bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parietal eye‐pineal morphology in lizards and its physiological implications
Authors: Gundy G. Craig , Wurst Gloria Z. 
Published: February 2005

AbstractPineal complexes in 85 species of lizards examined comprised seven morphological types. Members of the same family do not necessarily have the same pineal complex type. “Regressive” parietal eyes were not common except in certain arboreal lizards, primarily from the family Chameleontidae. The parietal eye is often retained in burrowing lizards, presumably because these animals are occasionally exposed to light and the parietal eye is a more suitable photoreceptor for a burrower than are lateral eyes. The pineal of certain lizards possesses a finger‐like projection that extends toward the parietal eye. This extension, along with pineal wall convolutions, results in more photoreceptor cells oriented for maximal absorption of light. It is rare to find convolutions and an extension in the same pineal. Cartilage deposits and blood sinuses may modify the intensity and wavelength of light reaching the pineal. These observations suggest that the intracranial pineal of lizards is a more important photoreceptor than was previously realized, a situation that may be a factor in the occasional “failure” of parietalectomy experiments.
Ultrastructure of the pars intermedia of pigmented rats: Observations of melanin‐like granules within secretory cells
Authors: Saland L. C. 
Published: February 2005

AbstractThe pars intermedia of non‐obese pigmented rats of the Zucker strain is described using transmission electron microscopy. Secretory cells appear similar to those described elsewhere in albino rodent hypophyses. Cells which may be equivalent to ACTH cells of non‐pigmented mice and rats are observed near theborder of the pars distalis. Melanocytes are observed to surround lobules of the pars intermedia and to penetrate among secretory cells. In addition, large granules which appear to be melanin are present within some pars intermedia cells. Portions of some cells near melanin or melanin‐like granules exhibit expanded rough endoplasmic reticulum and Golgi zones containing dense granules. Observations are discussed in relation to origin of the melanin, and its possible significance near cells known to produce melanocyte‐stimulating hormone (MSH).
Tridimensional reconstruction and histology of the intratesticular seminal pathway in the hamster
Authors: Cavicchia J. C. , Burgos M. H. 
Published: February 2005

AbstractThe present work reports a tridimensional reconstruction of the intratesticular seminal pathway in the hamster as studied with light microscopy of serial sections of the proximal pole of the testis. It has three portions: a “terminal segment” of the seminiferous tubules; the tubuli recti with three parts; and the rete testis with two parts, intratesticular and extratesticular.Experiments using ductuli efferentes ligation show a marked dilation of the rete testis and tubuli recti without a corresponding dilation of the seminiferous tubules. This may be due to a valve‐like action of the cells in the terminal segment of the tubules.
Integrated actions of masticatory muscles: Simultaneous EMG from eight intramuscular electrodes
Authors: Vitti Mathias , Basmajian John V. 
Published: February 2005

AbstractIn 29 normal persons with complete dental arches, the muscular activity of the temporalis, masseter, medial pterygoid, anterior belly of the digastric, mylohyoid and geniohyoid muscles was studied electromyographically with bipolar fine wire electrodes during various mandibular movements – both resisted and unresisted. Action potentials were recorded on FM magnetic tape and each experiment was also videotaped. Temporalis muscle was active during centric closing of the jaw with either contact of the teeth, or against resistance; during free lateral movements to the ipsilateral side, either against resistance or occlusal contact; during incisor gum chewing, molar gum chewing on ipsilateral or contralateral sides, during normal mastication; and during forceful centric occlusion.Activity occurred in the masseter and medial pterygoid muscles during the following movements: closing the jaw slowly either without occlusal contact or with occlusal contact and against resistance; free lateral movement to contralateral side, either against resistance or with occlusal contact; protraction of the jaw either without occlusal contact or with occlusal contact; swallowing either saliva or water; incisor gum chewing with either the ipsilateral or contralateral molars; normal mastication; and during forceful centric occlusion.Activity occurred in the digastric, mylohyoid and geniohyoid muscles during the following movements; opening of the jaw either slowly or maximally against resistance; closing the jaw against resistance; free lateral movement to ipsilateral and contralateral sides, either against resistance or with occlusal contact; protraction against resistance of the jaw either without or with occlusal contact; swallowing saliva and water; and protraction of the tongue. They work in antagonism (reciprocally) during gum chewing and normal mastication.
An electron‐dense extracellular material in the nervous system of Aplysia
Authors: Coggeshall Richard E. 
Published: February 2005

