bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the granule‐containing cells in the aortic wall of the young chick
Authors: Kondo Histake 
Published: February 2005

AbstractThe granule‐containing cells in the wall of the arch of the aorta proximal to its union with the ductus arteriosus in young chicks were examined by electron microscopy. These cells contain many electron‐opaque vesicles, about 1500 Å in an average diameter, and show basically similar cytological characteristics to the granule‐containing cells described in autonomic ganglia, around the abdominal aorta, and in the carotid body of mammals. Occasionally the cells are in close apposition to smooth muscle cells, fibroblasts or endothelial cells. Other surfaces of the granule‐containing cells are partly covered by satellite cells. Synapses are rarely found on the granule‐containing cells in the tunica media of the aorta.A few bundles of elongated cells which enclose several nerve fibers in the cytoplasm penetrate perpendicularly into the tunica media of the aorta. In these bundles are also a few granule‐containing cells. Three types of nerve endings terminate on the granule‐containing cells; that is, endings with small clear synaptic vesicles, with small cored vesicles, and with large cored vesicles. In addition, presumptive afferent nerve endings are found in the bundles. They show a variable diameter along their tortuous courses and contain numerous mitochondria.
Fine structural observations of ruthenium red binding in developing and adult rat lung
Authors: O'Hare Karen Hitchcock 
Published: February 2005

AbstractThe ruthenium red staining technique of Luft ('71b) was utilized in an electron microscopic investigation of developing and adult rat lung. Electron‐dense deposits of ruthenium red‐positive material were observed on all exposed surfaces of the tissue block, regardless of the stage of development. In the more central areas of the block, sites of ruthenium red binding changed with age. In early prenatal lung (days 16 to 20) dense accumulations of ruthenium red‐positive material were found in association with the basement membranes of endodermal epithelial cells. Ruthenium red binding was also observed between adjacent epithelial cells; however, their luminal surfaces were negative. The main intracellular site of ruthenium red binding in intact cells was the lamellar body of the developing type II pulmonary epithelial cells. By day 21 of development, accumulations of granular product were observed in association with most lamellar bodies, as well as on epithelial cell luminal surfaces. Ruthenium red binding in postnatal tissue decreases with increasing age. By the second postnatal week, the predominant site of binding is the luminal surface of the type I and type II pulmonary epithelial cells. When compared to fetal and early neonatal stages, adult rat lung has a still more limited distribution of ruthenium red‐positive material. Changes in the distribution of ruthenium red‐positive material correlate with numerous morphologic and biochemical events in rat lung development.
Cyclical changes in the vaginal epithelium of the rat seen by scanning electron microscopy
Authors: Parakkal Paul F. 
Published: February 2005

AbstractKeratinization or mucification of the epithelium of the rat vagina is related to the hormonal state of the animal. During the normal cycle and after the administration of exogenous hormones (estrogen and progestin) to spayed animals, the surface characteristics and topography of the vaginal epithelium were studied with the scanning electron microscope. During estrus and under the influence of estrogen, the superficial cells were keratinized, overlap each other like shingles, and are continuously sloughed off. Like the surface of other keratinizing epithelia, theirs has a characteristic microridge pattern. In ovariectomized animals, the apical surface is covered with microvilli instead of microridges, and the cells resemble hexagonally shaped units, tightly bound instead of overlapping each other. At the boundary between the cells, a ridge demarcates the cells. The surface configurations of progestin‐treated, progestin plus estrogen‐treated, and diestrous animals are the same as in spayed animals.
Superficial venous patterns in the cubital region of Indians
Authors: Halim A. , Abdi S. H. M. 
Published: February 2005

