bluuebunny/crossref_metadata_2025_split huggingface dataset:
A histologic description of certain epithelial and vascular structures in the kidney of the normal rat
Authors: Young Don , Wissig Steven L. 
Published: February 2005

AbstractThe cytology of the whole length of the collecting tubule of the rat kidney was studied by light microscopy. The tubule may be subdivided into four successive segments on the basis of the types of epithelial cells that form its lining. The morphology of other epithelial and vascular structures in the renal medulla and papilla was also studied. In fixed histologic specimens, morphologic characteristics of capillaries near the apex of the papilla and in retia mirabilia of the outer portion of the medulla suggest that their plasma is relatively concentrated in the living rat. First, plasma in capillaries of both regions stains deeply with certain histologic dyes. Second, in many specimens erythrocytes in capillaries near the apex of the papilla appear crenated. The significance of the morphologic findings is discussed with regard to current hypotheses concerning the physiologic function of the collecting tubule and other epithelial and vascular structures in the medulla and papilla.
An electron microscopic study of the ependyma and subependymal glia of the lateral ventricle of the cat
Authors: Klinkerfuss George H. 
Published: February 2005

AbstractPortions of the wall of the lateral ventricles of the cat were obtained directly and after initial chrome‐osmium perfusion. After further fixation they were embedded in Epon‐812, sectioned on a Porter‐Blum microtome and examined in the electron microscope. Observations on the ultrastructure of ependyma and subependymal glia of the feline lateral ventricle are described. The ependyma contains a pale cytoplasm with many vesicles, a network of fibrils, endoplasmic reticulum, Golgi apparatus and numerous dense mitochondria. Cilia are present along the luminal surface which have a well defined basal body from which cross‐striated rootlets diverge to make close contact with other ciliary rootlets and enter into complex relationships with a specialized cell juncture composed of mitochondria in linear arrangement along an intercellular membrane studded with zonula adherens. These rootlets thus form accommodating links between cilia and a morphologic relation to the plamsa membrane between ependymal cells. Theories of metachronal motion in ciliated mammalian epithelia may incorporate such structures in the future. Three varieties of subependymal glia are described. Oligodendrocytes are the least common but are observed in close relation to myelinated axons. Fibrous astrocytes send short processes beneath the ependyma, but ependymal astrocytes send thick processes deep into the underlying white matter. No ependymal cells are observed to send processes into the white matter, and it is suggested that in the adult cat this is the property of the ependymal astrocyte.
Ultrastructure of bovine spermatozoa. II. The neck and tail of normal, ejaculated sperm
Authors: Saacke R. G. , Almquist J. O. 
Published: February 2005

AbstractThe normal bovine sperm tail consists of the classical 9 + 9 + 2 fiber pattern bound anteriorly by the mitochondrial helix and posteriorly by the fibrous helix except for the last 2 to 3 μ.The outer ring of nine coarse fibers originate as laminated columns, beginning from a common base which is located in a recess at the base of the head. The fibers taper posteriorly ending at different levels in the principal piece. Evidence is presented for the alternate contraction and expansion of the laminated segments of the coarse fibers in the neck — the probable mechanism for initiating the flagellar wave.The mitochondrial helix is composed of several mitochondrial strands of different length. Each strand consists of several elongated mitochondria positioned end to end. Apparently the strands of mitochondria may begin or end at various locations along the middle piece. The number of turns in the mitochondrial helix was found to vary from approximately 65 to 75 turns among cells. The helix binds the axial fiber bundle with a pitch of 20 to 25° over most of the middle piece. The mitochondria are double‐walled and possess internal cristae that are vesicular or tubular in structure.The fibrous helix consists of dense, circumferential strands of variable thickness and shape with two longitudinal elements on opposite sides of the helix. Both the circumferential strands and the longitudinal elements become thinner as they progress posteriorly.
Morphologic observations concerning the release and transport of secretory products in the adenohypophysis
Authors: Salazar Hernando , Peterson Roy R. 
Published: February 2005

