bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microvascular networks in tympanic membrane, malleus periosteum, and annulus perichondrium of neonatal mongrel dog: A vasculoanatomic model for surgical considerations
Authors: Maher William P. 
Published: February 2005

AbstractIndia‐ink‐imaged blood‐vessel networks in cleared tympanic membranes and adnexa from ten neonatal dogs were examined microscopically and photographed. The major significance of the study lies in documentation of a dual source of arterial supply, a bilaminar relationship of arterial and venous plexuses intrinsic to the tympanic membrane, and a consistent major venous pathway relative to a definite locus (pars flaccida of the membrane). Illustration of all three types of blood pathways (arteries, veins, and capillaries) provides new vasculoanatomic data that are essential to ear surgery, specifically—to myringotomies and myringoplasties. A comparison was made between dog and human tympanic membrane structures and their arterial supplies. Close similarities suggested that dog tympanic membrane might serve as a suitable model for development of innovative surgical procedures and as a model for rehearsal of difficult techniques. The results of this investigation provide a valuable caveat to otologists.
Dentin resorption mediated by odontoclasts in physiological root resorption of human deciduous teeth
Authors: Sasaki Takahisa , Motegi Nobuo , Suzuki Hiroshi , Watanabe Chiaki , Tadokoro Katsumi , Yanagisawa Takaaki , Higashi Shohei 
Published: February 2005

AbstractExtracted human deciduous teeth undergoing physiological root resorption were fixed with a mixture of formaldehyde and glutaraldehyde and processed for scanning (SEM) and analytical transmission electron microscopy, as well as acid trimeta‐phosphatase cytochemistry. The granulated tissues, which are rich in multinucleated odontoclasts and capillary vessels, formed various resorption lacunae on the resorbing dentin surfaces. SEM observations of dentin surfaces treated with sodium hypochlorite revealed two types of resorption lacunae: deep, round lacunae in which the peritubular matrix of dentinal tubules was strongly dissolved; and shallow, irregular lacunae with intact peritubular matrix. In trypsin‐treated materials, the resorption surfaces were characterized by the presence of numerous collagen fibers in both the peritubular and intertubular matrices, suggesting demineralization of the surface dentin. Odontoclasts were characterized by the presence of abundant mitochondria, perinuclear stacks of Golgi membranes, various lysosomes, numerous endocytotic vacuoles, and a well‐developed ruffled border against the resorption lacunae. Most endocytotic vacuoles were distributed in the cytoplasm between the ruffled border and the nuclei. In undemineralized ultrathin sections, the surface dentin of resorption lacunae consisted of collagen fibers and apatite crystals and had a lower packing density than those in unresorbed, deeper dentin. Many apatite crystals were demonstrated to be present in the extracellular channels of the ruffled border and in adjacent endocytotic vacuoles derived from it. Lysosomes located in the perinuclear cytoplasm of odontoclasts contained amorphous dense material and/or a small amount of crystals. An energy‐dispersive x‐ray micro‐analysis of apatite crystals in undemineralized sections indicated that the energy spectrum peaks of Ca and P detected from crystals in resorbing dentin were much lower than those in unresorbed dentin. Similarly, lower spectrum peaks of Ca and P were obtained from crystals found in the ruffled border and endocytotic vacuoles of odontoclasts. A slight trace Ca peak also was detected in the amorphous dense material in lysosomes of odontoclasts. The enzyme cytochemistry of lysosomal acid trimetaphosphatase indicated that odontoclasts had intense enzymatic activity in the Golgi membranes, endoplasmic reticulum cisternae, lysosomes, and endocytotic vacuoles. Dense reaction precipitates of enzymatic activity also were found along the dentin surfaces of resorption lacunae occupied by odontoclast ruffled borders. These results suggest that, during physiological root resorption of human deciduous teeth, odontoclasts perform, at least in part, extracellular demineralization of the surface dentin and subsequently resorb and dissolve some liberated apatite crystals.
Development of dermal ridges in the volar skin of fetal pigtailed macaques (Macaca nemestrina)
Authors: Okajima Michio , Newell‐Morris Laura 
Published: February 2005

