bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation and perforation of closing plates in the chick embryo
Authors: Earle Waterman Robert
Published: February 2005

The morphology of the closing plates between adjacent pharyngeal arches was examined in chick embryos between stages 11 and 21 (HamburgerHamilton). Each closing plate is formed by apposition between the basal surfaces of portions of the pharyngeal pouch endoderm and the ectoderm of the overlying pharyngeal cleft. Initial contact between ectoderm and endoderm occurs at several small points which are separated by regions containing mesenchymal cells and extracellular material. Contact between the opposed epithelia is made by extension of cellular processes through the intervening basal laminae and extracellular space. Endodermal and ectodermal cells then interdigitate to create a cellular layer which rapidly thins. The interposed extracellular material is sequestered into small pools as cellular interdigitation proceeds. Perforations form through certain regions of closing plates 1–3 and persist during the stages studied. Small slit‐like depressions appear between cells of the closing plate just prior to perforation. The initial perforations enlarge until they are separated only by thin cellular strands. These strands presumably rupture, leaving small cellular accumulations which persist for a short time marking the junction between ectoderm and endoderm along the walls of adjacent pharyngeal arches. Clear evidence of cell degeneration is rare. These results suggest that cellular reorganization, rather than cell death, is a major mechanism of initial perforation.
Superior cervical ganglionectomy results in the loss of pineal concretions in the adult male gerbil (meriones unguiculatus)
Authors: Champney Thomas H. , Joshi Bhaskar N. , Vaughan Mary K. , Reiter Russell J.
Published: February 2005

Twelve weeks after bilateral superior cervical ganglionectomy, the number of pineal concretions in adult male gerbils was drastically decreased irrespective of photoperiodic treatment. These findings present further evidence that pineal concretions may be related to the metabolic activity of the gland. It is suggested that the pineal concretions of the gerbil are associated, in a yet unknown way, to the metabolism of the gland and that an active pineal is essential to maintain the large number of concretions seen in the normal state.
Number and size of rat thyroid C cells: No effect of pinealectomy
Authors: McMillan P. J. , Heidbüchel U. , Vollrath L.
Published: February 2005

A method for the estimation of the size and total number of calcitonin‐containing cells (C cells) in the rat thyroid gland has been devised. The total area, the number of C cells per unit area, and the areal fraction of C cells were determined for the C cell region using step serial sections. From these data it was estimated that from 0.3 × 106 to 1.0 × 106 C cells were evenly divided between the two thyroid lobes. Approximately 150 μm3 of cytoplasm were associated with each of these cells. In comparison with sham‐operated rats, pinealectomy had little effect on the number of C cells. In an experiment terminated in the summer, there was a statistically insignificant decrease 6 weeks postsurgery; no effect was seen at 12 weeks. On the other hand, a slight increase in the number of C cells was seen in January, 12 weeks postsurgery. The volume of cytoplasm per cell was not altered by pinealectomy.
Migration of macrophages from the marginal zone to germinal centers in the spleen of mice
Authors: Kotani Masahiko , Matsuno Kenjiro , Miyakawa Kazuhisa , Ezaki Taichi , Hayama Takeshi , Ekino Shigeo
Published: February 2005

Histological observations of the mouse spleen were carried out at different times after intravenous carbon injection. Large carbon‐laden macrophages appeared in great numbers in the marginal zone soon after injection. They came together favorably around the germinal centers. Possible migration of these cells toward the germinal centers diffusely from the periphery of the white pulp or through the periarterial lymphoid sheath was suggested. These macrophages entered the germinal centers on a large scale and clustered for a long period–at least 180 days. Since the same type of macrophages were observed persistently in the marginal zone, it was thought that some of them might arise from the blood stream. Possible migration of these cells from the marginal zone toward the germinal centers was also persistently observed.

A second type of much smaller carbon‐laden macrophages was seen in the white pulp. However, they never showed any favorable localization in the germinal centers as did large carbon‐laden macrophages.
Reduced number of brain cells in so‐called neural overgrowth
Authors: Desmond Mary E.
Published: February 2005

Patten described as neural overgrowth a folding of brain tissue into the ventricles in abnormal human embryos. Intubation of chick embryo brains releases cerebrospinal fluid pressure resulting in a similar folding. These folded brains have 2.5 times less tissue volume than control embryos of identical stage. This study shows, with total DNA measurements, that brain cell number is 50% less in folded brains (intubated embryos) as compared to control brain of identical staged embryos.
Benzo(a)pyrene inhibits ovulation in C57BL/6N mice
Authors: Swartz William J. , Mattison Donald R.
Published: February 2005

Successful female reproductive function requires follicle growth, ovulation, and formation of the corpus luteum. Treatment of C57BL/6N mice with a single intraperitoneal injection of benzo(a)pyrene in doses ranging from 1 to 500 mg/kg produced a dose‐ and time‐dependent decreaśe in the number of corpora lutea. This effect on the number of corpora lutea is most pronounced at 1 week after treatment, with a threshold of about 1 mg/kg, and an ED50 of 1.6 mg/kg. By 2 weeks after treatment partial recovery of follicle growth and ovulation occurred, as indicated by an increase in the ED50 to 20 mg/kg. Complete recovery of normal corpora lutea number occurs in mice treated with less than 100 mg/kg by 3 weeks after treatment, with little change in the ED50 noted between 3 and 4 weeks posttreatment, 78 mg/kg at both times. Mice treated with 100 or 500 mg/kg did not recover normal corpora lutea number over the course of this experiment. These data indicate that acute exposure to benzo(a)pyrene, and perhaps other polycyclic aromatic hydrocarbons, may have a transient adverse effect on follicle growth, ovulation, or formation of corpora lutea. A consequence of this effect, transient infertility, has been observed previously when exploring the effect of polycyclic aromatic hydrocarbons on murine reproduction.
The superficial sylvian vein in humans: With special reference to its termination
Authors: Bisaria Krishna Kumar
Published: February 2005