AbstractThe processes involved in the release of secretory products from the parenchymal cells and the movement of these products into the circulating blood were studied by electron microscopic observations on the adenohypophyses of virgin estrous rabbits. The released secretory products were found in the form of discrete granules, with or without a perigranular membrane, in intercellular spaces, between the plasma membrane and the parenchymal basement membrane, in the perivascular space, in the endothelial cytoplasm, and in the lumen of capillaries. Vesicles containing material which resembled that in the perivascular space were observed in endothelial cells.Interpretation of these observations has led to the proposal of the theory that secretory products of the adenohypophysis may be liberated from parenchymal cells in the following way: by fusion of the perigranular membrane with the plasma membrane (merocrine) or by the detachment of small processes containing secretory granules (“microapocrine”). It is further believed that the discharged products may be transported into circulation in three different manners: by diffusion of dissolved material through the fenestrated endothelium, by active transport of dissolved secretory products by the endothelial cells, or by active transport of intact secretory granules through the endothelial cytoplasm.
Cyclic changes of interstitial gland tissue of the human ovary
Authors: Mossman H. W. , Koering Marilyn J. , Ferry Darwin 
Published: February 2005

AbstractThree distinct types of gland cells occur in adult human ovaries and those of other mammals. These are: (1) Interstitial gland cells formed from the theca interna cells of degenerating (atretic) follicles, hence present from infancy to old age; (2) Thecal gland cells formed from the theca interna cells of ripening follicles, hence present only in individuals that are sexually mature or nearly so, and in these only at or near the time of ovulation; (3) Luteal cells formed from the granulosa cells of ovulated follicles and from the undifferentiated stroma cells surrounding these, and in certain species also from the same sources in relation to atretic follicles. These latter are the so‐called accessory corpora lutea. Primary and accessory corpora lutea are present normally only after ovulation occurs and appear to function for a relatively short time unless pregnancy ensues. In certain species other types of gland cells occur in the ovary and mesovarium; these include the paraluteal cells of the human ovary. Paraluteal cells are not persistent thecal gland cells, but are differentiated from surrounding stroma after the thecal gland disappears. They are probably intermediate stages in the differentiation of luteal cells from stroma cells. Planimetric measurements and computations made from serial sections of human ovaries indicate that in non‐pregnancy and early pregnancy the volume of interstitial gland tissue is less than 1% of the total ovarian volume. However, in the last trimester of gestation, the relative amount of interstitial gland tissue increases rapidly to roughly from 4% to 6% of the total ovarian volume. The largest amount in our series was 5.6%. Luteal gland tissue at the height of its development in the first trimester of gestation reached 31% of the total ovarian volume. In human ovaries the cells of the interstitial gland tissue of late pregnancy seem to be consistently larger and to have a more finely granular cytoplasm than those of early pregnancy or nonpregnancy. The literature shows that mammalian interstitial gland cells of comparable origin to the human cells discussed in this paper have the following characteristics which are known to be indicative of steroid secretors: Numerous birefringent, acetone soluble, autofluorescent granules which react with sulphuric acid and are Schultz and Schiff positive; mitochondria with anastomosing tubular cristae; and smooth tubular endoplasmic reticulum. Physiological studies so far reported have indicated possible estrogen, androgen, and progesterone production by interstitial gland cells, but all of the evidence is too scanty, indirect, and at times contradictory to be convincing. Since interstitial gland cells are present from birth to old age, and show cycles of abundance and differentiation correlated with the reproductive age and cycles, they may prove to be the most important ovarian gland cells when their function is fully understood.
The structure of the functional pronephros in larvae of Ambystoma opacum as studied by light and electron microscopy
Authors: Christensen A. Kent 
Published: February 2005

