bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fine structure of steroidogenic cells of a primate cutaneous organ
Authors: Sisson Jean Kneeland , Fahrenbach Wolf H. 
Published: February 2005

AbstractThe antebrachial organ of the ring‐tailed lemur (Lemur catta) is a highly differentiated cutaneous appendage composed of atypical apocrine sweat glands and of clumps of large interstitial cells. These cells have many similarities to steroid‐secreting cells, most notably an extensive agranular reticulum, which occurs in several forms. Commonly it consists of random tubules, but at times these are compacted into tight masses. The cisternae sometimes are distended with dense inclusions. Often the agranular reticulum differentiates into a rigidly patterned crystalloid composed of stacked layers of parallel, interconnected tubules. The three‐dimensional structure of the crystalloid is identical in both sexes, but the crystalloid of the male is scaled down in all its dimensions by a factor of about 0.9 as compared to that of the female. The interstitial cells, like steroidogenic tissue, exhibit intense 3β‐, 17β‐, and 20α‐hydroxy‐steroid dehydrogenase activity and contain abundant esterases; thiobutyric esterase activity is limited to the agranular reticulum.For comparative purposes, examination has been made of several other tissues having agranular reticulum: testicular interstitial cells, corpus luteum, adrenal cortex, and sebaceous cells of Lemur catta, rat meibomian glands, and the Leydig cells of human testis. The Reinke crystalloid of human testicular interstitial cells is totally unlike the crystalloid of the interstitial cell of the antebrachial organ.
Striated muscle cells in the thymus of reptiles and birds: An electron microscopic study
Authors: Raviola Elio , Raviola Giuseppina 
Published: February 2005

AbstractStriated muscle cells, the “myoid cells” of light microscopic literature, are consistently found in the thymus of reptiles and birds. Round or elongated myoid cells resemble adult skeletal or cardiac muscle fibers; however, the location of the nucleus, the course of the myofibrils, the arrangement and proportion of the thick and thin filaments, and the morphology and topography of the membranous components of the sarcoplasm are variable. Other myoid cells which contain either primitive myofibrils, irregular bundles of myofilaments associated with primitive Z plaques, or thick and thin filaments alone scattered throughout the cytoplasm, recall the various stages of the development of skeletal and cardiac muscle fibers. In these cells the ribosomes are often, but not always abundant and appear in places arranged in helices and rosettes. It is suggested that a postnatal myogenesis takes place in the thymus. Anomalous muscle cells contain thin filaments almost exclusively. In some of these cells, thin filaments are arranged in I‐segments that appear either independent of each other or interdigitated in pseudosarcomeres. Finally, some myoid cells appear to have degenerated. Desmosomes join myoid cells to reticular cells, to other myoid cells, and to epithelial cells in the walls of intraparenchymal cysts. The origin of the myoid cells from reticular cells is suggested.
The relationship of nucleotidase activity to catecholamine storage sites in adrenomedullary tissue
Authors: Wood Joe G. 
Published: February 2005

AbstractTissues were either fixed in 3% glutaraldehyde and treated histochemically to demonstrate nucleotidephosphatase activity and catecholamines or in 2.5% potassium dichromate (pH 4.1) for demonstration of catecholamines. Frozen sections (10 μ) were examined with the light microscope or following the histochemical procedures 1 mm cubes of tissue were treated with 1% OsO4 and prepared for electron microscopy.Light microscopy demonstrates groups of norepinephrine cells in adrenal medullary tissue of cats and rats. Nucleotidetriphosphatase activity is found along nerve fibers, between epinephrine cells and concentrated in norepinephrine cell areas. The same is true for diphosphatase localization but with less intense activity. Nucleotidemono‐phosphatase activity is located primarily at the site of norepinephrine cells.Electron microscopy shows triphosphatase activity along membranes of chromaffin cells and nerve fibers, at canaliculi and nerve terminals, and in sinusoidal cells. Diphosphatase activity is present at similar sites and shows some intracellular activity. Monophosphatase activity is present at cell membranes and intracellularly appears closely related to catecholamine storage granules. It is postulated that since nucleotides are apparently instrumental in the binding of catecholamines, nucleotidephosphatase action effects a mechanism of catecholamine release from the storage sites and permits passage through the cell membranes.
An autoradiographic study of satellite cells in autonomic ganglia
Authors: Schwyn Robert Conrad 
Published: February 2005

