bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biophysical aspects of lipid interaction with mineral: Liposome model studies
Authors: Eanes Edward David 
Published: February 2005

AbstractThe present paper reviews the use of liposomes as synthetic models for studying various biophysical aspects of matrix vesical calcification, especially the involvement of acidic phospholipids in the nucleation and growth processes which occur during the initial stages of mineral formation in and around these membrane‐bound structures. Recent results showed that acidic phospholipids incorporated into phosphatidylcholine‐rich anionic liposome membranes were ineffective in initiating extraliposomal calcium phosphate precipitation from metastable solutions at physiological pH. On the contrary, certain acidic phospholipids such as phosphatidic acid and phosphatidylserine retarded the development of such precipitation when the latter was endogenously induced. The extent of inhibition correlated with the strength of the electrostatic interaction between the polar head group of the acidic phospholipid and the surface of the mineral phase. The results suggest that acidic phospholipids may play an important role in controlling the rate of early mineral development in matrix vesicle calcification.
Multinucleated cells formed on calcified dentine from mouse bone marrow cells treated with 1α,25‐dihydroxyvitamin D3 have ruffled borders and resorb dentine
Authors: Sasaki Takahisa , Takahashi Naoyuki , Higashi Shohei , Suda Tatsuo 
Published: February 2005

AbstractOsteoclast‐like multinucleated cells were formed from mouse bone marrow mononuclear cells, and their morphology on coverslips and on calcified dentine slices was compared by means of transmission electron microscopy. Addition of 1α,25‐dihydroxyvitamin D3 [1α,25(OH)2D3] to bone marrow cells cultured on coverslips greatly stimulated the formation of multinucleated cells within 8 days. These multinucleated cells had the cytological features of osteoclasts (abundant pleomorphic mitochondria, a large number of vacuoles and lysosomes, many stacks of Golgi membranes, and an extensive canalicular system), but they developed neither ruffled borders nor clear zones. The multinucleated cells appeared to result from direct fusion of mononuclear progenitor cells, whose structural features were similar to those of multinucleated cells. Like isolated osteoclasts, both multinucleated cells and their precursors exhibited an intense reaction for tartrate‐resistant acid phosphatase (TRACP) in the cisterns of endoplasmic reticulum and lysosomes. Multinucleated cells formed from alveolar macrophages in the presence of 1α,25(OH)2D3 were totally negative for TRACP reaction. When marrow cells were cultured on dentine slices in the presence of 1α,25(OH)2D3, some of the multinucleated cells were located in the shallow resorption lacunae of dentine surfaces, and they developed the characteristic ruffled borders and clear zones. The narrow extracellular spaces of the ruffled borders, the adjacent pale endocytotic vacuoles, and the dark lysosomes located in the perinuclear cytoplasm of the multinucleated cells contained numerous apatite crystals delete in resorption lacunae. These results indicate that (1) the multinucleated cells formed on coverslips from mouse marrow cells treated with 1α,25(OH)2D3 exhibit non‐functional basic features of osteoclast morphology, and (2) differentiation of the multinucleated cells into functional osteoclasts requires some components of calcified dentine.
Vasoconstriction in Telencephalic Microvessels: A Response to One Model for Intraventricular Hemorrhage in Beagle Pups
Authors: Leuschen M. Patricia , Nelson Robert M. 
Published: February 2005

