bluuebunny/crossref_metadata_2025 huggingface dataset:
An Anatomical and Embryological Study of the Clavicle in Cats (Felis domesticus) and Sheep (Ovis aries) during the Prenatal Period
Authors: Rojas M.A. , Montenegro M.A.
Published: July 2008

The prenatal development of the clavicular area was studied in two species: the domesticated sheep, which lacks a clavicle, and the cat, with a nonfunctional, rudimentary clavicle. A morphological and computerized morphometric study of the clavicle was performed in 18 cat embryos between 25 and 48 days of gestation, and in 12 sheep embryos of 37-45 days. One group of embryos was processed with double staining in toto according to Hanken and Wassersug in 1981. The other group was examined by histological techniques: hematoxylin-eosin-Alcian blue and picrosirius. In both species, clavicular ossification is delayed (27% of gestation time elapsed in sheep and 53% in cats) compared to 16% in humans. Histological and morphological differences in shape and length of the clavicle were observed in both species. The clavicle is transient in sheep, whereas in the cat it persists with little change. In neither species does secondary cartilage develop. In cats, the periosteum is well developed with active osteoblasts, whereas in sheep the clavicle is surrounded by a single layer of epitheloid cells and the periosteum is less developed and contains osteoclasts. These results suggest that the morphogenetic pattern for the clavicle is altered at about day 34 in cats and day 40 in sheep, and is subsequently partly inhibited in the former and blocked in the latter.
Locational Relationship of the Supraorbital Notch or Foramen and Infraorbital and Mental Foramina in Koreans
Authors: Chung M.S. , Kim H.J. , Kang H.S. , Chung I.H.
Published: July 2008

The morphology and locational relationship of the supraorbital notch/foramen, infraorbital foramen, and mental foramen were studied from photographs of 124 Korean skulls (male 35, female 18, unknown sex 71). The infraorbital foramen was on the sagittal plane passing through the supraorbital notch/foramen (36.4%), or lateral to the plane (63.6%). The mental foramen was either on the plane (69.3%), lateral to the plane (21.8%), or medial to the plane (9.0%). The supraorbital notch/foramen, infraorbital foramen, and mental foramen were on the same sagittal plane in 38.1% of the cases. The supraorbital notch (69.9%) was found more frequently than the supraorbital foramen (28.9%). The average distance from the median plane to the center of the supraorbital notch/foramen, infraorbital foramen, and mental foramen was 22.7, 27.2 and 24.4 mm, respectively. The average length of the line from the center of the supraorbital notch/ foramen to the center of the infraorbital foramen was 45.6 mm, and the angle of this line to the sagittal plane was 5.8°. The average distance from the infraorbital margin to the center of the infraorbital foramen was 8.6 mm, and that from the inferior margin of mandible to the center of the mental foramen was 15.5 mm in males and 14.0 mm in females. The average horizontal width of the supraorbital notch/foramen, infraorbital foramen, and mental foramen was 4.7, 4.8 and 2.4 mm, respectively. Most commonly, the infraorbital foramen was lateral to the sagittal plane of the supraorbital notch/foramen, and the mental foramen was on that plane. This locational relationship would be helpful clinically to determine the location of the infraorbital and mental foramina, by palpation of the supraorbital notch.
Fiber Type Composition of Morphologic Regions in the Macaque Multitendoned Finger Muscles
Authors: Maurer J.J. , Singer M.A. , Schieber M.H.
Published: July 2008

The extrinsic multitendoned finger muscles seem likely to contain distinct neuromuscular compartments that can act as independent functional subdivisions serving different fingers. Little evidence of such subdivisions is available, however. Regional specialization of histochemical fiber type composition has been described in a number of monotendoned muscles, and in some muscles different neuromuscular compartments have been shown to have different fiber type proportions. Therefore, we examined the fiber type composition of morphologically defined regions in the macaque multitendoned finger muscles. Although some trends were noted, none of the five multitendoned finger muscles showed significant regional differences in fiber type composition. Nor were differences found between muscles of the flexor group or between muscles of the extensor group. Comparing flexors and extensors revealed a slightly but significantly lower proportion of type I fibers in the flexors. We conclude that unlike certain monotendoned wrist muscles (such as FCU), the multitendoned muscles that flex and extend macaque fingers have minimal histochemical specialization.
Glial-Schwann Cell Specialisations at the Central-Peripheral Nervous System Transition of a Cyclostome: An Ultrastructural Study
Authors: Fraher J. , Cheong E.
Published: July 2008