AbstractDevelopment of the dermal ridges in volar skin was investigated in 28 pigtailed macaque (Macaca nemestrina) fetuses of known gestational age, ranging from 51 days postconception to newborn. Histology, scanning electron microscopy, and staining of the abraded dermal surface were used in the study. Morphological features of the dermal‐epidermal system and their changes with advancing age are described. Chronology was established for stages in the development of the volar skin, i.e., the differentiation of the primary and secondary epidermal ridges (PER and SER) at the undersurface of the epidermis corresponding to the formation of primary and secondary dermal ridges (PDR and SDR) and the development of the dermal papillae. PDRs were first seen at 55 gestational days and SDRs at 93 days. Differentiation of sweat ducts occurred over the period between 60 and 119 gestational days. A regional sequence of differentiation starting with the digital apices of the hand and ending in the calcar area and the phalanges of the foot was documented. Generally, morphogenesis in the macaque was accelerated relative to that in the human fetus by approximately 3 weeks.
Innervation of developing intrafusal muscle fibers in the rat
Authors: Kucera Jan , Walro Jon M. , Reichler Judith 
Published: February 2005

AbstractThe chronology of development of spindle neural elements was examined by electron microscopy in fetal and neonatal rats. The three types of intrafusal muscle fiber of spindles from the soleus muscle acquired sensory and motor innervation in the same sequence as they formed—bag2, bag1, and chain. Both the primary and secondary afferents contacted developing spindles before day 20 of gestation. Sensory endings were present on myoblasts, myotubes, and myofibers in all intrafusal bundles regardless of age. The basic features of the sensory innervation—first‐order branching of the parent axon, separation of the primary and secondary sensory regions, and location of both primary and secondary endings beneath the basal lamina of the intrafusal fibers—were all established by the fourth postnatal day. Cross‐terminals, sensory terminals shared by more than one intrafusal fiber, were more numerous at all developmental stages than in mature spindles. No afferents to immature spindles were supernumerary, and no sensory axons appeared to retract from terminations on intrafusal fibers. The earliest motor axons contacted spindles on the 20th day of gestation or shortly afterward. More motor axons supplied the immature spindles, and a greater number of axon terminals were visible at immature intrafusal motor endings than in adult spindles; hence, retraction of supernumerary motor axons accompanies maturation of the fusimotor system analogous to that observed during the maturation of the skeletomotor system. Motor endings were observed only on the relatively mature myofibers; intrafusal myoblasts and myotubes lacked motor innervation in all age groups. This independence of the early stages of intrafusal fiber assembly from motor innervation may reflect a special inherent myogenic potential of intrafusal myotubes or may stem from the innervation of spindles by sensory axons.
Ultrastructural epithelial zonation of the primate endometrium (rhesus monkey)
Authors: Kaiserman‐Abramof Ita R. , Padykula Helen A. 
Published: February 2005

AbstractThe uterine endometrium of menstruating primates (rhesus monkey, human) consists of a germinal basalis that regenerates a transient func‐tionalis during each menstrual cycle. The endometrium is further subdivided into 4 zones that differ histologi‐cally and in epithelial mitotic rate along the longitudinal axes of the uterine glands and microvasculature (Bartelmez et al: Contrib. Embryol. Carnegie Inst., 34:99‐146, 1951; Bartelmez: Am. J. Obstet. GynecoL, 74:931–955,1957; Padykula et al.: Biol. Reprod., 32:1103–1118, 1984; Biol. Reprod., in press, 1988). The zones are defined as follows: functionalis I, luminal epithelium; functionalis II (upper straight gland segments); basalis III (middle gland segments), and basalis IV (bottoms of the glands). The surrounding stroma and microvasculature also differ zonally.Ultrastructural epithelial differences are evident among the 4 zones during 3 distinct functional states during natural menstrual cycles and after ovariectomy: (1) basal level after ovariectomy and (2) estrogen dominance and (3) progesterone dominance. Zonal structural differences persist at a minimal level of differentiation after ovariectomy and thus zonation is an inherent property. During estrogen dominance, distinctive ultra‐structural differences are evident among the 4 zones, such as epithelial cell heterogeneity in functionalis I and homogeneity in functionalis II. Also a distinctive glandular cell type occurs in basalis III and IV that is recognized by a highly irregular cisternal rough endo‐plasmic reticulum that permeates the cytoplasm. During progesterone dominance, ultrastructural differences exist among the 4 zones except for similarity between the epithelial cells of functionalis II and basalis III. Postovulatory epithelial cells of functionalis I and II and basalis III become postmitotic via progesterone inhibition but intracellular differentiation continues progressively. Postovulatory epithelial mitotic activity in basalis IV escapes progesterone inhibition as the [3H]thymidine labeling index continues to increase from 1 to 12% during the menstrual cycle (Padykula et al.: Reprod., 30(Suppl. l).‐92 (Abstr. 123), 1984). This post‐ovulatory proliferation coupled with progressive differentiation in basalis IV may represent a stem‐progenitor set of cells for postmenstrual endometrial regeneration or alternatively for creation of the maternal placenta.
Lectin histochemistry of the embryonic heart: Expression of terminal and penultimate galactose residues in developing rats and chicks
Authors: Fazel A. R. , Thompson R. P. , Sumida H. , Schulte B. A. 
Published: February 2005

