bluuebunny/crossref_metadata_2025_split huggingface dataset:
Horseshoe kidney: A new theory on lts embrogenesis based on the study of a 16‐mm human embryo
Authors: Doménech‐Mateu J. M. , Gonzalez‐Compta X. 
Published: February 2005

AbstractWe studied a human embryo of 16 mm crown‐rump (CR) length in excellent condition with a horseshoe kidney malformation. An exhaustive study of this specimen and a review of published material on the human embryo brings us to propose a new theory on the embryogenesis of this malformation. The most commonly accepted theory consists of a mechanical interpretation based on the relation between the metanephroi and the umbilical arteries during the development of the latter. Nevertheless, in those cases where renal parenchyma constitutes the isthmic region, we believe that these arise from nephrogenic cells that have migrated across the primitive streak in the final phase of gastrulation and thus arise from the posterior nephrogenic area of the epiblast.
Iron and aluminum deposition in the meninges of the lamprey: Identification of an aluminum‐ferritin inclusion body
Authors: Youson J. H. , Sargent P. A. , Pearce G. W. 
Published: February 2005

AbstractThe meningeal tissue of the brain and spinal cord of larval and juvenile adults of lampreys (Petromyzon marinus) was examined by routine electron microscopy, electron microscopic histochemistry, and electron‐probe x‐ray microanalysis to locate sites of iron deposition. A magnetometer was used for identification of ferromagnetic iron. Ferritin particles, representing ferric iron, are present in abundance within the cytoplasmic matrices and in dense bodies of meningeal cells of both the brain and spinal cord of larvae and juveniles. These round cells of the meninges also contain abundant glycogen and lipid. Small quantities of ferrous iron are associated to the latter inclusion. Aluminum deposits are present within an electrondense material of many ferritin‐containing inclusions of meningeal cells of the larval brain. Ferromagnetic material was not detected in larval and upstream‐migrant lampreys. The deposition of iron and aluminum in the meninges of lampreys may be related to physiological and environmental factors, respectively, and/or to an important interaction between the two metals.
The ultrastructure of ruffini endings in the periodontal ligament of rat incisors with special reference to the terminal schwann cells (K‐cells)
Authors: Maeda Takeyasu , Sato Osamu , Kobayashi Shigeo , Iwanaga Toshihiko , Fujita Tsuneo 
Published: February 2005

AbstractThe Ruffini endings and associated cells in the periodontal ligament of rat incisors were investigated by means of immunohistochemistry for glia‐specific S‐100 protein and electron microscopy. Numerous Ruffini endings, which were immunoreactive for S‐100 protein as well as for neurofilament protein, were distributed in the alveolus‐related part of the lingual periodontal ligament. In electron microscopy, the Ruffini endings displayed expanded axoplasmic spines filled with a large number of mitochondria and neurofilaments; some of the spines directly contacted the surrounding collagen fibers via fingerlike projections. The axoplasmic spines and Schwann sheath, for the most part, were covered alternately by single or multiple layers of the basal lamina.Several rounded cells showing S‐100 immunoreactivity occurred in the vicinity of the Ruffini endings. The rounded cells associated with Ruffini endings possessed a kidney‐shaped nucleus and enveloped the axoplasmic spines with their cytoplasmic processes. From these morphological features, the cells in question were identified as the K‐cells described by Everts et al. (1977). These K‐cells developed Golgi apparatus and rough endoplasmic reticulum, suggesting active synthesis of proteins. Immunohistochemistry at the electron microscopic level revealed an intense immunoreactivity for S‐100 protein in the cytoplasm of the K‐cell and led to a conclusion that the K‐cells were terminal Schwann cells associated with Ruffini endings, presumably corresponding to the lamellar cells in the inner bulb of sensory corpuscles.
Immunoperoxidase localization of prostatic inhibin peptide in human, monkey, dog, and rat prostates
Authors: Garde Seema V. , Sheth Anil R. 
Published: February 2005

AbstractA comparative study on the localization of prostatic inhibin peptide was carried out by the immunoperoxidase technique in prostates of humans, bonnet and langur monkeys, marmosets, dogs, and rats. A positive reaction was observed in the prostatic epithelial cells of humans, in all three species of monkeys, and in the rat, while the dog prostate did not exhibit any reaction. These observations indicate a close immunological similarity among human, monkey, and rat prostatic inhibin peptides.
Mammalian frontal diploic vein and the human foramen caecum
Authors: Thewissen J. G. M. 
Published: February 2005