This study describes for the first time the central (CNS)-peripheral (PNS) nervous system transitional zone (TZ) of a member of the vertebrate class Agnatha, namely, the sea lamprey. It is concerned in particular with the glial tissue contribution to the TZ and the Schwann cell-CNS interface. Plastic-embedded specimens of spinal cord and nerve roots were examined using light and electron microscopy. At the TZ of each root a glial barrier, continuous with and similar in form to the surrounding glia limitans, stretches across the nerve bundle. In possessing such a barrier the lamprey TZ follows the general vertebrate pattern and differs from the Cephalochordata and invertebrates where a corresponding barrier is absent. The glial barrier is of similar thickness to the glia limitans generally, unlike in the mammal where it is thicker at the TZ than elsewhere. All lamprey axons are unmyehnated peripherally and most of them traverse the glial TZ barrier singly in individual tunnels. In this they resemble mammalian axons of similar calibre (which are, however, myelinated), but differ from unmyehnated mammalian axons, which generally traverse it in bundles. The lamprey TZ has specialisations not found in mammals. These include prominent, multiple interconnected strata of microfilament bundles which are continuous deeply with glial filament bundles and which lie under the surface plasmalemma of the glia limitans, to which they are connected by hemidesmosomes. Features of the mature lamprey TZ resemble those of developing mammalian TZs. For example, slender Schwann cell processes extend below the cord surface and become closely apposed to glial processes. In addition, together with the axon, the TZ glial processes and the basal lamina, they bound an extensive periaxonal network of spaces at the TZ, into which fine Schwann cell processes project. Accordingly, the networks could represent a primitive form of node gap.
Interlaminar Astroglial Processes in the Cerebral Cortex of Adult Monkeys But Not of Adult Rats
Authors: Colombo J.A.
Published: July 2008

Three adult Cebus apella and two Saimiri sciureus monkeys, as well as four adult rat brains were processed for glial fibrillary acid protein (GFAP) immunocytochemistry. Irregular patches with relatively abundant, long astrocytic processes were found in monkey but not in rat brains, along the cingulate, as well as orbital, medial and dorsolateral cortices of the frontal lobe, and in temporal lobe cortical areas. The observed long astrocytic processes alternated in an apparent irregular fashion with others with a predominantly clear background and scattered GFAP-immunoreactivity (IR) astrocytes or with a predominant GFAP-IR-dense fibrillary meshwork. They usually stemmed from lamina I or II and coursed through deep laminae. Entorhinal cortex in rat brains showed occasional astroglial processes somewhat longer than those commonly observed in other cortical regions, albeit significantly shorter than those observed in Ceboidea monkeys and not truly interlaminar. These observations indicate a clear morphological difference in astroglial organization between nonhuman primates and a rodent brain. They further show that ‘interlaminar astrocytes’ are distributed nonhomogeneously in the frontal cortex of New World monkeys. No interlaminar processes were observed in cortical areas of rat brains. Even though the physiological role of interlaminar astrocytes in a primate brain remains unknown, their significant departure from the morphology of classical, stellate astrocytes suggest that they may subserve different cortical requirements.
Grafts of the Third Branchial Arch in Chick Embryos
Authors: Mérida-Velasco J.A. , Sánchez-Montesinos I. , Espín-Ferra J. , García-García J.D. , Roldán-Schilling V.
Published: July 2008

The parathyroid glands have been classically considered derivatives of the third and fourth pharyngeal pouches in most species, including humans. The presence of neural crest-derived cells in parathyroid glands connective tissue has apparently been established. However, our previous studies have provided a new hypothesis on the origin of these glands in human and chick embryos. To determine the true origin of the third parathyroid (parathyroid III) gland in the chick embryo, pieces of the third branchial arch from donor chick embryos at Hamburger and Hamilton’s stage 19 (embryonic day 3) were grafted to host chick embryos at the same stage of development. Starting from Hamburger and Hamilton’s stage 27 (embryonic day 5), a structure identified as the parathyroid III appeared in the ectodermal (epipharyngeal) placode of the third branchial arch graft, from which it subsequently became separated at Hamburger and Hamilton’s stage 28 (embryonic day 5.5) and continued to develop and mature. Our findings suggest the conclusion that the parathyroid III gland begins to develop from the epipharyngeal placode, so that this gland, from our point of view, could be considered ectodermal in nature.
Stromal Development in the Ventral Prostate, Anterior Prostate and Seminal Vesicle of the Rat
Authors: Hayward S.W. , Baskin L.S. , Haughney P.C. , Cunha A.R. , Foster B.A. , Dahiya R. , Prins G.S. , Cunha G.R.
Published: July 2008

The prostate and seminal vesicle (SV) are androgen-dependent secretory glands of the male genital tract. They produce the bulk of the seminal secretions. The object of the present study was to examine and document the ontogeny of stromal maturation in the rat anterior and ventral prostate and SV. These organs have a loosely organized cellular mesenchyme during fetal development. During prostatic development the mesenchyme condensed to form smooth muscle sheaths immediately surrounding the epithelium, with looser connective tissue between individual ducts. In the SV, a loose connective tissue layer called the lamina propria lies between the epithelium and developing muscle. Smooth muscle oc-actin, myosin, desmin, laminin, vinculin, vimentin and androgen receptor (AR) expression were examined by immunocytochemical methods during the pre- and postnatal developmental periods. The first marker to be detected was vimentin, which was initially found throughout the mesenchyme. During development vimentin became mostly restricted to the interductal tissue of the prostate and the lamina propria of the SV. Smooth muscle markers were expressed in an orderly sequence in a proximal to distal manner along prostatic ducts, from the urethra towards the tips. Expression of oc-actin was followed by vinculin, myosin, desmin, and laminin. These markers became localized to the developing smooth muscle sheaths and were not expressed in the interductal tissue of the prostate or the lamina propria of the SV. Organ culture experiments demonstrated that androgens were required for the differentiation of smooth muscle sheaths. Castration of adult rats demonstrated that androgens were required to maintain smooth muscle differentiation. In castrates, the stroma was relatively thicker but less dense than in intact animals. Following castration, expression of the smooth muscle markers was lost sequentially in the reverse order of their expression during development. In long-term castrates oc-actin, vimentin and a small amount of vinculin were detected. AR were first detected in the urogenital sinus mesenchyme immediately surrounding the epithelium at 16 days of gestation. As development progressed expression of AR became more widespread, and postnatally was found throughout the mesenchyme. As maturation of smooth muscle occurred, stromal expression of AR became localized to the muscular sheath immediately surrounding the epithelium. In the prostate the interductal connective tissue displayed very low levels of AR expression. In the SV, AR were also observed in the lamina propria. In summary, stromal differentiation and dedif-ferentiation in the rat prostate and SV were found to be androgen-dependent processes with ordered sequential ontogenic expression of specific markers.
Skeletal Muscle Fiber Cross-Sectional Area: Effects of Freezing Procedures
Authors: Roy R.R. , Pierotti D.J. , Edgerton V.R.
Published: July 2008