AbstractThis investigation was undertaken to observe and to correlate the responses of satellite cells in autonomic ganglia to increased neuronal and synaptic activity. By electrically stimulating preganglionic nerve fibers terminating in the superior cervical sympathetic ganglion in 19 adult cats and concurrently injecting thymidine‐H3 into the stimulated animal, it was possible to alter the neuronal and synaptic activity within the superior cervical ganglion and subsequently observe from autoradiograms the cellular absorption of thymidine‐H3. The specific reaction encountered was incorporation of thymidine‐H3 into the nuclei of satellite cells. Absorption of thymidine by satellite cells and incorporation of this compound into their nuclear structure could be accelerated or inhibited by exposing the organism to specific drugs (viz. neostigmine and atropine sulfate) during the stimulatory period.The results of this investigation combined with information gathered from studies in many other scientific areas implicate satellite cell participation in response to increased neuronal metabolism and possibly to increased synaptic activity. Satellite cells apparently proliferate to cope with the demands of increased ganglionic activity elicited by the experimental procedures employed in this study. Although specific reactions of satellite cells other than cellular proliferation were not identified in this study, their probability may provide a basis for further investigation.
Origin and distribution of portal blood in the sheep
Authors: Heath Trevor 
Published: February 2005

AbstractIn sheep, the gastrosplenic and mesenteric veins converge at an angle of about 140° to form the portal vein, which is joined, along its right ventral border, by the gastroduodenal vein. At the porta, right and left branches of the portal vein diverge at an angle of 65–70° to supply separate areas that join along a line between the fossa for the gall bladder, and the middle of the left branch. Right dorsal branches leave the portal vein or its right branch near the point of bifurcation.When 131I‐albumin that had been heated was injected into the right ruminal vein and entered the portal stream in the gastrosplenic vein, no significant differences existed in the levels of radioactivity between the areas supplied by the different portal branches. When the 131I‐albumin entered the portal stream from either the gastroduodenal or mesenteric veins, the area supplied by the right branch contained a significantly higher level of radioactivity than the remainder of the liver. When corrections were made for an unequal distribution of blood, it was found that blood from the gastrosplenic vein was distributed preferentially to the left branch, blood from the gastroduodenal vein to the right branch, and that blood from the mesenteric vein enters the right and left branches in preference to the right dorsal branches of the portal vein.
Histochemical investigation of fiber type ratios with the myofibrillar ATP‐ASE reaction in normal and denervated skeletal muscles of guinea pig
Authors: Karpati G. , Engel W. King 
Published: February 2005

AbstractThe myofibrillar ATPase histochemical reaction was utilized to determine the proportion of the two basic histochemical fiber types in three “mixed” skeletal muscles of guinea pig after denervation. In five normal control animals, there was no significant difference in the proportion of fiber types on the two sides. In 12 experimental animals from 6–27 weeks after right sciatic neurectomy, the intensity of the myosin ATPase activity was not appreciably altered in the denervated muscle fibers but the type II (dark) fibers underwent preferential atrophy. The fiber type ratio between denervated and control sides in the experimental animals was not significantly different from the same values in the normal control animals. This allowed the conclusion that, up to 27 weeks after denervation, the histochemical typing of a fiber by the myofibrillar ATPase reaction probably reflects the original fiber type. This reaction is the preferred method for fiber typing in denervated guinea pig muscle, especially since most other histochemical reactions show markedly reduced activity of muscle enzymes after denervation and are unsuitable for fiber typing. The soleus, which normally contains only type I fibers, showed numerous type II fibers at 27 weeks after denervation and this was interpreted as a dedifferentiating process.
Gonocyte degeneration in the postnatal male rat
Authors: Roosen‐Runge Edward C. , Leik Jean 
Published: February 2005

