bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein synthesis in vivo by preimplantation hamster embryos
Authors: Weitlauf Harry M. 
Published: February 2005

AbstractThe level of protein synthesis by hamster embryos in vivo, as inferred from the incorporation of 35S methionine, was determined for the four days of the preimplantation period by radioautography. The embryos incorporated 35S methionine throughout the preimplantation period. Furthermore, the hamster eggs continued to incorporate 35S methionine following ovariectomy. Therefore, the pattern of protein synthesis in hamster eggs differs from the mouse with its low levels in cleaving eggs and in blastocysts following ovariectomy and high levels in blastocysts influenced by estrogen and progesterone.This finding is of interest because unimplanted mouse embryos remain viable in ovariectomized females for many days, whereas hamster embryos rapidly degenerate. It is suggested that the inability of hamster eggs to reduce the level of protein synthesis and become “dormant” may prevent their survival if implantation is blocked by ovariectomy.
Sites of protein synthesis in the cells of the zona fasciculata of the young rat adrenal, as shown by electron microscope radioautography
Authors: Magalhãtes Maria C. , Magalhãtes M. M. , Coimbra Antonio 
Published: February 2005

AbstractYoung rats received 1 mCi of leucine‐H3 or tyrosine‐H3 intraperitoneally and adrenals were fixed in glutaraldehyde‐osmium after 10, 60 and 240 minutes. Epon ultrathin sections were coated with Ilford L4 nuclear emulsion for radioautography. Ten minutes after injection of both tritiated amino acids, labeling indicating the sites of protein synthesis was found principally over the endoplasmic reticulum (∼ 57% of the silver grains) and mitochondria (∼ 32%). Distances of silver grain centers to the nearest interface between these two organelles were plotted; the results seemed to confirm that protein synthesis occurred in the endoplasmic reticulum and mitochondria but was more active in the endoplasmic reticulum. Values remained the same at the other time intervals examined, suggesting the formation of sedentary protein. However, values for the Golgi apparatus were low at ten minutes, fairly high at 60 minutes and low again at 240 minutes, suggesting migration of a small fraction of the newly‐formed protein through the Golgi apparatus and subsequent discharge. The possibility is raised of this being an exportable protein.
The development of pigment cells in the eyes of rhesus monkeys
Authors: Hu Funan , Montagna William 
Published: February 2005

AbstractThe eyes of rhesus monkeys possess two lines of pigmented cells: those of the pigmented retinal epithelium and those of the uveal tract, also known as stromal pigmented cells. The cells of the pigmented epithelium differentiate first and are fully functional in 65‐day old fetuses. By contrast, stromal pigmented cells do not become recognizable until late gestation (140 days). The differences in development and structure of these cells may reflect a different and perhaps distinct function.
Differentiation of granulated metrial cells in the uterus of the pregnant rat: An electron microscopic study
Authors: Larkin Lynn H. , Cardell Robert R. 
Published: February 2005

AbstractThe fine structure of the granular metrial gland cell of the pregnant rat was studied during early stages of differentiation. “Precursor cells” were identified with the electron microscope that exhibited characteristic features of the mature cell as well as many cytoplasmic ribosomes. Notable features of differentiation were: a great increase in cell size, decrease in overall electron density, formation of a large centrosphere surrounding the centrioles, and accumulation of granules. The first sign of granule formation was the appearance of dense‐core vesicles in the Golgi complex. Subsequently, larger granules appeared which had small vesicles between a dense core and the limiting membrane. Finally, multilaminated myelin figures were noted in the mature granule in addition to the core material and vesicles. The possible role of coated vesicles in granule formation is discussed.
The fine structure of the Necturus (Amphibia) heart
Authors: Hirakow Reiji 
Published: February 2005