The cross-sectional area (CSA) of individual fibers is an important measure of skeletal muscle plasticity. To investigate the effects of different freezing procedures on CSA measurements, the CSA of type-identified fibers in the cat tibialis anterior were determined following quick-freezing the muscle at a fixed physiological length (ipsilateral, frozen at length) and compared to the fiber CSA following quick-freezing a mid-portion of the muscle where the fibers were allowed to freely shorten during tissue preparation (contralateral, frozen as a block). The mean CSA of each fiber type was significantly smaller in the muscles frozen at length vs. frozen as a block in both a deep (close to the bone) and a superficial (away from the bone) region of the muscle, except for the slow oxidative (SO) fibers in the superficial region. The percent difference in mean fiber CSA was smaller for the SO compared to the fast oxidative glycolytic and fast glycolytic fibers in both the deep (41, 47 and 56%, respectively) and superficial (20, 36 and 48%, respectively) regions. In addition, the differences in the mean CSAs of the fast fibers between the two freezing procedures were ∼10% larger in the deep compared to the superficial region. The fiber-type differential responses may be related, at least in part, to the architectural features of the fibers. These data indicate that the freezing procedures used to prepare the muscle tissue are an important consideration when determining the CSA of individual skeletal muscle fibers and consequently the specific tension, tension per unit CSA, of the muscle units.
Populations of Myelinated Nerve Fibers in the C8 and L4 Ventral and Dorsal Roots in the Opossum, Monodelphis domestica
Authors: Leblond H. , Cabana T.
Published: July 2008

A quantitative light-microscopic analysis of the ventral and dorsal roots at the C8 and L4 segments of the spinal cord was made in the opossum, Monodelphis domestica, to evaluate the number of myelinated fibers and their class distribution, and will serve as a baseline to a study of myelinogenesis in that species. In male opossums, the C8 ventral root comprises an average of 595 myelinated fibers (70.3% a:29.7%y), and the dorsal root 1,124 fibers (29.4% type I: 41.2% type 11:29.4% type III). The L4 ventral root has an average of 831 fibers (57.9% a:42.1%y), and the dorsal root 2,079 fibers (17.4% type 1:44.7 type II: 37.9% type III). The females have less fibers but their size and class proportions are comparable to those of the males. These data are discussed in relation to peripheral innervation and are compared to those reported for the rat and the cat.
Skeletal Maturation of Wrist and Hand Ossification Centers in Normal Spanish Boys and Girls: A Study Using the Greulich-Pyle Method
Authors: Jiménez-Castellanos J. , Carmona A. , Catalina-Herrera C.J. , Viñuales M.
Published: July 2008

The skeletal maturation of the upper limb distal segment was studied in 239 Spanish boys and girls between birth and 14 years of age. The atlas of Greulich and Pyle, offering standards of skeletal development of white North American children, was used as reference. The results obtained show firstly that in absolute terms, the ossification process is earlier in girls than in boys. This difference is maximum between 5 and 11 years of age. The boys show a delay of around 3 months with respect to their North American opposites. The girls, in contrast, show a better fit to the corresponding (female) standard of the atlas. In general, the highest agreement between bone age and chronologic age is for the ossification centers of the distal epiphysis of the ulna and radius and for those of the metacarpal bones. At the level of the carpus, individual analysis of the ossification centers shows that the capitate and hamate bones in the girls evolve most in accord with chronologic age. At the other extreme, and in both sexes, the ossification centers of the trapezium and trapezoid bones are statistically furthest from chronologic age.
Musculus sartorius bicaudatus
Authors: Melling M. , Zweymüller K.
Published: July 2008

While dissecting 88 lower limbs, a distal division of the sartorius muscle was detected in one of the specimens. The larger posteromedial portion was found to take a normal course to the so-called superficial pes anserinus. The thinner anterolateral portion attached to the medial meniscus anteromedially. The smaller anterolateral part approached the medial meniscus anteromedially, pushing the synovial membrane into the joint. Its meniscal attachment ensures that the medial meniscus is stabilized in its primary position during bending and external rotation in the knee joint, thus preventing its herniation or injury during sudden extension. The accessory part of the sartorius muscle thus acts as a protector of the medial meniscus.
Morphological Modeling via Isosurfacing: The Laryngeal Skeleton of Gekkonid Lizards as a Test Case
Authors: Rittenhouse D.R. , Russell A.P. , Phillips D.S.
Published: July 2008

