bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of thyroid and testicular hormones on globule leucocytes in the rat duodenal crypt epithelium
Authors: Carriere R. , Buschke M. 
Published: February 2005

AbstractThe globule leucocyte is a cell with a wide distribution in the digestive, respiratory, biliary, urinary and genital tract epithelia of homeotherms. It occurs in the crypts of the rat small intestine and within the epithelium on the villous bases but not on the remainder of the villi. A characteristic feature of this cell is the presence of acidophilic cytoplasmic granules, 0.5 to a few m̈m in diameter. The nucleus resembles that of intraepithelial intestinal lymphocytes. In this investigation, a quantitative study was made of the effect of thyroidectomy and/or castration on the number of globule leucocytes in the duodenal crypts of immature and adult rats. In sham‐operated rats, globule leucocytes were rare, occurring with a frequency of 1 or 2 per 1,000 epithelial cells. After thyroidectomy, they increased to 14‐20 per 1,000 epithelial cells. Castration did not influence the number of globule leucocytes but resulted in an increase in the number, size and acidophilia of their cytoplasmic granules. In immature rats, but not in adults, castration combined with thyroidectomy enhanced the effect of thyroidectomy, increasing globule leucocyte number to 32 per 1,000 epithelial cells.Treatment of thyroidectomized‐castrates with thyroxine, initiated 38 days after operation, reduced the crypt globule leucocyte population to normal, whereas treatment with testosterone did not. Growth hormone failed to influence the elevated number of globule leucocytes in thyroidectomized rats, suggesting that this action of thyroxine was not mediated via an influence on growth hormone release.Because of their similar nuclear morphology, intraepithelial crypt lymphocytes were also counted and there was no obvious relationship in the fluctuations of these two cell populations.It is suggested that the greater number of crypt globule leucocytes in thyroid deficiency may reflect changes in the intestinal secretory immunoglobulin system and this is being investigated, beginning with a study of the distribution of IgE.
Investigations on the turnover of adrenocortical mitochondria. XII. Studies on the mechanism of the acth‐induced elongation of the half‐life of rat zona fasciculata mitochondria
Authors: Nussdorfer Gastone G. , Neri Giuliano , Mazzocchi Giuseppina 
Published: February 2005

AbstractThe half‐life of rat adrenocortical mitochondria was determined by high resolution autoradiography and liquid scintillation spectroscopy as previously described (Mazzocchi et al., '76). The results obtained by the two approaches were in good agreement. In the normal rats the half‐life of adrenocortical mitochondria averaged 11 days. ACTH significantly increased mitochondrial half‐life to about 16 days, and chloramphenicol significantly decreased this parameter in both untreated and ACTH‐administered rats to about seven days. It is suggested that the ACTH‐induced maintenance and slowing down of the degradation rate of adrenocortical mitochondria requires continuous mitochondrial DNA‐dependent protein synthesis.
Supraependymal neurons overlying the periventricular region of the third ventricle of the guinea pig: A correlative scanning—transmission electron microscopic study
Authors: Mitchell J. A. , Card J. P. 
Published: February 2005

AbstractThe frequency of occurrence, distribution and morphology of supraependymal neurons associated with the third ventricular wall of the guinea pig were investigated by correlative scanning and transmission electron microscopy. Each of the specimens was located on the ciliated ventricular wall between the inferior border of the thalamus and the non‐ciliated ependyma associated with the median eminence. Prominent clusters of neuronal perikaria in association with massive process bundles were observed in 7 of the 31 specimens examined. In those specimens lacking prominent neuronal networks a more diffuse array of independent nerve fibers was sometimes seen on the ependymal surface. Neuronal perikaria exhibited numerous surface protrusions and were covered by a rich meshwork of crisscrossing, varicosed fibers. Many of these cells were associated with multiple processes of varying diameters and lengths which either coursed independently over the ventricular surface or formed fasciculated bundles. As process bundles traversed the ependymal surface, individual processes branched off and either terminated within the ventricular lumen or penetrated the subjacent ependymal lining. Fibers also made contact with adjacent supraependymal neuronal elements. Correlative transmission electron microscopic observations indicate that both the perikaria and processes of such supraependymal networks possess ultrastructural features characteristic of neurons. The morphological characteristics of the intraventricular neuronal networks suggest that they may be engaged in functional interactions with the cerebrospinal fluid, with adjacent supraependymal neuronal elements and with the subjacent neuropil.
Identification of neuro‐epithelial bodies in rabbit fetal lungs by scanning electron microscopy: A correlative light, transmission and scanning electron microscopic study
Authors: Cutz E. , Chan W. , Sonstegard K. S. 
Published: February 2005