AbstractThe fiber diameter in the heart of Necturus maculosus is not significantly different from that of other amphibian myocardial cells, averaging approximately 5 μ over most of its length and about 10 μ in the nuclear region. No transverse (T) tubular system was found. Instead, there were shallow invaginations of the sarcolemma and many pinocytotic vesicles at the periphery of the myocytes. Other intracellular membrane systems such as the Golgi apparatus and sarcoplasmic reticulum were also sparse and poorly organized. However, subsarcolemmal cisterns, specialized segments of the sarcoplasmic reticulum in close apposition with the sarcolemma, were clearly demonstrated. Nexal junctions were recognized at points of contact between myocytes, although they occupied smaller areas than those of mammalian myocardial cells. Mitochondria were small and few. Light cells with few organelles or myofibrils, which resembled Purkinje fibers of mammalian and avian hearts, were often observed. A nerve ending in close contact with muscle cells was described.
Effects of unilateral ovariectomy on follicular development and ovulation in cycling, aged rats
Authors: Peppler Richard D. 
Published: February 2005

AbstractCyclic rats were unilaterally ovariectomized at random stages of the cycle between 66 to 72 days of age and killed on day 2 (metestrus) of the estrous cycle after three cycles, and after 3, 6 or 12 months. Control (intact) rats were also killed at these time periods.Counts of tubal ova revealed that intact rats ovulated an average of 5.3 eggs per ovary after three cycles (N = 7); 4.8 after three months (N = 12); 4.2 after six months (N =12) and 3.5 after 12 months (N = 2). Following unilateral ovariectomy, compensatory ovulation (11 eggs) occurred in all rats after three cycles (N = 10) and at three months (N = 11). Only four to five eggs were ovulated at six (N = 13) and 12 months (N = 4) after hemicastration. The remaining ovary in rats unilaterally ovariectomized after three cycles, or 3, 6 and 12 months hypertrophied 38%, 64%, 55% and 118%, respectively.Follicular development on the second day of the cycle was the same in intact and hemicastrated rats. The total number of follicles larger than 352 μ in diameter did not differ between three cycles and three months. By six months a 50% reduction occurred and the number of follicles remained the same after 12 months. This decrease in follicular development supports the finding of an absence of compensatory ovulation in the hemicastrated rat after 6 or 12 months.
Regional differentiation in the heads of spermatozoa of rabbit, man and bull
Authors: Bernstein Maurice H. , Teichman Robert J. 
Published: February 2005

AbstractThe heads of the spermatozoa of rabbit, man, and bull are flattened in the dorsoventral plane and exhibit three distinct regions in the head coverings. The anterior one‐half to two‐thirds of the nucleus is covered by the acrosome, the middle of the nucleus by the thinned equatorial segment of the acrosome and the remainder of the head is covered by the postacrosomal segment. Species variation is evident in the head coverings; most prominent are the equatorial bands of the rabbit spermatozoon. The bands are subacrosomal bulges curving around the head; the arms of each band are displaced in the anteroposterior axis and do not cross the midline axis. The equatorial bands are visible in scanning electron micrographs, which also show a serrated junction between the equatorial segment and the postacrosomal region.
The secretory granules of the acinar cells of the mouse submaxillary gland
Authors: Martinez‐Hernandez Antonio , Nakane Paul K. , Pierce G. Barry 
Published: February 2005

AbstractAbsence of membranes from the secretion granules of the acinar cells of the submaxillary gland of the mouse had led to speculation concerning mechanisms of secretion of these cells. By means of rapid perfusion fixation, smooth membranes have been identified around the secretion granules, and the mode of secretion proves to be similar to that of the other exocrine glands. The evidence suggests that potent membranolytic agents of unknown nature, capable of rapidly destroying the membranes are present in these secretory granules.
Light and electron microscopic radioautography of glucose‐6‐H3 incorporation in the retina of the adult newt, Triturus viridescens dorsalis
Authors: Dickson D. H. , Hollenberg M. J. 
Published: February 2005