A novel technique for modeling microscopic anatomical structures in three dimensions was developed as part of a survey of gekkonid laryngeal skeletal morphology (Reptilia: Gekkonidae). Excised larynges were transversely sectioned at 10 um and stained using standard procedures. With a projection microscope, outline drawings of the sectioned laryngeal cartilages were made at regular intervals, depending on the rate and degree of structural change observed while sampling. The drawing set was digitized with a flatbed scanner, and aligned using ‘NIH Image’ for Macintosh computers. Physical connectivity between successive outlines was provided by inserting one or more artificial slices between those that had been digitized, and draping a skin of rendered contours over all of the interstitial spaces present in the template. The Application Visualization System, ageneral-purpose visualization package for UNIX-based computer systems, was used to visualize and render the resulting ‘isosurfaces’, which appear as solid three-dimensional objects and can be viewed from any perspective. Since iso-surfaced reconstructions can be based on as little as 20% of the cross-sections available, this procedure has the potential to be a valuable research tool for future morphological work at the microscopic level.
The Effect of Removal of the Medial Collateral Ligament on Subchondral Bone and Cartilage in the Growing Rat Knee Joint
Authors: Messner K. , Lundberg M. , Andersson B.
Published: July 2008

The growing knee joint in immature rats was chosen as a model to study quantitatively bone apposition and thickness of articular cartilage after surgical removal of the medial collateral ligament. In 32 rats, subchondral bone apposition was assessed by measuring double tetracyclin labelling, and the thickness of calcified and uncalcified articular cartilage was measured by image analysis. The results indicate that there was a significant increase in subchondral bone growth after removal of the medial collateral ligament, but no change in thickness of the calcified and uncalcified zones of the articular cartilage in the medial knee compartment. Further, despite an obvious increase in valgus laxity on manual examination, there were no signs of articular cartilage degeneration in any animal. The study shows that traumatic injury to ligaments and joint instability during the growing period may influence the development of subchondral bone in the knee joint.
Supravital Morphology of Small Branches of Lateral Striate Arteries as Observed with Nomarski Optics
Authors: Gouveia C.J.
Published: July 2008

Lateral striate arteries were dissected from the fixed brains of 6 patients of increasing age. Small branches of arteries were observed – unprocessed and unstained – by Nomarski optics. Among the findings there was fibrous intimal proliferation, replacement of medial muscle by collagen, tortuosity, twisting or coiling. The severity of changes seemed to progress with aging. The advantages of the used methodology that aims at avoiding artifacts of processing are discussed briefly.
The Scapula: Principles of Construction and Stress
Authors: Anetzberger H. , Putz R.
Published: July 2008

According to current generally accepted theories, analysis of the shape of a bone provides clues to the stresses acting upon it. Although many investigations have ensured that understanding of the lower limb is relatively advance, knowledge relating to the upper limb, and particularly to the scapula, is still far from complete. We have therefore endeavoured to interpret the shape of this bone morphometrically. To this end various scapular parameters have been standardised and statistically analysed, and the results examined both from the functional and the clinical points of view. Our investigation has established that, as in the case of the long bones, the form of the scapula is dependent upon both height and sex. Assessment of the architecture of the subacromial space and its possible parameters of influence have also demonstrated that the size of this space is essentially dependent upon the height of the subject and the size of the acromial and scapulospinal angles. A short distance between the acromion and the upper edge of the glenoid cavity and a small glenoid-spinal angle can be regarded from a functional point of view as factors predisposing to the development of the impingement syndrome. We have also been able to show that certain constant structural features produce an optimal distribution of the forces acting upon the scapula. In particular, the relationship of the supporting pillars (the lateral border and the spine) of this bone to one another appears to represent the expression of an ideal adaptation to the action of those forces.
Morphometry of Pineal Synaptic Ribbon Profile Numbers after Cytochalasin D Treatment
Authors: Peschke E. , Spessert R. , Spiwoks-Becker I. , Dorner P. , Vollrath L.
Published: July 2008

Synaptic ribbons (SRs) are electron-dense, plate-shaped synaptic organelles, to which electron-lucent synaptic vesicles (SVs) are attached by tiny stalks. In the mammalian pineal gland SRs are dynamic organelles, waxing and warning in number under different physiological and experimental conditions. The way in which SRs are formed, or catabolized, is not known. Since it has been suggested that actin may be part of SRs, in the present study the effect of the actin-disrupting drug cytochalasin D (CD, 1 ug/ml, for 4 h) was examined in cultured guinea pig and rat pineal glands. The glands were preincubated for 48 h so that intra-pineal sympathetic nerve fibres degenerate and no longer release noradrenaline which may distort the results. CD had no effect on SR profile numbers in guinea pigs, but decreased them in rats (p > 0.05). The nonsignificant depressive effect of CD in rats was verified in a second experiment. To clarify the issue, acutely cultured rat pineal glands were treated with CD for 4 h, without effect. The results taken together suggest to us that CD has no major effect on pineal SR profile numbers, but that in rats preincubation for 48 h makes them vulnerable to catabolic processes. In all the experiments, the electron-dense plate of the SRs was qualitatively unaffected. However, the SVs were often larger and more irregular in shape and the stalks linking the SVs with the SRs were less frequently seen in CD-treated glands. In guinea pig pineals, in which SRs frequently lie in groups and parallel to each other, neither the distance between neighboring SRs nor the thickness of individual SRs were affected by CD. It is concluded that actin is not a major component of the SRs and the connecting stalks.
Mandibular Molar Teeth and the Development of Mastication in the Miniature Pig (Sus scrofa)
Authors: Obrez A.
Published: July 2008

