bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ventricular myocardial architecture in marine fishes
Authors: Sanchez‐Quintana Damian , Hurle Juan M. 
Published: February 2005

AbstractThe fiber architecture of the ventricular myocardium has been studied in elasmobranch (Isurus oxyrhinchus, Galeorhinus galeus, Prionace glauca) and teleost (Xiphias gladius, Thunnus thynnus, Thunnus alalunga) fish species with hearts displaying mixed types of ventricular musculature (compact and trabecular). In all cases, the compact myocardium is organized in layers of fiber bundles with an orderly arrangement within the ventricular walls. The number of these layers appears to be dependent on the relative thickness of the compact myocardium. Differences in the pattern of myocardial fiber arrangement were observed among the different fish species. In elasmobranchs the compact myocardium at the level of the atrioventricular orifice is continuous with the trabeculated myocardium. Furthermore, in elasmobranchs the trabeculated myocardium displays a precise arrangement in arcuate trabeculae running from the auriculoventricular to the conoventricular orifices. In teleosts, the compact myocardium is independent of the trabeculated myocardium and a large number of fibers insert into the bulboventricular fibrous ring. The trabeculated myocardium in these species displays an anarchic arrangement except at the level of the bulboventricular orifice, where the fibers tend to be aligned longitudinally, also being inserted into the fibrous ring. Minor differences, consisting mainly of the presence of extra bundles of fibers, were also observed among different individuals of the same species. The possible relationship between myocardial fiber architecture and ventricular shape is discussed.
Immunoultrastructural studies of human NK cells: I. Ultracytochemistry and comparison with T cell subsets
Authors: Kang Yuan‐Hsu , Carl Mitchell , Grimley Philip M. , Serrate Susana , Yaffe Lyn 
Published: February 2005

AbstractHuman NK activity is known to be associated with a population of large granular lymphocytes (LGL) exhibiting several immunophenotypic surface markers including Leu‐11a (NKP‐15), Leu‐7 (HNK‐1), Leu‐3a (T4), and Leu‐2a (T8). Based upon correlation with cytolytic activity, Leu‐11a is now considered the most specific antigenic marker for human NK cells. Present investigation compared the ultrastructure of cells expressing Leu‐11a, Leu‐7, Leu‐3a, and Leu‐2a, both in human peripheral blood lymphocytes (PBL) and the purified LGL fraction. Subcellular cytochemical reactions were investigated in Leu‐7+ or Leu‐11a+ PBL or LGL and in cells conjugated with K562 targets (indicating NK cytolytic potential). The surface markers, localized with monoclonal antibodies, were detected by immunoelectron microscopy by using direct or indirect avidin‐biotin‐peroxidase (ABC) or colloidal gold methods. A peroxidase‐colloidal gold double‐labeling system was used to identify subsets of Leu‐7+ or Leu‐11a+ cells. Previously described ultrastructural features of LGL including a villous surface, reniform nuclei, low nuclear/cytoplasm ratios, and abundant cytoplasm with vesicles, vacuoles, electron‐dense granules, parallel tubular arrays (PTA), or paracrystalline inclusions were associated with Leu‐7+, Leu‐11a+, Leu‐7+/Leu‐11a+, Leu‐7+/Leu‐11a−, and Leu‐7−/Leu‐11a+ PBL or LGL. Results showed that the Leu‐7+/Leu‐11a+ cells were the most abundant NK cells in PBL. Lymphocyte subsets with Leu‐3a or Leu‐2a surface marker showed some ultrastructural features including PTA similar to Leu‐7+ cells and Leu‐11a+ cells, and their subsets. These T‐cells appeared ultrastructurally more similar to the Leu‐7+/Leu‐11a− subset.Cytochemical studies showed that electron‐dense cytoplasmic granules and PTA typical of the Leu‐11a+ cells and Leu‐7+ cells contained glycoprotein, acid phosphatase, and arylsulfatase. Large cytoplasmic vacuoles were heterogeneous and typically contained electron‐dense material with DAB reactivity, membranous material, PTA, and/or paracrystalline inclusions. Glycoprotein, acid phosphatase, and arylsulfatase, and peroxidase reactive material were also found in these vacuoles. These features suggested that the vacuoles could be secondary lysosomes. The coexistence of intact PTA or degenerating PTA in the same vacuoles with paracrystalline inclusions suggested that the latter are possibly derived from PTA.
Comparative study of the distribution of venous values in the lower extremities of black Africans and Caucasians: Pathogenetic correlates of prevalence of primary varicose veins in the two races
Authors: Banjo Adesegun O. 
Published: February 2005