AbstractTritiated glucose was administered to fasted newts to study glucose incorporation in the retina and particularly the photoreceptor cells. Incorporation of glucose into glycogen throughout the retina commenced at 30 minutes after injection. The first silver grain concentrations were observed over the photoreceptor myoid at two hours. Incorporation of glucose into glycogen reached a maximum at six hours with grains concentrated over photoreceptor paraboloids, the apices of Müller cells and the inner and outer plexiform layers. By 24 hours there was a reduction of the label in glycogen but silver grains were now visible over mitochondria in the photoreceptor ellipsoids and in increased amounts in the outer and inner plexiform layers and the nerve fiber layer. After three weeks, most radioactive material was observed over the photoreceptor cell outer segments. These results suggest that glycogen is added at the inner aspect of the photoreceptor paraboloid and then moves outward in a scleral direction, where it is metabolized by the ellipsoidal mitochondria.
An electron microscopic study of intimal cushions in intracranial arteries of the cat
Authors: Takayanagi Tetsuya , Rennels Marshall L. , Nelson Erland 
Published: February 2005

AbstractSubendothelial protuberances associated with the tunica intima have been described by light microscopy at branching sites of arteries in various animal species. These structures are termed intimal cushions or intimal pads. Some investigators regard them as being pathologic, preceding the appearance of atherosclerosis in the vessel wall. This fine structural study was done because of the possible role of intimal cushions in the regulation of cerebral blood flow at branching sites of intracranial arteries. The internal elastic lamina is split at the margins of a cushion to enclose irregularly arranged bundles of smooth muscle cells and collagenous fibrils. These smooth muscle cells are generally arranged at a right angle to smooth muscle cells in the underlying media. The outermost layer of the internal elastic lamina forms a boundary between the body of the cushion and the media; however, areas of discontinuity cause this border to be poorly defined in some instances. Perivascular autonomic nerves do not extend into either media or intimal cushions. Intercellular contacts between smooth muscle cells are observed within cushions as well as in the media, suggesting that cushions may be contractile and capable of modifying cerebral blood flow.
Placental development in the mongolian gerbil (Meriones unguiculatus). II. From the establishment of the labyrinth to term
Authors: Fischer Theodore V. , Floyd Alton D. 
Published: February 2005

AbstractPlacental development was studied in 24 gerbils from day 13 to term. Allantoic mesoderm contacts and vascularizes the chorionic‐trager plate of germinal cytotrophoblast on day 13. Soon villous extensions penetrate the plate, carrying with them a covering of three layers of trophoblast derived from it. As the villi elongate, clumps of germinal cytotrophoblast are carried peripherally by them. Further development of each villus results in a cylindrical mesenchymal core with a central arteriole, and radially arranged branching lamellar extensions carrying capillaries derived from the villus arteriole. Germinal cytotrophblast clusters disappear near term, but some indication always remains of the trilaminar covering of the villus and its lamellae. A typical countercurrent blood flow pattern occurs. The trophospongium is derived from the ectoplacental cone and the mesometrial surface of the germinal cytotrophoblastic plate. Although a few clusters of small cells occur, it is essentially a giant cell trophospongium and never contains cells resembling the clear cells of the rat. Late in pregnancy it becomes much reduced in thickness. The unique subplacental gland begins to degenerate soon after placental establishment and is gone by the last half of pregnancy. The metrial gland begins development at midterm and becomes a solid mass of cells filling the perivascular space of the mesometrial triangle at term.
Ultrastructural and fluorescence histochemical studies of developing sympathetic ganglia in the rabbit
Authors: Papka Raymond E. 
Published: February 2005

AbstractThe development of thoracic sympathetic ganglia was studied in rabbit fetuses at 14 to 30 days of gestation by light, electron, and fluorescence microscopy. Changes that occurred during the development of sympathetic neurons, supporting cells, and granule‐containing cells are described and the following conclusions drawn. (1) Sympathetic neurons and granule‐containing cells arise from a common “indifferent cell” precursor. (2) Monoamine fluorescence (a manifestation of the presence of catecholamines) appears early in the development of sympathetic neuroblasts. (3) The development of neuroblasts in a sympathetic ganglion is asynchronous; i.e., each neuroblast develops at its own rate, irrespective of the rate of development of its sister cells. (4) Granule‐containing and catecholamine‐storing cells develop rapidly and probably become potentially functional early in the life of the fetus, as inferred from the abundance of dense‐core vesicles and intense monoamine fluorescence. (5) The derivation of supporting cells (“satellite” and Schwann cells) could not be determined. They had differentiated into an easily recognizable cell form in the youngest specimens studied, and appeared to be enveloping cell bodies (as satellite cells) or axons (as Schwann cells) in all specimens.
The structure of compressed lungs in congenital diaphragmatic hernia
Authors: Boyden Edward A. 
Published: February 2005