AbstractThe cell population of the sex cords in rat testes from day 1 to day 10 after birth was investigated by means of microscopic observation and quantitation, and with the electron microscope. Certain gonocytes, rare during the first 2 days, more frequent thereafter, were found in various stages of pyknosis. In electron micrographs these were characterized mainly by condensed and sometimes fragmented nuclei and cytoplasmic vacuoles and vesicles. The mitochondria remained typical of gonocytes in all but the most advanced stages of necrosis. Degenerating cells were eventually surrounded by single supporting cells and apparently phagocytized by them. Gonocytes which appeared “swollen,” “fuzzy” and pale staining under the microscope were considered normal pre‐mitotic cells or possibly in some cases altered by artifacts of fixation. No evidence was produced microscopically or electron microscopically that cells of this type are degenerative. In many gonocytes, the electron microscope revealed some swollen mitochondria with irregular cristae, “B‐bodies” in varying numbers and occasional membrane breakage. The evidence was considered insufficient to interpret these as signs of impending cell death.Quantitative determinations of the numbers of gonocytes at various stages indicate that approximately one third of the cells are lost between day 1 and 4 post‐partum. In Sprague‐Dawley rats gonocytic mitoses resume on day 4. There is evidence that degeneration of gonocytes continues until day 7 or 8. The total number of cells dying may possibly be accounted for by the number of pyknotic cells observed. Incidental data are reported concerning the growth of sex cords and the proliferation of supporting cells. Comparison with results in the literature lead to the general conclusion that there is excellent evidence that many gonocytes die during the first postnatal week, but that many of the morphological criteria for dying cells used by previous investigators lack validity when rigorously examined.
The vascularization of the hypothalamic‐hypophyseal region of the eastern brook trout, Salvelinus fontinalis
Authors: Hill Joanna Jensen , Henderson Nancy E. 
Published: February 2005

AbstractThe hypophysis of the brook trout is irrigated by blood vessels which originate from the internal carotid arteries. These are: (1) branches of the ventral hypothalamic arteries that give rise to an extensive capillary plexus in the neurohypophysis from which vessels extend into all regions of the adenohypophysis; (2) branches of the caudal hypothalamic artery that irrigate the saccus vasculosus and continue anteriorly to supply the ventral areas of the meta‐adenohypophysis; (3) a caudal hypophyseal artery which vascularizes a portion of the meta‐adenohypophysis however, this vessel is not always present; (4) a pair of small arteries which supply the peripheral regions of the gland directly from the carotids.Most of the neurosecretory fibers of the preoptic‐hypophyseal tract terminate close to capillaries in the neurohypophysis. A few axons extend into meso‐adenohypophyseal tissue. It is suggested that the secretory activities of the pro‐, meso‐ and metaadenohypophyses are governed by hypothalamic factors that are chiefly transmitted to the gland cells via the vascular system (indirect control). However, the activity of the meso‐adenohypophysis may also be regulated by factors which are transmitted directly to the cells from the endings of neurosecretory fibers which have traversed the neurohypophysis (direct control). The distribution and abundance of neurosecretion in the ventral hypophysis suggest the possibility of storage of hypothalamic products within this region.
The fine structure of the hamster pineal gland
Authors: Sheridan Michael N. , Reiter Russel J. 
Published: February 2005