AbstractThe incidence of valves in the major veins of the lower extremities of Africans and Caucasians was studied. Valves are absent in the inferior vena cava in both races. In the common iliac veins, 1–7% of Caucasians and 1% of Africans have rudimentary valves.Normal valves exist in the following veins: the external iliac veins—22–33% of Caucasians and 9% of Africans; the femoral vein segment above the saphenofemoral junction—67–81% of Caucasians and 93% of Africans; the 3‐cm‐length of the femoral vein below the profundofemoral junction—90% of Caucasians and 100% of Africans; the terminal 3 cm of the great saphenous vein—100% Caucasians and 98% Africans.The lower incidence in the number of valves in Caucasians may account for the high prevalence (10–18%) of varicose veins in Caucasians; the reverse of this relationship is suggested for the low prevalence (1–2%) of the condition in Africans. Factors influencing the development of incompetent valves are discussed.
Skeletal changes in the hindlimbs of bipedal rats
Authors: Kay Elizabeth D. , Condon Keith 
Published: February 2005

AbstractExperimental bipedalism in rats has been proposed as a model for studying evolutionary and orthopedic change. This study quantified the skeletal changes which occur in the hindlimbs of these bipedal rats. Bipedalism was produced in 16 male rats by forelimb amputation during the neonatal period. The rats were sacrificed at maturity and the femurs and tibia‐fibulas from randomly selected hindlimbs were weighed and measured. Out of a total of 25 parameters, only one, anteroposterior diameter of the proximal femur, was found to differ statistically between the bipedal and control groups. No changes were found in bone length, weight, or curvature. The results of other bipedal studies were reviewed, in light of these findings; and it is concluded that rats do not achieve true bipedalism, or increased hindlimb loading.
3H‐mannose utilization by fibroblasts of the periodontal ligament
Authors: Cho Moon‐Il , Garant Philias R. 
Published: February 2005

AbstractThe synthesis, intracellular translocation, and secretion of mannose‐containing glycoproteins(s) by periodontal ligament fibroblasts have been investigated by means of electron microscopic radioautography. Tritiated mannose was administered to young mice via jugular vein, and radioautographs were prepared at 5, 10, 20, and 35 minutes, 4 and 8 hours after injection. Analysis of electron microscopic radioautographs revealed a maximum labeling (94%) with 3H‐mannose of the rough endoplasmic reticulum at 5 minutes. Labeling of the Golgi components started to increase from 10 minutes (14%) and reached a maximum level at 20 minutes (31.2%). At 35 minutes, secretion granules, dense bodies, profiles of intracellular collagen, and the cell surface were labeled. At 8 hours, most labelling (79.2%) was extracellular, and associated either with the collagenous matrix (43.7%) or the cell surface (35.5%). Cytoplasmic vesicles containing dense materials around collagen fibrils were also labeled at 8 hours. It is concluded that mannose is directly incorporated into the rough endoplasmic reticulum (RER), and that mannose‐containing glycoprotein(s) are packaged in the Golgi apparatus into secretory granules. Mannose‐containing glycoproteins(s) become distributed on the periodontal ligament (PDL) fibroblast cell surface, cytoplasmic dense bodies, and the extracellular matrix.
Healing of experimentally produced lesions in articular cartilage following chondrocyte transplantation
Authors: Grande Daniel A. , Singh Inder J. , Pugh James 
Published: February 2005

AbstractArticular cartilage is known to have limited ability to heal once injured, and attempts to heal lesions in cartilage have yielded equivocal results. The following experiments were performed to investigate healing in cartilage following transplantation of chondrocytes grown in vitro. The knee joint of the New Zealand White rabbit was used as the experimental model. An initial baseline study was made to determine the intrinsic capability of cartilage for healing defects that do not fracture the subchondral plate. A second experiment examined the effects of autologous in vitro grown chondrocytes on the healing rates of these defects. The results were evaluated by qualitative and quantitative light microscopy.In control defects not grafted with chondrocytes, 6 weeks after the initial defect was created, there was little repair. Macroscopic and histological findings were consistent with an osteoarthritic pathology such as synovitis and “cell nests.”Macroscopic results from grafted specimens displayed a marked decrease in synovitis and other degenerative changes. Defects which had received transplants had a significant amount of cartilage reconstituted (82%) compared to ungrafted controls (18%). Controls showed a healing rate comparable to that obtained in the initial baseline study.
Incorporation of strontium into the calcium carbonate crystals of the endolymphatic sac in the tree frog (Hyla arborea japonica)
Authors: Kawamata Seiichi 
Published: February 2005