AbstractAn electron dense material is found in the extracellular space of the nervous system of Aplysia, a marine mollusc whose ganglia are widely studied by neurobiologists. This material appears to consist of irregular electron‐dense granules, with diameters of approximately 600 Å. This material is found between the glial cells that surround the neuronal perikarya. It is not found in other regions of the nervous system. Because it is found in the ganglion cell layer of the nervous system and because the neurons contain what may be the precursor of this substance, the electron‐dense material is regarded as most probably being a neuronal product. The importance of this material is that it is one of the few examples of visible structure in the extracellular space of the nervous system.
Fine morphological changes in the penicillate nerve endings of human hairy skin during prolonged itching
Authors: Cauna Nikolajs 
Published: February 2005

AbstractMorphological changes in cutaneous nerve endings were investigated electron microscopically in patients suffering from certain kinds of urticaria with associated itching and in normal skin in which wheals and local itching were induced either by application of nettle hairs or by intracutaneous injections of a timothy pollen extract. Skin samples were obtained with a high speed dermal punch without anesthesia from the wheal areas.It was found that some subepidermal free nerve endings derived from nonmyelinated nerve fibers (penicillate endings) showed accumulations of extracytoplasmic glycogen which was localized in the distended spaces between the axolemma, the Schwann cell membrane and the nerve basement membrane. In some cases, the glycogen was found to be so abundant that it occupied most of the cross sectional area of the ending. No morphological changes were observed in the pappilary endings, in nerve endings of the hairs or in the autonomic terminals. The conducting segments of all cutaneous nerve fibers showed normal morphology.The unusual morphological changes that occur in some penicillate nerve endings during the wheal development indicate that these endings are involved in the skin reaction and therefore they may be the specific end organs that are associated with itch, at least in urticaria.
Pulmonary circulation—vertebral venous interconnections in the chicken
Authors: Burger R. E. , Estavillo J. A. 
Published: February 2005

AbstractInjections of India ink colored blood, latex, and plastic followed by study of corrosion casts and dissections were used to determine the interconnections of the vertebral venous system and pulmonary circulation in the chicken. Multiple, minute connections are found to the intercostal veins, small mesenteric veins and others connected to the vertebral venous system. Thus, blood can flow in quantities between the vertebral venous system and the pulmonary circulation depending upon pressure gradients.
The vertebral level of origin of spinal nerves in the rat
Authors: Gelderd John B. , Chopin Suzzette F. 
Published: February 2005

AbstractSeveral dissections were performed to determine the level of spinal cord termination and the vertebral level at which the dorsal and ventral roots of spinal nerves C1‐S4 emerged from the spinal cord in the rat.These levels of emergence were then compared to the level of exit from the vertebral canal. The dissections demonstrated that the effect of differential growth between spinal cord and vertebral column begins in the lower cervical region and becomes progressively more pronounced throughout thoracic and lumbar levels. The disparity between the vertebral level of emergence of spinal roots from the spinal cord and their level of exit via intervertebral foramina was found to be considerably larger than was previously reported by Greene ('68). It was further noted that the spinal cord terminated at the level of the intervertebral disc between the third and fourth lumbar vertebrae, not between the fourth and fifth lumbar vertebrae as reported by Greene ('68).
Alterations in the endoplasmic reticulum and golgi complex of intestinal epithelial cells during fat absorption and after termination of this process: A morphological and morphometric study
Authors: Friedman Harold I. , Cardell Robert R. 
Published: February 2005

