bluuebunny/crossref_metadata_2025_split huggingface dataset:
Golgi studies of the nucleus gracilis in the rat
Authors: Gulley Robert L. 
Published: February 2005

AbstractWith the use of Golgi‐Kopsch and rapid Golgi techniques, seven different neuronal types were described in the nucleus gracilis of the rat. In the caudal part of the nucleus the dendrites were grouped in vertical bundles origented parallel to the collaterals of the fibers in the fasciculus gracilis. Some neurons had dendrites associated with several dendritic bundles separated in the horizontal or parasagittal planes. Two types of interneurons were found in the caudal part of the nucleus. The first had its axon confined within a dendritic column formed in part by its own dendritic arborization. The axon of the second interneuron projected to a nearby dendritic column. In the rostral part of the nucleus, the various neuronal types had dendrites oriented either transversely or along the axis of the nucleus. Fibers from the fasciculus gracilis, at rostral levels, bend to course across the nucleus sending collaterals along the parasagittal plane. Thus the dendrites of the neurons in this region were directed perpendicular and/or parallel to the afferent fibers. Afferent axons to the nucleus gracilis from the pyramidal tract and medullary reticular formation were also described.
Ultrastructural localization of alkaline phosphatase activity in the developing thyroid gland of the rat
Authors: Calvert R. 
Published: February 2005

AbstractThe localization of alkaline phosphatase activity during morphogenesis of the thyroid gland was studied at the fine structural level in Holtzman rats from the fifteenth day of foetal life till the first day after birth. The present work deals with the formation of thyroid follicles in the median thyroid primordium only. Since the rat thyroid does not develop synchronously, the three stages described may overlap during a given day of development. In the precolloid stage that extends roughly from the fifteenth to the nineteenth day of development, alkaline phosphatase activity is localized in Golgi saccules and vesicles and also in smooth membrane tubules and vesicles found in the cytoplasm near the lateral plasma membranes. At the end of this stage the lateral plasma membranes become strongly reactive and a cluster of positive vesicles and tubules appears immediately under the junctional zone. The second phase, the early colloid stage (17–19 days), is characterized by the formation of the colloid cavity in center of the disc‐like junctional zone: at this moment the newly formed apical plasma membrane bearing the microvilli shows the reaction product. During the third stage (18 days onwards), which starts with a gradual increase in the diameter of follicular lumina, a drastic fall in alkaline phosphatase activity is observed. In one day old rats, follicular cells are completely negative. These findings are briefly discussed in connection with thyroid cell differentiation.
The integrated roles of longus colli and sternocleidomastoid muscles: An electromyographic study
Authors: Vitti Mathias , Fujiwara Makoto , Basmajian John V. , Iida Masaru 
Published: February 2005

AbstractUsing bipolar fine‐wire electrodes, we examined the right and left longus colli (LC) and sternocleidomastoideus (StM) muscles electromyographically in ten healthy young adults. Action potentials were recorded on FM magnetic tape and each experiment was also videotaped. The head‐neck motions were recorded using a special neck goniometer. The muscles were studied in sitting, supine, prone and lateral positions, both during free movements and against resistance. There was complete inactivity in both muscles in relaxed sitting, normal breathing, deep expiration, and wet and dry swallowing. There was very marked synchronous EMG activity of the LC and StM muscles during resisted forward flexion, marked activity during neck flexion against head weight in the supine position, and during resisted right and left side‐bending. Variable activity was found in both muscles during deep breathing, coughing, forceful blowing, loading on top of the head, resisted backward extension, neck holding against head weight in the prone position and in twisting movements downwards and upwards. During free flexion‐extension movements, LC and StM act synchronously. During free lateral bending they work homolaterally, but during free rotation to the right, the right LC works with the left StM and vice versa.
The origin of equine endometrial cups. II. Invasion of the endometrium by trophoblast
Authors: Allen W. R. , Hamilton D. W. , Moor R. M. 
Published: February 2005

