bluuebunny/crossref_metadata_2025_split huggingface dataset:
A technique for the light microscopy of tissues fixed for fine structure
Authors: Rosen William C. , Basom Charles R. , Gunderson Leonard L. 
Published: February 2005

AbstractYoung adult female rats were perfused with buffered aldehydes. Selected tissues were prepared for light microscopy by standard techniques. The only procedural modifications permitted were those required by the special physical and chemical characteristics of the tissue. Extreme brittleness called for special precautions in all manipulative steps from excision to final embedment. Turbulence during the early stages of dehydration was lessened by drop‐by‐drop addition of the next concentration of ethanol. High melting‐point paraffins and celloidin‐paraffin embedments were used to accommodate the hardness of the tissues and to prevent disarrangement during mounting. Steel knives specially sharpened with fine abrasives on plate glass were fitted with fluid reservoirs. Four micron sections were obtained routinely. Sections were transferred individually from the reservoir to glass slides. The common dyes used in light micoscopy tended to overstain these tissues. This tendency was overcome by using shorter exposure times, lower concentrations and blocking agents. The chromatic staining techniques familiar to histologists and pathologists were useful after minor modifications.
Homology of form in plant and animal Golgi apparatus
Authors: Mollenhauer H. H. , Morré D. J. , Bergmann Louise 
Published: February 2005

AbstractIn both negatively stained and sectioned preparations, Golgi apparatus of mouse spleen, liver and kidney consist of dictyosomes having cisternae with tubular peripheries. The extent of the tubular portion varies among tissues and among cisternae of a given dictyosome. Animal dictyosomes closely resemble those from plants in both form and sedimentation characteristics. In these respects, plant and animal Golgi apparatus are homologous structures.
Morphology of the specialized conducting tissue in the atria of the equine heart
Authors: Bishop Sanford P. , Cole Clarence R. 
Published: February 2005

AbstractThe gross and microscopic anatomy of the sinus node (SN), atrioventricular node (AVN) and specialized fibers in the atrium were studied in 19 horses and eight mules. The SN is supplied with blood by a branch from the left circumflex artery which subdivides within the node. The SN has a body and long tapering cranial and caudal crura which encircle the lateral margin of the precaval orifice. The AVN, which has no large artery consistently present within its structure, is located within the fibrous septum above the septal leaflet of the tricuspid valve and anterior to the coronary sinus.Histologically most of the fibers in the SN and AVN are similar to those in other species. They are smaller, paler staining and much more interwoven than ordinary myocardial fibers. In the caudal crus of the SN, the fibers are clumped together with loss of individual characteristics.Large, glycogen‐rich cells morphologically similar to ventricular Purkinje fibers are found in the right atrial subendocardium. The distribution of these fibers suggest that they may be concerned with intraatrial spread of excitation. Muscular pathways between the SN and AVN are composed of ordinary myocardial fibers. The large atrial myocardial fibers do not connect directly with SN or AVN fibers.
The ampulloglomerular organ: An unusual neurovascular complex in the suboccipital region
Authors: Parke Wesley W. , Valsamis Marius P. 
Published: February 2005

AbstractA group of venous sacculations associated wth a system of glomerular arteriovenous anastomoses and numerous nerves lies adjacent to the vertebral artery. As thin walled extensions of a dural sinus, these ampullae are structurally capable of responding to changes in venous pressure. The function of their glomerular connections to branches of the vertebral artery is not apparent.
Developing boundary (basement) membranes in the chick embryo
Authors: Low Frank N. 
Published: February 2005

AbstractThe primordia of boundary (basement) membranes are present in the freshly laid egg along the basal surface of the epiblast. This location provides boundary membranes for all ectodermal derivatives including the central nervous system. Entodermal boundary membranes begin to form during the first half of the second day and eventually serve all entodermal derivatives. Mesodermal boundary membranes are slower to form. Those around the myotomes undergo considerable remodeling before the adult arrangement is reached. Endothelial boundary membranes are very slow to develop, not having appeared at 36 hours incubation.
A radioautographic study of cell proliferation in the mammary gland of the pregnant mouse
Authors: Traurig Harold H. 
Published: February 2005

