bluuebunny/crossref_metadata_2025_split huggingface dataset:
Innervation of rat molar teeth: II. A quantitative analysis of primary sensory neurons innervating a mandibular molar tooth
Authors: Aker F. David 
Published: February 2005

AbstractThis study was conducted to determine the source and number of primary sensory neurons (PSNs) innervating a mandibular molar tooth of a population of 15–18‐week‐old Sprague‐Dawley rats. The pulpal tissue was exposed to horseradish peroxidase (HRP) pellets for 24 hours. Subsequently the animals were perfusion fixed and the following PSN structures were examined for the presence of HRP‐labelled cells: trigeminal (TGs) and cervical dorsal root ganglia (DRGs) and mesencephalic nucleus (MN).Only the TGs contained labelled cells and they thus were the sole source of PSN pulpal innervation. The number of TG cells was highly variable, 49–407, but most of this variability was attributable to insufficient HRP filling of the pulp chamber or leakage of HRP into periapical tissue. Selection of TGs whose respective experimental teeth demonstrated that HRP filled and was restricted to the pulp chamber revealed a narrower range of TG cells providing pulpal innervation to the first molars, 142–288, with an average of 213. A detailed mapping of these cells indicated a somatotopic distribution within the mandibular territory of the TGs. It was concluded that these findings represent TG's contribution to the pulpal innervation of this specific population of rat first molar teeth. This suggests that from animal to animal the density of innervation may be quite variable and it is hypothesized that the sensitivity of the pulp would likewise vary. In addition, these findings may contribute to the explanation of why there is variability in the stimulus strength needed to elicit a pain response in the human dentition.
Use of animals in experimental research: A scientist's perspective
Authors: Bulger Ruth Ellen 
Published: February 2005

AbstractThe present article was written as an attempt to understand the position of animal rights groups, to stimulate scientists to define their own positions, and to encourage scientists to interpret their use of animals to the rest of society. The article attempts to generate a statement of practices that might be useful in experiments that utilize animals in research. The statement is an extension of the three R's originally proposed by Russell and Burch (W.M.S. Russell and R.L. Burch [1959]: Principles of Humane Experimental Technique, Springfield, IL, Charles C. Thomas) into four R's: refinement, reduction, replacement, and review.
In vivo evaluation of teratogenesis and cytogenetic changes following methylmercuric chloride treatment
Authors: Curle D. C. , Ray M. , Persaud T. V. N. 
Published: February 2005

AbstractMercury is a major environmental pollutant and a proven teratogen in man and animals. Its teratogenicity and effects on fetal chromosomes were investigated in mice. Various dose levels of methylmercuric chloride (MMC) were administered via an intragastric tube to pregnant ICR Swiss/Webster mice on day 9 of gestation. On day 18 of gestation the animals were killed and the fetuses were removed. Fetal lung and liver tissues were processed for cytogenetic studies. Fetuses were also fixed in Bouin's solution for subsequent teratological examination by using Wilson's technique. Mercury levels were determined in maternal blood and randomly selected fetuses. One fetus from each litter was processed for skeletal staining with Alizarin Red S.A significant increase in embryonic deaths and resorptions was observed at all dose levels. The incidence of fetal anomalies was significantly increased following maternal treatment with 10, 15, or 20 mg/kg of MMC. Maternal weight between day 9 and day 18 of gestation decreased significantly. The LD50 of MMC in pregnant mice was determined to be 20 mg/kg of body weight; the LD100 was 30 mg/kg. A significant difference was observed between the mean fetal weights at the various dose levels.Levels of mercury were found to be significantly higher in treated animals and fetuses, and increased in a dose‐related manner. The levels of mercury were significantly higher in the fetuses than in the mothers at the same dosage, indicating a correlation between the levels of mercury in maternal mice and corresponding higher levels in their fetuses.Cytogenetic studies revealed significant clumping of chromosomes in metaphase at all dose levels and the frequency of clumping increased as dosage increased. The euploidy number (2n = 40) of chromosomes per cell did not vary between the treatment groups and control groups. The frequency of nucleolus‐organizing regions per cell did not change significantly between the treatment groups and the control. The frequency of sister chromatid exchanges increased significantly as the dosage increased.
Glucose 6‐phosphatase and glycogen phosphorylase activities in chondrocytes in epiphyseal cartilage of growing rats
Authors: Tokunaga Hirohiko , Watanabe Jun , Kanai Kazuo , Sakaida Minoru , Kanamura Shinsuke 
Published: February 2005