AbstractEarlier investigations of intestinal fat‐absorption have stressed the importance of continued protein synthesis to provide membranes which are utilized for the intracellular transport of resynthesized lipid. The resulting membranes, when incorporated into the endoplasmic reticulum (ER) and Golgi complex, serve as vehicles for the movement of fat within the cell and for its release to the extracellular space. In the current study, attention was focused on the morphological changes in the ER and Golgi complex both during fat absorption and at successive time intervals after fat‐absorption termination. Morphological interpretations were confirmed by morphometric analysis. This investigation supports the interpretation that during fat absorption, membrane synthesis by the rough endoplasmic reticulum (RER) is insufficient to accomodate membrane utilization and intraconversion, resulting in a decrease of both ER and Golgi complex components. However, following fat‐absorption termination, the cell is able to replace previously depleted components of the ER and Golgi complex and regain the full membrane complement of the fasted state. Replenishment of cellular membranes is postulated as resulting from a continued synthesis of new membranes by the RER which eventually exceeds membrane utilized during lipid transport.
Investigations on the turnover of adrenocortical mitochondria VI. An autoradiographic study of the effect of acth on the radioactivity decay in the mitochondrial compartment from the zona fasciculata of 3h‐thymidine injected rats
Authors: Nussdorfer Gastone G. , Mazzocchi Giuseppina , Robba Claudia , Belloni Anna S. , Gambino Anna M. 
Published: February 2005

AbstractThe radioactivity decay of the mitochondrial compartment from the zona fasciculata of the adrenal cortex of 3H‐thymidine‐injected rats was followed by high resolution autoradiography. The number of days in which the radioactivity of the mitochondrial compartment was reduced to a half was calculated from the semilogarithmic plots of radioactivity versus time. Since DNA is a very stable molecule, it was assumed that this parameter can be an estimate of the half‐life of adrenocortical mitochondria. The half‐life of mitochondria from the zona fasciculata of the normal rat averaged 11.17 days, and ACTH was found to increase significantly this figure to about 15 days. It is hypothesized that the ACTH‐elicited stimulation of the growth of rat adrenal zona fasciculata mitochondria involves not only hypertrophy and proliferation of the organelles (Nussdorfer et al., '74b), but also the slowing down of the degeneration rate of mitochondria.
Ultrastructure of in vitro type 2 epithelial cell cysts derived from adult rabbit lung cells
Authors: Rosenbaum R. M. , Picciano P. , Kress Y. , Wittner M. 
Published: February 2005

AbstractFragments of adult rabbit lung, composed chiefly of terminal airway obtained by a trypsin digestion technique were maintained on collagen‐coated cellulose sponges in Ham's F12 medium. Cell‐sponge associations were examined with light microscopy, scanning and transmission electron microscopy over a period from 6 to 28 days. After an initial 24‐ to 48‐hour period of cell migration from the airway fragment, sponge matrices became lined with cells suggestive of alveolar macrophages. After one week in culture, cysts appeared to be composed entirely of type 2 epithelial cells. These were characterized by a microvillous apical border and an elaborate junctional complex. The lumen of these cysts contained both myelin‐like lamellar configurations and tubular my‐elin structures such as have been described from pulmonary washings. Consistent with the age of the sponge cultures, one or more cyst types described as young, middle and late could be found simultaneously. Middle aged cysts showed signs of active secretion into the lumen. Late cysts showed changes in the epithelium comprising the cyst wall suggestive of a cell type intermediate between type 1 and type 2 epithelial cells.
Mitochondrial granule distribution in tooth germ cells
Authors: Sayegh F. S. , Abousy A. 
Published: February 2005

AbstractIncisor and molar tooth germs of albino rats sacrificed at the eighteenth and twentieth days in utero and one to seven days after birth were studied with light and electron microscopy. Observations of the various stages of tooth development in molars established that intramitochondrial granules in odontoblasts were comparable to the intramitochondrial granules of other hard tissue cells. These electron‐dense deposits appeared in mitochondria in an appreciable number only when odontoblasts become engaged in dentin mineralization. When dentin mineralization was advanced the odontoblast mitochondria appeared devoid of these deposits. Mesenchymal cells and preodontoblasts of the pulp were not involved in this activity.
The site of remodelling of collagen in the periodontal ligament of the mouse incisor
Authors: Beertsen W. , Everts V. 
Published: February 2005