AbstractThe pineal gland of the hamster has been examined with the electron microscope. The gland is composed of two types of parenchymal cells, a “light” and a “dark” cell. Blood vessels are infrequently encountered and display little perivascular space. Axons, nerve endings, pineal cell processes, and occasional glial processes ramify within the parenchyma of the gland.The parenchymal cells display abundant mitochondria, many with a tubular internum. Smooth and rough surfaced endoplasmic reticulum, a Golgi apparatus and lipid droplets are regular features of both cell types. Vesicles of varying size and containing electron dense centers are present in the cell body.Parenchymal cells branch extensively and are characterized by the presence of microtubules in addition to the usual organelles encountered in the cell body. Pineal cell process terminations regularly show accumulations of vesicles with electron dense granulations.
The embryonic origin of the abdominal (ventro‐lateral) musculature in the albino rat
Authors: Parry William 
Published: February 2005

AbstractA study comprising both descriptive and experimental data was undertaken. The descriptive portion utilizes transverse, sagittal, and frontal serial sections of 10 through 20 day old rat embryos.As development proceeds, the somites lengthen along their dorsoventral dimension, and epithelial‐lined “buds” (ventral somite buds) extend into the lateral plate somatopleure. Concomitantly epithelium lining the somite “body” is converted to a loosely associated mass of mesenchyme, beginning at the deep medial border and extending around the cephalic and caudal faces of the somite to involve the superficial surface. Lastly, this process transforms the epithelium covering the ventral somite buds into a mesenchymal aggregation. Anlagen of the abdominal ventrolateral muscles arise in the precise position of the mesenchymal aggregation derived from the ventral somite buds.The experimental section tests the development capacities of isolated portions of the trunk body wall when implanted in the anterior chamber of the eye. Grafts of somite material are highly proficient in forming striated muscle, while grafts of somite‐free somatopleure have little ability to form striated muscle. Grafts of ventral body wall become more proficient in forming striated muscle with age. The increase in muscle‐forming ability correlates directly with the invasion of material from the ventral somite buds into the ventral body wall. It is concluded that the ventrolateral (abdominal) musculature is of somitic origin.
The subcutaneous implantation of autogenous rat molars
Authors: Irving James T. , Bond James A. 
Published: February 2005

AbstractMaxillary molars were extracted, and decalcified or devitalized prior to subcutaneous implantation in the same animals. All molar implants attracted large numbers of leukocytes during the first week of implantation. After two weeks small basophilic mononuclear cells appeared which penetrated the dentinal tubules of decalcified molars and were associated with considerable resorption of dentin and predentin. Giant cells were not usually observed near decalcified molars, but large numbers of them were attracted to FDNB treated molars. Giant cells appeared in moderate numbers around devitalized molars and were associated with resorption of intact root surfaces after 56 days. The significance of these results is discussed.
An electron microscopic study of uterine arteries during pregnancy
Authors: Albert Ernest N. , Pease Daniel C. 
Published: February 2005

AbstractThe mesometrial arteries of pregnant guinea pigs are not mere blood conducting channels. Instead they are dynamic in nature. The cells forming the intima and media exhibited significant structural modifications during pregnancy. The endothelial cells became hypertrophied and attenuated. Their cytoplasm showed an increase in the amount of ribosomes, rough endoplasmic reticulum and lysosome‐like bodies during pregnancy. Dense bodies that were often closely associated with the Golgi apparatus were seen in pregnant animals. These bodies exhibited a graduation in size within each cell and were thought to be the precursors of the lysosome‐like bodies. Similar structures were also seen in smooth muscle cells of the mesometrial arteries of pregnant animals.The endothelium of these arteries was often discontinuous in full term pregnant animals. In that case, the underlying smooth muscl4 cells provided the lining surface. Irrespective of which type of cells formed the lumen of these arteries, they became coated with a “fuzzy” layer which specifically stained intensely with phosphotungstic acid, suggesting that this layer might be a mucoprotein. The smooth muscle cell of the arterial media also became hypertrophied during pregnancy. The cytoplasm exhibited a gradual increase in free ribosomes and rough endoplasmic reticulum, mitochondria and microtubules throughout pregnancy. During the latter half of pregnancy many smooth muscle cells developed extensive amounts of smooth endoplasmic reticulum whose vesicles often were filled with an electron opaque secretory material. It is suggested that the development of unusually large quantities of smooth endoplasmic reticulum might be associated with steroid metabolism. Unusually thick basement membranes were formed around the modified smooth muscle cells of full term pregnant animals and the surfaces of these cells often exhibited large numbers of microvilli. The microvilli seemed to disrupt the continuous patterns of the basement membrane.
Autoradiographic investigation of calvarial growth in the rat
Authors: De Angelis Vincent 
Published: February 2005

