bluuebunny/crossref_metadata_2025_split huggingface dataset:
The fine structure of ependymal processes in the teleost optic tectum
Authors: Kruger Lawrence , Maxwell David S. 
Published: February 2005

AbstractEpendymal cell processes in the optic tectum of the adult sand bass, Paralabrax nebulifer, extend across the neural tube to the pial surface of the brain and exhibit several unique cytoplasmic features, which readily distinguish these cells from other elements in the brain when examined in the electron microscope. These include large, perpendicularly oriented bundles of filaments cross‐striated by a series of irregular membranous structures (“ependymal reticulum”), glycogen granules and dense‐core vesicles in the outer portions and lateral protuberances of the main ependymal shaft, large clear vacuoles more numerous near the pial surface, large mitochondria with a distinctive pattern of tubular cristae and a flocculent matrix and fasciae occludentes at sub‐pial endfoot contacts. These morphological findings suggest that ependymal cells do not simply constitute a primitive source for new cells or merely serve as structural support, but rather are highly specialized and may display secretory activity.
An evaluation of possible intracellular nucleic acid quenching of carcinogenic hydrocarbon fluorescence
Authors: Shires Thomas K. 
Published: February 2005

AbstractAn investigation was made to evaluate the role of intranuclear nucleic acids on the reported lack of accumulation of fluorescent, polycyclic, carcinogenic hydrocarbons (CH) within the nucleus of the live cell. Analysis of CH distribution with integrated phase‐contrast and u‐v‐fluorescent microscopy was performed on whole cells and subcellular nuclear fractions from which nucleic acids had been removed and on ultracentrifuged live cells whose nuclei were stratified into nucleic acid‐rich and nucleic acid‐poor regions. No intranuclear fluorescence was found in any experimentally‐treated material or in the live cell controls after their exposure to CH. The absence of any evidence for the quenching of CH fluorescence by intranuclear nucleic acids supports the u‐v‐fluorescence microscopists' contention that little or no CH enters live cell nuclei.
The ultrastructure of myofibers in a reptilian heart: The boa constrictor
Authors: Leak Lee Virn 
Published: February 2005

AbstractElectron microscopic observation of cardiac myofibers from the boa constrictor depict several features that differ from other vertebrate cardiac and striated muscle cells. The indentations in the sarcolemma do not penetrate into the deep sarcoplasmic matrix to form a transverse tubular system, instead the regular indentations extend the circumference of the myofiber at the regions of the Z line and are continuous with the latter via a dense homogeneous material that occurs at regular intervals along the subsarcolemmal surface. This dense material provides a direct contact between the sarcolemma and the contractile system.A complex sarcoplasmic reticulum was not observed around the myofibrils or in the sarcoplasmic matrix, instead there were small vesicles dispersed about the sarcoplasm. These myofibers are compared with the slow or tonic muscle fiber (Felderstruktur) which also lacks a transverse tubular system and contains an irregular sarcoplasmic reticulum.
The structure and relationships of horizontal cells and photoreceptor‐bipolar synaptic complexes in goldfish retina
Authors: Stell William K. 
Published: February 2005

AbstractAfter impregnation of goldfish retina by the rapid Golgi method, two classes each of photoreceptor, bipolar, and horizontal cells were observed by light microscopy. Interconnections between these elements in the outer plexiform (first synaptic) layer were investigated by electron microscopy of ultrathin sections, in which the processes of impregnated cells are easily distinguished. Dendrites of large bipolar cells (Cajal's “bipolaires destineés aux bâtonnets”) appeared to contact the synaptic endings of both rods and cones, while those of small bipolars (Cajal's “bipolaires destinées aux cónes”) appeared to contact only cones. Processes from horizontal cells of the vitread level (Cajal's “cellules horizontaux intermédiaires”) appeared to contact only rods, while those from horizontal cells of the sclerad level (Cajal's “cellules horizontaux externes”) appeared to contact only cones. The structures formerly called “synaptic vacuoles” are the terminals of horizontal cell processes in the goldfish, and by analogy they should be so identified in all vertebrates. Teleostean horizontal cells are not typical of neurons or glia cells, but are morphologically intermediate between them. Their most interesting properties are their unique relationship to photoreceptor synaptic endings and their segregation into rod and cone subsystems along with the corresponding photoreceptor and bipolar cells. Although their specific function is not clear, some role in information processing therefore appears likely.
Primary vestibulocerebellar fibers in the monkey: Distribution of fibers arising from distinctive cell groups of the vestibular ganglia
Authors: Carpenter Malcolm B. , Stein Bennett M. , Peter Philip 
Published: February 2005