AbstractIn the present study, neuro‐epithelial bodies (NEB) were identified by scanning electron microscopy (SEM) within the bronchial epithelium of near‐term rabbit fetuses. The surface features and topography of NEB were correlated by light and transmission electron microscopy.In SEM, the surfaces of NEB were easily visualized in smaller peripheral airways because of paucity of ciliated cells in these regions. The NEB formed crater‐like pits, which were lined with microvilli and had smooth‐surfaced non‐ciliated cells around the rim. Stereo‐pair photographs revealed that the latter cells protruded above adjacent bronchiolar mucosa. The SEM also revealed that NEB were preferentially located near or at bronchiolar bifurcations.This is the first report of the three‐dimensional structure of pulmonary NEB. Their direct contact with the airway lumen, as well as their strategic location in bronchiolar mucosa, support the suggestion that they are intrapulmonary receptors and help to regulate air‐flow in peripheral airways.
An electron microscope study of crystal calcium carbonate formation in the mouse otolith
Authors: Nakahara Hiroshi , Bevelander Gerrit 
Published: February 2005

AbstractThe ultrathin sections of the developing otolith of mouse fetuses 15.5 days to 20 days after birth were observed with the aid of the electron microscope.The first step of otolith formation is an aggregation of organic clusters observed in the sacculus of the 15.5‐day fetus. These organic structures are modified and assume a hexagonal shape in the 17.5‐day fetus. The unmineralized stages of the otolith referred to as the preotolith, serve as the template for future development.One day after birth, at either end of the preotolith, minute tube‐like structures develop in which needle‐shaped crystallites are initiated. Crystallites continue to develop throughout the hexagonal template which give rise to a structure containing many regularly arranged needle‐shaped crystallites. Based on the present observations, the mouse otolith is considered a multi‐iso‐oriented crystal.
Endoplasmic reticulum‐Golgi apparatus relationships in the rat spermatid
Authors: Hermo L. , Clermont Y. , Rambourg A. 
Published: February 2005

AbstractThe appearance of the spermatid Golgi apparatus was studied, both in thin sections of rat testes fixed in glutaraldehyde and treated with either tannic acid or ferrocyanide‐reduced osmium, and in relatively thick sections (0.25‐0.5 μm) of glutaraldehyde fixed tissue impregnated with uranyl acetate followed by lead and copper citrate. With any one of these three procedures, the Golgi apparatus of young spermatids examined at the Golgi and cap phases appeared as a compact hemispherical mass whose base was located next to the developing acrosomic system. The cortical region of the hemisphere was composed mainly of several stacks of saccules. The central core or medullary region contained numerous vesicular and tubular membranous profiles. Numerous cisternae of the endoplasmic reticulum (ER) were closely applied to the surface of the Golgi apparatus. In thin sections, the ER cisternae were separated from the stacks of saccules by small spherical or elongated membranous profiles. In thick sections, most of these elements formed a network of tubules, some of which being continuous with ER cisternae. Cisternae of the endoplasmic reticulum near the cis‐face of the Golgi stacks also branched and traversed the cortical region of the Golgi apparatus through gaps seen between the stacks of saccules to reach the central core region. Some of these were closely applied to the trans elements of Golgi stacks although never in continuity with them. Finally, ER cisternae were found located within the stacks themselves between Golgi saccules; here the membranes of the closely apposed cisternae of the endoplasmic reticulum and Golgi saccules remained separated by a space of about 12 nm. Thus, in the spermatid, the endoplasmic reticulum was closely related with all components of the Golgi apparatus.
Localization of a highly specific neuronal protein, serotonin binding protein, in thyroid parafollicular cells
Authors: Bernd Paulette , Gershon Michael D. , Nunez Eladio A. , Tamir Hadassah 
Published: February 2005

