bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron microscopic observations of non‐specific lead staining in the smallintestine of the cat after lipid or carbohydrate feeding
Authors: Napolitano Leonard , Howard John 
Published: February 2005

AbstractA series of experiments utilizing the technique of Rostgaard and Barrnett which purported to demonstrate lead‐lipid complexes was performed to study the efficacy of using lead as a marker in lipid absorption.The jejunal mucosa from adult cats fasted 48 hours and fed corn oil by stomach tube was fixed in buffered glutaraldehyde for two hours, washed in cacodylate buffer and then incubated for 20 minutes in tris‐maleate buffer (pH 7.2) which contained 4mM of lead nitrate. Following osmication, dehydration and embedding in Epon, thin sections, either stained or unstained were examined in an electron microscope. Lead deposits of varying size were observed in, on and about the microvilli. In addition, lead deposits were observed related to mucous cells. The jejunal mucosa of cats fasted 48 hours and fed 5% dextrose and treated as the lipid‐fed animals gave similar results. Fasted animals had few lead deposits related to the gut epithelium.When jejunal mucosa from lipid‐ or carbohydrate‐fed animals was extracted in lipid solvents prior to incubation in tris‐maleate containing 4mM of lead nitrate, the lead densities persisted.In view of the foregoing, the occurrence of lead precipitates following a fatty meal does not offer an unequivocal means of tracing lipid absorption in the small intestine.
Transformation of rat small lymphocytes with pokeweed mitogen (PWM)
Authors: Schwarz M. Roy 
Published: February 2005

AbstractWhen lymphoid cells from the thoracic duct lymph, blood, lymph node, spleen and thymus of the rat were exposed to pokeweed mitogen (PWM), large primitive cells appeared after 24–30 hours of culture. This response was not limited to tissues of adult animals but was also demonstrated in cultures of cells from the thymus glands, lymph nodes and spleens of newborn, 48 hour and three‐day‐old rats, respectively. The transformed rat cells, in contrast to the cells observed in human PWM cultures (Chessin, Bőrjeson, Welch, Douglas and Cooper, '67), could not be divided into two populations on the basis of cytoplasmic basophilia, PAS positive granules or alcian blue staining. In addition, the thoracic duct lymphocytes from rats thymectomized within 24 hours of birth showed a marked deficiency in transformation, characterized by decreased numbers of enlarged cells and minimal cytoplasmic basophilia, when compared to similar cells from non‐operated or sham‐thymectomized controls.In the thymus cultures, some of the small lymphocytes served as precursors of the transformed cells without undergoing division. Subsequently, these enlarged cells proliferated giving rise to small lymphocytes and additional transformed elements. Exposing lymphoid cells to PWM for up to 14 days did not result in the development of plasma cells.
A histochemical study of mucoid cells in the Pars distalis of the human hypophysis
Authors: Conklin James L. 
Published: February 2005

AbstractSections of the human hypophysis were fixed in either formalin or Bouin's fluid and stained by a variety of mucoid and acid stains in order to demonstrate the staining characteristics of the mucoid cells of the pars distalis.Five types of mucoid cells were revealed and designated as cell types III, IV, V, VI and IX according to the classification system of Ezrin. Cell types III, IV, V and VI were present throughout the pars distalis while cell type IX was observed only in the posterior zone.The cells were tinctorially distinguished by the PAS‐orange G affinity of the type III cell, the alcian blue‐PAS reactivity of the type IV cell, the alcian blue staining of the type V cell and the affinity of the type VI cell for alcian blue‐PAS‐orange G. Cell type IX was recognized by the affinity of its cytoplasmic granules for most of the stains employed. Modified and degranulated forms of these cells were observed and are also described.
Development of pancreases and adrenals of rat embryos in organ culture
Authors: Wells Lemen J. , Erlandsen Stanley L. , Eguchi Yasunobu 
Published: February 2005