AbstractResults of autoradiographic investigations utilizing tritiated proline reveal an intricate mechanism of rat calvarial growth and reshaping from age two days through 75 days. Generalized intramembranous bone growth dominates the growth process from two through eight days; however, this simple bony enlargement is terminated early. At eight days a differential apposition‐resorption process begins dorsally in the calvarium and progresses rostrally within a ten day period. This process includes differential apposition on the ectocranial and endocranial periosteal surfaces accompanied by a differential apposition‐resorption pattern on the endosteal surfaces. The wave‐like process begins in the occipital bone and progresses ventrally to the frontal bone resulting in a flattening of the bony components. At 35 days bone accretion is again generalized on most calvarial surfacse. However, at 40 days another change in the growth process evolves on the occipital and frontal bones. These bones are now seemingly displaced in a superior direction as bone apposition continues on their superior surfaces, namely, the ectocranial periosteal and endocranial endosteal surfaces and resorption progresses on the two inferior surfaces. The magnitude and duration of the process described in this paper is sufficient to account for calvarial flattening in the absence of bony spatial reorientation due to bending at sutures. The findings described here when compared to proposed in vitro studies can help put the importance of the so‐called “functional matrix” related to bone growth into its proper perspective.
Cell division in injured spinal cord
Authors: Adrian Erle K. 
Published: February 2005

AbstractThymidine‐H3 radioautography was used to study the proliferative response to penetrating wounds of the mouse spinal cord. In one group of animals mononuclear leukocytes which infiltrate nervous tissue wounds were labeled by injecting thymidine‐H3 prior to injury. In two other experimental groups the cells which synthesized DNA in the nervous tissue following the injury were labeled by giving either a single injection of isotope shortly before sacrifice or by giving four injections during the 24 hours prior to sacrifice. The animals were sacrificed over a five day period following spinal cord injury. Although the labeled nuclei in all three groups were similar in appearance, their distribution about the lesion was very different. The labeled blood cells were greatly concentrated at the wound, while the cells that responded to injury by DNA synthesis were much more evenly spread throughout the tissue. When these distributions were converted to straight lines and compared statistically, there was a very low probability that the group of cells labeled before injury and the two groups labeled after injury were samples from the same population. Although mononuclear leukocytes do proliferate in and around nervous tissue wounds, other cells originally present in the nervous tissue wounds, other cells originally present in the nervous tissue must also proliferate.
Ultrastructure of granulated arteriolar cells (juxtaglomerular cells) in kidney of a fresh and a salt water teleost
Authors: Bulger Ruth Ellen , Trump Benjamin F. 
Published: February 2005

AbstractGranulated juxtaglomerular cells have been identified in the media of afferent arterioles in the fresh water goldfish and in a marine English sole. Electron microscopy demonstrated the following five types of granules in the modified smooth muscle cells: (1) Small homogeneous granules near the Golgi apparatus; (2) larger homogeneous granules throughout the cytoplasm; (3) granules containing a bundle of hexagonally packed tubules; (4) autophagic vacuoles; and (5) granules containing membranous and granular debris. The granulated juxtaglomerular cells are morphologically similar to mammalian granulated cells and therefore may be the site of renin secretion. They exist with no relation to a distal tubule and hence appear to occupy an interesting position in the evolution of the juxtaglomerular apparatus.