AbstractGlycogen, glycogen phosphorylase, and glucose 6‐phosphatase (G6Pase) activities were examined cytochemically in chondrocytes of femoral epiphyseal cartilages and cartilaginous ribs of 3‐ and 7‐day‐old rats. G6Pase activity was also examined biochemically. Glycogen was abundant in chondrocytes of the reserve zone, while it became scarce in the cells of the proliferative zone. From the upper part (adjoining the proliferative zone) to the lower part of the hypertrophic zone, glycogen accumulated in chondrocytes and decreased in the cells of the degenerative zone. Inversely, glycogen phosphorylase a and G6Pase activities were relatively high in chondrocytes of the proliferative zone and upper hypertrophic zone and were low in the cells of the reserve zone, lower hypertrophic zone, and degenerative zone. The reaction product for G6Pase was present in the endoplasmic reticulum and nuclear envelope of all types of chondrocytes composing the cartilages, although the amounts of reaction product varied with the cell types in parallel with the histochemical results. Biochemical G6Pase activity was higher in epiphyseal cartilages than in cartilaginous ribs.The possible mechanism and significance of the accumulation and decrease of glycogen in chondrocytes of the epiphyseal cartilage were discussed.
Morphometric and experimental studies of the red nucleus in the albino rat
Authors: Strominger Robert N. , McGiffen Jean E. , Strominger Norman L. 
Published: February 2005

AbstractCytoarchitectural observations showed that the red nucleus of the albino rat consists of three distinct neuronal populations. Neurons with coarse Nissl bodies occupy the caudal end of the red nucleus and extend in diminishing number to the rostr tip. Neurons with finely granular Nissl material are the predominant cell type at the rostral tip of the red nucleus and interdigitate with the coarse neurons except at the caudal end of the nucleus. Coarse neurons, in contrast to fine neurons, are multiangular in contour and tend to be larger, although the two populations overlap in size. A population of interneurons, almost entirely smaller than the other cell types and less numerous, is ubiquitous within the red nucleus.Injections of horseradish peroxidase (HRP) at different levels of the spinal cord established that the coarse neurons on the contralateral side are the source of the rubrospinal tract and are topographically organized. The dorsal‐medial part of the red nucleus emits axons which project to the cervical cord and the ventral‐ventrolateral part of the nucleus to the lumbar cord. The thoracic cord receives projections from rubral neurons at intermediate positions. Further, coarse neurons from the entire rostrocaudal axis of the red nucleus contribute fibers to the rubrospinal tract.
Effects of actinomycin D on the lysosomes of newborn rat hepatocytes
Authors: Kotoulas O. B. 
Published: February 2005

AbstractThe effects of actinomycin D on newborn rat liver were studied by using biochemical assays, electron microscopy, and quantitative morphometry. Actinomycin prevented the normal postnatal rise in acid a 1,4 glucosidase (maltase) activity and the breakdown of lysosomal glycogen. The results suggest that the postnatal increase in acid glucosidase activity is protein synthesis dependent. This enzyme is critical for the catabolism of the lysosomal glycogen in newborn rat hepatocytes.
Postnatal growth of the sheep lung: A morphometric study
Authors: Davies Paul , Reid Lynne , Lister George , Pitt Bruce 
Published: February 2005

AbstractStereologic methods were used to study lung development in sheep from 2 to 171 days of age. Most growth occurs within the first 2 months when there is a threefold increase in lung volume, but allometric relationships show that this increase does not keep pace with body weight. Alveolar and capillary surface areas increase as lung volume to a power only slightly large than 1, suggesting a modest increase in complexity; this is confirmed by only a two‐to threefold increase in total alveolar number. Allometric power functions are essentially unchanged even during the first 30 days so that throughout development, the surface for gas exchange is added at a fairly constant rate. A slight increase in septal volume during the first 30 days is probably due to relative increase in capillary luminal volume through a progressive distension of capillaries. The results suggest that the active newborn lamb requires an alveolar lung, but in the postnatal period functional needs increase only moderately. In contrast, other mammals, such as the rat, are helpless as newborns and have a primitive saccular lung that must undergo considerable morphogenesis to meet the demands of the active adult.
On the presence of intermediate cells in the small intestine
Authors: Calvert Raymond , Bordeleau Guy , Grondin G. , Vezina A. , Ferrari J. 
Published: February 2005

