvement in initial osteogenesis has been observed in a system where differentiation into osteoblasts and initial calcification takes place in vitro, suggesting that the events responsible for these phenomena have occurred within the cells prior to their morphological differentiation.
The effects of continuous illumination (LL) and continuous darkness (DD) on the daily rhythms of membrane‐bound and microsomal enzymes in the adrenal gland and kidney of the rat
Authors: Margolis Ronald 
Published: February 2005

AbstractA daily rhythm was demonstrated in levels of specific activity for the Na, K‐ATPase and glucose‐6‐phosphatase enzymes in adrenal and renal subcellular fractions in the rat. A bimodal daily rhythm was observed for 5′‐nucleotidase in a renal subcellular fraction. The rats were maintained on a 12:12 light‐dark (LD) regimen. Animals were killed at approximately 4‐hour intervals.The daily rhythm in Na, K‐ATPase and glucose‐6‐phosphatase activities persisted in animals maintained under continuous illumination (LL) and continuous darkness (DD). The 5′nucleotidase activity persisted under LL, and under DD.The data from the enzyme assays were analyzed by fitting to a cosinor regression model designed to assess the rhythmic nature of the findings. A linear transformation method was applied to assess the closeness of fit to the cosinor regression model.The Na, K‐ATPase and glucose‐6‐phosphatase activities appeared to be endogenous circadian rhythms. Glucose‐6‐phosphatase activity in renal fractions appeared to be influenced by the feeding cycle. The 5′‐nucleotidase enzyme appeared to have an ultradian rhythm. The ultimate derivation and significance of these observed rhythms remains to be determined; however, they appear to be independent of the light‐dark cycle.
Electron microscopy of degenerating axons and terminals in spinal trigeminal nucleus after tooth pulp extirpations
Authors: Westrum Lesnick E. , Canfield Robert C. 
Published: February 2005

AbstractFollowing multiple tooth pulp extirpations, electron microscopic preparations show degenerating axons and synaptic terminals in the same region of the brain stem trigeminal nucleus previously demonstrating degeneration by light‐optical methods. The observations confirm the phenomenon of transganglionic degeneration in this system and identify the class of central nervous system axons and synapses specifically related to innervation of the teeth.
Sarcotubules and subsarcolemmal caveolae and their continuity with the sarcolemma in frog striated muscle
Authors: Leeson Thomas S. 
Published: February 2005

AbstractAfter using tannic acid mordanting, T‐tubules and subsarcolemmal caveolae show a dense staining with lead citrate, with some increase in contrast also of the sarcolemma, in frog muscle. While a few T‐tubules show direct continuity with the extracellular space, the majority open indirectly via caveolae. Caveolae lie immediately beneath the sarcolemma, mainly in a single row, and are more numerous in relation to I‐bands.
Fenestrations in regenerating skeletal muscle capillaries
Authors: McKinney Ralph V. , Singh Baldev B. , Brewer Phyllis D. 
Published: February 2005

AbstractA new observation of fenestrae with diaphragms in the endothelial wall of regenerating skeletal muscle capillaries is described in seven‐day‐old wounds of the cremaster muscle of adult male guinea pigs. The fenestrations were 44 nm in diameter and contained diaphragms with a central dense structure. These findings suggest an additional route for physiological exchange mechanisms in wound capillaries.
Elastic tissue in the limiting membrane of the human seminiferous tubule
Authors: De Menezes Amadeu Peixoto 
Published: February 2005

AbstractThe structure and distribution of elastic tissue were studied in the limiting membrane of the seminiferous tubule from normal human testis. The elastic and elastic‐related fibers (oxytalan and elaunin) were recognized by their tinctorial and ultrastructural characteristics. The connective structures of the limiting membrane, including the fibrotubules and the amorphous material of the elastic system, were studied after tannic acid‐glutaraldehyde fixation. Fibrotubules (oxytalan fibers) were observed in almost all intercellular spaces of the limiting membrane, closely related to the contractile cells; the elaunin fibers (patches of amorphous material surrounded by bundles of fibrotubules) were evident in the outermost layers. The function of this system of elastic tissue and myoid cells is discussed, considering the permeability of the limiting membrane and the role of the myoid cells in the elastogenesis and contractility of the seminiferous tubule.
Studies of the mechanism of spleen cell cure for osteopetrosis in ia rats: Appearance of osteoclasts with ruffled borders
Authors: Marks Sandy C. 
Published: February 2005