AbstractThe case of a full term, stillborn infant with herniation of the viscera through a so‐called left Bochdalek foramen is analyzed. Graphic and wax reconstructions of the uninflated left lung record the degree of differentiation and the histologic appearance of the atelectatic parenchyma. To this is appended a discussion of the probable sequence of events during gestation; and an explanation of why such hernias usually protrude into the left, and not the right pleural cavity.
The effects of acute starvation on parotid acinar cells. Ultrastructural and cytochemical observations on Ad Libitum‐fed and starved rats
Authors: Hand Arthur R. 
Published: February 2005

AbstractParotid acinar cells from ad libitum‐fed and starved rats were studied using electron microscopic and cytochemical techniques. Lysosomes containing acid phosphatase and non‐specific esterase activity were present in cells of both ad libitum‐fed and starved rats. They included lipofuscin‐like bodies, smaller round or irregularly‐shaped bodies, multivesicular bodies, and coated vesicles. After 16–24 hours of starvation, lipid droplets had accumulated in the basal cytoplasm, and secretory granules showed evidence of degeneration. These altered granules consisted of irregular clumps of dense material in a less dense matrix. After 48–72 hours of starvation, the altered granules increased in number and fused to form large aggregates. Some of the aggregates also contained vesicles, membranous material, and lysosomal residues. The altered granules and aggregates were reactive for acid phosphatase and non‐specific esterase. The formation of the altered granules appeared to occur by spontaneous degeneration of the secretory granules, with secondary fusion with pre‐existing lysosomes and other altered granules. The results suggest that the lysosomal system of the parotid acinar cell functions to segregate and digest secretory granules during periods of reduced secretory stimulation.
Steroid‐protein interactions. XXV. Binding of progesterone and cortisol in pregnancy sera; progesterone‐binding globulin and uterine cytosol receptor in the pregnant guinea pig
Authors: MacLaughlin David T. , Harding George B. , Westphal Ulrich 
Published: February 2005

AbstractThe question of the identity of the high‐affinity binding sites for progesterone with those of the corticosteroid‐binding globulin (CBG) was investigated in pregnancy serum of man, rabbit, rat and mouse. Chromatographic techniques failed to separate a potential progesterone‐binding macromolecule from CBG in any of the sera. Competition studies with enriched fractions containing added [3H] progesterone and [14C] cortisol strongly bound to protein showed displacement of [3H] progesterone by an excess of unlabeled cortisol, and vice versa. It is concluded that CBG is the principal progesterone binder in the pregnancy sera investigated and that no other protein with high affinity for progesterone is present in significant quantity.In contrast, the progesterone‐binding globulin (PBG) in the serum of the pregnant guinea pig is distinct from CBG and has been separated from it. The PBG differed from the uterine cytosol receptor for progesterone in its sedimentation coefficient (sucrose gradient centrifugation) and its molecular size (gel filtration). With both the uterine receptor and PBG, norethynodrel displaced radiolabeled progesterone from the specific binding sites. This is in contrast to analogous binding systems involving other steroid hormones and other species, where the synthetic hormonal agent interacts strongly with the receptor protein of the target tissue, but not with the high‐affinity binder in the serum.
Ultrastructural changes in renal Glomeruli of rats during experimentally induced hypertension and uremia
Authors: Lee M. L. , Purkerson M. L. , Agate F. J. , Dempsey E. W. 
Published: February 2005