AbstractThe patterns of the superficial veins of the cubital region were studied in 536 Indian subjects both living and dead. Three basic pattern types were noted. Type I had a median cubital vein joining the cephalic and basilic veins in the cubital region. Type II had the cephalic vein itself draining into the basilic vein in the cubital region. Type III showed the absence of a direct communication between the cephalic and basilic veins in the cubital region. The median vein of the forearm in these latter cases joined either of the cephalic and the basilic veins (type III A) or after bifurcating into a median cephalic and a median basilic vein joined both these veins (type III B). Type I was found to be the most common pattern (67.5%) followed by type II (19.5%), with types III A and III B accounting for 6% and 6.5% of the cases, respectively. Renaming of the median cubital vein as the oblique cubital vein because of its direction and renaming of the median basilic and lateral basilic veins as medial and lateral cubital veins since they follow the medial and lateral borders of cubital fossa respectively has been suggested.
The postnatal development of blood vessels in the substantia gelatinosa of rat cervical cord — an ultrastructural study
Authors: Hannah Richard S. , Nathaniel E. J. H. 
Published: February 2005

AbstractLight microscopy of semithin sections revealed an increase in blood vessel profiles between one and three weeks postnatal. Ultrastructurally, at birth, there were few patent vessels, but endothelial cells enclosing a slit‐like lumen were numerous. The endothelial cells contained a high concentration of free ribosomes and pinocytotic vesicles. Pseudopod projections of the endothelial cells into the vascular lumen were often present. The nuclei were very irregular and dense with clumped chromatin. The basal lamina varied in thickness. During the period between one and three weeks the nuclei of endothelial cells became less dense; the lumen became patent and the endothelial wall progressively thinner. The periphery of the vessel became completely surrounded by glial end feet and the basal lamina was regular and prominent. By three weeks, most blood vessels resembled blood vessels observed in a mature animal. Pericytes were present at all stages of development. The extracellular space which was quite conspicuous at birth was greatly reduced by the third week.
An ultrastructural analysis of spontaneous activation of hamster eggs aged in vivo
Authors: Longo Frank J. 
Published: February 2005

AbstractIn an effort to elucidate various aspects involving the initiation of development, the morphogenesis of the spontaneously activated egg of the golden hamster was examined at the light and electron microscopic levels of observation. Spontaneous activation of the unfertilized hamster egg occurs upon prolonged incubation within the oviduct, i.e., aging in vivo, and may include the formation of the second polar body and the development of one or several pronuclei. In many instances the activated egg resembles the inseminated ovum at the pronuclear stage of fertilization. Occasionally the activated egg will divide and yields a structure which is morphologically similar to the two‐cell stage. Development beyond the two‐cell stage was not observed. Even though a number of events exhibited by the aging hamster egg mimic those of the fertilized, many are indicative of cellular degeneration. Such processes include, for example, the aggregation of organelles into fairly homogeneous clusters, the budding of portions of the cortex of the egg containing cortical granules into the perivitelline space, the accumulation of vesicles within the ooplasm and the structural modification of microvilli. All activated eggs, at every period investigated (6 to 66 hours post‐ovulation), contained cortical granules.
Persistence of cell types in monolayer cultures of dispersed cells from the pituitary pars distalis as revealed by immunohistochemistry
Authors: Baker B. L. , Reel J. R. , van Dewark S. D. , Yu Y.‐Y. 
Published: February 2005

AbstractThe objective was to study the fate of specific secretory cell types of the rat hypophysis when grown in primary monolayer cultures for periods ranging up to 32 days. The cells were identified immunohistochemically using peroxidase‐labeled antibody. Early in the culture period TSH‐cells were scarce and by 12 days they could no longer be identified. In most cultures LH‐cells were well stained and common for eight to 12 days, after which they underwent involution. Growth hormone cells were a prominent feature up to six days but by 12 days they were declining in number, size, and stainability; in contrast, prolactin cells proliferated and were large and intensely stained throughout the period of study, ultimately becoming the dominant secretory cell type. Corticotropic cells also continued throughout the period of study without regression. Thus drastic shifts occur with time in the relative proportions of cell types in monolayer cultures of rat pituitary cells.
Distribution of mitotic nuclei in the biceps brachii of the mouse during post‐natal growth
Authors: Aziz‐Ullah  , Goldspink G. 
Published: February 2005