AbstractAfter ia (osteopetrotic) rats receive whole body radiation and an injection of spleen cells from a normal littermate, the dense, sclerotic skeleton characteristic of osteopetrosis is rapidly remodeled and becomes normal in appearance radiographically and histologically within three weeks. The mechanism of this skeletal transformation has been explored in cured ia rats by light and electron microscopic examination of osteoclasts.In ia rats less than 25 days of age, osteoclasts viewed by electron microscopy lack a ruffled border‐the extensive elaboration of plasma membrane next to the bone surface. Cured ia rats have osteoclasts with ruffled borders indistinguishable from those of normal littermates. In ia rats that receive only 600 rads whole body radiation, osteoclasts are still present three weeks later, but appear abnormal by light microscopy, with dense nuclei and lacking cytoplasmic vacuoles next to the bone surface. Cured ia rats have two types of osteoclasts, one type indistinguishable from osteoclasts of normal littermates by light microscopy, the other resembling osteoclasts of ia rats that received radiation only.These data indicate that the mechanism of the spleen cell cure for osteopetrosis in ia rats is rapid remodeling of the skeleton produced by osteoclasts with ruffled borders. Whether normal spleen cells produce these osteoclasts directly by cell division or indirectly by elaboration of some unknown local factor required for formations of ruffled borders by ia osteoclasts is not known.
A freeze‐fracture study of exocytosis and reflexive gap junctions in human ovarian decidual cells
Authors: Herr John C. , Heidger Paul M. 
Published: February 2005

AbstractFine‐structural features of ovarian decidual cells and their mode of secretion were examined by means of freeze‐fracture microscopy. Unique cortical peduncular processes contained secretory vesicles within the expanded peduncle tip, the membrane‐leaflets of which exhibited a particle‐poor E face adjacent to the vesicle lumen and a P face containing a greater particle number. Exocytosis from attached peduncles involved release of vesicular profiles 40–55 nm in diameter; small particles 8.5–11.5 nm in diameter were also observed at degranulation sites. In fractures revealing the E face of the plasmalemma, cytoplasmic portals at the bases of peduncular stalks were distinguishable from endocytic vesicles.The frequent occurrence of reflexive gap junctions associated with peduncles was shown by freeze‐fracture. However, there appeared to be no consistent spatial relationship between gap junctions, secretory peduncles, or sites of exocytosis. Freeze‐fracture analysis of the topography of reflexive gap junctional profiles revealed that such gap junctions share basic similarities with intercellular gap junctions. These similarities include particle size (8–10 nm); number of particles within clusters (20–40); and the presence of 5–15 nm particle‐free aisles. The finding in the present study of reflexive gap junctions occurring between peduncles and the cell soma, as well as between peduncles, suggests that the original definition of reflexive gap junctions as those existing between processes of the same cell should be broadened to include any gap junctional specialization formed between portions of the plasma membrane of one cell.
Evidence for a relationship between lymphoid cells and osteoclasts: Bone resorption restored in ia (osteopetrotic) rats by lymphocytes, monocytes and macrophages from a normal littermate
Authors: Marks Sandy C. , Schneider Gary B. 
Published: February 2005

AbstractOsteopetrosis in the ia rat is known to be due to reduced bone resorption and the absence of ruffled borders in osteoclasts. The disease can be cured by the temporary parabiotic union with, or by transfusion of spleen, thymus, or liver cells from, normal littermates. This investigation was pursued in an attempt to determine the cellular basis of this cure by testing the relative effectiveness of populations of mononuclear cells — lymphocytes, monocytes, and tissue macrophages, from spleen and thymus of normal rats — in curing the disease, compared with cell suspensions of the entire organs. The mononuclear fractions were separated from cell suspensions of spleen or thymus by an adaptation of the Ficoll‐Hypaque density‐gradient‐centrifugation procedure. The mononuclear isolates were evaluated by conventional histological procedures and non‐specific esterase histochemistry and found to contain approximately 97% lymphocytes and 3% monocytes from the spleen and 99% lymphocytes and less than 1% monocytes from the thymus.The results of these transplantations were evaluated radiographically and histologically three weeks after treatment. No difference in the rate of skeletal cure was observed in the ia rats that received cells from either whole spleen or thymus, or the mononuclear isolate from these organs. Osteoclasts from the ia animals cured by the transplantation of the mononuclear isolate were examined by electron microscopy and found to have ruffled borders.We conclude that the mononuclear cells isolated from either the spleen or thymus of normal littermates have positive effects on osteoclasts and bone resorption in the ia rat, either indirectly, by elaboration of some local factor that affects the mutant osteoclasts, or directly by transformation into osteoclasts.
The neurohypophyseal capillary bed II. Specializations within median eminence
Authors: Page Robert B. , Leure‐Dupree Alphonse E. , Bergland Richard M. 
Published: February 2005