AbstractLight and electron microscopic examination of tissues fixed in situ by perfusion of the gravid horn of the uteri of mares between 36 and 38 days of gestation revealed that the equine endometrial cups are composed of trophoblast cells which originate from the discrete annulate portion of the foetal membranes known as the chorionic girdle. This structure consists of closely opposed villous projections of elongated trophoblast cells and it becomes firmly attached to the endometrium around the thirty‐sixth day of pregnancy. The specialized girdle cells invade and phagocytose the endometrial epithelium and then migrate through the basal lamina into the endometrial stroma where they develop into endometrial cup cells.
Electron microscopic study of involuting thymus of “lethargic” mutant mice
Authors: Dung H. C. 
Published: February 2005

AbstractThe thymus, which undergoes spontaneous involution three weeks after birth in “lethargic” mutant mice, was studied by electron microscopy. Ultrastructural alterations observed in the involuting thymus of “lethargic” mice resemble those of acute thymic involution induced by the administration of adrenal corticosteroids. The responsive cells in thymic involution of “lethargic” mice were cortical thymocytes, macrophages, and epithelial cells. The first indication of the involution was the appearance of a large number of degenerating thymocytes in the cortex. Pyknotic nuclei of degenerating thymocytes were observed within the macrophages. Macrophages of the involuting thymus were characterized by their content of thymocyte pyknotic nuclei as well as a variety of cytoplasmic inclusions. Cytoplasmic inclusions were also found in the epithelial cells. The inclusions were of two different types: (a) tonofibrils in markedly increased numbers in relation to a non‐involuted thymus, and (b) large vacuoles with dense bodies and/or myelin figures, as found in a normal cell, but several times the number one would expect to find. A large number of lipid‐laden cells were found in the involuted thymus. This type of cell was not seen in the normal thymus. Numerous Hassall's corpuscles were also found in the involuted thymus of “lethargic” mice.
Fine structure of the agranular cytoplasmic tubules in the lamprey chloride cells
Authors: Nakao Taisuke 
Published: February 2005

AbstractThe chloride cells of the lamprey, Lampetra japonica, have been studied by electron microscopy. The most characteristic feature of the chloride cells in lamprey is that the cytoplasm is filled with a large number of mitochondria and numerous agranular cytoplasmic tubules arranged as bundles or as branched reticular networks. These tubules are frequently continuous with the plasma membrane. They are also characterized by a coating on the cisternal surfaces with a dense material which appears ridge‐like at high magnification. These ridges are oriented spirally along the cisternal surface of the tubule. They are regularly spaced at an interval of about 160 Å and have a pitch of about 45°. The functional significance of the cisternal coat is unknown. Sometimes, intracisternal tubules are observed to be contained within the lumina of the agranular cytoplasmic tubules. These intracisternal tubules are considered to be formed by an intracisternal deflection of only one leaflet of the unit membrane of the agranular cytoplasmic tubules. Membrane fusion is observed to occur between closely associated agranular cytoplasmic tubules.
Specialized intercellular junctions in the intercalated disc of the bat heart
Authors: Hagopian Martin , Anversa Piero , Nunez Eladio A. 
Published: February 2005

AbstractThe intercalated discs of the myocardium from the active and hibernating bat hearts were investigated by means of electron microscopy and use of lanthanum and horseradish peroxidase as tracers. The discs are composed of four zones: intermediate junctions, desmosomes, nexuses, and undifferentiated areas. Of particular interest are the two different types of nexuses. Nexus I without lanthanum displays a 150 Å overall width and an apparent 80 Å intercellular space, ranges from 0.5 to 4.0 μ in length, and is seen in the longitudinal segments of the intercalated disc. With application of lanthanum, however, nexus I shows that the tracer has penetrated a 20 Å gap junction and resembles nexus II. Nexus II with and without lanthanum has a 200 Å overall width and a gap junction of about 20 Å, is generally less than 0.3 μ in length, and is found on the transverse or oblique segment of the intercalated disc. Both nexuses I and II seem to block the passage of peroxidase. The plasma membranes of nexus I may have a different molecular organization from those in nexus II as reflected by their contrasting response to fixation and/or staining. Combinations of the various junctions show that the zones of adhesions (intermediate junctions and desmosomes) are adjacent to the regions of possible lowered resistance (nexus I and II). These findings suggest that adhesion sites insure the proper connection and functioning of the nexuses and support the electrical observations that the heart forms a “physiological syncytium”.
The effect of eifferent estrogen‐progesterone ratios on DNA synthesis in the rat uterus
Authors: Krueger Wayne A. , Bo Walter J. , Garrison Benjamin M. 
Published: February 2005