The only components of the orofacial complex that are fully developed as soon as they establish function are the occlusal surfaces of teeth. It is usually assumed that the occlusal surface of the molar teeth influences the orientation of the power stroke in spite of the fact that the data supporting this claim are lacking. The purpose of this longitudinal study was therefore to determine whether or not this hypothetical form-function relationship existed during development and whether or not it was related to growth. Serial dorsoventral and lateral radiography, and dorsoventral cineradiography were performed during natural feeding of 5 Hanford miniature pigs (Sus scrofa) of both genders between their 8th and 18th weeks. Sequences of power strokes were analyzed frame by frame and compared between sessions, and related to the position of the fourth primary mandibular molar (dm4). The changes in direction of the power stroke and in position of the dm4 relative to the midline were subsequently related to growth. The results of this study indicate that changes in orientation of the power stroke, though significant only on the balancing side, occur independently of the repositioning working and balancing side mandibular molars, as well as of skeletal growth. The null hypothesis that the mandibular primary molars influence the transverse orientation of the power stroke during growth is therefore refuted.
Abnormality of the Labyrinthine Artery and Its Topographical Relation to the Abducent Nerve
Authors: Melling M. , Koos W.T.
Published: July 2008

A case of duplication of the labyrinthine artery arising from the basilar artery is described. The more slender branch takes a dorsal course and penetrates the abducent nerve in its uppermost fibres, while the thicker branch passes by the nerve on the ventral side. The two branches of the labyrinthine artery run separately to the internal auditory meatus. This variant was found only in one brain and only on the left side. The clinical relevance of this finding is discussed.
Roles of Kringle Domain-Containing Serine Proteases in Epithelial-Mesenchymal Transitions during Embryonic Development
Authors: Théry C. , Stern C.D.
Published: July 2008

Transformation of an epithelial sheet into a migrating mesenchymal cell population implies the destruction of the basal lamina underlying the epithelium, and the subsequent localized digestion of the extracellular matrix by the migrating cells. Proteases are involved in these processes. Among them, molecules containing both a serine protease domain and at least one kringle domain have been identified as possible important effectors. Interestingly, related proteins containing an inactive serine protease domain also seem to play a role, suggesting that the function of these molecules in epithelial-mesenchymal transformation is not confined to proteolytic digestion of cell attachments. Instead, these molecules act through specific tyrosine kinase receptors in the membrane of the responding cells. In this review, we summarize data implicating this family of molecules in various epithelial-mesenchymal transitions during embryonic development. Our major focus of attention are: hepatocyte growth factor/scatter factor (HGF/SF), its tyrosine kinase receptor proto-oncogene c-met, and the related peptide factor HGF-like/macrophage-stimulating protein (HGF1/MSP), whose receptor is the Ron tyrosine kinase, c-met and Ron also have another close homolog in the chick, called Sea, whose ligand remains unknown. Interestingly, HGF/SF is activated by other plasminogen-related molecules which, apart from a specific activator, include the protease urokinase. HGF/SF, c-met and HGF/MSP are expressed in dynamic ways during early embryonic development, correlating with regions undergoing epithelial/mesenchymal transformations. Moreover, several assays are now starting to reveal great pleiotropism of function during development, including both the loss and the acquisition of epithelial morphology according to the cell type and assay used, as well as angiogenesis, kidney tubule morphogenesis, cell motility, the maintenance of competence for neural induction and some aspects of the later development of the musculoskeletal and nervous systems.
Model Systems of Epithelium Mesenchyme Transitions
Authors: Boyer B. , Vallés A.M. , Thiery J.P.
Published: July 2008

This contribution discusses which factors bring about the transformation of epithelium to mesenchyme. Amongst biological agents which have this role are a number of cytokines (e.g. EGF, FGF-1, TGF-β, HGF/SF) and extracellular matrix macromolecules, such as collagens. The coordinated changes in cell morphology, associated with the induction of cell motility and the loss of intercellular junctions, are under the control of signaling molecules that transduce the signal emanating from the plasma membrane, which ultimately lead to changes in gene expression.
Ultrastructure and Characteristics of Eggshells of the Olive Ridley Turtle (Lepidochelys olivacea) from Gahirmatha, India
Authors: Sahoo G. , Mohapatra B.K. , Sahoo R.K. , Mohanty-Hejmadi P.
Published: July 2008