AbstractTelencephalic microvessels were morphologically and morphometrically evaluated in beagle pups at 24, 48, and 72 hours of age following an experimental insult consisting of exposure to acute hypovolemic hypotension followed by rapid corrective blood reinfusion. Animals were anesthetized throughout the procedure and maintained for 75 minutes prior to sacrifice. Microvessels from the germinal matrix, where intraventricular hemorrahge (IVH) most commonly occurs, were compared to those of the adjacent cerebral cortex and choroid plexus. Perfusion, fixation and processing of the tissue followed our previously published protocol (Leuschen et al.: Anatomical Record 208:435–443, 1984). Both germinal matrix and cortical microvessels had collapsed lumens and normal endothelial cell morphology; mitochondria contained distinct cristae, junctional complexes were present and a basement lamina completely surrounded most vessels. Morphometric data on matrical and cortical microvessels supported vasoconstriction. Microvessels from choroid plexus were not vasoconstricted; tight junctions were infrequently seen and microvesicular elements were present. An increased cerebral blood flow to the germinal matrix and the adjacent cerebral cortex has been reported during and immediately following hypovolemic hypotensive insult. Insult. By 75 minutes following insult, our ultrastructural studies support a rebound phenomena including vasoconstriction of microvessels. The resulting vasocontriction and associated cerebral ischemia may play an important role in subsequent tissue damage to the matrical area and ultimately to the etiology of IVH.
The morphology of release of vitamin A‐containing lipid droplets by hepatocytes in rat liver
Authors: Kudo Shigeharu 
Published: February 2005

AbstractVitamin A‐containing lipid droplets in the hepatocytes of rat liver were found to be exocytotically released from the cells in the form of a “lipid droplet—retinol‐binding protein (RBP)—immunoreactive complex” following intraportal injection of retinol (17, 33, 67, or 100 μg). Evidence that the lipid droplets contain vitamin A was obtained by fluorescence microscopy of vitamin A. Intraportal injection of retinol produced varied numbers and sizes of vacuoles in the hepatocytes. The substance within the vacuoles exhibited a meshwork‐like configuration in sections from slices incubated in a medium for revealing acid phosphatase activity or the corresponding control medium and was RBP‐immunoreactive and proteinaceous in nature. The occurrence and number of the vacuoles depended on the dosage of injected retinol, being greatest at a dosage of 100 μg of retinol and becoming progressively less at dosages of 67, 33, and 17 μg. The vacuoles were formed by vacuolization of cisternae of the rough endoplasmic reticulum. The formation of vacuoles reached a maximum 30 min after intraportal injection of 100 μg retinol, and the vacuoles and lipid droplets had almost disappeared from the hepatocytes after 90 min. Little or no esterase activity was found in lipid droplets in the hepatocytes before intraportal injection of retinol, but after the injection, lipid droplets that had fused with the vacuoles become strongly positive for this enzyme activity. This suggests that hydrolysis of retinyl esters may occur in the process of complex formation in rat hepatocytes.
In vitro reconstruction of a cartilage matrix granule network
Authors: Phillips Frank M. , Pottenger Lawrence A. 
Published: February 2005

AbstractThe cartilage extracellular matrix contains electron‐dense granules and fine filaments when studied electron microscopically after staining with ruthenium red. The matrix granules contain proteoglycans, while the filaments are thought to represent hyaluronic acid. In the present study partial extraction of proteoglycans from the cartilage prior to staining reduced the density of matrix components to allow visualization of a well‐developed network involving the matrix granules and hyaluronic acid filaments. The matrix granules frequently had multiple filamentous attachments and the network appeared to be formed by intersecting filaments with the matrix granules at points of intersection. A similar network was created in Sepharose CL‐2B beads when proteoglycans, link proteins, and hyaluronic acid were concentrated in the beads. Elimination of any one of these components resulted in failure to form a complete network. Purified proteoglycan monomers alone were sufficient to create matrix granules in the beads. Filaments were seen only when hyaluronic acid was added to the beads. The nature of the network suggests that some type of association between separate aggregates is occurring both within cartilage and within the Sepharose CL‐2B beads.
Effects of hypofunction on the distribution of 3H‐proline in the transseptal fibers of the periodontium of the rat
Authors: Johnson Roger B. 
Published: February 2005