AbstractThe influence of different estrogen‐progesterone ratios on DNA synthesis in the rat uterus was investigated. Ovariectomized rats were injected subcutaneously daily for three days with either oil, 1 μg estradiol‐17β dipropionate or estradiol and 1, 5, 10 or 15 mg progesterone. Tritiated thymidine was administered one hour prior to necropsy. Thymidine indices were determine for both the luminal and glandular uterine epithelia while the total number of labeled nuclei in the stroma was ascertained. In all tissues studied, significantly more nuclei from uteri of rats given only estrogen replicated DNA than from those of the oil‐treated controls. While concurrent treatment with estradiol and 1 or 15 mg progesterone did not statistically alter the extent of thymidine incorporation in the luminal epithelium and stroma from that observed following estrogen alone, 5 or 10 mg progesterone given with estrogen significantly suppressed the labeling activity in the luminal epithelium and stroma from that of the estrogen‐treated rats. However, the thymidine indices of the glandular epithelium from uteri of rats injected with all combinations of both hormones were significantly lower than that from uteri of estrogen‐treated rats. These data indicate that the estrogen–progesterone ratio is important in regulating cell turnover in the luminal epithelium and stroma of the rat uterus but not in glandular epithelium.
Intramural blood supply of porcine heart. A postmortem angiographic study
Authors: Jöunsson Lennart , Johansson Göuran , Lannek Nils , Lindberg Paul 
Published: February 2005

AbstractThe intramural arteries, arterioles and capillaries of the hearts of 23 crossbred pigs, six months old, of Yorkshire and Swedish landrace were presented.The vascular pattern was basically the same in both the ventricular walls. Large branches of two types emerged from the extramural arteries and traversed the myocardial wall, terminating in the subendocardial zone. The largest vessels supplied the papillary muscles and trabeculae carneae. The terminals of these branches formed the subendocardial anastomotic network. No other anastomoses were observed in the ventricular walls. The capillaries had a course parallel to the muscle fibers and anastomosed freely. Most of the interventricular septum was supplied by branches from both the left and the right descending arteries. Only a minor part of the septum was supplied by the anterior and posterior septal arteries.The ventricular vascular pattern of the pig was found to be very similar to that of the human heart. It was concluded that the pig, in contrast to the dog, has ideal attributes for comparative cardiovascular research in man.
Ultrastructure of ependymal cells of the shark median eminence
Authors: Saland L. C. , Evan A. P. , Demski L. S. 
Published: February 2005

AbstractThe ultrastructure of ependymal cells of the median eminence in young Pacific blacktip reef sharks is described. Three major cell types have been observed. The first type is an irregularly‐shaped, electron dense cell with many long microvilli and occasional cilia projecting into the ventricle. A second type contains dense cytoplasmic granules in sizes ranging from 1000–2000 Å, and may be morphologically equivalent to “liquor‐contacting neurons” observed in ependymal linings elsewhere. The third type appears very similar to crown cells of saccus vasculosus of this and other species. Cells of the third type possess large, lipid‐like inclusions, bulbous projections originating from basal bodies, and prominent smooth endoplasmic reticulum. The crown‐like cells are compared to cells of saccus vasculosus of young and adult sharks, and their possible significance is discussed.
Medial occipital projections to the nucleus of Darkschewitsch of rhesus monkey
Authors: Wright Sanford , Hilsz Joyce , Locke Simeon 
Published: February 2005