AbstractIn a series of monkeys attempts were made to determine the distribution of primary vestibulocerebellar fibers arising from cell groups of the vestibular ganglia that innervate distinctive parts of the labyrinth. Lesions in the vestibular ganglia were produced by extradural surgical approaches in cell groups which innervate: (1) the cristae of the anterior and lateral canals, (2) the macula of the utricle, (3) the macula of the saccule, and (4) all receptor components of the labyrinth. In a control series selective lesions were produced in the cochlea and cochlear nerve. Vestibular and cochlear lesions were studied in serial sections of the petrous bones stained with Sudan black B. Degeneration in the brain stem and cerebellum was studied in sagittal and transverse sections stained by the Nauta‐Gygax and Wiitanen technics.Vestibular fibers projecting to parts of the cerebellum represent ascending branches of root fibers which largely traverse the superior vestibular nucleus and enter the cerebellum via the juxtarestiform body. In the cerebellum fibers divide into medial and lateral bundles. Medial branches projecting fibers to the ipsilateral nodulus, uvula (lamina d) and lingula appear to arise from cells in all parts of the vestibular ganglia. Cells in the superior vestibular ganglion (SVG) innervating the cristae of the anterior and lateral canals project fibers to floccular folia 5 to 10; the utricular cell groups of SVG projects fibers mainly to floccular folia 5 and 6 while the saccular cell group of the inferior vestibular ganglion (IVG) projects fibers to floccular folia 3, 4, 5 and 6. Collaterals of fibers passing laterally in the peduncle of the flocculus end in ventromedial parts of the dentate nucleus.Some vestibular fibers projecting to parts of the flocculus penetrate the entire thickness of the granular layer and break up into fragments near Purkinje cells and in basal parts of the molecular layer. Such fibers appear to represent climbing fibers.Cochlear lesions produce degeneration in localized regions of the ipsilateral dentate nucleus.Cell groups of the vestibular ganglia innervating different receptor components of the labyrinth have unique areas of predominant projections in different folia of the flocculus and common regions of termination in portions of the nodulus and uvula.
Reproduction in the long‐tongued Bat, Glossophaga soricina. II. Implantation and early embryonic development
Authors: Rasweiler John J. 
Published: February 2005

AbstractEarly development of the bat, Glossophaga soricina, was investigated histologically using 71 pregnant animals removed from a laboratory colony at timed intervals after mating.Implantation was initiated between days 12 and 14 post‐coitum, i.e., shortly after entrance of the blastocyst into the simplex uterus. The site of implantation was a narrow, tubular segment, the intramural uterine cornu, interposed between the end of the oviduct and the main uterine cavity. The intramural uterine cornu is probably homologous to the cranial end of a horn in a bicornuate uterus. Attachment of the blastocyst was central and circumferential, and orientation of the inner cell mass was cephalad in line with the long axis of the cornu. Implantation was secondarily interstitial in the fundal endometrium, as the lumen of the intramural uterine cornu was obliterated and the decidua filled in around the expanding blastocyst.The yolk sac was formed between days 15 and 24 by the expansion and coalescence of pockets within a meshwork of endoderm. Endoderm completely surrounded the inner cell mass until the onset of amniogenesis and served to suspend the inner cell mass from the cytotrophoblast. A decidual reaction first appeared on day 15 after trophoblastic penetration to the endometrial stroma. Syncytiotrophoblast developed as engulfment of maternal capillaries began on day 16, and the capillary endothelium was rapidly disrupted. Amniogenesis occurred by cavitation, beginning on day 26, and shield formation was complete in some animals by day 32.
The corpus luteum of the rhesus monkey (Macaca mulatta) during Late pregnancy. An electron microscopic study
Authors: Gulyas Bela J. 
Published: February 2005