AbstractThe functional pronephros in early larvae of Ambystoma opacum, studied in serial sections, consists of an anterior and posterior nephrostome, respective proximal tubules which fuse into a common proximal tubule, a ciliated intermediate segment, and a distal tubule, which leaves the pronephros posteriorly as the nephric duct. In the coelom medial to each pronephros is a glomus, arising from the dorsal aorta.In electron micrographs of osmium‐fixed, methacrylate‐embedded pronephros and glomus, the fine structure generally resembles that seen in adult kidneys. Proximal tubule cells show a brush border of irregular microvilli, tubular invaginations, resorption granules, and very few basal infoldings. Cells of the distal tubule have numerous radially‐oriented mitochondria, and the basal infoldings are generally well developed. The fine structure of the nephric duct seems to resemble that of the distal tubule. Cells of the nephrostomes and intermediate segment bear cilia of usual fine structure, and contain melanin granules, lipid droplets and slender mitochondria. The glomus resembles a glomerulus in having an endothelium with sparse pores, a basement membrane, and epithelial cells with numerous interdigitating foot processes.The similarity at the fine structure level between the pronephros and the more posterior mesonephros and metanephros of adult vertebrates suggests the serial homology of vertebrate nephrons, and thus constitutes further evidence for the archinephros or holonephros theory of the origin of vertebrate kidneys.
Spermatogenesis in animals as revealed by electron microscopy. X. The fine structure and function of endoplasmic reticulum and of peculiar bodies appearing in atypical maturing spermatids and nutritive cells of Cipangopaludina malleata reeve
Authors: Yasuzumi Gonpachiro 
Published: February 2005

AbstractIn an early stage of metamorphosis of atypical spermatids of a pond snail, Cipangopaludina malleata Reeve, numerous vesicles of a circular form appear in the juxtanuclear region. These vesicles represent the rough‐surfaced endoplasmic reticulum of the atypical spermatids. As amorphous contents within the vesicles increase in density an amount, Palade granules, 130 to 150 A in diameter, attached to the external surface of the vesicles, disappear gradually and at the same time an apparently single layered limiting membrane is transformed to a double layered structure.It has been revealed that a Feulgen‐positive material appearing in the vesicles transforms into a PAS‐positive material in the atypical maturing spermatids, and such material is transported as D bodies through intercellular spaces into the nutritive cell. In the nutritive cell, G bodies make their appearance as a transitional form of mitochondria. Structural changes from a homogeneous appearance to concentric and parallel lamellar structures have been traced in both bodies. It is a noticeable fact that a lamellar structure is often found surrounding an electron‐lucent space of both bodies. An occurrence of the electron‐lucent space within both bodies suggests that the contents of the bodies may be transported via the tubular system of the endoplasmic reticulum in the mantle to the typical maturing spermatids.Turnbull's blue tests have shown that the dense particles, 50 to 70 A in diameter, appearing in the D and G bodies are organic iron compounds. It is interesting that lipid is found in a helical appearance along the typical maturing spermatid head part, suggesting that lipid is located in the cytoplasm surrounding the nucleus.
The production of congenital malformations using tissue antisera. II. The spectrum and incidence of malformations following the administration of kidney antiserum to pregnant rats
Authors: Brent Robert L. 
Published: February 2005

AbstractRabbit anti‐rat‐kidney antiserum, when injected into rats seven, eight, nine and ten days pregnant, results in embryonic death, growth retardation and malformations. The spectrum of malformations is different for each day of gestation studied. The kidney malformations produced are related to its qualities as a potent general teratogenic agent and not to any specific effect on the developing urinary system. The utilization of low doses of kidney antiserum can result in a significant increase in the incidence of malformations without interfering with either the survival or growth of the exposed fetuses. It is not known whether the teratogenicity of this antiserum is due to (a) induced maternal biochemical or physiological pathology, (b) direct toxicity to the embryo or (c) interference with the deciduo‐trophoblast. Although some other antisera have not been found to be teratogenic, rabbit anti‐rat‐placental serum has also been found to be a potent teratogenic agent having similar properties to kidney antiserum.The relevance of potent teratogenic proteins to the problem of human malformations is purely hypothetical and further investigation may reveal that no relationship exists between teratogenic proteins and human malformations. In spite of this, the findings reported herein should prove to be both stimulating and provocative.
Aldehyde‐fuchsin positive material in brain of squirrel monkey (Saimiri sciureus)
Authors: Creswell George F. , Reis Donald J. , MacLean Paul D. 
Published: February 2005