AbstractInternal vascular ultrastructural detail of renal microcirculation observed by a combination of latex injection/corrosion/scanning electron microscopy techniques can be correlated with structures visible in transmission electron micrographs. Glomeruli of normal and hypertensive rats have been examined using both techniques. In the casts, indentations occur which are comparable in size, shape and frequency to nuclei of endothelial cells; and other irregular indentations may be correlated with the occurrence of platelet thrombi and endothelial cell proliferation. From these observations we conclude that ultrastructurally accurate casts of blood may be visualized by scanning electron microscopy. Such visualization offers much promise for the study of microcirculatory structures in states of disease and altered function.
The utility of antiserums to subunits of TSH and LH for immunochemical staining of the rat hypophysis
Authors: Baker Burton L. , Pierce John G. , Cornell James S. 
Published: February 2005

AbstractThe objective was to assess the effectiveness of antiserums to the β‐subunit of bovine TSH (thyrotropin) and α‐ and β‐subunits of LH (luteinizing hormone) for immunochemical staining of rat pituitary cells and in so doing to acquire more information about the properties of the subunits. For the following reasons it was concluded that antiserum to TSH‐β is specific for demonstration of TSH‐cells. The morphology and distribution of the presumptive TSH‐cells so revealed conform to the descriptions presented by other investigators who have used histological techniques. When pituitary TSH content was reduced by thyroidectomy or administration of propylthiouracil or thyroxine, the stainability of TSH‐cells was reduced; it was increased with elevation of TSH content during rebound after cessation of propylthiouracil treatment. The effectiveness of anti‐TSH‐β was lost after absorption with bovine TSH.The specificity of antiserum of LH‐β for demonstration of LH‐cells was indicated since the cells demonstrated with it correspond to the gonadotropic cells described by others with respect to morphology, distribution and response to gonadectomy. Antiserum to LH‐α, the nonspecific subunit of LH, permitted staining of both TSH‐ and LH‐cells. The individuality of TSH‐ and LH‐cells, as revealed immunochemically with antiserums to the respective specific β‐subunits, was demonstrated by double staining and by comparison of adjacent sections stained with one of the two antiserums.
Sexual dimorphism of the miniature pig submandibular glands
Authors: Pinkstaff Carlin A. 
Published: February 2005

AbstractThe submandibular salivary glands of 14 Pitman‐Moore miniature pigs were examined to determine whether they exhibit sexual dimorphism. Sections of the glands from seven male and seven female animals were stained by several histochemical methods. No morphological sex differences were noted in hematoxylin and eosin‐stained sections but differences were found with all of the histochemical methods utilized. Most noticeable was the higher concentration of sialic acid‐containing mucosubstances in mucous acini of the female submandibular gland sections when they were stained with either the Alcian blue (pH 2.5), Alcian blue (pH 2.5)‐periodic acid‐Schiff or periodic acid‐phenyl‐hydrazine‐Schiff methods. Unlike mucous acini, demilunes of the male submandibular gland possessed a higher concentration of sialic acid‐containing mucosubstance than did those of the female. The miniature pig, unlike other animal orders studied, possesses sexual dimorphism at three weeks of age, thus differing markedly from other animals in which sexual dimorphism of the salivary glands does not occur until after the onset of puberty.
Relationship between the cell cycle and cell localization in crypts of the guinea‐pig ascending colon
Authors: Rowiński J. , Sawicki W. 
Published: February 2005

AbstractGuinea‐pigs were injected with either 3H‐thymidine or colchicine and killed at various time intervals after the injections. Duration of the over‐all cell cycle and of the G1, S and G2 phases was determined with autoradiography for cells in the short, medium and long crypts of the colon as well as for the lower, middle and upper segments of the crypt.The duration of mitosis estimated with the colchicine method increased from the mouth of the crypt downward to the bottom, from about one to three hours. The cells located in the crypt between the mouth and approximately the twentieth cell position have a cell cycle of about 15 hours whereas those located in the crypt section between the twentieth cell position and the bottom have a cell cycle of about 25 hours. This difference is due mainly to a change in the G1 phase. The results of planimetry for the first and second waves of labeled mitoses suggest that in the lower segment of medium and long crypts, cells in the G0 phase occur. It is concluded that the factor(s) controlling cell cycle duration in the colon crypt appears either at the crypt mouth or nearby.