AbstractTree frogs were loaded with strontium chloride (SrCl2). The incorporation of strontium metal into the calcium carbonate (CaCO3) crystals located both in the inner ear and in the endolymphatic sac was studied by x‐ray microanalysis (XMA) and scanning electron microscopy (SEM). In the inner ear, strontium was not recognized except for traces in a few crystals. When observed by SEM, these crystals had a faceted body and two pointed ends with rather smooth surfaces. However, in the endolymphatic sac, which greatly expands into the spinal canal, strontium was clearly present at every surface of all crystals. Careful examinations by point and line XMA revealed that strontium x‐ray counts were highest at the pointed ends and decreased sharply and then gradually toward the equator of the crystals. SEM observations revealed that the crystals in the endolymphatic sac always had rough and irregular surfaces regardless of their shapes and sizes. Calcium was always found in crystals of both organs. Except for calcium and strontium, other elements including sodium and heavier elements were negligible in XMA. These findings suggest that strontium is incorporated into the crystals only in the endolymphatic sac, and the rough‐surfaced covering of these crystals reflects newly deposited strontium salt. It seems to indicate that these crystals grow predominantly by accretion.
Stereological analysis of the muscle‐tendon junction in the aging mouse
Authors: Trotter J. A. , Samora A. , Hsi K. , Wofsy C. 
Published: February 2005

AbstractTransmission of contractile tension from skeletal muscle fibers to connective tissue elements is thought to occur at the muscle‐tendon junctions, specialized regions at the extreme ends of the fibers. Previous stereological studies on adult mouse and chicken fibers have shown that, with reference to equal cross‐sectional areas of myofibrils, the muscle‐tendon junctions of faster fibers have significantly more surface membrane devoted to force transmission than do those of slower fibers (Trotter et al.: Anat. Rec. 213:16–25, 1985a; Trotter et al.: Anat. Rec. 213:26–32, 1985b; Trotter and Baca: Anat. Rec. 218:256–266, 1987). In the present study we have analyzed the muscle‐tendon junctions of 30‐month‐old mice, employing techniques for scanning and transmission electron microscopy and for ultrastructural stereology which are identical to those previously used to study the same muscles in 4‐month‐old mice. Whereas the principal structural features of the muscle‐tendon junctions of fibers from adult and aged mice are indistinguishable, stereological analyses of the fiber‐tendon interfaces indicate that, in aging animals, the interfacial ratio (the ratio of the surface area of force‐transmitting membrane to the cross‐sectional area of force‐generating myofibrils) is significantly reduced. While the interfacial ratio of fast‐twitch fibers of the adult plantaris is about 14.5, the corresponding ratio in aged animals is about ten. In the predominantly slow‐twitch fibers of the adult soleus, the interfacial ratio is about ten at the insertion and about 12.7 at the origin, whereas the corresponding ratios in the aged animals are both about ten. These findings are consistent with the notion that the amount of surface area specialized for force transmission is related to the contractile speed of the fiber.
Differential effects of tissue processing on human embryonic and fetal skin
Authors: Foster Carolyn A. 
Published: February 2005

AbstractTo most accurately evaluate quantitative data from studies of developing epidermis, the effects of tissue processing on human embryonic and fetal skin (8–20 weeks gestational age) were examined using two different techniques: 1) EDTA‐separated epidermal sheets that were briefly fixed in 2% paraformaldehyde, processed through Permount infiltration, and prepared as whole mounts on glass slides, and 2) skin that was fixed in Karnovsky's fixative and embedded in Epon. Based on en face measurements of surface area before and after tissue processing, both procedures caused differential, age‐dependent shrinkage. However, the trend of increasing shrinkage was inversely related to increasing age in the paraformal‐dehyde‐fixed epidermal sheets (y = 57.14 + 1.26x, where x = gestational age in weeks and y = % of original surface area), but directly correlated with aging in the Karnovsky‐fixed skin (y = 955.62 − 232.77x + 20.38x2). Shrinkage of epidermal sheets occurred during the dehydration and clearing steps, whereas most of the dimensional changes in whole skin took place during fixation in Karnovsky's. These differences are probably due to greater cross‐linking of proteins and longer fixation time in the more concentrated and fast‐acting Karnovsky's as well as the influence of increasing quantities of fibrous proteins in the dermis of whole skin.
Analysis of crystallite shape in rat incisor enamel
Authors: Warshawsky H. , Bai P. , Nanci A. 
Published: February 2005