AbstractIn the squirrel monkey, nerve cells in certain areas of the brain are characterized by abundant granules which stain intensely with aldehyde‐fuchsin but not with chromium hematoxylin.These cells fall into three main types: Type A, with a polar clumping of the granules, characterize the region surrounding the stria terminalis in the amygdala and the supratrochlear nucleus of the mid‐brain. Type B, which have a heavy diffuse granulation, are found in the lateral and caudal hypothalamus and in nucleus raphes ventralis. Less heavily granulated cells classified as Type C distinguish the entire nucleus subthalamicus, and are prominent in nucleus septalis triangularis, rostral midline thalamus, and area CA2 of the rostral hippocampus. Cells of these corresponding types and distribution are not seen in the brains of cat, rat and mouse.The cerebellum and pineal body contain extracellular material which stains with aldehyde‐fuchsin but not chromium hematoxylin.The granules of the nerve cells stain with PAS, Sudan black B, and oil red O, suggesting that they have carbohydrate and lipid components.As in other species, the neurosecretory substance of the paraventricular and supraoptic nuclei is stained both by aldehyde‐fuchsin and chromium hematoxylin. Material showing a positive reaction to both these stains is also found in the glia of the nucleus septalis triangularis, subfornical organ, lateral hypothalamus, and locus caeruleus. All these regions, except the lateral hypothalamus, show similarly staining material in the extracellular spaces.Of anatomical interest is the close association of the aldehyde‐fuchsin positive neurons with phylogenetically ancient cellular structures and fiber systems of the brain. In the squirrel monkey they would seem to provide a basis for further characterization of certain nuclei and a new division of the amygdala.
Pathways of intestinal lymph drainage in normal sheep and in sheep following thoracic duct occlusion
Authors: Heath Trevor 
Published: February 2005

AbstractThe pathways by which intestinal lymph enters the blood were studied with radiologic and radioactive tracer techniques in normal sheep and in sheep after thoracic duct occlusion. It was concluded that direct connections between the intestinal lymphatics and blood vessels in the abdomen and caudal thorax in normal sheep are very uncommon if they occur at all.During the first few days after the thoracic duct of sheep was occluded in the thorax, transfer of protein from intestinal lymph to blood was slow. At this time, the abdominal lymphatics were grossly dilated and lymphatic valves incompetent. After about 1–2 weeks, the abdominal lymphatics were of more normal size and drainage of lymph protein to the blood occurred more rapidly. At least some of this protein entered the blood within lymph nodes. After 4–7 weeks, direct vascular connections between the thoracic duct and hemiazygos vein had developed.
Electron microscopic observations on primary decidua formation in the rat
Authors: Jollie William P. , Bencosme Sergio A. 
Published: February 2005

AbstractCytological changes in uterine stromal cells of the rat during induced primary decidua formation have been examined electron microscopically. Decidua forming stroma was examined at daily intervals for the five days during which the reaction reaches maximal hypertrophy and hyperplasia and was compared with pseudopregnant, non‐decidual (control) endometrium. Stromal cells of control uteri resemble embryonic fibroblasts. They appear to be of two types, depending on whether they contain rough – or smooth‐surfaced endoplasmic reticulum. As the decidual reaction progresses, the cells enlarge and become binucleate; cells which contain exclusively rough surface endoplasmic reticulum no longer are evident. Glycogen and fat become abundant, the former in association with smooth‐surfaced membranes of the endoplasmic reticulum. Mitochondria become more numerous, smaller, and show evidence of a rearrangement in internal organization. There is a pronounced increase in a fine intracytoplasmic fibrillar component; and a spectrum of “microbodies” and lysosomes appears. At the height of the reaction, the stroma appears epithelioid. The possible functional significance of these changes is discussed.
Histochemical and electron microscopic observations on the salt secreting lacrymal glands of marine turtles
Authors: Abel John H. , Ellis Richard A. 
Published: February 2005