AbstractA highly specific serotonin binding protein (SBP) has been found in serotonergic neurons in both brain and gut. This protein has an extremely high affinity for serotonin and may be a storage protein. Serotonin is found in many endocrine cells, including parafollicular cells of the sheep thyroid, as well as in neurons. SBP is also present in sheep thyroid. The present study was done to localize the protein in the gland. Thyroid glands were divided into five segments. Concentrations of serotonin and SBP, as well as parafollicular cell volume were measured in each. Serotonin was assayed by enzymatic conversion to melatonin using tritiated S‐adenosylmethionine. SBP was assayed by molecular sieve chromatography on sephadex G‐50. The relative volume of parafollicular cells was obtained by stereological analysis of electron micrographs. Experiments were also done to demonstrate these cells by histofluorescence and radioautography following incubation with tritiated 5‐hydroxytryptophan. Good correlations were found between serotonin and SBP concentrations, and parafollicular cell volume. These peaked in the rostro‐central portion of the gland and were minimal at the poles. We conclude that thyroid SBP is probably localized in parafollicular cells.
The differential absorptive activity of epithelial cells of the rat epididymus before and after castration
Authors: Moore H. D. M. , Bedford J. M. 
Published: February 2005

AbstractHorseradish peroxidase introduced into the lumen of the rat epididymis was taken up by the columnar cells of the epithelium by five minutes and more so after longer periods. The apical cells and particularly the clear cells in the caput and cauda epididymidis, respectively, showed significantly greater endocytotic activity than the principal cell in both locations. Within 14 days after castration, however, such differences in absorptive activity among the various cell types were essentially obscured because of increased endocytosis by the androgen‐deficient principal cells. The results are discussed briefly in terms of the function of different epithelial cell types and secretory/absorptive activity in the epididymis.
The guidance of optic axons in the developing and adult mouse retina
Authors: Goldberg Stephen , Frank Beryn 
Published: February 2005

AbstractPrevious studies in chick embryos (Goldberg, '77) indicated that unidirectional guidance of retinal axons toward the optic nerve is restricted to the vitread portion of the ganglion cell fiber layer (GCFL) of the retina; random fiber growth was noted after deflection of the optic axons sclerad to the GCFL.The present study on mice confirms these observations. Silver‐stained flat mounts of retinal colobomas were examined. Many optic axons in colobomas do not exit normally from the eye, but travel randomly when deflected sclerad to the GCFL. Newborn mouse axons grew around retinal lesions in a highly directed manner. Such axons were always situated in the vitread portion of the GCFL.The unidirectional guidance found in newborn mice was absent in adults. Deflected adult axons traveled randomly regardless of their level within the GCFL. We propose that defective guidance largely accounts for failure of axonal regeneration in the adult mouse retina. The inability of the adult axons to fasciculate (adhere to one another and form fiber bundles) suggests that impaired cellular adhesivity may be part of the mechanism of regenerative failure.
Formation of concentric saccules in murine parietal cells after injection of diazo‐oxo‐norleucine
Authors: Michaels John E. 
Published: February 2005

AbstractAfter treatment with various chemical and physical agents, flattened or ring‐like saccules may occur in the cytoplasm of parietal cells of the gastric glands of several species of mammals. In the current investigation, similar structures appeared after treatment with high dosages of diazo‐oxo‐nor‐leucine (DON), a glutamine antagonist. A tentative sequence for their formation is suggested. Saccules formed of unit membrane became abundant in some parietal cells of the treated mice. Single saccules often had narrow lumens and peripheral distensions. The saccules, either singular or several stacked together, became progressively more curved, enclosing a region of cytoplasm that often contained glycogen‐like particles and occasionally vesicles or other organelles. Many of the concentric saccules were close to an intracellular canaliculus. Membrane bound cytoplasm containing glycogen‐like particles occasionally occurred in the canaliculi, suggesting that exocytosis had occurred. Cytochemistry revealed that glycoproteins were associated with the concentric saccules, probably located on the luminal surface. The glycogen‐like particles in all locations stained in a manner characteristic of glycogen. It is suggested that the concentric saccules may form from, vesicles of the tubulovesicular system.
Cell death during detachment of the lens rudiment from ectoderm in the chick embryo
Authors: Garcia‐Porrero J. A. , Colladoand J. A. , Ojeda J. L. 
Published: February 2005