AbstractRat embryos at days 10‐18 of gestation and chicken embryos at days 3‐6 of incubation were fixed and processed for lectin histochemistry. The distribution of binding sites for a lectin from the peanut Arachis hypogaea (PNA) conjugated to horseradish per‐oxidase (HRP) was determined on tissue sections both before and after enzymatic cleavage of sialic acid with neuraminidase (sialidase). Endocardial cushion tissue in the rat, but not in the chick, reacted with PNA‐HRP prior to digestion with sialidase. Endocardium of both species (12 and 13 days in rat, 5 and 6 days in chick), particularly at the level of endocardial cushions, reacted strongly with the sialidase‐PNA sequence; this staining decreased markedly after day 14 of gestation in the rat. PNA binding sites capped by sialic acid were most abundant in the developing rat heart during the critical period of endocardial cushion formation and decreased as development proceeded. The marked changes in the appearance and distribution of cardiac cell and tissue glycoconjugates during cardiogenesis support the concept that rapid changes occur in the structure of complex carbohydrates during embryonic and fetal development. The findings also suggest that such glycosylation‐related events may be species specific.
Cell death by apoptosis during involution of the lactating breast in mice and rats
Authors: Walker Neal I. , Bennett Rosemary E. , Kerr John F. R. 
Published: February 2005

AbstractThe role of cell death in involution of lactating breast was investigated in mice and rats by light and electron microscopy. Apoptosis, recognized by sharply demarcated compaction of chromatin against the nuclear envelope and by shrinkage and budding of the whole cell to form membrane‐bounded apoptotic bodies, was responsible for major loss of cells in both species. In the mouse, rapid involution during the first 2 days was associated with shedding of large numbers of apoptotic bodies derived from alveolar epithelial cells into alveolar lumens. This was followed by more gradual regression, during which the bodies were mostly phagocytosed by macrophages within the epithelium. In the rat, glandular involution was a more gradual and uniform process, with shedding of apoptotic epithelial cells into alveolar lumens being much less conspicuous. Apoptosis of myoepithelial cells was observed in mice, the resulting apoptotic bodies being phagocytosed by intraepithelial macrophages, but was not detected in rats. Apoptosis of capillary endothelial cells caused rapid regression of the capillary beds in both mice and rats. Intraepithelial macrophages increased in number during involution, developed cytoplasmic lipofuscin pigment, and either remained within the epithelium or migrated to the interstitium and regional nodes. Cell loss by apoptosis has been demonstrated during involution and atrophy of a variety of other glands. It characteristically results in shrinkage of a tissue without disruption of its basic architecture.
Structural changes in the luminal epithelium of the porcine uterus between days 10 and 19 of the estrous cycle
Authors: Keys J. L. , King G. J. 
Published: February 2005