AbstractDistribution of mitotic nuclei in the biceps brachii of five day old mice has been studied after subcutaneous injection of 1 μCi/gm body weight 3H‐thymidine. Serial transverse sections at 5 μm thickness were cut and the number of labeled nuclei per hundred fibers were determined on every fortieth section starting from the proximal end of the muscle.The proximal region of the muscle has significantly more labeled nuclei than either the belly region (P < 0.005) or the distal region (P < 0.001) of the muscle. The distal region of the muscle and the belly of the muscle did not differ significantly.Thus, most of the fiber elongation seems to take place at the proximal region of the muscle. As far as the transverse growth is concerned it appears that either every fiber at this stage is increasing in diameter or else the fibers which are undergoing an increase in diameter are randomly distributed throughout the body of the muscle, as no significant differences have been found in the percentage labeled nuclei in the four transverse areas of the muscle in the belly region.
The role of nerves in the regeneration of minced skeletal muscle in adult anurans
Authors: Hsu L. 
Published: February 2005

AbstractThe course of reinnervation and the effects of denervation and immobilization on muscle development were examined during the regeneration of minced muscle in anurans. Reinnervation occurs in the second week, at the time of myotube formation and differentiation. At the end of thirty days, nerves are plentiful and extensively distributed within the regenerating muscle. Cholinesterase activity within the regenerated muscle cannot be demonstrated at this time. Denervated regenerates develop normally during the first two weeks, but, thereafter, the young muscle fibers exhibit signs of degeneration and retarded growth. Denervated regenerates become fibrotic and contain few muscle fibers at the end of four weeks. Regenerates from muscles denervated prior to mincing show an accelerated appearance of presumptive myoblasts in the first week, but despite this precocious development, these denervated regenerates become regressive. On the other hand, the effect of disuse on muscle regeneration is not detrimental; the fibers of reinnervated but immobilized regenerates develop normally and do not become degenerative. These results suggest that nerves are unnecessary for the early myogenic processes of proliferation and fusion, but are essential to later stages of growth, maturation and maintenance of the regenerated muscle fibers.
Nerve fibers in the sympathetic trunk of Rana pipiens: A quantitative electron microscope study
Authors: Davis Wanda M. , Nunnemacher Rudolph F. 
Published: February 2005

AbstractThe numbers and diameters of nerve fibers were determined for the first time for all interganglionic rami of the sympathetic chain of the frog. The number of myelinated fibers ranged from 57 to 263 and was generally highest in the anterior portion (207) and lowest at the posterior end (57) of the chain. The exception was between the fourth and fifth ganglia where the middle splanchnic nerves arise — the number of myelinated fibers was highest here (263). Unmyelinated fiber counts were similar throughout the chain (417–814) except above and below the first sympathetic ganglion (7325 and 3026, respectively), and at the level where the middle splanchnic nerves arise (3780). Unmyelinated fibers constituted 75–97% of the fibers of the chain. The myelinated fibers ranged in diameter from 0.5 to 9.0 μ, 75% of them measuring between 1.5 and 3.0 μ. The diameter range for unmyelinated fibers was 0.1 to 5.0 μ with 78% being 0.1 to 1.0 μ.
The production of extracellular connective tissue fibrils by chick notochordal epithelium in vitro
Authors: Carlson Edward C. , Upson Rosalyn H. , Evans Darrell K. 
Published: February 2005

AbstractFertile hens eggs were incubated 48 hours. Embryos were removed from the shell and the cervical region from each excised and placed in a balanced salt solution containing 1% trypsin for 40 minutes. Notochords were isolated by microdissection and further incubated in vitro 48 or 72 hours. Following trypsinization, unincubated notochords were rod‐shaped and were shown by electron microscopy to be devoid of extracellular materials or contaminating mesenchymal cells. Extracellular materials, ultrastructurally indistinguishable from those in the perinotochordal connective tissue space in vivo, are present on the surfaces of cell clusters at 48 hours of in vitro incubation. Areas of fibrillogenesis, in which microfibrils are separated from the surface of cells by intermittent basement lamina, are common. At 72 hours of in vitro incubation fibrogenic activity is less evident, but occasionally intense concentrations of small and large microfibrils, basement lamina and other extracellular substances are seen adjacent to notochordal cell surfaces. These observations are of special interest in light of the known role of the notochord in embryonic induction and recent demonstrations that surface‐associated substances (specifically collagen) are necessary for normal cytodifferentiation.
Morphological classification of rat incisor ameloblasts
Authors: Warshawsky H. , Smith C. E. 
Published: February 2005