AbstractIn the small intestine, the presence of transitional cells or cells intermediate between Paneth cells and goblet cells has been reported frequently for 100 years. Light microscopy and, more recently, fine structural studies have indicated that secretory granules observed in intermediate cells share some morphologic characteristics with those of granular goblet cells and of Paneth cells. In order to verify if intermediate cells in the jejunum and ileum of the adult mouse have functional similarities with either granular goblet or Paneth cells, we have studied the incorporation of sulfur‐35 by radioautography and the localization of lysozyme by immunocytochemistry. After radioautography, goblet cells and, to a lesser extent, granular goblet cells had incorporated sulfur‐35, whereas Paneth cells and intermediate cells were completely negative. Immunolocalization of lysozyme was done by using rabbit anti‐rat lysozyme and protein A‐peroxidase. After demonstration of peroxidase activity, only Paneth cells were stained and intermediate cells were negative. Therefore, intermediate cells do not contain sulfomucinn or lysozyme, and they are functionally different from goblet and Paneth cells. Their function remains unknown.
Stereological assessment of age‐related changes in lipid droplet surface area and vascular volume in rat interscapular brown adipose tissue
Authors: Nnodim Joseph O. 
Published: February 2005

AbstractThe surface area of stored triglyceride and the volume of capillaries in the interscapular brown fat pad of the rat have been adopted as morphological indices of the overall thermogenic capability of the tissue. The present study examines the relationship between the chronological profiles of these parameters and reported senile changes in the biochemical and physiological characteristics of brown adipose tissue.Lipid droplet surface density and vascular volume density were estimated by computer‐assisted planimetry with electron micrographs prepared from interscapular brown adipose tissue samples obtained from rats of various ages. The volumes of the fat pad at these ages were also determined and used to calculate droplet surface areas and vascular volumes.Triglyceride surface area showed a 20‐fold enhancement in the early postnatal period (0.44 × 102 cm2 at birth; 9.43 × 102 cm2 at 4 weeks). A further but less remarkable increase occurred in adulthood (11.67 × 102 cm2 at 6 months) and, in old age, only a slight fall was noted (9.66 × 102 cm2 at 2 years). Intralobular capillary volume also rose sharply early during the first week after birth, reaching a peak at 4 weeks (2.40 × 10−2 cm3). The values recorded in adulthood and old age (1.90 × 10−2 cm3 at 6 months; 1.76 × 10−2 cm3 at 2 years) were not significantly different from that obtained at 4 weeks of age.These results show that the attainment of maximum values of lipid droplet surface area and vascular volume in rat interscapular brown adipose tissue coincides with the period of the tissue's peak metabolic capacity. However, although the thermogenic requirements of the older animal are less than those of the young, the relative constancy of these parameters in adulthood is consistent with the persistent ability of brown adipose tissue to respond to appropriate stimuli by hyperemia and rapid intracellular lipid mobilization.
Lectin‐gold cytochemistry of mucin oligosaccharide biosynthesis in golgi apparatus of airway secretory cells of the hamster
Authors: Wasano Kojiro , Nakamura Keiichiro , Yamamoto Torao 
Published: February 2005