AbstractDeveloping pancreases from rat embryos of the sixteenth day of pregnancy and adrenals from embryos of the nineteenth day were grown in organ culture for six days. The cultures were transferred to fresh media twice, after 48 hours and after 96 hours of incubation. Control cultures consisted of pancreas alone and of adrenal alone.The pancreatic islets which were too young to have granulated beta cells on the sixteenth day of pregnancy differentiated into islets with many granulated beta cells during the culture period of six days. The pattern of granulated beta cells and the estimated number of these cells in cultures with adrenals were variable (not consistently different from those in the control cultures without adrenals).The adrenals from embryos of the nineteenth day had two zones of the fetal cortex outer and inner. Cultures of adrenals survived. The adrenals, whether minced or unminced at the time of the explantation and whether cultured alone or with pancreases, underwent little if any additional differentiation during the culture period.
Distribution of thyrotrophic activity in the hypophysis of necturus before and after thyroidectomy as measured by I131 bioassay in mice
Authors: Aplington H. W. , Tedrow Brant W. 
Published: February 2005

AbstractHypophyses of non‐thyroidectomized and thyroidectomized winter Necturi were divided into rostral and caudal portions which were frozen‐dried refrigerated, and injected into mice for bioassay according to the method of McKenzie' ('58). Each mouse received the homogenized equivalent of two pituitary portions, either rostral or caudal. The per cent increase in blood I131 which resulted was used as a gauge of thyrotrophic activity.In the non‐thyroidectomized Necturus, nearly two‐thirds of the thyroid stimulating activity was in the rostral portion which consisted of the rostral two‐thirds of the anterior zone tissue. The remaining TS activity was in the caudal portion which consisted of the caudal third of the anterior zone, the transitional zone and basophilic bed area. These bioassay results coincide with the distribution of basophile cells described previously as thyrotrophs on the basis of histological observations.After thyroidectomy, caudal portions yielded 95% of the thyrotrophic activity. This observation is consistent, with some reservation, with the number and distribution of thyroidectomy cells that differentiate after thyroidectomy, taking into account the vacuolation and degranulation of these cells which occurs in rostro‐caudal sequence.
Nuclear elimination from the normoblast of fetal guinea pig liver as studied with electron microscopy and serial sectioning techniques
Authors: Campbell Ferrell R. 
Published: February 2005

AbstractThe process of denucleation in normoblasts of fetal guinea pig liver was studied with electron microscopy employing serial sections. In the late normoblast the nucleus becomes eccentrically located in the cytoplasm. Continued maturation results in a nucleus which is protruding from the normoblast. Still later the nucleus separates from the remainder of the cell and is phagocytized by a reticular cell. Nuclei which have been extruded are surrounded by a narrow border of cytoplasm and possess a nuclear envelope, nuclear pores, and internal nuclear structure similar to that of normoblasts. The cytoplasmic border and nuclear structure are observed for some time after ingestion by reticular cells. Dissolution of nuclei inside the phagocytes is characterized by disappearance of the cytoplasmic border and nuclear envelope, loss of density of the chromatin, and appearance of dense particles in the interchromatin. It was concluded that under normal conditions, the sole mechanism of denucleation in definitive erythroblasts is extrusion. Mitochondria are partially degraded inside the late erythroblasts, forming a membranous residue which is later extruuded.
The vertebral level of the arytenoid cartilages
Authors: Koppel Harold J. , Kendrick George S. , Moreland James E. 
Published: February 2005

AbstractA group of 27 females and 24 males between the ages of eight years four months and 15 years seven months was examined to determine the vertebral level of their arytenoid cartilages. An apprasial of their lateral cephalometric radiographs which included the cervical vertebra was made under rigid conditions. Each cervical vertebra was divided into three sections in order to relate its position more precisely to the cartilages. The age of each subject was recorded and then compared with the vertebral level of their arytenoid cartilages. General consistency seemed to prevail throughout the group at given sex and age levels. Visualization of the arytenoid cartilages was excellent. No evidence of mineralization in the laryngeal cartilages was noted in the age group studied.
Effects of estrogen on pituitary morphology in goitrogen treated rats. An electron microscopic study
Authors: Potvliege Paul R. 
Published: February 2005