AbstractLight and electron microscopy were used to study the morphology of uterine lu–minal epithelium from 4 or 5 gilts slaughtered Oft each of days 10,13,16, and 19 of the estrous cycle. Ultrastructural evidence indicated that metabolic activity and accumulation of glycogen by the uterine epithelium increased between days 10 and 16 of the estrous cycle. This phase of high synthetic activity had been terminated by day 19, as evidenced by the reduction or absence of glycogen deposits and decreased incidence of organelles associated with synthetic activity. Diffuse degeneration of epithelial cells occurred throughout the period of study but was maximal between days 16 and 19. Mitotic activity indicated that cell replacement also occurred between day 16 and day 19.
Functional units in rainbow trout (Salmo gairdneri, Richardson) liver: III. Morphometric analysis of parenchyma, stroma, and component cell types
Authors: Hampton James A. , Lantz R. Clark , Hinton David E. 
Published: February 2005

AbstractHepatic stroma and parenchyma with its component cell types were quantitatively described in adult male and female actively‐spawning 5‐year‐old rainbow trout (Salmo gairdneri, Richardson). Point‐count morphometry of glycol methacrylate sections estimated volume compartments for stroma and parenchyma. Veins composed 85% of the stroma while arteries and bile ducts occupied approximately 6–7% each. Parenchyma accounted for 95% of hepatic volume. Point‐count morphometry of transmission electron micrographs estimated volume compartments as well as numerical and surface density measurements for parenchymal components. Within the hepatic parenchymal compartment, hepatocytes occupied 85% and showed significant sex differences. Female hepatocytes were significantly more numerous but were smaller, only 60% of the volume of male hepatocytes. Since hepatocyte nuclear volume was equal in both sexes, differences were due to reduced cytoplasmic volume in females. Perisinusoidal macrophages of females occupied larger volumes of their respective parenchymal compartments, and their larger mean cytoplasmic volumes suggested activation. Biliary epithelial cells of preductules and ductules were numerous. Ratios of numerical density of hepatocytes to biliary epithelial cells were consistent with a tubular arrangement of hepatocytes. Factors possibly mediating the sexual dimorphism are discussed.
Morphological study of the innervation pattern of the rabbit sinoatrial node
Authors: Roberts L. A. , Slocum G. R. , Riley D. A. 
Published: February 2005

AbstractThe pattern of nerves, ganglia, and fine nerve processes in the adult rabbit sinoatrial node, identified by microelectrode recording, was defined by staining histochemically for cholinesterase followed by silver impregnation. A generalized repeatable pattern of innervation was recognized, including (1) a large ganglionic complex inferior to the sinoatrial node; (2) two or three moderately large nerves traversing the sinoatrial node parallel to the crista terminalis; (3) nerves entering the region from the atrial septum, the superior vena cava, and the inferior vena cava; and (4) a fine network of nerve processes, particularly extensive in the morphologically dense small‐cell part of the sinoatrial node. When the site of initial depolarization in the node was located and marked by a broken‐off electrode tip, it was found, after cholinesterase staining, to be characterized by a cluster of cells enclosed in a nest or basket of fine nerves. Similar nested cell clusters were observed elsewhere in the sinoatrial node in this same preparation and in other hearts. A complex interweaving of atrial muscle fibers was observed medial and inferomedial to the sinoatrial node, which may form the anatomical basis for the lack of conduction through this region. The morphological pattern of nerves, ganglia, and myocardial cells described in this study emphasizes the complexity of innervation of the sinoatrial node, including its intrinsic neural elements. Cholinesterase/silver staining can be useful in the definition and comparison of electrophysiologically identified sites within the sinoatrial node.
Electron microscopic study of subcutaneous and intraperitoneal splenules in the mouse
Authors: Johnson Joan , Weiss Leon 
Published: February 2005