The structure of a chelonian eggshell is of prime importance for the developing embryo. It acts as a protective covering as well as mediator in the exchange of heat and water. The fresh eggshell of the olive ridley (Lepidochelys olivacea) turtle displays a variety of structural forms in their aragonite framework. Its netted substrate, loose texture and poorly organised crystallites favour the easy exchange of air and water during its development. The shell consists mostly of calcium in carbonate form and K, Mg, Fe, Ni, Pb, Zn, Co, Cr, Cu, Mn and Cd in traces. Ba and Sr in traces are also a feature of the thermal analysis graph. Phosphorus was not detected in the shell and its absence eliminates an earlier suggestion of it being a key factor in the development of aragonite crystals in the inorganic structure of marine turtle eggshells. Its combustion characteristics, which have not been previously reported, are recorded.
The Connective Tissue Compartment in the Terminal Region of the Developing Rat Lung
Authors: Wasowicz M. , Yokoyama S, , Kashima K. , Nakayama I.
Published: July 2008

The present study was designed to analyze the connective tissue compartment in the terminal region of the developing rat lung. Lungs of rat fetuses (at 17, 19 and 21 days of gestation) and of newborns (2, 4, 7, 10, 14 and 21 days after birth) were examined by several ultrastructural techniques: staining with tannic acid for elastic fibers (EFs), collagen fibers (CFs) and basement membranes (BMs); staining with ruthenium red for glycosaminoglycans; and immunoelectron microscopy for visualization of collagen type IV, laminin and fibronectin (FN). Dynamic changes in the levels and distribution of the components of the extracellular connective tissue were observed in parallel with the formation and maturation of the alveoli. The terminal regions of the respiratory tract of the rat fetus and of the lungs of early newborns contained few CFs and EFs, and the BMs in these lungs were incomplete. However, strong immunolabeling of FN was observed (in BMs, CFs and in spaces among fibroblasts). Starting from 4 or 7 days newborns had increasing numbers of CFs and EFs and BMs became more extensive. In rat newborns, immunolabeling specific for FN was weak and irregularly distributed. Furthermore, the present results provide a summary of the changes in connective tissue that occur in the rat lung during different stages of its development, from the pseudoglandular stage, through the canalicular and saccular stages, to the alveolar stage.
Distribution of Chondroitin Sulfate Proteoglycans during Bovine Fetal Ruminal Papillae Formation
Authors: Takanosu M. , Amasaki H. , Miura T. , Asari M. , Suzuki K.
Published: July 2008

The present paper demonstrates the immunohistochemical distribution of proteoglycan (PG) molecules carrying chondroitin sulfate (CS) chains with 6-sulfated hexosamine residues, or CS and/or dermatan sulfate (DS) chains with 4-sulfated residues in the developing bovine ruminal papillae (RP) using monoclonal antibodies (mAbs) 3B3, 2B6 and M0225. These PGs carrying chondroitin 6-sulfate that were detected by mAb 3B3, and the glucuronic acid 2-sulfate-N-acetyl-galactosamine 6-sulfate unit that was detected by the mAb M0225 were distributed in the mesenchyme and epithelial basement membrane in the rumen, and were thus correlated to the outgrowth of the RP. The PG carrying DS was detected by the mAb 2B6 and was distributed in the lower region of the mesenchyme and intermuscular connective tissue during the development of the RP. These findings suggest that PGs carrying CS chains with 6-sulfation are involved in the growth of the RP, and that PGs carrying DS are involved in organization in the mesenchyme.
Preservation into Old Age of Synaptic Number and Size in the Supragranular Layer of the Dentate Gyrus in Rhesus Monkeys
Authors: Tigges J. , Herndon J.G. , Rosene D.L.
Published: July 2008

In order to determine whether there are age-related changes in the supragranular layer of the dentate gyrus of the rhesus monkey, we examined this layer in monkeys 4-35 years of age, spanning the entire range of adulthood of this species. Electron microscopic analyses were conducted to determine whether there is an age-related change in the number of synapsing axon terminals, in the cross-sectional area of these terminals, or in the length of the postsynaptic density at the synaptic junction. Only asymmetrical synapses in the anterior dentate gyrus were evaluated. In a subset of our monkeys (n = 6, ages 4-31 years), we compared three different approaches to the estimation of synaptic density: (1) the conventional profile method, in which synapse numbers are expressed per unit area of the examined tissue section; (2) the empirical formula of Colonnier and Beaulieu for converting areal densities into number of synapses per unit volume, and (3) the ‘disector’ method, a stereological approach to the estimation of the number of synapses per unit volume that makes no assumption about the shape of the objects. Data are presented validating the small-fold method of estimating section thickness for the disector. The three methods were highly intercorrelated (r’s ≈ 0.89), and none of the methods revealed an age-related loss of synapses. Analysis of the thickness of the dentate gyrus molecular layer suggests that the reference volume in which these synapses were counted does not change with age. In addition, the conventional profile method showed no age-related change in the number of axodendritic or axospinous synapses, the cross-sectional area of the synapsing terminals, or the length of the postsynaptic densities of synapses. Together, these data suggest a remarkable age-related preservation of synapses in the normal aging monkey.
Quantitative Clinical Anatomy of the Human Cornea in vivo
Authors: Longanesi L. , Cavallini G.M. , Toni R.
Published: July 2008