AbstractThe influence on pituitary cytology of propylthiouracil (PTU) and estradiol benzoate (EB) administered singly and in combination was studied by electron microscopy in adult female rats. PTU alone induced striking changes in the morphology of thyrotroph cells, which were all transformed into typical thyroidectomy cells, characterized by enormously dilated ergastoplasmic sacs; the acidophils were degranulated and some of them took the appearance of relatively quiescent prolactin cells rather than degranulated somatotrophs. EB alone caused no definite changes in the morphology of thyrotroph cells; its essential effect was the development of a large number of prolactin cells. When both treatments were combined, thyroidectomy cells were found, existing side by side with untransformed thyrotrophs and exhibiting less dilated ergastoplasmic sacs than after PTU alone; prolactin cells were present in great number and showed a more developed ergastoplasm than after EB alone. Thyroid weight and height of the follicular cells were not changed by EB given singly; they were both increased under the influence of PTU; thyroid weight but not mean height of the follicular cells was slightly less increased when EB was added to PTU. It is tentatively concluded that estrogen may have a dual action on the thyro‐pituitary axis: on one hand, a depressing influence on thyrotroph cells and on the other hand a direct stimulatory effect on the thyroid gland.
Fine structure of the carotid body of normal and anoxic cats
Authors: Al‐Lami Fadhil , Murray Raymond G. 
Published: February 2005

AbstractCertain modifications and clarifications of current concepts of the fine structure of the carotid body are described. The two principal cell types are here designated “enclosing” and “enclosed” to emphasize the enveloping nature of the former. The enclosed cells have numerous processes, contain lysosome‐like bodies which are sometimes related to crystals with a period of about 100Å. In addition to the typical dark‐cored vesicles, a few with lighter content are always present. The enclosing cells are in most respects similar in their contents to the enclosed, even to the presence of occasional dark‐cored vesicles. The fenestrations of the blood vessels apparently are closed by thin diaphragms.In addition to the type of nerve endings previously described, there is a second type which extensively surrounds the enclosed cells, in the manner of a basket, and differs from the first type in having relatively empty cytoplasm with few synaptic vesicles or mitochondria. It is postulated that this is the afferent ending, while the former may be efferent.Severe anoxia rendered both cell types more dense than normal. In contrast to previous reports, the dark‐cored vesicles of the enclosed cells did not disappear but rather increased in relative number, and their mitochondria were less opaque. No comparable changes were noted in control anoxic tissues of liver, kidney or adrenal medulla. The possibility is discussed that the enclosing cell has more than a simple supportive function, as the usual name “sustentacular” seems to imply.
Central distribution of trigeminal primary afferent fibers in anuran amphibians
Authors: Joseph Barry S. , King Robert B. , Whitlock David G. 
Published: February 2005

AbstractTrigeminal ganglia were unilaterally macerated manually through the foramen ovale in three forgs. Rana catesbeiana, and in two toads, Bufo marinus. Following a two to three week post‐operative survival, each animal was anesthetized and was systemically perfused with formalin. Serial transverse frozen sections, 50 μ in diameter, were then prepared from the CNS of each animal. Selected tissue sections were stained according to a uranyl nitrate modification of the Nauta silver technique. The distribution of degenerating fibers was subsequently assesed by microscopic analysis.Degenerating trigeminal fibers could be traced from the trigeminal root into the vicinity of the chief sensory nucleus of the trigeminus and into the spinal V tract and nucleus in both toad and frog. The spinal V tract passed into the cervical spinal cord in all animals but did not pass further caudally than the third spinal segment. In some animals, degenerating fibers passed into the fasciculus solitarius and the nucleus solitarius. No trigeminal primary afferent fibers could be followed into the cerebellum or into the immediate vicinity of any of the cranial motor nuclei, in cluding the trigeminal motor nucleus. The distribution of Gasserian ganglion collaterals recorded in this study is discussed with reference to previous findings in the trigeminal systems of amphibians, birds and mammals.
Reproductive organ DNA and RNA of male and female rats from birth to 100 days of age
Authors: Desjardins C. , Macmillan K. L. , Hafs H. D. 
Published: February 2005