AbstractThe course of the frontal diploic vein in the mole Talpa and the tree shrew Tupaia is described and compared to the frontal diploic vein of other mammals. The frontal diploic vein in Talpa and Tupaia connects the dorsal sagittal sinus to the veins of the orbit and has an emissary function. In certain other mammals it has a diploic function and may drain towards the orbit (e.g., Orycteropus) or towards the dorsal sagittal sinus (e.g., Didelphis). The frontal diploic vein of these mammals is not homologous to the vein of the human foramen caecum, but to the human frontal diploic vein. The vein of the formen caecum is a problematic structure: its incidence in embryos and children is not clear.
Body weight gain as related to craniofacial and calvarial volumetric changes in growing rabbits
Authors: Alberius Per , Malmberg Martin 
Published: February 2005

AbstractThis investigation was conducted to evaluate the relationship between calvarial and craniofacial volumetric growth relative to body weight gain. Ten male New Zealand white rabbits received spherical tantalum bone markers in the nasal, frontal, parietal, and temporal bones: a minimum of two in each bone segment. The animals were followed from age 32 to 144 days using a roentgen sterophotogrammetric system and an accurate scale. Implant stability was checked at each sterometric examination. Sutural growth and volumetric changes were computed and correlated to weight increase. Successive calvarial and craniofacial polyhedron expansion, as well as weight, showed considerable variability and interindividual variation throughout the observation period. Calculated coefficients of determination, linear regressions, and the correlation coefficients for each age interval demonstrated weak correlations, especially for calvarial to weight data. Consequently, this study suggests a low dependence of calvarial volumetric growth, reflecting the neural mass expansion on body weight development. Thereby, further indications of the low reliability of weight as a parameter of general health evaluation was provided.
Glyoxylate cycle in the epiphyseal growth plate: Isocitrate lyase and malate synthase identified in mammalian cartilage
Authors: Davis Walter L. , Jones Ruth G. , Farmer Gene R. , Matthews J. L. , Goodman David B. P. 
Published: February 2005

AbstractPeroxisomes were identified in chondrocytes from all zones of the mammalian epiphyseal growth plate by using light microscopic techniques for the cytochemical demonstration of catalase, the marker enzyme for these organelles. Additional cytochemistry showed the presence of malate‐synthase‐positive structures within the chondrocytes. The latter enzyme, also associated with peroxisomes, is unique to the glyoxylate shunt, a metabolic pathway thought to be absent in vertebrate tissues. The glyoxylate cycle allows the net conversion of lipid to carbohydrate, i.e., gluconeogenesis. Biochemical studies on growth plate cartilage indicate that this tissue has the capacity to carry out cyanide‐insensitive B‐oxidation of fatty acids. The latter takes place in a nonmitochondrial compartment, most likely the peroxisomal compartment. Additionally, both of the unique enzymes associated with the glyoxylate cycle, i.e., isocitrate lyase and malate synthase, were also identified in a cell‐free homogenate of this cartilage. These studies indicate that cartilage, a poorly vascularized tissue characterized by its low oxygen tension and anaerobic glycolysis, may have the capacity to convert lipid to carbohydrate, i.e., gluconeogenesis via the glyoxylate pathway. In this way, cartilage may be unique among mammalian tissues.
Heart contains receptors for dihydrotestosterone but not testosterone: Possible role in the sex differential in coronary heart disease
Authors: Sheridan Peter J. , McGill Henry C. , Aufdemorte Thomas B. , Triplett Robert G. , Holt Richard G. 
Published: February 2005