AbstractProjection from medial occipital cortex (area OB) to the nucleus of Darkschewitsch is demonstrated in six Macaca mulatta hemispheres by the technique of Fink and Heimer. Degeneration was present as well in the lateral pons, nucleus lateralis dorsalis, nucleus lateralis posterior, lateral pulvinar and nucleus parafascicularis. Centrum medianum, dorsal lateral geniculate body and interstitial nucleus of Cajal were spared.
The postnatal growth of the rat lung. I. Morphometry
Authors: Burri Peter H. , Dbaly Jaroslav , Weibel Ewald R. 
Published: February 2005

AbstractThe postnatal growth of the lung was quantitatively investigated in rats aged 1, 4, 7, 10, 13, 21, 44 and 131 days by light and electron microscopic morphometry.Lung volume (VL) increased first directly with body weight (W). After day 10 VL followed the function W0.70. Based on the quantitative findings the postnatal lung growth could be divided into three phases.
Lung expansion (up to day 4): Lung volume increase resulted almost exclusively from an 87% enlargement of the existing air spaces.
Tissue proliferation (day 4 to 13): All tissue compartments showed a pronounced mass increase, followed by a high gain in capillary volume. Alveolar and capillary surface areas (Sa, Sc) developed rapidly due to subdivision of the primitive air sacs.
Equilibrated growth (third week to adult age): An initial period of redistribution of tissue mass with septal lengthening and further rapid increase in Sa and Sc was followed by proportionate alveolar growth. In the adult further lengthening of the interalveolar septa or continued alveolar formation could not be excluded.
During the period of fundamental internal remodelling of the lung, its function, as determined by the morphometric pulmonary diffusing capacity, was not impaired.
Evidence for a retinohypothalamic pathway in the golden hamster
Authors: Printz Richard H. , Hall James L. 
Published: February 2005

AbstractEvidence for a direct neural projection from the retina to the hypothalamus in the golden hamster (Mesocricetus auratus) is presented. In 25 blinded animals degeneration was followed in sections prepared according to the Wiitanen ('69) silver impregnation method. Degenerative axons were found in the optic tract, chiasm, and nerve, terminating in the lateral geniculate body and superior colliculus. A large collateral bundle of degenerating axons was observed curving medially and dorsally to enter the hypothalamus at the level of the mamillary body. This bundle turned diffusely rostrally and terminated on neurons in the ventromedial nucleus of the hypothalamus.It is proposed that two alternate pathways exist for the effect of photoperiodicity on the reproductive cycle in the hamster, one involving the pineal gland directly and the hypothalamus indirectly, and the other a direct retino‐hypothalamic projection.
The effects of diets enriched with corn oil on the ultrastructure of articular chondrocytes
Authors: Silberberg Ruth , Hasler Mary 
Published: February 2005

AbstractThe ultrastructure of articular cartilage of the femoral head was examined in growing male mice of strain C57Bl fed diets containing supplements of 25 or 40% corn oil for periods of 10 days, 2 and 4 weeks and 2 and 3 months. The ration containing 25% corn oil did not produce conspicuous effects. The ration containing 40% corn oil exerted a slight stimulation on the size, the ER, and the mitochondria of the articular chondrocytes. The findings are consistent with the long range effects of oil‐enriched diets on the knee joints of mice and in particular with the failure of such diets to promote the development of osteoarthrosis in mice of strain C57Bl. The results are discussed in relation to earlier observations of the injurious action of diets containing comparable amounts of saturated fat.
Direct contact between a neuron soma and myocardial cells; an electronmicroscopic finding in the sinus venosus of the turtle heart
Authors: Yamauchi Akio , Fujimaki Yoko , Kumagai Kenichi 
Published: February 2005