AbstractProliferation of the mammary gland epithelium on days 2, 3, 4, 6, 8, 12, 16, and 19 pregnancy has been studied in mice, by means of radioautography. Each animal received an intraperitoneal injection of 25°c of tritiated thymidine and was killed one hour later. The inguinal mammary glands were processed for paraffin sectioning and radioautographs prepared using the dipping technique. The rate of mammary epithelial cell proliferation was quantitated for each animal by determining the percent of labeled epithelial cells in a large sample (> 2000 cells) of cells (labeling index).The data showed that the proliferative activity of the mammary epithelium during pregnancy followed a bimodal distribution. The first evidence of a proliferative response to pregnancy was noted on day 3. By day 4, the labeling index reached a maximum of 25.3%. The labeling index declined on days 6 and 8 to 7.5% and 8.0% respectively. On day 12, the labeling index increased to 12.1%, then fell to 7.9% and 1.3% on day 16 and 19, respectively.Separate labeling indexes were determined for the interlobular epithelium (ducts) on day 12, 16, and 19. The data showed that the labeling indexes of the interlobular and intralobular epithelium during these stages of pregnancy were not significantly different. The correlation of the hormones secreted during pregnancy with the data on mammary epithelial proliferation is discussed.
Congenital anomalies induced in normal and adrenalectomized rats by amniocentesis
Authors: Kendrick Francis J. , Feild Lee E. 
Published: February 2005

AbstractSprague‐Dawley rats, which are not susceptible to the teratogenic effects of adrenalectomy, adrenal corticoids, and corticotropin noted in other species, were subjected to amniocentesis and to amniocentesis plus adrenalectomy.Amniocentesis was shown to be teratogenic when performed at any time between the fourteenth and eighteenth gestational days inclusive, but no malformations occurred either in control fetuses or when amniocentesis was performed on the thirteenth day of gestation. Fetal resorptions were increased following single amniocentesis on any gestational day from the thirteenth to the eighteenth inclusive. The predominant defects induced were cleft palate and limb deformity. Cleft palate occurred only after amniocentesis on the fourteenth, fifteenth, or sixteenth days of gestation, principally on the fifteenth day. However, limb deformity, consisting primarily of malrotation, syndactyly, and varying degrees of agenesis, occurred following single amniocentesis on any day of gestation from the fourteenth to the eighteenth inclusive, but principally on the fifteenth day. Adrenalectomy did not alter significantly either the nature or the incidence of the anomalies induced by amniocentesis.The data indicate that amniocentesis is teratogenic in the rat, and that the adrenal glands are neither essential for, nor do they exert any detectable influence upon the induction of those malformations.
The effect of bilateral or unilateral adrenalectomy and bilateral thyroidectomy on the anterior pituitary of perinatal rats
Authors: Eguchi Yasunobu , Morikawa Yoshio 
Published: February 2005

AbstractMeasurements of volume of the anterior pituitary and diameter of pituitary cells and differential counts of acidophilic and basophilic cells were made under normal or experimental condition of bilateral or unilateral adrenalectomy or bilateral thyroidectomy in late fetal and newborn rats. The pituitary volume showed a consistent rise from the twentieth day of pregnancy to the third day after birth, but not as rapidly relatively as did body weight. Just after birth, the cell diameter declined. Acidophilic and basophilic cells increased in per cent and stained more intensely.In fetuses, bilateral adrenalectomy caused an increase in both the “pituitary volume/body weight” ratio and the cell diameter. Unilateral adrenalectomy caused an increase in the cell diameter. Thyroidectomy showed an increase in both the cell diameter and the per cent of basophilic cells which were partially degranulated.In newborns, bilateral adrenalectomy caused the death of all operated rats. Unilateral adrenalectomy caused no significant change in all categories observed. Thyroidectomy showed an increase in per cent of basophilic cells, but not to the extent observed in fetuses. The basophilic cells were somewhat degranulated.The observations support the views that in the rat the pituitary‐adrenal and pituitary‐thyroid systems begin to function before birth and that the functioning of both systems is slightly reduced just after birth.
Cellular dynamics in the jejunum of essential fatty acid deficient mice
Authors: Snipes Robert L. 
Published: February 2005