AbstractThe hydroxyapatite crystallites of mammalian enamel appear as hexagons when seen in cross‐sections examined with the transmission electron microscope. Using goniometric transmission electron microscopy, stereo‐pair electron micrographs and freeze‐fracture replicas, two models have been proposed to explain the hexagonal crystallite profile. The “hexagonal ribbon” model proposes that hexagonal profiles are true cross‐sections of elongated hexagonal ribbons. The “rectangular ribbon” model proposes that crystallite profiles are three‐dimensional rectangular segments (parallelepipeds), which are contained in the Epon sections and project as opaque hexagons in routine transmission electron micrographs. Morphological observations together with predictions from models indicate that the crystallites in rat incisor enamel are flat ribbons with rectangular cross‐sectional profiles. The hexagonal images seen in electron micrographs of thin sections of enamel result from viewing parallelepiped‐shaped segments of these crystallites as two‐dimensional shadows.
Effects of orthodontic forces on the morphology and diameter of sharpey fibers of the alveolar bone of the rat
Authors: Martinez R. H. , Johnson R. B. 
Published: February 2005

AbstractThere is little information available concerning the effects of functional and therapeutic forces on Sharpey fibers and adjacent bone matrix. In the present study, springs were placed between the left first and second maxillary molar teeth of rats and retained for 1, 2, 3, 4, or 5 days. The right side served as a control. Tissues from sham‐operated, untreated animals were also studied. Maxillae were removed, fractured, rendered anorganic with sodium hypochlorite, and then examined by scanning electron microscopy (SEM). Some tissues were demineralized and examined by high‐voltage electron microscopy (HVEM). Sharpey fibers were studied at the alveolar wall and at the midline of the interdental septum (intra‐septal Sharpey fibers). In 5‐day experimental tissues, SEM showed intra‐septal Sharpey fibers had either a reduced number of, or lacked, unmineralized cores. Unit collagen fibrils in 5‐day tissues viewed by HVEM were densely packed into Sharpey fibers which had no afibrillar areas. Sharpey fibers at the alveolar wall demonstrated no observable changes in morphology or in pattern of mineralization. After 5 days of spring placement, the mean diameters of intra‐septal fibers were significantly less than those at the alveolar wall (p < 0.001). The disparity in Sharpey fiber diameters of treated and untreated control animals suggests that untreated controls are essential to the design of studies of rodent tooth movement. This study suggests that orthodontic tooth movement produces changes in the morphology and mineralization patterns of Sharpey fibers which might affect the mechanical strength of the periodontium.
Cyclic localization of actin and its relationship to junctional complexes in maturation ameloblasts of the rat incisor
Authors: Nishikawa Sumio , Josephsen Kaj 
Published: February 2005

AbstractThe patterns of fluorescence associated with maturation ameloblasts of mandibular incisors labeled with 7‐nitrobenz‐2‐oxa‐1,3‐diazole‐phallacidin (NBD‐phallacidin) for the detection of F‐actin were investigated in normal and fluoride‐treated rats. In normal rats, bands of smooth‐ended ameloblasts (SA) exhibited intense fluorescence at their proximal ends only. Bands of ruffle‐ended ameloblasts (RA) exhibited strong fluorescence at their distal ends as well as at their proximal ends. Regional differences in degree of intensity within the bands and between bands were displayed. In the apical part of the RA bands the proximal fluorescence was intense; it then decreased in an incisal direction; and it finally was absent close to the adjacent SA band. The incisal extension of strong proximal fluorescence in RA bands was short in early maturation and long in late maturation. The fluorescence pattern at both ends of the ameloblasts was cyclically repeated throughout the region of ameloblast modulation corresponding to the numbers of SA bands. In rats receiving 113 ppm fluoride in their drinking water for 2 months the number of fluorescence and ameloblast modulation cycles was reduced equally indicating that the cyclic F‐actin localization is a phenomenon related to ameloblast modulation. Electron microscopy revealed that areas of strong fluorescence contained filament bundles, presumably actin filaments, in relation to continuous junctions occluding the interameloblast spaces. Areas of weak or no fluorescence were related to discontinuous macular junctions. The results suggest that the changes in F‐actin distribution correlate well with junctional complex development, and therefore, possible functions related to the interameloblast spaces within the RA bands may be redistributed as the ameloblasts are carried incisally by the erupting incisor.
Comparison of regional differences in cardiac myocyte dimensions in rats, hamsters, and guinea pigs
Authors: Campbell Scott E. , Gerdes A. Martin , Smith Teri D. 
Published: February 2005