AbstractVascular casts of the pituitary gland, median eminence and hypothalamus from several mammalian species were examined by scanning electron microscopy. These observations were correlated with light microscopic studies of injected, cleared median eminence‐pituitary specimens and with light microscopic examination of serial sections of injected hypothalamic, median eminence, and pituitary specimens employing reflected lighting or epiillumination. Transmission electron microscopy was employed to study long portal vessels on the ventral surface of the rat median eminence.In each of the species examined, the median eminence (infundibular) capillary bed is subdivided into an external and an internal plexus. The external plexus (the neurohemal contact zone) receives an arterial supply from the superior hypophyseal arteries and is continuous with the capillary bed of the infundibular stem and process.Egress from the external plexus is possible via three vascular routes: (a) by fenestrated portal vessels and capillaries to the adenohypophysis, (b) by capillary connections to the medial basilar hypothalamus and, (c) by internal plexus capillaries to the ependyma of the median eminence.Median eminence vasculature is structurally organized to deliver (1) hypothalamic and neurohypophyseal peptides to the glandular pituitary via portal vessels, (2) hypothalamic and pituitary secretions to the medial basilar hypothalamus via capillaries, and (3) hypothalamic and pituitary secretions to distant brain sites through cerebrospinal fluid via ventricular and subarachnoid routes.
Investigations on the turnover of adrenocortical mitochondria. X. A correlated biochemical and stereological study of the effects of Chronic treatment with chloramphenicol on the mitochondria of the rat zona fasciculata
Authors: Mazzocchi Giuseppina , Neri Giuliano , Robba Claudia , Belloni Anna S. , Nussdorfer Gastone G. 
Published: February 2005

AbstractThe effects of chloramphenicol (CAP) on rat adrenocortical cells were investigated by biochemical and stereological methods. It was found that administering 50 mg/kg of CAP every 12 hours provoked a persistent inhibition of the incorporation of 3H‐leucine into mitochondrial proteins. Chronic treatment (up to 15 consecutive days) with this dose of CAP induced a significant decrease in the volume of the mitochondrial compartment, in the surface area of the outer and inner mitochondrial membranes and in the number of mitochondria per cell. These results confirm the hypothesis that the ACTH‐induced maintenance of adrenocortical mitochondrial growth requires continuous mitochondrial DNA‐dependent protein synthesis.
The basilar membrane of the bat, Pteronotus p. parnellii
Authors: Henson Miriam M. 
Published: February 2005

AbstractThe basilar membrane of Pteronotus p. parnellii was studied by light and scanning electron microscopy in order to examine the relationship of membrane structure to the sharply tuned sense of hearing in this bat. The basilar membrane was found to differ from those of other mammals and other bats by showing virtually no change in width except at the extreme ends. Thickenings of the pars pectinata and pars tecta are well developed in Pteronotus; they show no sudden changes in their dimensions and in this way differ from the thickenings found in the European horseshoe bat whose sharply tuned sense of hearing seems at least partially dependent on sudden, marked changes in the structure of the basilar membrane. In Pteronotus the greater part of the basilar membrane, 7.5 mm or approximately 58%, lies within the enormous basal turn and within this turn there are steeply banked curves and one small 0.5‐mm region where the membrane is straight. The straight portion is associated with a region of the cochlea where there is a marked change in the density of nerve fibers and where the stria vascularis, spiral ligament and fluid‐filled spaces of the ear are enlarged.
Descending monoaminergic pathways in the primate spinal cord
Authors: Crutcher Keith A. , Bingham W. G. 
Published: February 2005

AbstractThe distribution of monoamine axons and terminals within the spinal cord of a primate (Macaca mulatta) was studied with the Falck‐Hillarp histofluorescence technique for the demonstration of biogenic amines. Catecholamine and indoleamine varicosities appeared qualitatively similar to those previously reported for the rat although the indoleamine terminals were difficult to visualize and were not studied in great detail. Catecholamine fibers innervate the substantia gelatinosa, marginal layer, intermediolateral cell column, ventral horn and the region surrounding the central canal. The location of monoamine axons, as revealed by spinal cord ligation, corresponds to that in the rat and cat with the exception of the dorsolateral region of white matter where fluorescent axons are not visible in the primate.