AbstractThe population dynamics of the jejunal epithelium of mice maintained on a semi‐synthetic diet deficient in the essential fatty acids (EFA) has been investigated. Colchicine was employed to collect mitotic figures for the determination of mitotic indices. Twenty‐five crypts in longitudinal section were counted per animal and the mean mitotic index computed as the number of mitoses per total number of crypt cells. EFA‐deficient animals had a mean mitotic index of 36.56 as compared with 26.51 and 16.74 for the linoleic acid‐supplemented and chow‐fed control animals, respectively. Counts of the number of epithelial cells on one side of a villus and crypt indicated that the height of the villi, but not the crypts, of the EFA‐deficient animals was significantly lower than either control group. In the EFA‐deficient animals the mean percentage of villi having extrusion zones exceeded that of both control groups. Radioautography demonstrated that 36 hours after injection of tritiated thymidine the majority of villi in the EFA‐deficient animals were labeled at their tips, whereas in control samples label was restricted to the lower one‐half to three‐fourths of the villus. Thus, EFA‐deficiency induces increased rates of mitosis, migration and sloughing, resulting in alterations in villous architecture.
The development of the human fetal adenohypophysis
Authors: Conklin James L. 
Published: February 2005

AbstractUnderstanding the development of the human adenohypophysis is dependent on visualizing the growth of Rathke's pouch. This embryonic structure gives rise to bilateral anterior and posterior, superior and inferior segments. These segments differ in their potential to produce various types of hypophyseal chromophils. The potential differences are described in the text.Further, by application of specific staining procedures it has been possible to determine the approximate time that specific chromophils appear in the adenohypophysis. The chromophils of the adenohypophysis develop in the order: cell type III, I, IV, II, V, VI and IX. There may be a relationship between the development of certain chromophils and the onset of function in target endocrine glands.
Special ultrastructural features of parathyroid cells from Swiss mice bearing Ehrlich's ascites tumor
Authors: Latta John S. , Rutz Timothy J. 
Published: February 2005

AbstractAs part of studies on Ehrlich's ascites tumor cells transplanted into Swiss mice some unique myeloid figures, were found with electron microscopy in parathyroid cells, consisting of electron dense rings partially or completely encircling the nuclei of many cells in 7 of the 30 treated animals examined. These dense rings were seen to be made up of tightly matted bands, which at free ends, spread out to become continuous with agranular endoplasmic reticulum. The nuclei of these altered cells were quite pleomorphic and were closer together than in normal tissue, indicating decreased cell volume. Rough endoplasmic reticulum was scarce, mitochondria were long and slender and free ribosomes were widely scattered in the cytoplasm. A possible explanation for the development of these focal areas of degeneration is given.
Lipofuscin pigment accumulationin the nervous system of aging mice
Authors: Samorajski T. , Ordy J. M. , Rady‐Reimer P. 
Published: February 2005

AbstractThis morphologic investigation was undertaken with an inbred strain of C57BL/10 male mice to examine the accumulation of lipofuscin in nerve cells of dorsal ganglia and the cerebellum at 4, 8, 20, and 30 months of age. Histological examinations revealed that at four months of age, cells contained only a few small sudanophilic bodies distributed fairly uniformly throughout the cytoplasm. By 30 months, pigment aggregations became very prominent cytoplasmic features of many nerve cells in the dorsal ganglia and cerebellum. A more detailed examination of neurons from the dorsal ganglia with the electron microscope revealed particles of variable size with a high electron density at four and 8 months. By 20 and 30 months, the pigment bodies appeared to be larger and were more concentrated near the nucleus. In Purkinje cells of the cerebellum the pigment granules were observed only rarely at four and eight months. By 20 and 30 months, the granules in the Purkinje cells appeared to be larger, considerably more numerous, and concentrated between the nucleus and the apical dendrite. The intracellular pigment concentration was also estimated by calculations of the per cent of area occupied by pigment granules as well as by the per cent of the cells that contained pigment bodies at 4, 8, 20 and 30 months. A progressive increase in the intracellular pigment concentration was readily noted.
Nerve endings in the temporomandibular joint of the Rhesus macaque
Authors: Keller Jack H. , Moffett Benjamin C. 
Published: February 2005