AbstractLongitudinal sections through the incisors of the rat show a continuous layer of ameloblasts on the labial surface of the tooth. This layer contains the entire sequence of developmental stages in enamel production. Using 1 μm Epon sections from the upper and lower incisors of 100 gm male rats, the ameloblast layer was divided into three main zones which were themselves subdivided into regions: (1) Presecretory zone which includes (a) region of ameloblasts facing pulp, itself comprising a posterior portion (upper 172 ± 35 μm; lower 187 ± 37 μm) and an anterior portion (upper 458 ± 28 μm; lower 503 ± 36 μm); (b) region of ameloblasts facing dentin (upper 1210 ± 81 μm; lower 1381 ± 90 μm). (2) Secretory zone, (a) region of inner enamel secretion (upper 2573 ± 141 μm; lower 4274 ± 160 μm); (b) region of outer enamel secretion (upper 1211 ± 60 μm; lower 868 ± 72 μm). (3) Maturation zone (upper 7335 μm; lower 10615 μm), (a) region of postsecretory transition; (b) region of maturation proper, consisting of portions of ameloblasts with striated border and portions of ameloblasts with unmodified apices; (c) region of pigmentation; (d) region of reduced ameloblasts.These regions are readily identified using clear cut morphological criteria. Length measurements made on a group of 40 rats established the reproducibility of this classification. Therefore, this classification will be used as a basis for future studies of cell population kinetics.
Localization of muscle spindles in the human Extensor indicis muscle for biopsy purposes
Authors: van Gorp Paul E. , Kennedy William R. 
Published: February 2005

AbstractThe number and spatial relations of muscle spindles in the extensor indicis have been determined. Approximately forty spindles lie adjacent to the motor end plate zone dispersed rather equally through this area of the muscle with a modest increase in density among the distally originating fibers. A study of the entire innervation pattern of this muscle has also been completed.These findings have greatly facilitated the isolation of spindles for electron microscopic study and attempts to perform in vivo recording from the sensory nerves of muscle spindles in this laboratory. It is now possible, with the aid of suitable magnification and stimulating and recording devices, to more rapidly find muscle spindles relative to the gross innervation and the easily located motor end plate zone.
Action of metabolic hormones on the fine structure of rat liver cells III. Effects of adrenalectomy and administration of cortisone
Authors: Cardell Robert R. 
Published: February 2005

AbstractElectron microscopic studies were made of hepatocytes from sham‐operated rats, adrenalectomized animals fasted 15 hours, and adrenalectomized rats fasted 15 hours but given a single I.P. injection (10 mg) of cortisone acetate. The objective of this work was to define the earliest morphological response of hepatocytes to injection of a glucocorticoid and to provide additional information on the mechanism of hormone action at the cellular level. Hepatocytes from fasted, adrenalectomized rats contained no glycogen particles and very little smooth endoplasmic reticulum (SER). In addition the rough endoplasmic reticulum was disorganized and showed fewer ribosomes and polysomes than found in liver cells from sham‐operated rats. Two hours after glucocorticoid injection glycogen particles were seen in numerous centrilobular cells and some periportal hepatocytes. Elements of SER were associated with the glycogen particles. By 4 hours after hormone injection abundant glycogen was found in all hepatocytes. Centrilobular cells showed dispersed glycogen with extensive tubules of SER associated with the glycogen particles. Periportal hepatocytes accumulated glycogen as dense masses scattered throughout the cytosome. SER occurred mainly at the edges of the glycogen masses. Midlobular cells showed glycogen patterns intermediate between periportal and centrilobular cells; masses of dispersed glycogen with abundant SER occurred within and around the glycogen areas of the cells. Glucocorticoid stimulation also caused cisternae of RER to align in parallel arrays, and more ribosomes and polysomes appeared on membranes of RER than in similar cells from adrenalectomized rats. The interpretation is offered that the glucocorticoid‐stimulated proliferation of SER is the morphological expression of induced microsomal enzyme synthesis (glucose‐6‐phosphatase) known to occur under these hormonal conditions.
Protein secretion in the rat ventral prostate and the relation of Golgi vesicles, cisternae and vacuoles, as studied by electron microscope radioautography
Authors: Flickinger Charles J. 
Published: February 2005