AbstractTo elucidate the mechanism for the biosynthesis of O‐linked mucin oligosaccharides, airway secretory cells of the hamster trachea were embedded in Lowicryl K4M resin, and section were examined by lectin‐gold cytochemistry with special attention focused on the Golgi apparatus. The interrelations between the Golgi cisternae stained with five different lectins were determined by double‐staining procedures using various combinations of lectins conjugated with 14‐nm and 8‐nm colloidal gold. Several cis cisternae were stained only with HPA (Helix pomatia aggulutinin specific for terminal α‐N‐acetylgalactosamine). The next medial cisternae were not stained with HPA. but reacted positively with two lectins, GSII (Griffonia simplicifolia agglutinin II specific for terminal α‐ or β‐N‐acetlyglucosamine) and RCAI (Ricinus communis agglutinin I specific for β‐galactose). The transcisternae as well as condensing and mature secretory granules were labeled with four lectins, UEAI (Ulex europaeus aggulutinin I specific for terminal α‐L‐fucose) and LFA (Limax flavus aggulutinin specific for terminal N‐acetyl or N‐glycolyl neuraminic acid) in addition to HPA and RCAI. The same number of trans cisternae were positive to HPA and UEAI, whereas LFA bound to a few transmost cisternae but fewer than were stained with HPA or UEAI. The observed sequential appearance of different sugar residues in different levels of Golgi cisternae (from cis to trans cisternae) coincides quite well with the sugar sequence of airway mucin oligosaccharide (from reducing to nonreducing ends) proposed by biochemical analysis. It is suggested that airway mucin oligosaccharides elongate during a vectorial movement through the Golgi stack from cis toward trans and that the stack consists of at least three functionally distinct segments, cis, medial, and trans; in these three segments there take place, respectively, the initial O‐glycosylation of mucin core peptide, the formation of a core region of oligosaccharide chain, and the completion of chain growth by addition of terminal sugar moieties.
In vivo localization and biological effect of anti‐yolk sac monoclonal antibodies
Authors: Sobis Halina , Van Hove Luc , Vandeputte Michel 
Published: February 2005

AbstractTwo monoclonal antibodies directed against rat yolk sac antigen 1 (mab 6D1) and yolk sac antigen 2 (mab 3C3) were injected i.v. into pregnant or tumorbearing rats. Immunofluorescent examination of the different organs from animals killed, 2, 24, or 48 hours after inoculation showed the specific binding of mab 6D1 to the free surface of visceral endoderm cells in pregnant animals and on visceral cells of yolk sac carcinoma. The mab 3C3 reacted only with the endoderm of parietal yolk sac and with a distinctive parietal pattern of the tumor. The reaction was strong after 2 and 24 hours following injection and much weaker after 48 hours. The 3C3 mab had an embryotoxic effect, whereas the 6D1 mab did not influence the development of the fetus.
Effect of colchicine on the transport of precursor enamel protein in secretory ameloblasts studied by 3H‐proline radioautography in vitro
Authors: Matsuo Saburou , Takano Yoshiro , Wakisaka Satoshi , Ichikawa Hiroyuki , Nishikawa Shinji , Akai Michio 
Published: February 2005

AbstractThe incorporation of 3H‐proline into the secretory ameloblasts of rat molar tooth germs cultured with or without colchicine was studied by light and electron microscope radioautography to determine the function of microtubules in the transport of precursor enamel protein from the rough‐surfaced endoplasmic reticulum (rER) to the Golgi cisternae. The grain counts over the transitional vesicles, which accumulated in various cellular regions with colchicine treatment, continued to increase with chase time, unlike in controls. At 30 and 90 min chase, these counts were significantly higher than in controls. Moreover, the total grain count over the organelles (rER, pale granules, and transitional vesicles), which are positioned before the Golgi cisternae in the synthetic pathway, maintained a significantly higher level at 90 min chase in colchicine‐treated tooth germs than in controls. The transport of synthesized protein to the Golgi cisternae via transitional vesicles was suppressed in colchicine‐treated tooth germs. Some grains appeared with time over pale granular materials that appeared in the intercellular spaces of secretory ameloblasts with colchicine treatment. However, at each chase period, the grain count over pale granular materials was not so high as the count over the enamel in control. The present results indicate that colchicine affects the transport of newly synthesized protein from the rER to the Golgi cisterna via transitional vesicles, probably by interfering with the oriented transport related to microtubular function. It is suggested that the microtubular system may be concerned with the movement of the transitional vesicles.
Ultrastructural features of type II alveolar epithelial cells in early embryonic mouse lung
Authors: Ten Have‐Opbroek Ank A. W. , Dubbeldam Jacqueline A. , Otto‐Verberne Caroline J. M. 
Published: February 2005