AbstractThe distribution and cytological characters of physiological cell death associated with formation of the lens vesicle in the chick embryo was studied by means of vital staining, light and electron microscopy.We have established a constant pattern of cell death which differs in some aspects from that reported for mammals and amphibians. The necrotic process is observed initially in the dorsal part of the lens cup (stage 15). The necrotic area progressively surrounds the lens pore as invagination proceeds (stage 16) and at stage 17 is located in the zone of fusion of the invaginated lens. After detachment of the lens (stages 18, 19 and 20) dead cells appear in the ectoderm, in the superficial epithelium of the lens vesicle and in the space between both structures.Ultrastructurally we observe isolated dead cells in different stages of degeneration and in phagocytosed cells. Phagocytosis is carried out by the neighboring healthy epithelial cells. Phagocytic activity was detected concomitant with the beginning of the necrotic process. Cell fragments were occasionally detected within the lens cavity.
The cellular pattern of corpus luteal growth during pregnancy in the rat
Authors: Meyer Geoffrey T. , Bruce Neville W. 
Published: February 2005

AbstractThe cellular pattern of corpus luteal (CL) growth was studied in rats at Days 6, 10, 12, 14, 16, 17 and 22 of pregnancy: term is Day 23. Measurements were taken of the percentage of the CL occupied by luteal cells, connective tissue and vascular space, luteal cell and nuclear volumes, and the number of luteal and endothelial cells in each of three CL in both ovaries of five rats at each stage of pregnancy. Total CL volume increased from 1.08‐3.23 μl over Days 10‐17. This was mainly due to an increase in luteal cell volume from 3.72 pl to 9.30 pl. Neither the number of luteal cells per CL (range 212,000‐287,000) nor the percentage of the CL occupied by luteal cells (range 85‐90%) had much influence on growth. Nuclear volume increased roughly in proportion to cytoplasmic volume but near term it decreased despite little change in cytoplasmic volume. The number of endothelial cells per CL increased steadily from 398,000 at Day 6 to 1,545,000 at Day 22. There was a strong negative correlation (r = −0.78) between the number of luteal cells per CL and mean luteal cell volume that was evident at all stages of pregnancy. There was a positive, but weaker correlation (r = 0.35) between number of luteal cells and CL volume. Thus, CL volume seems to be partly determined by the number of luteal cells at Day 6 but this effect is moderated by local control of luteal cell volume.
Distribution of glycogen in prefusion human palatal epithelium
Authors: Meller Samuel M. , Barton Lorraine H. 
Published: February 2005

AbstractVarious stages of embryonic human secondary palatal development were examined for the presence of epithelial glycogen. Utilizing periodic acid‐Schiff's reagent staining of thich plastic sections and osmium ferrocyanide enhancement of thin sections, dramatic changes in epithelial glycogen distribution were noted during palatogenesis. Prior to fusion, the epithelium destined to adhere in the midline exhibited a marked diminution of glycogen in the superficial cell layer. This cell layer was composed of slender dense cells and cuboidal cells undergoing lysis. Adjacent nonfusing epithelium was markedly different and contained large glycogen reserves in its superficial cell layer. Glycogen may play a role either as precursor for specific adhesive macromolecules or as a physical agent capable under the influence of appropriate enzymes of causing cell lysis.
Scanning electron microscopy of frozen sections: A method for studying selected planes in small specimens
Authors: Carri Nestor , Suburo Angela 
Published: February 2005

AbstractA procedure for studying small biological specimens with the SEM, using frozen sections of fixed material is described. Controlled fixation schedules and convenient handling of sections insure optimal preservation of cell shape and size. The greatest advantage of the method presented is to allow scanning through any desired plane of the specimen, even in those planes parallel to an epithelial face. SEM of frozen sections is thus helpful for the study of cell distribution and organization within a tissue.
Degeneration of mouse oocytes in response to polycyclic aromatic hydrocarbons
Authors: Gulyas Bela J. , Mattison Donald R. 
Published: February 2005