AbstractFine structural observations on the corpus luteum of late pregnancy in rhesus monkeys (Macaca mulatta) are described. Ovariectomy was performed between 141 and 146 days of pregnancy. Granulosa lutein cells measured 25 to 30 μ and were supplied by fenestrated capillaries. The plasma membranes of neighboring cells formed intercellular canaliculi which were bordered by microvilli. The nuclei were large and contained a nucleolus and peripheral heterochromatin. The central region of the cytoplasm contained a high concentration of: (1) rod‐shaped mitochondria with tubular cristae and some electron‐opaque inclusions in their matrices, (2) elaborate Golgi complexes and associated large tubular cisternae, and (3) tubular as well as cisternal agranular endoplasmic reticulum. The more peripheral region of the cytoplasm was filled with: (1) well developed parallel arrays of granular endoplasmic reticulum, (2) bundles of 50 Å filaments with dense areas, and (3) dispersed lipid droplets. Membrane‐bound granules of various types were observed in most cells. Large lacunae were present in the cytoplasm which were not confluent with the intercellular canaliculi or the perivascular spaces. Microvilli projected into the empty‐appearing lumen of the lacunae. It was concluded that the morphological features of the granulosa lutein cells of late pregnancy were consistent with those considered to be necessary for steroidogenic function.
Localization of luteinizing hormone‐releasing hormone in the mammalian hypothalamus
Authors: Baker B. L. , Dermody W. C. , Reel J. R. 
Published: February 2005

AbstractUtilizing immunohistochemistry with rabbit antiserum to synthetic luteinizing hormone‐releasing hormone (LRH), LRH was localized in the peripheral region of the median eminence in the mouse and rat, and more generally in the median eminence of the guinea pig.
An autoradiographic study on the question of retrograde axoplasmic transport following the injection of 3H‐leucine into the tongue
Authors: Gilmore Shirley Ann , Daniels John S. 
Published: February 2005

AbstractRetrograde transport in peripheral nerve was investigated by injecting 3H‐leucine unilaterally into tongues of adult rats. The animals were killed at varied intervals up to 14 days following injection, and autoradiographs were prepared. Labeled material was observed in intrinsic nerves of the tongues in all animals studied. The somata of hypoglossal neurons, however, were not labeled, indicating that radioactive material had not been transported throughout the length of the nerve cells.
Ultrastructural comparison of basophilic leukocytes and mast cells in the guinea pig
Authors: Murata F. , Spicer S. S. 
Published: February 2005

AbstractDifferences in the ultrastructure of basophils in the bone marrow reflect transition from early to late stages of cell development. Mast cells in the trachea, stomach and duodenum lack such developmental changes, but one cell encountered in mitosis indicates a low rate of replication by apparently mature cells. Mast cells differ from basophils in shape and in the structure, shape, and position of the nucleus. The Golgi complex clearly participates in granulogenesis in early basophils but not in late basophils or mast cells, and in mast cells appears associated with rough coated vesicles and mitochondria. In basophils precursor granules mature into a homogeneous granules population. The more numerous, smaller, rounder, granules of the mast cells differ also in varying widely in structure and not evidencing a clear maturational sequence. Increased density of mast cell granules apparently correlates with decreased size and increased indentation by a lucent focus and with the presence of lucent vacuoles in the cytoplasm. Laminated, crystal‐like foci replacing the thread‐like component in the periphery of some granules appear rigid and resist the indentation deforming the granule elsewhere. Mast cells of the adult differ from those of fetal guinea pigs in lacking the concentric lamination and having more dense granules. Many mast cells reveal several small, dense bodies which apparently constitute a second granule type, and often occupy the lucent indentation of the large granule.
Hemoglobin stability in bull sharks
Authors: Burke Jack D. 
Published: February 2005

AbstractNo significant differences in oxyhemoglobin affinity, or electrophoretic patterns of hemoglobin were found in 18 bull sharks collected in selected regions of Lake Nicaragua, the Rio San Juan, and the Caribbean Sea. The half‐saturation of hemoglobin with oxygen (P50) was 11 and 17 mm Hg at pH 7.4 and 6.8, respectively (25° C, 3% hemoglobin solution, potassium phosphate buffer, 0.3 ionic strength). Electrophoresis resolved the hemoglobin into a minor and a major band. Planimetry of densitometric recordings showed that the major band constituted 54% of the total hemoglobin; the minor band, 46%. On the basis of these hemoglobin studies, no subspeciation of bull sharks in Lake Nicaragua was identified, although marine bull sharks have free access to the lake and have been there, at least, since 1535; the synonymy of Carcharhinus nicaraguensis with C. leucas was confirmed.
The effect of pinealectomy on adrenocortical rhytmhm in the blinded rat
Authors: Jacobs John J. 
Published: February 2005