AbstractImmunofluorescence studies of type II alveolar epithelial cells indicate that they first apper in the pseudoglandular period of mouse lung development (around day 14.2). They are the only cell type to line the prospective pulmonary acinus at this time. The ultrastructural characteristics of this cell are defined by investigating embryos aged 13–16 days with transmission and scanning electron microscopy.Early embryonic type II cells appear as low‐columnar or cuboid cells having large, approximately round nuclei and distinct ultrastructural features, including a welldeveloped Golgi apparatus with many associated vesicles, multivesicular bodies, dense bodies, and large apical and basal glycogen fields. These fields represent a distinctive property of the cell. Frequently, they show compartmentalization due to the presence of membrane systems, and association with dense bodies of various sizes.
Morphological and immunocytochemical studies of fibronectin‐coated, plasma membrane‐limited vesicles in the early chicken embryo
Authors: Harrisson Fernand , Vanroelen Chris , Vakaet Lucien 
Published: February 2005

AbstractVesticles with a mean outside diameter of 32.8 nm have been observed in the early chicken embryo after fixation with a mixture of glutaraldehyde and tannic acid. Densitometric tracing has revealed that the vesicles are limited by a unit membrane. The presence of complex carbohydrates is suggested by the increased electron density of the vesticles after addition of tannic acid to the fixative. Immunocytochemical staining with a monoclonal antibody directed against chicken cellular fibronectin demonstrated the presence of this glycoprotein along the surface of the vesicles. These results suggest a cellular origin of the vesicles, since their surface shares morphological and biochemical similarities with the cell surfaces of the embryonic tissue layers. Recyling of plasma‐membrane vesicles may occur, as vesicles were found in the vicinity of coated vesicles. We postulate that extracellular materials of the cell surface, which may affect cell and tissue interactions, are shed in the environment together with plasma‐membrane vesicles. The difficulties encountered in observing the vesicles stems from facts that an adequate visualization method is necessary and that they are few in number. The latter reason suggests their transient nature. The vesicles probably rapidly disintegrate in the extracellular milieu or are recycled by the cell surface.
A quantitative study of myonuclear and satellite cell nuclear size in Duchenne's muscular dystrophy, polymyositis and normal human skeletal muscle
Authors: Watkins Simon C. , Culien Michael J. 
Published: February 2005

AbstractThe dimensions of myonuclei and satellite cell nuclei in Duchenne's muscular dystrophy (DMD), polymyositis, and normal controls were compared in order to determine whether differences in satellite cell populations (previously reported by these and other authors) could be attributable to changes in the relative dimensions, thereby biasing the counts. The nuclei were measured directly from semithin resin sections using computerized measureing techniques, thereby avoiding errors due to photographic enlargement. In both the control and polymyositic groups, the satellite cell nuclei (8.30 μm and 8.81 μm respectively) were significantly shorter than the myonuclei (11.75 μ and 13.00 μm). Dystrophic myonuclei (10.98 μm) were significantly shorter than polymyositic myonuclei, but dystrophic satellite cell nuclei (11.62 μm) were significantly longer than both polymyositic and normal control satellite cell nuclei. The mean nuclear area in transverse sections was significantly greater in both myopathies than in the control material for both myonuclei and satellite cell nuclei. Myopathies were significantly larger than satellite cell nuclei in all groups. When the values for the lengths of the nuclei were used to adjust previous estimates of satellite cell populations, it was found that earlier conclusions were still valid, i.e., that there is a significant increase in the number of satellite cells in the dystrophic muscle fibre population.
The ultrastructure of megakaryopoietic cells of the yolk sac and liver in mouse embryo
Authors: Matsumura George , Sasaki Kazunobu 
Published: February 2005

AbstractMegakaryopoietic cells in the yolk sac and liver of mouse embryos were examined by electron microscopy. At 10 days' gestation, yolk sac vitelline vessels contained a few free megakaryopoietic cells. On the basis of the development of demarcation membranes and granules, yolk sac megakaryopoietic cells were classified into three types: YM1, YM2, and YM3. The YM1 cells, which comprised 75% of the yolk sac megakaryopoietic cells, had poorly developed demarcation membranes and few granules in the cytoplasm. The YM2 cells had a developed demarcation membrane system around the nucleus and comprised 24% of the yolk sac megakaryopoietic cells. The YM3 cells, the rarest type, had an eccentrically located nucleus and a cluster of demarcation membrane structures. In the liver of 11‐day embryos, immature megakaryopoietic cells were present in both the sinusoidal lumen and the hepatic cords. Most of the hepatic megakaryopoietic cells of 11‐day embryos had ultrastructural features similar to those of YM1 cells or intermediate between YM1 and YM2 cells.