AbstractIn an attempt to localize the site of remodelling of collagen in the periodontal ligament of the continuously erupting mouse incisor a radioautographic and stereologic investigation was undertaken. Grain distributions in radioautographs for light microscopy were studied at various time intervals after administration of [3H]‐proline. The distribution of rough endoplasmic reticulum cisternae in fibroblasts and the incidence of collagen phagocytosis across the ligament were studied by means of stereologic methods at the electron microscopic level.No significant differences were found in half lives of [3H]‐labelled substances among the various regions across the ligament. Roughendoplasmic reticulum cisternae within fibroblasts were distributed more or less uniformly throughout the entire width of the ligament. Analysis of the distribution of collagen phago‐cytosis, however, revealed that in the midregion of the ligament the amount of phagocytosed collagen was approximately four times as high as in the area adjcent to the tooth and about nine times as high as in the alveolar compartment.It is concluded that synthesis and turnover of total protein occurs throughout the periodontal ligament but that remodelling of collagen predominantly takes place in an intermediate area of the ligament.
Muscle spindles in nonhuman primate extrinsic auricular muscles
Authors: Lovell M. , Sutton D. , Lindeman R. C. 
Published: February 2005

AbstractMuscle spindles were sought in peri‐auricular muscles of several primate species (rhesus monkey, woolly monkey, and baboon). Transverse sections cut at 10 μ and stained primarily by a silver impregnation technique were examined using light microscopy. Spindles were identified on the basis of standard criteria. Posterior and/or superior auricular muscles of each species were found to contain spindles. At least some muscles innervated by facial nerve have classical spindles as component structures.
Intramembranous particle distribution in human erythrocytes: Effects of lysis, glutaraldehyde, and poly‐L‐lysine
Authors: Pricam Claude , Fisher Knute A. , Friend Daniel S. 
Published: February 2005

AbstractFreeze‐fracture combined with quantitative electron microscopy of the intact human erythrocyte (RBC) and ghost revealed significant differences in their intramembranous particle coefficients. External (E) fracture‐faces of unfixed ghost membranes were found to contain 40% fewer particles than those of intact unfixed RBC. The particle distribution of the intact RBC membrane depended on the use of glutaraldehyde fixation and glycerol cryoprotection. Whereas glutaraldehyde‐ and glycerol‐treated cells disclosed 70% fewer E‐face particles than did intact unfixed cells, poly‐L‐lysine‐treated, intact, unfixed RBC showed no such differences. Treatment with a combination of poly‐L‐lysine and glutaraldehyde, however, increased the amount of E‐face particles while reducing those of the protoplasmic (P) face. The poly‐L‐lysine effect varied with its concentration and was unaffected by previous application of neuraminidase. Nor did the lectin phytohemagglutinin induce particle rearrangement in intact cells.Our data demonstrate that the processes of glutaraldehyde fixation and glycerol cryoprotection modify the RBC membrane by decreasing the number of E‐face particles present. In addition, the combination of poly‐L‐lysine and glutaral‐dehyde alters the affinity of some particles for one half of the membrane, suggesting that in freeze‐fractured RBC, chemical bonds formed at the extracellular surface of the membrane can influence particle partitioning.
Neonatal muscle: An electron microscopic study
Authors: Ontell Marcia 
Published: February 2005