AbstractThe lobular, compound, branched, tubular, salt‐secreting lacrymal glands of two marine turtles,Chelonia mydas and Caretta carettaare similar in structure and in histochemical reactivity. Blood from the centrolobular arteries flows through a rich capillary bed counter to the flow of tubule secretion. The capillary endothelium is reactive for adenosine triphosphatase (ATPase). Nerves containing cholinesterase pervade the connective tissue. At the blind ends of the secretory tubules small basophilic peripheral cells contain an abundance of glycogen, monoamine oxidase (MAO) and phosphorylase but little succinic dehydrogenase (SDH) or cytochrome oxidase (CTO). Non‐mitochondrial ATPase is concentrated at the luminal interface of these cells. The larger principal cells, lining the major portion of the secretory tubules, are rich in SDH and CTO but contain relatively little glycogen, MAO or phosphorylase. Broad intercellular channels reactive for mucopolysaccharide are formed by intermeshing, pleomorphic microvilli that fringe the extensive lateral surfaces of the principal cells. The cytoplasm of these cells contains profiles of smoothsurfaced endoplasmic reticulum (SSER), abundant mitochondria, and prominent Golgi membranes. Profiles of SSER and small membrane bound vesicles fill the apical cytoplasm but mitochondria are lacking. The luminal secretory border of the cell is extremely limited in area.Two types of epithelial cells line the duct system: basal cells that react strongly for non‐specific esterase and MAO; and goblet cells containing mucopolysaccharide, acid phosphatase, cholinesterase, and ATPase.The principal cells, close to the arterial blood supply, contain the highest concentrations of oxidative enzymes and have special modifications of the cell surface consistent with their role in salt concentration and secretion.
Cell dynamics in the intestine of the mouse from late fetal life to maturity
Authors: O'Connor Thomas M. 
Published: February 2005

AbstractA normal developmental pattern of the mitotic index, growth of villi and crypts, rate of cell extrusion, and number of villi per duodenal cross section is presented for mice ranging in age from the seventeenth day of gestation through 48 days after birth. These patterns are correlated with the normal increases in both length and weight of the intestine as a whole during this period. Two periods were observed during which there is a 25% reduction in the mitotic index. There is essentially no change in the mitotic index after the twenty‐first postnatal day. Approximately 43% of the 48‐day villus‐crypt height is reached by birth, and approximately 83% of the 48‐day level is reached by the twenty‐first day. No extrusion zones were observed in mice before birth, and a threefold increase in the rate of extrusion was observed between the fifteenth and twenty‐first postnatal day. Growth of the villus‐crypt epithelial cell population appears to be a result of a rate of cell extrusion which is much lower in the young than in the adult animal.
Embryonic modifications of lacertilian intracranial arteries
Authors: Burda Doris J. 
Published: February 2005

AbstractIntracranial arteries were studied in Crotaphytus adults and in a series of Lacerta embryos. At an early embryonic period, the mesencephalic artery develops posterior to the bifurcation of the cerebral carotid; as the pontine flexure forms at a subsequent stage, the carotid bifurcation becomes relocated further posteriorly, with the result that the definitive mesencephalic artery becomes an outgrowth of the anterior encephalic artery. Additional significant modifications include the progressive fusion of the two posterior encephalic arteries and the extensive branching of the middle cerebral artery along the lateral regions of the hemisphere. During late stages of development, the circulation to the olfactory region is gradually assumed by extracranial arteries, although remnants of intracranial olfactory arteries may occasionally be retained.