AbstractMethylene blue preparations and silver impregnated material were used to demonstrate the sensory nerve endings in the temporomandibular joint of the Rhesus monkey. Sixteen millimeter motion picture sequences of the various nerve endings were photographed while the microscope was slowly focused up and down through the entire thickness of the nerve ending. A 15‐minute film with descriptive sound track was prepared to demonstrate these nerve endings in three dimensions. The following types of nerve endings (listed in decreasing order of frequency) were seen in the articular capsule and peripheral portions of the articular disk: free, Ruffini, Golgi, and Paciniform endings. The sphenomandibular and stylomandibular ligaments in these monkeys gave no gross appearance of a ligamentous structure and did not contain any specialized proprioceptive nerve endings. Physiologic studies indicate that the nerve endings seen in the temporomandibular joint provide sensory mechanisms for the rception of pain, the autonomic control of vascular supply, and the recording of information concerning joint position and change in rate of movement.
Cell sizes and frequencies in the human nucleus intercalatus
Authors: Radmanesh H. 
Published: February 2005

AbstractA considerable area of the floor of the fourth ventricle, extending from the facial colliculus down to the vagal triangle, is underlaid by the nerve cells of the nucleus intercalatus. Only a minor portion of this nuclear complex is actually “intercalated” this portion comprising about 2,500 cells or 6% of the total. The great majority of cells making up this nucleus, 80% or 32,000 are found in front of the oral pole of the hypoglossal nucleus. The remaining 14% of cells or about 6,000 form a third distinct group located opposite the medial vestibular nucleus. The mean cell sizes in the three parts of the nucleus are also different, they are 90 μ2, 135 μ2 and 190 μ2 respectively. These differences of cell sizes and of location were the basis for the division of this nucleus into three parts by some authors. In the three cases studied, this division was, however, not so complete as to permit a separate cell count for each part to be kept. The mean of the cell frequencies in the three cases is 36349 ± 4114 cells.
Formation of ceroid pigment in subcutaneous implants in mice
Authors: Winnail Douglas S. , Williams W. Lane 
Published: February 2005

AbstractMice of the RF and C57 black strains, fed an adequate diet, were donors and recipients of subcutaneous tissue implants. Abundant ceroid formed in implants of liver, heart, and adrenal. The pigment developed concurrently with degenerative changes in hepatocytes and myocardial fibers. Ceroid was intracellular in implants of adrenal gland and limited to cortical cells. Skeletal muscle and multilocular fat cells were next most productive sources of ceroid. Unilocular fat cells produced only traces. Isogeneic and allogeneic implants of corresponding tissues revealed comparable amounts of ceroid after two weeks of transplantation. Formation of pigment was correlated with the type of tissue transplanted rather than to specific host‐graft responses.Implants of liver tissue were an ideal model for studying genesis of ceroid pigment. Granules of ceroid appeared first at the periphery of the implant in tissue adjacent to obviously degenerating cells of the graft. These small granules of pigment were then engulfed by macrophages. In most instances liposis preceded formation of ceroid. The presence of large amounts of lipid in the tissue at time of implantation did not augment ceroid formation. Hyper‐ and hypovitaminosis E, choline deficiency (to produce fatty livers), hyperestrogenism, and the administration of immunosuppressive drugs to recipients failed to influence appreciably the production of ceroid. In livers and other tissues containing little fat a relatively rapid post‐implantation liposis preceded ceroid formation.
The role of Spleen in development of lympho‐hemopoietic tissues: Effect of splenectomy on development of blood cells, bone marrow, thymus and lymph node
Authors: Kalpaktsoglou Pitsa K. , Yunis E. J. , Good R. A. 
Published: February 2005