AbstractThere is little information concerning the effect of altered occlusal forces on the turnover of collagenous proteins of transseptal fibers of the periodontium. In the present study, hypofunction was induced in rats by extraction of the maxillary teeth, allowing the mandibular teeth to supererupt (hypofunctional side, herein). The contralateral side served as an internal control, although it was likely experiencing occlusal hyperfunction (hyperfunctional side, herein). Untreated animals were also studied (external controls, herein). Animals were injected with 3H‐proline and silver grains were counted on radioautographic preparations. The study demonstrated significant differences in the synthesis and degradation of collagenous proteins coincident to altered occlusal function; 3H‐proline was most heavily incorporated into the transseptal fibers of hyperfunctional and least rapidly into the external control tissues (P<.001). Significant differences in grain counts were evident during the first 3 weeks after injections. Collagenous proteins were degraded most rapidly in transseptal fibers of the hyperfunctional and least rapidly in hypofunctional tissues (P<.001). The study also demonstrated regional variability in the turnover of labeled collagenous proteins, that is, proteins were synthesized and degraded most rapidly in the middle third and least rapidly in the mesial third of the ligament (P<.001). “Whole” counts (mean of counts over middle, mesial, and distal thirds) were not similar to those of any specific region and could provide erroneous information concerning remodeling of collagenous proteins of transseptal fibers. Transseptal fibers, labeled by the 3H‐proline pulse, migrated occlusally with the teeth; new transseptal fibers and bone were formed at the crest of the interdental septum.
Cell distribution in tracheal surface epithelium and the effects of long‐term pilocarpine and atropine administration
Authors: Gatto Louis A. 
Published: February 2005

AbstractCell distribution and the effects of 12 daily injections of 80 mg/kg pilocarpine or 5 mg/kg atropine were studied in rat tracheal epithelium. Ciliated, periodic‐acid‐Schiff‐positive (PAS+), Alcian blue‐positive (AB+), nonstaining, and basal cells were counted and their order of occurrence was recorded. Pilocarpine caused a decrease in ciliated and an increase in PAS+, basal, and nonstaining cell numbers. Atropine caused similar changes, although to a much lesser extent. AB+ cells were rare. Cell occurrence was randomized by computer, and comparisons with nonrandomized counts were made to discern between 1) differences in cell arrangement owed to variations in cell numbers, and 2) actual biases in cell distribution. In general, ciliated areas amounted to a few cells and were separated by nonciliated patches of comparable size. The grouping characteristics of cells supported the notion that basal cells were surrounded by their progeny and that daughter cells were displaced by siblings. It was concluded that the cells were not randomly distributed. Basal cells were dispersed, and probably immediately related to PAS+ cells but not to ciliated cells. A bias toward grouping implied concurrent differentiation of clusters of sibling cells. With drug treatment, a substantial increase in PAS+ cells without increase in cell concentration suggested a decrease in ciliated cell differentiation. Larger groups of secretory cells with treatment suggested cell division without differentiation through the basal cell pathway. Cholinergic agents were not the predominant modulators of this epithelium, and their effect was probably secondary to influence over mucociliary function.
Technique for estimating fetal mouse thoracic volumes through image analysis of histological sections
Authors: Bradford Hepworth W. , Carter Melvin W. , Seegmiller Robert E. 
Published: February 2005

AbstractIn a previous study we estimated fetal mouse thoracic volume by use of paraffin casts. While this procedure provided useful information, it did not allow histologic examination of thoracic viscera. In the present study the thoracic volumes of day 14–18 fetal mice were determined through serial histological sections. The thoracic cavity was traced from the sections and the area of each tracing was determined by computer image analysis. These areas were summed and then multiplied by the thickness of each section to derive the thoracic volume. This procedure thus permitted both volumetric determinations and histological inspection of the thoracic viscera. In addition, two randomized sampling methods designed to increase the utility of such volumetric estimates were compared for reliability. The method best suited for this study was a random stratified sampling method because it reproduced estimates with minimal standard deviation.
Circaseptan (about 7‐day) modulation of circadian rhythm in corneal mitoses of holtzman rats
Authors: Tsai T. H. , Scheving L. E. , Sánchez De La Peña S. , Marques N. , Halberg F. 
Published: February 2005