The cornea is the most important refractive element in the human ocular system, providing approximately two thirds of the eye’s refractive power in the nonaccommodative state. The methods of description and analysis of the corneal anatomy in vivo continue to be refined thanks to the increased interest aroused by the advent of corneal refractive surgery, which aims to modify the dioptric power of the ocular system by altering the thickness and the radius of curvature of the cornea. In the present study we report quantitative morphometric data of corneal thickness and the radius of curvature of the anterior surface of the cornea obtained in vivo from normal human subjects using ultrasonic pachymetry and computer-assisted topographic videokeratoscopy. We found a highly significant statistical correlation in the distribution of corneal thickness and the radius of curvature of the anterior surface of the cornea along the principal corneal meridians (horizontal and vertical meridians) and within three different concentric zones of the cornea, 2, 4 and 6 mm, respectively, from the geometric center along the principal meridians. Correlation was also found for the same morphometric parameters between the right and the left eye. By contrast, no correlation was found between corneal thickness and the radius of curvature of the anterior surface of the cornea. These findings suggest that the adult human cornea is a structure characterized by a highly ordered tridimensional architecture and symmetry and that a specific distribution of corneal thickness and the radius of curvature of the anterior corneal surface along the principal meridians may be essential for the refractive function of the human corneal diopter in vivo.
Mast Cells in the Laryngeal Mucosa of the Rat
Authors: Lidegran M. , Domeij S. , Forsgren S. , Dahlqvist Å.
Published: July 2008

Mucosal mast cells (MMCs) and connective tissue mast cells (CTMCs) in the epiglottic and subglottic regions in the rat larynx were characterized and quantified by immunohistochemistry and by light and electron microscopy, in control rats and rats injected intraperitoneally with dexamethasone and compound 48/80. Considerable regional differences were observed in the distribution of mast cells, especially in the epiglottis, where most cells were located on the laryngeal side. In the epithelium of the subglottic region the MMCs showed immunoreactivity for 5-hydroxytryptamine, in contrast to the epithelial MMCs in the epiglottis. In ultrathin sections, the subglottic MMCs contained larger but fewer granules compared with the epiglottic MMCs. After treatment with dexamethasone, the MMCs in the epithelium disappeared, while after treatment with compound 48/80 a large number of the CTMCs in the lamina propria became degranulated, though still present. This study shows that MMCs in the epiglottic and subglottic regions may be of two subtypes, differing in number and size of the granules as well as in chemical content.
Functional Sexual Differences in Rat Mammillary Bodies: A Quantitative Ag-NOR Study
Authors: González-González S. , González-Pardo H. , Vallejo G. , Arias J.L.
Published: July 2008

The mammillary bodies of the posterior hypothalamus are one of the CNS structures in which structural sexual dimorphism has already been described. This study quantifies the argyrophilic nucleolar organizer regions (NORs) of the neurons from this region in the male and female rats, the latter during two major phases of the estrous cycle (estrus-diestrus). The number and relative area of these NORs stained with a silver nitrate technique are considered as an index of the global protein synthesis of the neurons in the different nuclei from the mammillary bodies. Our results show the existence of statistically significant differences between sexes and estrous cycle phases. These findings suggest a significant influence of gender and the hormonal state on the neural activity of the MB.
Temporal MRI Assessment of Intracerebral Hemorrhage in Rats
Authors: Knight Robert A. , Han Yuxia , Nagaraja Tavarekere N. , Whitton Polly , Ding Jennifer , Chopp Michael , Seyfried Donald M.
Published: July 2008

Background and Purpose—

MRI was used to evaluate the effects of experimental intracerebral hemorrhage (ICH) on brain tissue injury and recovery.

Methods—

Primary ICH was induced in rats (n=6) by direct infusion of autologous blood into the striatum. The evolution of ICH damage was assessed by MRI estimates of T
2
and T
1sat
relaxation times, cerebral blood flow, vascular permeability, and susceptibility-weighted imaging before surgery (baseline) and at 2 hours and 1, 7, and 14 days post-ICH. Behavioral testing was done before and at 1, 7, and 14 days post-ICH. Animals were euthanized for histology at 14 days.

Results—

The MRI appearance of the hemorrhage and surrounding regions changed in a consistent manner over time. Two primary regions of interest were identified based on T
2
values. These included a core, corresponding to the bulk of the hemorrhage, and an adjacent rim; both varied with time. The core was associated with significantly lower cerebral blood flow values at all post-ICH time points, whereas cerebral blood flow varied in the rim. Increases in vascular permeability were noted at 1, 7, and 14 days. Changes in T
1sat
were similar to those of T
2
. MRI and histological estimates of tissue loss were well correlated and showed approximately 9% hemispheric tissue loss.

Conclusions—

Although the cerebral blood flow changes observed with this ICH model may not exactly mimic the clinical situation, our results suggest that the evolution of ICH injury can be accurately characterized with MRI. These methods may be useful to evaluate therapeutic interventions after experimental ICH and eventually in humans.
The MRA-DWI Mismatch Identifies Patients With Stroke Who Are Likely to Benefit From Reperfusion
Authors: Lansberg Maarten G. , Thijs Vincent N. , Bammer Roland , Olivot Jean-Marc , Marks Michael P. , Wechsler Lawrence R. , Kemp Stephanie , Albers Gregory W.
Published: July 2008

Background and Purpose—

The aim of this exploratory analysis was to evaluate if a combination of MR angiography (MRA) and diffusion-weighted imaging (DWI) selection criteria can be used to identify patients with acute stroke who are likely to benefit from early reperfusion.