AbstractThe sex differential in coronary heart disease is well documented but poorly understood. Previous studies have demonstrated receptors for dihydrotestosterone (DHT) in the myocardium and smooth muscle cells of arteries from a number of species. In this autoradiographic study, we further investigated and characterized the in vivo uptake and retention of the androgen binding in the male baboon. Adult castrated male baboons were injected with 1 μg/kg bw 3H‐testosterone; 1 hr after the injection, the animals were rapidly exsanguinated while under anesthesia. The heart and arterial system were removed and processed for autoradiography. As a negative control, one animal received both 3H‐testosterone and 100‐fold unlabeled testosterone. For positive controls, the pituitary gland, prostate, seminal vesicles, and other tissues were also removed and processed for autoradiography. In contrast to our previous finding with 3H‐DHT, no nuclear uptake and retention of 3H‐steroid was found in any of the cells in either the heart or the arterial system. In the positive control tissues, pituitary gland, prostate, seminal vesicles, and others, a very distinct nuclear uptake and retention of 3H‐steroid was observed, which was completely inhibited by the simultaneous injection of 100‐fold unlabeled testosterone. In the binding study, Scatchard analysis of the cytosol prepared from a 17‐year‐old female baboon demonstrated levels of androgen receptor (as determined by the use of radiolabeled R1881) comparable to that found in young adults. The results of these studies suggest that, in contrast to the generally accepted hypotheses, (1) circulating DHT, not testosterone, is the androgenic hormone that interacts with the cardiovascular tissue of the baboon and (2) there are separate receptors for testosterone and DHT in different tissues rather than a single receptor capable of binding both steroids.
Banding Patterns in rat incisor enamel stained by histochemical complexing methods for calcium
Authors: McKee M. D. , Warshawsky H. 
Published: February 2005

AbstractA characteristic banding pattern can be visualized at the surface of the rat incisor in the maturation zone of amelogenesis by staining with glyoxal bis(2‐hydroxyanil) (GBHA). Other banding patterns can be obtained with certain histological and fluorochrome stains and by radioautography following 45Ca injection. In this study, several histochemical reagents known to complex with different states of calcium were used to stain the surface of enamel. Rat incisors were quickly dissected and immediately immersed in solutions containing the following calcium‐binding reagents: arsenazo III, calmagite, murexide, N, N‐naphthaloylhy‐droxylamine, and calcein. Routinely, one contralateral lower incisor from each pair was counterstained with GBHA in order to relate each of the staining patterns to the banded distribution of maturation ameloblasts that is reflected by the characteristic GBHA staining pattern in the enamel. Each of the reagents used in this study demonstrated a staining pattern consisting of a series of broad bands running transversely and obliquely across the enamel. In all cases, the dyes stained predominantly that enamel associated with ruffle‐ended ameloblasts, i.e. enamel left unstained by GBHA. Some of the reagents also stained enamel in the secretion zone. The appearance and distribution of the staining patterns reflect the banded distribution of maturation ameloblasts and appear to be controlled on a time scale related to the rapid modulation of these cells.
The intersegmental anastomoses between spinal nerve roots
Authors: Moriishi Johji , Otani Katsumi , Tanaka Koichi , Inoue Shun‐Ichi 
Published: February 2005

AbstractFrequency and morphological characteristics of the intersegmental anastomoses between the spinal roots were investigated in 100 adult spinal cords from the cervical to lumbar segments. The frequencies of dorsal root anastomoses were 61, 7, and 22% of the cervical, thoracic, and lumbar cords, respectively. On the other hand, the incidence of anastomosis between the ventral roots was significantly low in both the cervical (10%) and lumbar (5%) cords as compared with that between the dorsal roots in these regions (P < .01). No anastomotic connections were found in the thoracic ventral roots. The anastomoses were classified into four types: types A and B; the borders between the spinal segments were cranially and caudally shifted, respectively; type C, anastomosis attached to the spinal cord at the border between the segments; and type D, anastomosis bridged between the adjacent rootlets and coursing parallel to the cord. The proportions of the four types at each spinal level disclosed that type A was most commonly observed compared with the other three types in the dorsal roots (P < .01). In the lumbar cord, the proportion of type C anastomosis between the dorsal roots increases noticeably toward the sacral level, while a complementary decrease occurred in type A. In the cervical ventral roots, types C and D predominated over the other two types (P < .01). The lumbar ventral roots contained types B and/or C. Type D anastomosis occurred exclusively in the cervical segments.
Morphology of the pterygomandibular raphe in human fetuses and adults
Authors: Shimada Kazuyuki , Gasser Raymond F. 
Published: February 2005