AbstractAn infradian modulation with a 168 h or circaseptan period characterizes epithelial corneal mitoses in adult female and male Holtzman rats, standardized at 24 ± 1°C and ∽50% relative humidity on six different sequences of light (L) alternating every 12 h with darkness (D). To approximate sampling over a 24 h LD span by convenient sampling within a single hour, the LD 12:12 regimen was staggered by 4 h in the six environments. Bedding was changed 3 days before each day of killing. During each of eight or 12 consecutive days, male and female rats, respectively, were killed and the eyeballs were removed. Mitotic indices in the cornea were determined separately for each eye and the data were analyzed by linear and nonlinear least‐squares rhythmometry. For a prominent circadian component of mitotic activity, the 95% confidence interval (CI) of the period extends from 23.6 to 24.3 h for the data from males and from 23.7 to 24.2 h for those from female rats. The circadian amplitude is larger in males as compared to females. The peaks in the 24 h cosine functions best approximating the data, the circadian acrophases, are at −64° or −48°, i.e., 4 h 16 min or 3 h 12 min from lights‐on in male and female rats, respectively. In the data from the two genders, the 24 h synchronized circadian acrophases are thus only 16°, i.e., 1 h and 4 min apart. A test for an anticipated circaseptan (7‐day) period shows that this particular infradian periodicity is superimposed upon the circadian one in data from both genders. A circasemiseptan, about‐half‐weekly (84 h), period is also found in data from the rats of both genders. In the spectral region examined, the circadian component predominates in amplitude over infradians. As a whole, the circadian‐infradian modulation of corneal mitosis need no longer remain a large, unassessed source of variation. Instead, it is a newly resolved multifrequency time dimension of the organism, apparent in health in the basic process of cell division. The underlying multiple rhythmic intermodulations at several frequencies among neuroendocrine coordinators of physiologic function, the feedsideward mechanisms, can now be studied in Holtzman as well as Lewis rats in the light of the temporal mitotic reference standards described herein.
Demonstration by lectin‐gold cytochemistry of transfer of glycoconjugates of oviductal origin to the zona pellucida of oocytes after ovulation in hamsters
Authors: Kan Frederick W. K. , Roux Emmanuelle , St.‐Jacquesz Sylvie , Bleau Gilles 
Published: February 2005

AbstractWe have previously localized an antigen of oviductal origin to the zona pellucida of superovulated hamster oocytes (Kan et al.: Journal of Histochemistry and Cytochemistry 36:1441—1447, 1988) and described the intracellular distribution of this antigen in the oviductal epithelium (Kan et al.: Biology of Reproduction 40:585—598, 1989). These results led to our hypothesis that the oviduct is a bona fide site of origin of certain components of the zona pellucida. In this report, using the high resolution lectin‐gold approach with Helix pomatia lectin (HPL)‐colloidal gold complex, we present cytochemical evidence to show that glycoconjugates containing terminal N‐acetyl‐D‐galactosamine residues are absent from the zona pellucida of ovarian oocytes but are synthesized and secreted by the nonciliated secretory cells of the oviduct and later become associated with well‐defined structural elements of the zona matrix of oocytes during passage through the oviduct. The nature of the HPL‐binding glycoconjugates was determined by biochemical analyses. Electrophoretic and immunological experiments demonstrated that the glycoconjugates correspond to the high molecular weight polydispersed glycoprotein that we have previously described. We have designated this glycoprotein “hamster oviductin 1” (IIm OV‐1). Our results further substantiate the belief that the oviduct is a source of origin of zona pellucida constituents.
Distribution of cell surface glycoconjugates during secondary neurulation in the chick embryo
Authors: Griffith C. M. , Wiley M. J. 
Published: February 2005

AbstractLectin histochemistry was used to examine the expression of cell surface glycoconjugates during secondary neurulation in chick embryos. Fourteen lectins were applied to serial sections of the caudal region of embryos at the various stages of tail bud development. The lectins Bandeiraea simplicifolia, Dolichos biflorus agglutinin, Phaseolus vulgaris leukoagglutinin, soybean agglutinin, Sophora japonica agglutinin, Ulex europaeus agglutinin and succinylated wheat germ agglutinin (sWGA) showed very light or no binding to the developing medullary cord of the tail bud. With the other lectins, staining occurred throughout the early tail bud and solid medullary cord. During cavitation, however, differential expression of cell surface glycoconjugates by different cell populations was observed. The lectins concanavalin A, Lens culinaris agglutinin, Pisum sativum agglutinin, Phaseolus vulgaris erythroagglutinin, Ricinus communis agglutinin and WGA showed basic similarities in the distribution of lectin binding. Of these, the binding pattern of WGA was the most striking. As the medullary cord cells were separating into central mesenchymal and peripheral epithelial populations, WGA bound preferentially to the epithelial cells and the notochord. The lectin PNA, however, became preferentially bound to the mesenchymal cells. Heavy staining by WGA (specific for N‐acetylglucosamine and sialic acid) where sWGA staining (specific for N‐acetylglucosamine only) was faint suggested that WGA binding was due to the presence of sialic acid containing glycoconjugates.
Retrograde trafficking of tracer protein by the internal ovarian epithelium in gravid goodeid teleosts
Authors: Schindler Joachim F. 
Published: February 2005