AbstractMale and female rats were adjusted to six pups per litter and weaned at 20 days of age. Groups of ten males were killed at five‐ to ten‐day intervals between one and 100 days of age and groups of 12 to 45 females were killed between ten and 100 days. Accumulation with age of gonadal, seminal vesicular, and uterine weight, DNA, and RNA, were compared with body growth in relative growth analyses to delimit puberty and quantify reproductive growth.Males and females possessed similar body growth to 40 days, after which age females grew more slowly while males continued rapid growth to 60 days. Relative to body growth, testes grew more rapidly from ten days whereas ovarian growth generally paralleled body growth until 50 days of age. A shift in gonadal RNA/DNA ratio from less than to greater than unity occurred early in puberty in both sexes. Nucleic acid contents of accessory reproductive organs indicated that effective levels of gonadal steroids promote pubertal growth beginning at about 40 days in males and about 33 days of age in females. These marked pubertal growths ended at 70 days in males and 60 days of age in females.
Vascularization and basement membranes of the chick brain in light microscopy
Authors: Peterson Richard G. 
Published: February 2005

AbstractBlood vessels were first observed in the hindbrain of chick embryos at stage 20 (three to three and one half days incubation). At this time the central nervous system had a complete PAS‐positive basement membrane. The surrounding blood vessels did not have a similar investment. An attenuated basement membrane, continuous with the one on the nervous tissue, enveloped each invading vessel. Invading vascular sprouts entered as solid cords which soon developed lumens and became functional capillaries.
Localization and distribution of adenosine triphosphatase activity in the femurs of young mice
Authors: Severson Arlen R. , Tonna Edgar A. , Pavelec Mildred 
Published: February 2005

AbstractThe localization and distribution of ATPase activity in the femurs of young mice was evaluated using the lead‐ATPase histochemical method. The skeletal system demonstrated an intracellular distribution of ATPase activity. Enzyme activity of osteoclasts, and metaphyseal and perichondrial osteoblasts was high. Endosteal and periosteal osteoblasts varied in activity depending upon the area under observation. Preosteoblasts (progenitive cells) of the osteogenic periosteum, osteochondrogenic cells of the perichondrial region, chondrocytes, and cells of the fibrous periosteum demonstrated minimal activity. Osteocytes were negative. The distribution of osteoblast APTase activity coincided with areas of active collagen synthesis.
Regional differences in androgenic sensitivity of the chick comb and effects related to volume of inuncted vehicle
Authors: Wollman Arthur L. , Hamilton James B. 
Published: February 2005

AbstractCombs of chicks were divided surgically into posterior (P‐comb) and anterior (A‐comb) portions of equal weight, thus providing two separate target organs in the same animal. Inunction with testosterone propionate stimulated equal increments in P‐ and A‐combs with regard to values for length + height, but weight of the P‐comb increased significantly more than that of the A‐comb as a result of greater increase in width of the P‐ than of the A‐comb. The P‐ was five times more responsive than the A‐comb and contained larger amounts of ground substance as shown by histological examination and larger amounts of hexosamine as shown by chemical study. It was concluded that these two portions of the comb differed greatly in capacity to grow in response to androgenic stimulation.Reduction in the volume of the vehicle from 5 to 0.5 μl resulted in a sevenfold greater response of the chick comb to androgens.Restriction in the volume of vehicle and the use of the P‐comb alone did not alter the precision of assay. Use of these procedures would permit measurement of androgens in amounts hitherto too small for assay.
The effects of prolonged low level radiation on the Coronary vessels of the developing chick embryo
Authors: Davis J. E. 
Published: February 2005

AbstractMicrocurie amounts of p32, Na22, Fe59, and Cl36 in normally occurring compounds were injected directly into the vitelline vessels of developing chick embryos at stage 24 (Hamburger and Hamilton, '51). The surviving embryos were sacrificed at stage 41. Hearts were removed and examined intact or sectioned for later examination. Coronary vessels were identified, classified according to size (large, diameter = > 80 μ; medium, diameter = 40–80 μ; small, diameter < 40 μ) and counted. There was a significant increase in the numbers of small and medium vessels which had developed in the presence of gamma radiation emitted by Na22‐ and Fe59‐compounds. The p32‐ and Cl36‐containing compounds did not affect the numbers of vessels of any size. The resulting increased vascularity is shown to be a matter of a distinct increase in numbers of blood vessels as opposed to a simple alteration of the normally occurring vessels.
The architecture of the thyroid gland: A 3‐dimensional investigation
Authors: Isler H. , Sarkar S. K. , Thompson B. , Tonkin R. 
Published: February 2005