AbstractThe development of splenules derived from slices of freshly removed autologous spleen implanted subcutaneously or intraperitoneally was followed by light and electron microscopy from day 2 to day 70. Within 48 hr after transplantation, a rough space filled with blood, unlined by endothelium, formed just under the surface of the splenic fragment. The tissue central to this vascular space was disrupted and necrotic. In the outer portion of the vascular space, fibroblasts appeared and created locules which developed into a highly vascular, hematopoietic red pulp. From the inner portion, blood percolated into the central necrotic tissue.At 1 week the splenule was divisible into concentric structures. The capsule was outermost. A shell of vascularized, highly hematopoietic red pulp lay within the capsule, having replaced the vascular space. Central to the red pulp lay a band of fibroblasts and macrophages. Next was a layer of fibroblasts in a matrix of degenerating cells, and, at the center, a necrotic core. As fibroblasts and macrophages moved centrad, the red pulp moved with them, expanding and replacing the necrotic tissue.The splenule differed in character from the original spleen. Splenular red pulp, especially near the surface, was unusually hematopoietic. The circumferential reticulum of white pulp was reduced or absent, and the boundary between red and white pulp was sometimes indistinct. Some white pulp was subcapsular, and the capsule and surrounding connective tissue were infiltrated by lymphocytes. The necrotic core of the splenule was typically surrounded by a zone containing large blood vessels, connective tissue, and adipocytes.
Use of colloidal gold cytochemistry in the study of the basic cell biology of cancer
Authors: Willingham Mark C. 
Published: February 2005

AbstractWe are currently investigating the morphologic aspects of two areas of the basic cell biology of cancer: tumor‐specific surface antigens as targets for immunotoxins, and the phenomenon of multidrug resistance in chemotherapy of human tumors. Colloidal gold cytochemistry has provided a useful method for the electron‐microscopic cytochemical detection of materials endocytosed by cells in culture. This technique has been used to study the internalization pathway of ligands bound to the surface of cancer cells, particularly antibodies for use as immunologic targeting reagents for the construction of immunotoxins. These colloidal gold conjugates with monoclonal antibodies have demonstrated the internalization of these immunologic reagents through coated pits and reeeptosomes, which is a necessary step in the delivery of immunotoxins into the cell where they can mediate their cell‐killing functions. Morphologic methods have been employed for the screening and selection of monoclonal antibodies reactive with the surface of human ovarian cancer cells for use as immunotoxins and have demonstrated the in vivo activity of immunotoxins made with these antibodies and Pseudomonas exotoxin in a nude mouse model system. In other studies, we have employed such reagents for the immunocytochemical detection of the surface expression of P170, the cell‐surface efflux pump protein responsible for the phenotype of multidrug resistance in tumor cells, and to investigate the distribution of this protein by using immunocytochemistry in normal human tissues. These results have suggested a role for P170 in normal cell membrane transport of metabolites in various organ systems.
Immunogold‐surface replica study of ADP‐induced ligand binding and fibrinogen receptor clustering in human platelets
Authors: Isenberg William M. , McEver Rodger P. , Phillips David R. , Shuman Marc A. , Bainton Dorothy F. 
Published: February 2005

AbstractPlatelet cohesion requires the binding of fibrinogen to its receptor, a heterodimer consisting of the plasma‐membrane glycoproteins GPIIb and GPIIIa. Although the GPIIb‐IIIa complex is present on the surface of unstimulated platelets, it binds fibrinogen only after platelet activation. We have used an immunogold‐surface replica technique to study the distribution of GPIIb‐IIIa and bound fibrinogen over broad expanses of surface membranes in unstimulated and ADP‐activated human platelets. We found that the gold probe was monodispersed · over the surface of unstimulated platelets, although the cell surface lacked immunoreactive fibrinogen. To ascertain whether the receptors clustered prior to ligand binding or as a consequence thereof, we studied the surface distribution of GPIIb‐IIIa after stimulation with ADP, which causes activation of the fibrinogen receptor function of GPIIb‐IIIa without inducing the secretion of fibrinogen. In the absence of added fibrinogen, the unoccupied, yet binding‐competent receptors on ADP‐stimulated platelets were mono‐dispersed. The addition of fibrinogen caused the GPIIb‐IIIa molecules to cluster on the cell surface. Clustering was also induced by the addition of the GPIIb‐IIIa binding domains of fibrinogen–namely, the tetrapeptide Arg‐Gly‐Asp‐Ser on the α‐chain or the γ‐chain decapeptide γ402–411. These results show that receptor occupancy causes clustering of GPIIb‐IIIa in activated platelets.