AbstractThe effects of splenectomy at birth and two and four weeks of age on the development of lymphoid and hematopoietic tissues has been compared in C3H/Bi mice. During the neonatal period normal mice showed changes in total leukocyte count, and in absolute members of the specific cell types. The predominant changes included an initial fall of numbers of granulocytes and steady increase in numbers of lymphocytes during the first six weeks of life. Neonatal splenectomy interfered with the normal developmental pattern by interfering with normal growth of numbers of circulating lymphocytes while splenectomy at two and four weeks of age produced increases in numbers of both circulating lymphocytes and granulocytes. Neonatal splenectomy produced effects on development of bone marrow, peripheral lymph nodes and thymus. The major influence seemed to involve decrease in percentages of small, densely stained lymphocytes in thymus and peripheral lymph nodes.
Surgically induced hypertrophy in skeletal muscles of the laboratory mouse
Authors: Rowe R. W. D. , Goldspink G. 
Published: February 2005

AbstractTwo surgical techniques were used to increase the work load per fiber in mouse skeletal muscles. These were, part removal of the muscle and incapacitation of a synergetic muscle. Both techniques were used for the soleus muscle. They resulted in the fiber size distribution of this muscle, which was normally unimodal, becoming distinctly bimodal. The same effect was obtained for the part removal of the anterior tibialis muscle. For the above mentioned muscles the extent of hypertrophy was very considerable. The recorded increase in the mean fiber cross‐sectional area was in the region of 56% to 92%. Part removal of the biceps brachii however produced only a comparatively slight increase in fiber size (9%). In this case the normal muscle was bimodal and the effect of part removal was to slightly increase the size of the second peak. The reason for the two peaks occurring in the distributions of fiber size in some muscles was due to the presence of fibers at a basic level of development and also the presence of hypertrophied fibers. The increase in mean fiber size resulting from an increased work load was in all cases, due to a proportion of the basic fibers undergoing hypertrophy and not due to a gradual increase in the size of all the fibers.
Cytology and duration of the cycle of the seminiferous epithelium of the boar; duration of spermatozoan transit through the epididymis
Authors: Swierstra E. E. 
Published: February 2005

AbstractThe cycle of the seminiferous epithelium of the boar was divided into eight stages which are described. The relative frequencies of the stages were determined for ten Yorkshire and ten Lacombe boars approximately 11 months of age. The mean relative frequencies for stages 1 through 8 were 10.8, 14.4, 3.5, 11.6, 8.9, 20.3, 18.5 and 12.0%, respectively. Generally, there was a constancy of the relative frequencies of the stages between breeds, among boars within breeds and between testes within boars.The absolute duration of the cycle of the seminiferous epithelium and the duration of spermatozoan transit through the epididymis were determined by injecting a single dose of 19 mCi of thymidine‐methyl‐H3 into the marginal ear vein of each of four Yorkshire (15.2 months old) and four Lacombe boars (14.9 months old). Unilateral castrations were performed at 0.2, 11.5, 20.0, 24.0 and 25.0 days after the isotope injection. Two intact and two unilaterally castrated animals were ejaculated for eight and seven weeks, respectively, to determine the interval between the thymidine‐H3 injection and the appearance of the isotope in the ejaculated semen. Autoradiographs were prepared from the testis tissues and the semen smears. The most mature germ cells that incorporated the thymidine‐H3 were the late preleptotene primary spermatocytes. Twenty‐five days after injection the label had progressed from late preleptotene primary spermatocytes to spermatozoa leaving the testes. Epididymal transit times for four boars (ejaculated daily) were 9, 10, 10 and 12 days. The duration of one cycle of the seminiferous epithelium based on 12 estimates was 8.6 ± 0.1 days. The durations of stages 1 through 8 were 0.9, 1.2, 0.3, 1.0, 0.8, 1.7, 1.6 and 1.0 days, respectively. The life span of primary spermatocytes was 12.3 days, of secondary spermatocytes 0.4 days, of spermatids with round nuclei 6.3 days, of spermatids with elongated nuclei 1.5 days, and of spermatozoa 6.2 days.