AbstractThe pterygomandibular raphe as described in current anatomy textbooks is not supported by actual observations in cadavers. A study was made on 60 adult Caucasian and Negro cadavers (52 right and 58 left sides, giving a total of 110 sides) providing comparison with an earlier study on Japanese specimens. In addition, 50 fetuses (25 mm crown‐rump length to term) were examined to determine the arrangement of the raphe prenatally. Variations in the morphology of the raphe region were classified into three types: Type A—only the upper portion of the raphe could be identified and had a broad, triangular shape. Type B—the buccinator and superior pharyngeal constrictor muscles were widely separated by a broad, fascial region. Type C—the raphe was absent with complete continuity of the buccinator and superior pharyngeal constrictor muscles. A prominent, narrow, tendinous band with attachments as described in current textbooks was never found in adults. There was a complete absence of the raphe in 36% of the specimens resulting in continuity of the buccinator and superior pharyngeal constrictor muscles (type C). However, the remaining adult specimens (64%) exhibited some form of a broad, fascial region that either completely (type B, 36%) or partially (type A, 28%) separated the two muscles. All of the fetuses exhibited the type B arrangement exclusively, indicating that changes in the shape of the raphe occur postnatally. The frequency of appearance of the raphe types in adults differs significantly according to race.
Patterns of keratin expression in the murine thymus
Authors: Farr Andrew G. , Braddy Steven C. 
Published: February 2005

AbstractPolyclonal and monoclonal antibodies recognizing different species of keratin molecules were used to characterize the expression of keratins by epithelial cells in the murine thymus. Some of the reagent antibodies used in this study were raised against human keratins and cross‐react with murine keratins. Both cortical and medullary thymic epithelial cells were found to contain keratin with apparent molecular weight of 52 KD, which is considered to be associated with simple or stratified epithelium. In addition, medullary epithelial cells were found to contain other species of keratin molecules, ranging in apparent molecular weight from 40 to 67 KD. This latter population of keratins is thought to be associated with stratified and/or keratinizing epithelia.
Distribution of laminin, collagen type IV, collagen type I, and fibronectin in chicken cardiac jelly/basement membrane
Authors: Little Charles D. , Piquet Dominique M. , Davis Lynn A. , Walters Luanne , Drake Christopher J. 
Published: February 2005

AbstractLight microscopic immunolabeling studies were designed to identify and locate structural components within the cell‐free extracellular matrix which lies between the embryonic endocardial and myocardial tubes. Affinity‐purified antibodies were used to examine stage 15‐22 embryonic chicken hearts. Specimens were immunolabeled by using three different methodologies: (1) postembedding labeling of 10 μm cryostat sections, (2) preembedding labeling (en bloc) of whole hearts, and (3) postembedding labeling of ethanol/acetic acid‐fixed paraffin sections. Our results establish the spatial distribution of collagen type I and demonstrate for the first time the presence of collagen type IV and laminin in the myocardial‐basement‐membrane/cardiac jelly.
Circadian variation of epidermal growth factor receptor in mouse liver
Authors: Scheving Lawrence A. , Tsai T. H. , Scheving Lawrence E. , Feuers Ritchi E. J. , Feuers Ritchi E. J. 
Published: February 2005

AbstractThe liver undergoes a biochemical and morphological circadian transformation. In this paper, we document circadian variation in the binding parameters of the hepatic epidermal growth factor receptor (EGFR). Liver membranes were prepared from ad libitum fed or fasted male CD2F1 mice killed at different circadian phases at 4 h intervals. Bmax (maximum binding) and Kd (dissociation constant) varied in a rhythmic fashion. The range of change for Bmax along the 24 h time scale was 423%. For Kd, it was 162%. Both peaked late in the dark span, and decreased late in the light span. Fasting and EGF treatment reduced Bmax and the amplitude of circadian variation.
S‐100 protein in white preadipocytes: An lmmunoelectronmicroscopic study
Authors: Cinti Saverio , Cigolini Massimo , Morroni Manrico , Zingaretti M. Cristina 
Published: February 2005