AbstractA spaced serial section, electron microscopic study of the extensor digitorum longus of the 2‐day‐old rat was undertaken to determine whether all cells wedged between the basement membrane and the sarcolemma of a muscle fiber, regardless of their morphology, were true myosatellite cells. The muscle was relatively immature, containing groups of cells enclosed in a common basement membrane (clusters) and exhibiting primitive myoneural junctions. Cells of the muscle line included in the clusters were primary fibers, satellite fibers, myotubes in different stages of development and myosatellite cells. In single ultrathin sections, some early myotubes lacked myofilaments and were difficult to distinguish from myosatellite cells. Spaced serial sections revealed that all myosatellite cells have heterochromatic nuclei and a high nuclear/cytoplasmic ratio, and that all pale staining nuclei were found in cells with a lower nuclear/ cytoplasmic ratio, containing variable quantities of myofilaments. In addition to the cells of the muscle line, mast cells, fibroblast‐like cells and other “unclassified” cells were entirely or partially enclosed within the cluster's basement membrane. This study demonstrated that location alone or location and the morphological appearance of cells in a single ultrathin section failed to provide sufficient criteria to properly classify all of the cells found in neonatal muscle clusters.
Identification of phosphatases on the membranes of guinea pig sperm
Authors: Gordon Mildred , Dandekar Pramila V. , Eager Patricia R. 
Published: February 2005

AbstractGuinea pig epididymal sperm, incubated for ATPases at pH 7.0 or pH 9.0, localize reaction product on both the periacrosomal segment of the plasmalemma and the outer acrosome membrane. In other species, e.g., rabbit, Ca++‐ATPase is identified with the outer acrosome membrane. It may transport Ca++ into the acrosome for activation of enzymes released during the acrosome reaction. The neutral ATPase is demonstrable on the periacrosomal plasmalem‐ma and possibly modifies Ca++ concentration in the fluid around the acrosome. In guinea pig sperm, Ca++‐ATPase is sensitive to centrifugation or washing of sperm which indicates that the ductal fluid has unusual properties for preservation of the acrosome. Inhibition of the enzyme by these treatments suggests that conditions on the plasmalemmal surface affect the acrosome membrane. Inability to separate reaction product on the plasmalemma from that on the acrosome membrane may be due to migration of reaction product across the periacrosomal space. However, the ATPases are elicited in the guinea pig under the same conditions as in other species. The pH 9.0 enzyme requires Ca++ while the enzyme at pH 7.0 has no ion specificities. Demonstration of these enzymes indicates that mechanisms of acrosome activation, similar to those in other sperm, are relevant to the guinea pig.
Lymphatic vessels of the mammalian heart
Authors: Leak Lee V. , Schannahan Anne , Scully H. , Daggett Willard M. 
Published: February 2005

AbstractAn in situ heart lung preparation was developed to label lymphatics of the actively beating dog heart with subsequent fixation by vascular perfusion. Immediately after interstitial injections of trypan blue and colloidal carbon, a rich plexus of lymphatic vessels was visualized in the epicardium of the actively beating heart. With this method of fixation, tissue preservation is generally excellent and uniform throughout the heart. In thin sections examined with the electron microscope, lymphatic vessels are easily recognized by the content of plasma proteins which is preserved as an electron dense precipitate that is evenly dispersed throughout the lumen. An extensive plexus of thin walled lymphatic vessels is observed throughout the epicardial, myocardial and subendocardial regions. Numerous anchoring filaments are observed closely apposed to the abluminal endothelial surface which extend into the surrounding connective tissue. The distribution and ultrastructure of the cardiac lymphatic vessels are discussed in relation to their role in the removal of interstitial fluid from the heart.
Development of adrenergic innervation of the iris and fluorescent ganglion cells in the choroid of the chick eye
Authors: Kirby Margaret L. , Diab Ihsan M. , Mattio Thomas G. 
Published: February 2005

AbstractThe developing innervation of the chick eye has been studied using catecholamine histofluorescence. The innervation of the pupillary dilator by the superior cervical ganglion begins on day 13 of incubation when fluorescent axons can be seen in the ciliary zone circumscribing the dilator. On day 14 a few processes are seen to branch from this band into the dilator. The number of processes in the dilator increases on days 15 and 16. After day 16 there is a reorganization of the fibers radially accompanied by a moderate increase in the number of processes. In addition, a group of fluorescent cells can be seen in the choroid adjacent to the ciliary body. These cells are bipolar at day 9 and become multipolar by 12 days of incubation. These cells contribute to a fluorescent plexus of processes in the choroid which stops abruptly at the border of the choroid and ciliary zone. It is thought that they represent a terminal sympathetic ganglion receiving preganglionic input from the carotid nerve.