AbstractIsolated myocytes were prepared from Sprague Dawley rats, golden Syrian hamsters, and Hartley guinea pigs to investigate regional variations in myocyte size. Cell volume (V) was measured with a Coulter Channelyzer, cell length (L) was measured directly, and cross‐sectional area (CSA) was calculated from V/L. Compared to values from the left ventricle (LV), right ventricular L was shorter in the rat (P < .01) and hamster (P < .05) and longer in the guinea pig (P < .01). Guinea pig atrial L was shorter (P < .01) than L in the right ventricle (RV) but did not differ from L in the LV. No significant differences in L existed between endomyocardium, middle myocardium, and epimyocardium of the LV in all three species. In rats and hamsters, myocytes from the RV had smaller V and CSA values (P < .01) compared to any region of the LV. A transmural gradient of cellular dimensions existed in the LV of the rat, but not in hamster, with V and CSA of endomyocardium being largest and epimyocardium smallest (P < .01). Endomyocardial V and CSA were larger (P < .01) than all other regions in the hamster, but the difference was not significant compared to epimyocardial V. In the guinea pig, no significant differences in V existed between RV and LV or between the three LV regions. No pattern of regional differences was seen between ventricular CSA values in the guinea pig. Guinea pig atrial V and CSA values were smaller (P < .01) than those for ventricular myocytes. Therefore, regional differences in cardiac myocyte size vary among different rodent species.
Development of ciliated cells in the human fetal oviduct: An ultrastructural study
Authors: Konishi Ikuo , Fujii Shingo , Parmley Tim H. , Mori Takahide 
Published: February 2005

AbstractPrenatal development of ciliated cells in the human fallopian tube was studied by light and electron microscopy in specimens obtained from 12 fetuses, aged 12–40 weeks. On light microscopy, transverse sections of the ampullary portion of the tube revealed a slit‐like lumen at 12 weeks. The lumen began to fold by 15 weeks, and formed the typical villous structures by 31 weeks. On electron microscopy, the epithelial cells contained a large number of sub‐ and supranuclear glycogen particles until 18 weeks and an occasional solitary cilium. At 20–22 weeks, instead of glycogen particles, cytoplasmic organelles such as mitochondria, rough endoplasmic reticula and Golgi apparatus were well developed, and some cells possessed cilia with a 9 + 2 microtubular structure. Between 22 and 31 weeks, ciliated cells were sporadically observed. At 31 weeks, the epithelial cells accumulated a large number of sub‐ and supranuclear glycogen particles. Afterwards, numerous ciliated cells with well‐developed cytoplasmic organelles were observed by 40 weeks.
Localization of calbindin‐D28K in calcitonin containing cells of chick ultimobranchial glands
Authors: Taylor Alan N. , Inpanbutr Nongnuch , Deftos Leonard J. 
Published: February 2005

AbstractSpecific antisera raised against calbindin‐D28K (CaBP), the vitamin D‐dependent calcium‐binding protein from chick intestine, was used to localize the protein in chick ultimobranchial glands (UB glands) by the peroxidase‐antiperoxi‐dase technique. CaBP was localized in secretory cells in the cell cords and in a few cells of the epithelium lining the follicles. It was not found in the fibroblastlike cells in the cell cords nor in islands of parathyroid tissue present in the UB gland. The immunomarker for CaBP was distributed throughout the cytoplasm and nucleus of the secretory cells. The same cells demonstrated a positive reaction in their cytoplasm when reacted with an antiserum specific for salmon calcitonin (CT), thus confirming the presence of CaBP and CT in the same UB‐gland secretory cells. In other tissues, the presence of CaBP is regarded as an end‐organ marker for actions of the vitamin D endocrine system. This novel demonstration of CaBP in UB‐gland cells responsible for secretion of calcitonin suggests a direct effect of the vitamin D endocrine system on those cells in addition to an indirect effect through the stimulation produced by elevated circulating calcium levels.