AbstractProteins, including enzymes such as acid phosphatase, are among a variety of substances secreted into semen by the prostate gland. The formation, intracellular transport, and discharge of protein components of prostatic secretion were studied in the rat ventral prostate following an injection of leucine‐3H. Samples were prepared for light and electron microscope radioautography at intervals ranging from four minutes to two hours after the injection. In samples prepared four or ten minutes after administration of the precursor, most of the silver grains overlay the rough endoplasmic reticulum. Beginning 30 minutes after the injection, while label associated with the endoplasmic reticulum was declining, the proportion of grains over the Golgi apparatus began to increase, reaching a maximum in one‐hour samples. Secretory vacuoles at the apical ends of the cells became heavily labeled two hours after administration of the leucine‐3H. Labeling of secretions in the lumen of the prostatic alveoli was observed in samples taken two hours after the injection. These results indicate that secretory proteins in the prostate are synthesized in the rough endoplasmic reticulum, transported to the Golgi apparatus, and packaged into secretory vacuoles, which move to the apical ends of the cells and release their contents to the lumen. Additional analysis of the pattern of labeling of different elements of the Golgi apparatus suggests that some protein is transported sequentially from Golgi vesicles to stacks of cisternae and finally into Golgi vacuoles. Radioactive secretory proteins move through prostatic cells more slowly than through the seminal vesicle epithelium of the same animals. The main mode of protein secretion in the prostate appears to be a merocrine type, since apical protrusions such as have been suggested to participate in an apocrine form of secretion were observed infrequently and did not become heavily labeled.
Selective histochemical staining of cartilage matrix by RivanolR
Authors: Wezeman Frederick H. , Kuettner Klaus E. 
Published: February 2005

AbstractRivanolR, a fluorescent ethoxy derivative of acridine, interacts at different pH's with both glycosaminoglycans and proteins. The present study utilizes the specific interaction of RivanolR with acidic substances of the ground substance for histochemical studies of the cartilage matrix. This stain was applied to newborn mouse epiphyseal cartilages which were either unextracted or dissociatively extracted by graded concentrations of guanidinium chloride (GuHCl) from 0.5–3.0 M for four days at 25°C. Routinely prepared sections were then stained (0.1% solution) for two minutes at pH's ranging from 2.2–11.2. Stainability of the interterritorial matrix as well as the inner halo zone and outer corona zone of the lacunar matrix varied with pH. Whereas the interterritorial matrix decreased in stainability with rising pH, the halo and corona persisted in stainability up to pH 10.7. Dissociative extractions using GuHCl revealed the unextractable nature of the inner halo zone as well as the extractable nature of the corona above 1.0 M GuHCl concentration. Anionic sites on polyelectrolytes such as glycosaminoglycans are known to stoichiometrically bind many cationic dyes. The precise localization of stain‐reactive glycosaminoglycans or proteoglycans in the region of the perichondrocytic matrix by RivanolR supports prior observations using other cationic stains. Our data demonstrates that RivanolR enables one to visualize the unique perichondrocytic matrix which may be interpreted to be both chemically and morphologically a “matrix within a matrix”.
Functional differentiation of the chick endocrine pancreas: Insulin storage and secretion
Authors: Benzo Camillo A. , Green Tim D. 
Published: February 2005

AbstractA radioimmunoassay for insulin, together with ultrastructural observations of the endocrine pancreas, were utilized to investigate developmental aspects of insulin storage and secretion in the chick embryo. Immunoreactive insulin was detected from the fifth embryonic day onwards, in both the pancreas and blood plasma. In addition, margination of well‐developed beta granules, and emiocytotic events were observed as early as the fifth embryonic day. The initial appearance of insulin, together with its subsequent developmental profile, correlate well with major metabolic events occurring in the embryonic chick, and are discussed in relation to a functionally responding system, the developing liver. The present data show that the chick endocrine pancreas has the potential for activity very early in development, and that insulin may be secreted at earlier embryonic stages than hitherto accepted.