AbstractDifferentiation of adipocytes from their precursor cells (preadipocytes) is an important problem in the study of the pathogenesis of obesity. Unfortunately, among the immature stages of adipocytes, only relatively differentiated forms can be identified by their fine structure; because early preadipocytes cannot be distinguished from fibroblasts solely on the basis of their morphology, it is impossible to assess the size of the preadipocyte population. S‐100 protein has been identified in various mammalian tissues and recently mature adipocytes have been shown to be positive for this protein. Because fibroblasts are negative for S‐100 protein, the present study tested the S‐100 immunoreactivity of preadipocytes by the peroxidase‐antiperoxidase (PAP) preembedding method at the ultrastructural level both in vivo and in culture. Mature adipocytes and early preadipocytes, including fibroblast‐like cells devoid of lipid droplets, were positive both in vivo and in culture. Endothelial cells and pericytes were negative; but flattened, lipid‐free, fibroblast‐like cells surrounding the pericytes were positive. True fibroblasts both in vivo and in culture were negative. Therefore, S‐100 protein can be a useful biochemical marker in distinguishing fibroblasts from early preadipocytes.
Quantitative assessment of the biological effects of follicle regulatory protein on dihydrotestosterone‐maintained spermatogenesis in hypophysectomized rat
Authors: Ahmad Nazir , Toppari Jorma , Dizerega Gere S. , Warren Dwight W. 
Published: February 2005

AbstractFollicle regulatory protein (FRP) isolated from porcine ovarian follicles influences folliculogenesis through a paracrine mechanism. A similar protein has been found in the testes and seems to have some inhibitory effects on spermatogenesis when administered to intact male experimental animals. On the basis of female and male studies, it has been ascertained that the effects of FRP are at the level of gonads and not the pituitary or the hypothalamus. In the studies with intact males it was not possible to determine the exact site of FRP action on the testes. Dihydrotestosterone (DHT) has been shown to maintain spermatogenesis in hypophysectomized rats. In order to determine if the inhibitory effects of FRP are at steps prior to the formation of DHT, FRP was administered to hypophysectomized rats that were injected with DHT. Groups of adult rats were hypophysectomized and treated daily with FRP, DHT, FRP + DHT, or vehicle alone for 30 days. At necropsy, body, testes, prostate glands, and seminal vesicle weights were recorded. One testis and sexual accessory glands were fixed for histological evaluation. The contralateral testis was decapsulated, six 2 mm segments of seminiferous tubules, representing defined stages of spermatogenesis, were isolated by transillumination‐assisted microdissection, and spermatogenic cells were quantified by DNA flow cytometry. Histologically, the seminiferous tubules of vehicletreated hypophysectomized controls showed advanced regression. Rats treated with FRP alone showed similar degeneration. On the other hand, rats treated with DHT showed maintenance of spermatogenesis comparable to normal controls. The testes of rats treated with FRP + DHT were indistinguishable from those treated with DHT only. Flow cytometric quantification of germinal cells from all groups confirmed the histological findings. In this study FRP did not exert deleterious effects on DHT‐maintained spermatogenesis. This finding suggests that the inhibitory effects of FRP on spermatogenesis in intact animals may not be a direct effect on spermatogenic cells but may impair androgen action or production or DHT formation.
Development and maintenance of a polycystic condition in ovaries autotransplanted under the kidney capsule
Authors: Desjardins Gina C. , Brawer James R. 
Published: February 2005

AbstractA single injection of estradiol valerate (EV) produces a polycystic ovarian (PCO) condition in the rat. The development of the PCO condition coincides with alterations in the endogenous plasma gonadotropin patterns, suggesting that PCO may be a response to abnormal gonadotropin stimultion. Other factors, however, such as direct autonomic innervation, also contribute significantly to the regulation of the ovary and could be important in generating and/or maintaining PCO. We have, therefore, removed and autotransplanted one ovary in each of eight rats under the capsule of the ipsilateral kidney, thus totally disrupting its innervation. The animals were injected with EV and both ovaries of each animal were examined 8 weeks later. In a second group of animals, we induced the PCO condition, autotransplanted one polycystic ovary in each animal under the kidney capsule, and examined the ovaries 2 weeks later. In both groups the autotransplanted ovaries exhibited the full range of polycystic morphology, as did the intact ovary in each animal. We conclude that since a major perturbation in innervation affects neither the development nor the maintenance of PCO, autonomic innervation does not play a crucial role in this disorder.