AbstractThe effect of the pineal on circadian periodicity of plasma corticosterone in rats was studied. Male rats were pinealectomized, blinded, or pinealectomized and blinded, and exposed to a lighting cycle of 12 hr of light and 12 hr of darkness.The diurnal variation in plasma corticosterone in pinealectomized animals was not different from that found in intact controls. Blinded rats did not show normal steroid cyclicity. In contrast, rats that were both blinded and pinealectomized had a diurnal variation similar to that of the controls. The pineal gland, then, appears to contribute to the disturbed plasma corticosterone rhythm found in blinded rats.
Scanning electron microscopy of epiplexus cells (macrophages) in the fetal rat brain
Authors: Chamberlain Jack G. 
Published: February 2005

AbstractIntraventricular macrophages were observed with the scanning electron microscope on the choroid plexus in developing rat brains. Cell membrane configurations of these large, epiplexus cells (8‐10 μm) were typified by folds, flange‐like surface projections and long, thin pseudopodia interdigitating with subjacent brain cell microvilli; discrete, periodic enlargements were observed at intervals along the pseudopodial processes.
Phagocytosis of spermatozoa in the terminal region and gland of the vas deferens of the rat
Authors: Cooper T. G. , Hamilton D. W. 
Published: February 2005

AbstractThe existence of a discrete group of cells that are able to phagocytose spermatozoa is reported in the terminal vas deferens of the rat. In addition it is shown that phagocytosis of spermatozoa occurs in the gland of the vas deferens. The cytological mechanisms involved in the phagocytotic process are discussed, and the role that this activity may have on the removal of surplus spermatozoa is discussed.
Tanycytes of the third ventricle of the neonatal rat: A golgi study
Authors: Card J. P. , Rafols J. A. 
Published: February 2005

AbstractThe morphology and vascular relations of tanycytes in the walls and floor of the third ventricle (3rd V) of neonatal rats (4–10 days of age) were studied with a modification of the rapid Golgi method (Valverde, '70). Serial frontal sections through the infundibular recess revealed that tanycytes may be assigned to two distinct populations based on location and structure. Tanycytes in the ventral one third of the walls as well as the floor of the third ventricle comprise the first group. The cell body of these tanycytes was subependymal in location and possessed two main processes. A centrally directed short neck‐process abutted upon the ventricular lumen and often exhibited one or more protrusions extending into the cerebrospinal fluid (CSF). Issuing from the opposite pole of the cell body, a second smooth, relatively unbranched tail process either projected directly to the ventral surface of the brain or terminated in contact with capillaries of the median eminence. A second group of tanycytes was located more dorsally in the walls of the third ventricle. The somatic apical surface of this group generally abutted directly upon the ventricular lumen and exhibited protrusions of diverse configuration projecting into the ventrical lumen. Tanycytes of the latter group were also characterized by a tortuous tail‐process which arched laterally and ventrally to terminate either in the adjacent neuropil or at the surface of the brain. Unlike those of the ventral group, these processes exhibited numerous appendages, varicosities and side branches, many of which ended as expansions in direct contact with blood vessels. In addition, segments of beaded afferent fibers of fine caliber were often seen to contact processes of both groups of tanycytes. The observed relationships between CSF, tanycytes and blood vessels support recent hypotheses of tanycyte involvement in neuroendocrine regulation, CSF composition and neuronal metabolism.
Testicular involution after optic enucleation: Ultrastructure and alkaline phosphatase cytochemistry of the peritubular tissue
Authors: Gravis Curtis J. 
Published: February 2005