AbstractDestruction of mouse oocytes in primordial and small primary follicles in response to treatment with 3‐methylcholanthrene (MC) was studied at the ultrastructural level. Four‐week old C57Bl/6N (B6) strain mice received a single injection of 80 mg/Kg MC in corn oil intraperitoneally. Controls received only corn oil. Ovaries from animals were prepared for light and electron microscopic examination at specified intervals after treatment. The number of primordial follicles remained constant in control animals. In contrast, their number decreased significantly (P < 0.01) by three days, and they were depleted by seven days after MC treatment. Subtle degenerative modifications were noted in the ooplasm of primordial follicles two days after treatment. These changes consisted of vesiculation of mitochondrial cristae, increased electron density of the mitochondrial matrix, myelin structures in lipid droplets and in mitochondria. More advanced stages of degeneration of primordial follicles were characterized by further vesiculation or disappearance of mitochondrial cristae, chromatin clumping, and increased density of the ooplasm. Small primary follicles had undergone similar initial degeneration as primordial follicles. In more advanced stages of degeneration nuclear and cytoplasmic contents condensed, endoplasmic reticulum, Golgi complex and mitochondria swelled, small vesicles and multivesicular bodies appeared. In the most advanced stages of degeneration of small primary follicles it appeared that small portions of the oocyte were engulfed by the surrounding follicular cells. It is concluded that exposure of B6 mice to a single dose of MC results in atresia of oocytes in primordial and small primary follicles. Ultrastructurally, these degenerating oocytes of treated mice looked much like the spontaneously atretic oocytes in untreated animals.
Scanning electron microscopy of bronchiolar neuroepithelial bodies in neonatal mouse lungs
Authors: Hung Kuen‐Shan , Chapman Albert L. , Mestemacher Michelle A. 
Published: February 2005

AbstractScanning electron microscopy of the bronchiolar neuroepithelial bodies (NEB's) in the neonatal mouse lungs was undertaken and correlated with the accompanying transmission electron microscopy. The NEB's appeared as isolated organoids along the entire length of the bronchioles, and often were located at the branching points. The boundary of the NEB's was outlined by the ciliated and Clara cells. Both granulated cells and modified Clara cells participated in the formation of the NEB. The modified Clara cells covered most of the surface of the NEB leaving only small oval areas for the exposed surfaces of the specialized cells which contained numerous cytoplasmic granules. Short and regular microvilli projected from the exposed surfaces of the granulated cells, while only sparse microvilli of irregular length were seen on the surfaces of the modified Clara cells.This scanning electron microscopy of the NEB's further established these organoids as separate morphological entities. In addition, the findings that the NEB's could be easily identified with the scanning electron microscope and subsequently dissected out for further studies would help future investigations of their functions which are not clearly known.
Intraepidermal cell surface fine structure: Preservation and examination at high resolution
Authors: Lempert Todd E. , Elias Peter M. 
Published: February 2005

AbstractMorphological and functional studies on cell surfaces have been limited largely to cultured cells because of injury wrought to cells of solid tissues by commonly employed mechanical, enzymatic, or chelator dispersal methods. By using the staphylococcal epidermolytic toxin we avoided this problem; the toxin cleaves the intercellular spaces of human and mouse squamous epithelia without ultrastructural evidence of cytotoxicity. We studied the cell surface topography of neonatal mouse epidermis obtained two hours after injection of highly purified epidermolytic toxin. Immediately after sacrifice intraepithelial surfaces were exposed while the animals were immersed in fixative. Specimens were either freeze‐fractured or embedded for transmission electron microscopy, or were critical‐point‐dried prior to platinum/carbon replication for transmission and scanning electron microscopy. Replicas could be prepared for transmission electron microscopy only if they were first stabilized with parloidion and then cleaned with both bleach and 40% chromate. By using these four complementary morphological methods (freeze‐fracture, scanning electron microscopy, transmission electron microscopy of surface replicas, and standard thin sections), we could positively identify external membrane structures. The convoluted surface was studded by tenuous microvilli, scattered 15‐20 nm particles, and hemispherical desmosomal mounds. Desmosomal plaques displayed randomly arrayed 15‐20 nm globular particles comparable in distribution and density to particles observed in freeze‐fractured desmosomes, and suggesting that desmosomal integral membrane particles span the external leaflet of the plasma membrane.