Methods—

Data from DEFUSE, a study of 74 patients with stroke who received intravenous tissue plasminogen activator in the 3- to 6-hour time window and underwent MRIs before and approximately 4 hours after treatment were analyzed. The MRA-DWI mismatch model was defined as (1) a DWI lesion volume less than 25 mL in patients with a proximal vessel occlusion; or (2) a DWI lesion volume less than 15 mL in patients with proximal vessel stenosis or an abnormal finding of a distal vessel. Favorable clinical response was defined as an improvement on the National Institutes of Health Stroke Scale score of at least 8 points between baseline and 30 days or a National Institutes of Health Stroke Scale score ≤1 at 30 days.

Results—

Twenty-seven of 62 patients (44%) had an MRA-DWI mismatch. There was a differential response to early reperfusion based on MRA-DWI mismatch status. Reperfusion was associated with an increased rate of a favorable clinical response in patients with an MRA-DWI mismatch (OR, 12.5; 95% CI, 1.8 to 83.9) and a lower rate in patients without mismatch (OR, 0.2; 95% CI, 0.0 to 0.8).

Conclusions—

The MRA-DWI mismatch model appears to identify patients with stroke who are likely to benefit from reperfusion therapy administered in the 3- to 6-hour time window after symptom onset. The criteria established for the MRA-DWI mismatch model in this study require validation in an independent cohort.
Racial/Ethnic Differences in Ischemic Stroke Rates and the Efficacy of Warfarin Among Patients With Atrial Fibrillation
Authors: Shen Albert Yuh-Jer , Yao Janis F. , Brar Somjot S. , Jorgensen Michael B. , Wang Xunzhang , Chen Wansu
Published: July 2008

Background and Purpose—

Warfarin reduces stroke risk in studies of predominantly white patients with atrial fibrillation (AF). Whether nonwhites also have lower rates of stroke while treated with warfarin is unclear.

Methods—

A multiethnic stroke-free cohort hospitalized with nonrheumatic AF was identified in a large health maintenance organization. Stroke risk factors (advanced age, diabetes, hypertension, and heart failure), warfarin use, and anticoagulation intensity were assessed. Crude ischemic stroke rates were calculated by Poisson regression for each group while using and not using warfarin. Cox proportional hazard models were constructed to assess the independent effect of race/ethnicity on ischemic stroke.

Results—

Between 1995 and 2000, we identified 18867 AF hospitalizations (78.5% white, 8% black, 9.5% Hispanic, and 3.9% Asian). Over the course of 63204 person-years follow-up (median, 3.3 years), 1226 ischemic strokes were identified. The percent-time on warfarin did not differ by race/ethnicity. The median percent-time on warfarin that international normalized ratio was 2 to 3 was 54.5% overall, but it was lower in blacks at 47.8%, whereas the other groups had a rate of ≈54%. The rate ratios (95% CI) of ischemic stroke with warfarin compared to without warfarin for whites, blacks, Hispanics, and Asians were 0.79 (0.68 to 0.90), 0.92 (0.65 to 1.30), 0.71 (0.48 to 1.05), and 0.65 (0.34 to 1.23), respectively.

Conclusions—

In this cohort, we did not observe a statistically significant lower rate of stroke with warfarin therapy among nonwhites (in particular blacks) with previous AF hospitalizations. The relatively small numbers of nonwhites renders our estimates less than precise and should be interpreted with caution.
Dietary Calcium Intake and Risks of Stroke, Its Subtypes, and Coronary Heart Disease in Japanese
Authors: Umesawa Mitsumasa , Iso Hiroyasu , Ishihara Junko , Saito Isao , Kokubo Yoshihiro , Inoue Manami , Tsugane Shoichiro
Published: July 2008

Background and Purpose—

Although it has been hypothesized that a high intake of dietary calcium may reduce the risk of cardiovascular disease (CVD), no prospective studies have been conducted to examine the specific association between calcium intake and incidence of stroke or coronary heart disease among Japanese with a low average calcium intake.

Methods—

To investigate the association between calcium intake and risk of CVD, a total of 41 526 Japanese men and women age 40 to 59 years without a history of CVD or cancer and who had completed a food consumption frequency questionnaire were enrolled in this study. The subjects were followed up from 1990 to 1992 to 2003, and after 533 692 person-years of follow-up, 1321 incident cases of stroke (664 ischemic, 425 intraparenchymal hemorrhage, and 217 subarachnoid hemorrhage) and 322 of coronary heart disease were documented.

Results—

Total calcium intake showed an inverse association with the risk of total stroke; the multivariable hazard ratio and 95% CIs for the highest versus the lowest quintile were 0.70 (95% CI, 0.56 to 0.88;
P
for trend=0.02). Dairy calcium intake was inversely associated with risks of total and ischemic stroke with respective multivariable hazard ratios (95% CIs) of 0.69 (0.56 to 0.85;
P
for trend=0.007) and 0.69 (0.52 to 0.93;
P
for trend=0.05). Dietary calcium intake was not significantly associated with risk of coronary heart disease.

Conclusions—

Dietary calcium intake, especially calcium from dairy products, was found to be associated with a reduced incidence of stroke among middle-aged Japanese.