AbstractTwo months after blinding hamsters, the seminiferous epithelium had undergone pronounced involution. Spermatogonia were the only germ cells consistently present in the seminiferous tubules, although some tubules also contained primary spermatocytes. The peritubular tissue in the blinded hamster had undergone marked distortion. Irregular projections extended from the myoid cells and protruded toward the seminiferous epithelium. All layers of the peritubular tissue developed irregular contours and underwent thickening. The myoid cell nuclei were highly infolded, giving the nucleus a lobulated appearance. Golgi stacks often occupied recesses in the cytoplasm created by nuclear folding. Numerous vesicles were located at the poles of the Golgi stacks and were scattered between the Golgi stacks and the plasmalemma. Vesicles were also observed fusing with the plasmalemma. Alkaline phosphatase was localized cytochemically in the Golgi apparatus and the myoid cell vesicles. The appearance of the myoid cells in the involuting testes was similar to that of contracting smooth muscle; therefore, we postulate that the cytological alterations observed in the myoid cells may be a result of myoid cell contractions. Myoid cell vesicles have previously been thought to selectively take up substances at the interstitial surface of the myoid cell, transport the material across the cytoplasm and release their contents at the surface adjacent to the seminiferous epithelium. The findings reported in the present investigation indicate that some of these vesicles are involved in exocytosis of substances synthesized in the myoid cell. It appears that myoid cell exocytosis may be involved in formation of the alkaline phosphataserich basal laminae of the peritubular tissue.
A study on the blood vascular system of the lamprey gill filament
Authors: Nakao Taisuke , Uchinomiya Kunihiko 
Published: February 2005

AbstractThe blood vessels in the gill filaments of lamprey, Lampetra japonica, were studied with an electron microscope. Each gill filament is supplied by an afferent filament artery (afa) flanked by a pair of filament veins (fv), along the outer border of the axial plate, and an efferent filament artery (efa) along the inner, free border. Between these arteries are interposed the cavernous body and the blood lacunae. The marginal channel arises from the cavernous body, which leads to the afa, runs along the free border of the secondary lamella collecting oxygenated blood from the lamellar blood lacunae, and finally joins efa. This channel is considered to play an important role in the gill circulation as a bypass between afa and efa. Pillar cells were found only in the blood lacunae of the axial plate and the secondary lamellae. The basal lamina is generally absent on the vascular wall, but only a small amount of dense material could be seen on the basal surface of endothelial cells of afa and fv: this is regarded as an anchoring device between the cell and connective tissue fibrils. Fenestrations are generally absent in the endothelial layer but numerous gaps were seen in the wall of fv. Arterio‐venous anastomoses were found between afa or the cavernous body and fv, and between efa or the collecting arteries of the efferent branchial artery and the peribranchial venous sinus. The anastomosing channel consists of the inner endothelial layer and the outer smooth muscle layer, which is thicker in the intermediate portion of the channel. The endothelial cells called “AVA cells” here are characterized by (1) dense cytoplasm, (2) apical microvilli and (3) basal cytoplasmic processes closely associated with smooth muscle cells.
Hypophysial portal vascular infusion of TRH in the rat: An ultrastructural and radioimmunoassay study
Authors: Wilbur D. L. , Yee J. A. , Raigue S. E. 
Published: February 2005

AbstractThe hypophysial portal vessels and anterior pituitary gland of adult male Wistar rats were exposed surgically. A hypophysial portal vessel was cannulated and infused for one minute with saline or thyrotrophin (TRH). Anterior pituitary glands were collected at 1, 5, 15, 30, or 60 minutes after cessation of infusion, for light and electron microscopic examination. Before and immediately after cannulation of a portal vessel, a 1‐ml sample of blood was collected at 1, 5, 15, 30, or 60 minutes, from the femoral vein for radioimmunoassay (RIA) of growth hormone. Thyrotrophs from anterior pituitary glands of rats infused with TRH displayed emiocytic activity at all time‐periods studied. Rough endoplasmic reticular (RER) cisternae were dilated at 15 minutes following infusion and remained dilated at 30 and 60 minutes. TRH was observed to stimulate emiocytic activity in most pituitary cell‐types. Extensive dilations of RER cisternae were also observed in mammotrophs and gonadotrophs, but were not observed in somatotrophs or adrenocorticotrophs. The demonstration that thyrotrophs, mammotrophs, somatotrophs, and gonadotrophs respond to TRH suggests that some common features may be shared by these cells. Preliminary analysis of the RIA data show that TRH was potent in elevating radioimmunoassayable growth hormone levels. Significant increases (p < 0.02) in plasma GH levels were present at the earlier time periods studied (1, 5, and 15 minutes) following the infusion of TRH, but not at 30 or 60 minutes. These findings provide additional support for the non‐specific action of TRH upon the various adenohypophysial cell types, and demonstrate that TRH stimulates these cells by a direct action on the adenohypophysis.