AbstractThe three‐dimensional structure of the thyroid gland was investigated by reconstructing three‐dimensional models from serial sections of the rat thyroid, stained with the periodic acid‐Schiff technique to identify the basement membrane. It was found that the follicles were not completely separated from each other by connective tissue, reticular fibers, or basement membranes. At some points, the base of the epithelium of a follicle was in direct contact with the base of the epithelium of an adjacent follicle. An area of contact involved about a dozen follicular cells in each follicle. One follicle usually had two or more areas of epithelial contact. All follicles examined in three dimensions (over 100), showed epithelial contacts, in one‐year‐old as well as in younger rats. The area of contact between parenchyma and stroma, as marked by the basement membrane, consisted of a branching system of anastomosed and partially pinched sacs, within which the epithelia of the follicles were in direct contact. Thus, each follicle can no longer be considered as being completely surrounded by connective tissue or even wrapped by a basement membrane discrete from those of neighbour follicles, and therefore its individuality is essentially due to the fact that it owns a discrete lumen.
Fibrillovesicular cells in the Fundic glands of the canine stomach: Evidence for a new cell type
Authors: Hammond James B. , Ladeur Linda 
Published: February 2005

AbstractBiopsies of the gastric fundal mucosa were obtained from 25 dogs and processed for light and electron microscopy. A cell distinguishable from superficial mucous, mucous neck, chief, parietal, or argentaffin cells was observed.By light microscopy in resin‐embedded, methylene‐blue‐stained sections, this cell was noted to have a prominent apical region which protruded into the gland lumen, a conspicuous terminal web traversed by parallel fibrils, and a crescent‐shaped nucleus; secretory granules were absent.By electron microscopy this cell had the following features: (1) short, stubby microvilli with well developed terminal web, (2) fibril‐bundles constituting the cores of microvilli and extending through the apical cytoplasm to the paranuclear region, (3) characteristic vesicles and tubular structures in the apical cytoplasm, (4) spiral structures, and (5) oval dense bodies.Morphological evidence supported the hypothesis that this is a distinct cell type; it is referred to as a fibrillovesicular (FV) cell.
Linear growth and appearance of sex difference in the rabbit pelvis
Authors: Lowrance E. W. 
Published: February 2005

AbstractRoentgenograms of the pelves of a population of rabbits were secured once each week between 15 and 92 days after birth and once every two weeks thereafter to 204 days. Measurements were made of projections of certain pelvic dimensions on the roentgenograms.With one exception (pelvis width, day 36), no significant differences at the 1% level between males and females were found in os coxae length, ilium length, pelvis width and bi‐ischial width. However, interacetabular width of the female became significantly greater than that of the male by day 57.Mean measurements of all dimensions showed characteristic rates of increase with age. Nine‐tenths of total increase in lengths of os coxae and ilium occurred by 106 days; pelvis width, by 120 days; bi‐ischial and interacetabular width each, by about 148 days.Between 35 mm to 105 mm of tibia length taken as a basis of reference, all dimensions studied showed approximately straight line relative growth trends.Variation in measurements was relatively high, with greatest variation in all except bi‐ischial width tending to occur before 50 days, when growth was most rapid. It was lowest in the period 64 to 120 days.
Studies on the experimental induction of overgrowth in chick embryos
Authors: Burda Doris J. 
Published: February 2005

AbstractAn analysis has been made of the experimental conditions under which overgrowth can be produced in the brains of chick embryos. A total of 122 individuals were obtained from six series of embryos subjected to varying degrees of surgical manipulation involving the anterior rhombomere and/or its substratum. The results indicate that in addition to the cases of overgrowth obtained by the standard technique of removing the entire anterior rhombomere, overgrowth could also be successfully induced when a portion of the chordamesoderm underlying the anterior rhombomere was either removed or merely dissociated from the neural tissue, while leaving the latter relatively intact. In embryos in which the roof and sides of the anterior rhombomere were removed, overgrowth could not be obtained in the absence of damage to the substratum.