AbstractElectron microscopy of the turtle sinus venosus shows an unusual neuron soma which is immediately surrounded by myocardial cells so as to form a somato‐muscular complex. Studies of 36 sections cut through this neuron soma indicate that 27.4% of the somal surface studied is directly covered by cardiac muscle cells without any intervening basal lamina. Similarly, 18.8% of the somal surface studied is in contact with unmyelinated axons which at places make typical axosomatic synapses. A coupling of peripheral cisterns of the sarcoplasmic reticulum and the sarcolemma exists at the somato‐muscular contiguity as well as at the border between cardiac muscle cells. It is suggested that neural influences upon the pacemaking activity of the turtle heart sinus can well be exerted through the somato‐muscular pathway. Additionally, an axon which is presynaptic to the neuron soma has been observed to be simultaneously in a synaptic relation with a cardiac muscle cell; a remarkable deviation from the classical picture of the efferent nervous outflow to the heart.
Investigations on the innervation of the human diaphragm
Authors: Hidayet M. A. , Wahid H. A. , Wilson A. S. 
Published: February 2005

AbstractIn 2 dogs, 5 cats and 30 human cadavers the diaphragmatic innervation has been studied macroscopically and microscopically. General findings of previous authors regarding phrenic and intercostal nerve contributions have been confirmed and subdiaphragmatic connections from the coeliac plexus to the diaphragm have been clearly demonstrated. The presence of this viscerosomatic interconnection in half of the human subjects studied, highlights the possible importance of autonomic control of diaphragmatic musculature. The finding of comparable autonomic connections in dogs raises the possibility of pursuing the question experimentally by carrying out nerve degeneration studies. In addition the matter of surgical incisions in the diaphragm has been reconsidered and the suggested placements have been illustrated.
Alterations in the epithelial surface of human palatal shelves prior to and during fusion: A scanning electron microscopic study
Authors: Waterman Robert Earle , Meller Samuel M. 
Published: February 2005

AbstractThe surface topography of palatal shelves was examined by scanning electron microscopy prior to and during secondary palate formation in 72 therapeutically aborted human embryos and fetuses ranging in age from 37 days to 12 weeks (post‐fertilization). Alterations in epithelial surface appearance were observed in the prospective region of fusion prior to contact between the shelves. First seen as an elliptical area along the anterior portion of the presumptive medial edge, a zone of alteration spread progressively along the anterior four‐fifths of the medial edge prior to shelf contact, and continued along the posterior one‐fifth of the shelf as fusion proceeded. The altered zone eventually extended onto the oral surface in the middle of the shelf but was restricted to a narrow zone along the medial edge posteriorly. Initially characterized by elongation and “intertwining” of superficial cells, alterations later included cell death, desquamation and possible active migration of surface cells. The shelf epithelium subjacent to the zone of alteration exhibited increased irregularity in thickness and numerous “invaginations” into the underlying mesenchyme. These alterations are thought to reflect intrinsic changes within the shelf and may play a role in the fusion process. Evidence for surface remodeling following fusion was also observed.
Loss of mitotic response of the thyroid gland to TSH in hypophysectomized rats and its partial restoration by anterior and posterior pituitary hormones
Authors: Isler H. 
Published: February 2005

AbstractThe follicular cells of thyroid glands of intact rats respond to TSH challenge by an intense mitotic stimulation and a higher functional activity as measured by the epithelium height. In hypophysectomized rats the same intense response was observed when the thyroid was challenged immediately after hypophysectomy. However, one week later the mitotic response was almost completely absent and the functional response much weaker. This indicates that, although TSH is the main regulating factor of the functional activity and cell proliferation of the thyroid follicle, its effect is conditioned by additional factors. These factors may originate both from the anterior and/or posterior pituitary, since a significantly higher response was obtained by injecting anterior or posterior pituitary powder during the interval between hypophysectomy and TSH challenge. Prolactin, vasopressin and oxytocin also boosted the mitotic response to TSH. Posterior pituitary powder alone (without TSH challenge) was not mitogenic for the thyroid gland either in intact or hypophysectomized rats, while it was mitogenic for the adrenal glomerulosa. The low thyroid mitotic responsiveness does not reflect a general unspecific effect on mitoses of all cells, since the esophageal epithelium was not similarly affected by hypophysectomy or by replacement therapy.