AbstractGravid goodeid females harbor embryos in a preformed ovarian cavity for prolonged periods of gestation. Various nutrients for embryonic growth are provided by the internal ovarian epithelium (IOE). Its cells flatten during late stages of gestation and form an attenuated layer of cytoplasm covering a dense network of protruding capillaries, with the nuclear domains mostly recessing between the vascular meshes. The IOE in both Xenotoca eiseni and Girardinichthys viviparus exhibit morphological features associated with vesicular transport of macromolecules. The amounts of rough endoplasmic reticulum in the IOE cells seem insufficient to effectively synthesise proteinaceous secretions. Apparently, it rather serves as a transit route for serum‐derived products.Cationized ferritin (CF) was injected into the ovarian cavity of gravid females. The electrostatic ligand spotwise attached to the luminal surface of the IOE and gained access by adsorptive micropinocytosis. Many tracer molecules were sequestered into lysosome‐like vacuoles that became increasingly swollen after prolonged incubation intervals. In addition, CF traversed the IOE within small vesicles. At the basal pole of the cells the contents of transcytotic vesicles were evacuated, and localization of small CF‐clusters was regularly in the basement lamina, in the underlying connective tissue, in vacuoles within migrant cells, in vesicular compartments of the capillary endothelia, in capillary lumina, and in intravascular leucocytes. Tracer molecules were never observed to enter stacked Golgi cisternae. Since the cationic marker probably follows retrograde pathways of the protein secretion, the experimental data support the morphologically derived conclusions that postulate a major role for the IOE in transepithelial transport.
Harderian gland and the lacrimal gland of the lizard Podarcis s. sicula: Histology, histochemistry, and ultrastructure
Authors: Baccari Gabriella Chieffi , Minucci Sergio , Matteo Loredana Di , Chieffi Giovanni 
Published: February 2005

AbstractHistology, histochemistry, and ultrastructure of the Harderian gland and lacrimal gland of the lizard Podarcis s. sicula were investigated. The Harderian gland, located at the medial corner of the orbit, can be divided into three zones showing different tinctorial features either with Mallory or hematoxylineosin stains. The glandular cells of the acinar medial zone secrete predominantly acidic sulphated mucosubstances. The acinar cells of the intermediate zone contain secretory granules that show a weak reaction to the histochemical tests for mucosubstances. The lateral zone has a tubulo‐acinar type of structure and tests strongly for proteins, whereas Alcian‐PAS staining is very weak. The lacrimal gland is smaller than the Harderian gland and lies in the region of the posterior commissure of the eyelids. It shows the same histological and histochemical characteristics of the medial zone of the Harderian gland, i.e., it is mucous secreting. At the ultrastructural level the zonation is well defined, especially when the secretory granules are examined. Granules of the mucoid type are found in the lacrimal gland and the medial zone of the Harderian gland. The secretory granules of the lateral part of the Harderian gland show a composite structure never described before. Therefore, they have been called “special secretory granules”. Each of these granules is composed of three sharply separated components. It is not known whether the three components correspond to different secretions. Histochemical tests suggest that they are of the serous type. Both mucous and serous granules are secreted by the same glandular cells of the intermediate zone of the Harderian gland. The two types of granules usually occupy different cell compartments. The mechanism of secretion appears either merocrine or apocrine in both the Harderian gland and the lacrimal gland.