A study of the termination of the superficial middle cerebral vein in 140 human specimens revealed that in 80 cranial cavities (51.1%) the vein drained into both the sphenoparietal sinuses, in nine cranial cavities (6.4%) into the sphenoparietal and cavernous sinuses, and in 19 cranial cavities (13.6%) into the sphenoparietal sinuses and middle meningeal veins. In 20 cranial cavities (14.3%) the vein drained into the cavernous sinuses alone and in eight cranial cavities (5.7%) it drained into the cavernous sinuses and middle meningeal veins. In one cranial cavity (0.71%) it drained into the vein in the foramen lacerum and the sphenoparietal sinus, in one cranial cavity (0.71%) into the sphenoparietal sinus and the superior petrosal sinus, in one cranial cavity (0.71%) into the middle meningeal veins on either side, and in another cranial cavity (0.71%) into the superior sagittal sinus, a finding which has not been reported in the past. The presence of an uncal vein draining the medial surface of the temporal lobe was observed occasionally (5.7%) in this study. A part of the superficial middle cerebral vein and sphenoparietal sinus in the form of a vein running a short course between the two layers of the lateral wall of the cavernous sinus is an observation previously not reported. This should be of value to neurosurgeons in the approach to the internal carotid artery through Parkinson's triangle.
Canalicular communication in the cortices of human long bones
Authors: Curtis Todd A. , Ashrafi Shahid H. , Weber Dennis F.
Published: February 2005

A scanning electron microscopic (SEM) cast method that has been utilized to examine the internal structure of dentine was modified to examine canalicular communications in the cortices of a human femur and ulna. Although some preparations in which all of the matrix was removed were examined, etched preparations were found to be the most informative. Casts of lacunae and canaliculi along with the underlying matrix could be visualized in these preparations. In the femur, whose cortex exhibited a typical lamellar pattern, canalicular communication was seen between first and second generation osteons and occasionally between osteons and interstitial regions. The interstitial regions in the ulna appeared to be primarily woven rather than lamellar bone. Extensive communication between the outermost lacunae of osteons and interstitial regions was observed in the ulna.
Postnatal enlargement of human tracheobronchial airways and implications for particle deposition
Authors: Phalen Robert F. , Oldham Michael J. , Beaucage Christine B. , Crocker T. Timothy , Mortensen Jd
Published: February 2005

In support of predictions for inhaled particle deposition, morphometric measurements were taken on 20 replica airway casts of people aged 11 days to 21 years. Measurements of right upper lobe airway lengths, diameters, and branching angles were made such that a growth model suitable as input to predictive equations for particle deposition efficiency was obtained. The tracheobronchial airways growth was describable by linear regressions on body length. The length‐to‐diameter ratio of growing airways did not change in any simple way as a function of airway generation. Airflow rates for a given state of physical activity for various ages were found from previously published data to be describable by linear regressions on body mass. Three states of physical exertion–low activity, light exertion, and heavy exertion–were used for modeling purposes. The computed particle deposition efficiencies indicate that under most circumstances smaller (younger) people will have greater tracheobronchial deposition efficiencies than larger (older) people. For example, tracheobronchial dose on a per kilogram body mass basis for 5‐μmdiameter particles may be more than 6 times higher in the resting newborn than in the resting adult assuming equivalent deposition efficiencies above the larynx.
Structure of the sinus‐lining cells in the popliteal lymph node of the rabbit
Authors: Compton Carolyn C. , Raviola Elio
Published: February 2005

The structure of the sinus walls in the popliteal lymph node of the rabbit was studied with the electron microscope. In the marginal sinus, the endothelial cells are connected by gap junctions, puncta adherentia, and surface specializations characterized by focal approximation of the adjoining membranes without fusion. They possess large numbers of simple and compound uncoated invaginations of the plasma membrane that are closed by a diaphragm with a central thickening. The tissue strands that straddle the lumen of the sinus consist of a fibrous core containing both collagen and elastic fibers, surrounded by endothelial cell identical to those composing the outer sinus wall. Cortical sinuses that run independently of the trabeculae were identified by exploiting the fact that their endothelial cells accumulate lymph‐borne ferritin, and their lumen is outlined by horseradish perox‐idase administered intravenously. They are lined by a flattened, continuous endothelium and lack luminal strands. The walls of the medullary sinuses consist of endothelial cells and macrophages. The endothelial cells are interconnected by specialized junctions and contain fewer plasmalemmal vesicles than in the cortex; furthermore, dense granules are present in their cytoplasm. Macrophages adhere to the surface of the endothelial cells; typically, none of the junctional specializations that characterize the interface between endothelial cells connect endothelial cells to macrophages. However, at points along the contact region with the endothelium, the plasmalemma of the macrophage is decorated by an attachment plaque of fluffy cytoplasmic material. Sinus endothelial cells slowly accumulate lymph‐borne ferritin like vascular endothelial cells elsewhere in the body, whereas macrophages contain both ferritin and engulfed erythrocytes.
The presence of lymphatic stomata in the ovarian bursa of the golden hamster
Authors: Shinohara Harumichi , Nakatani Toshio , Matsuda Takeshi
Published: February 2005

The histology and function of the lymphatic system in the ovarian bursa of the golden hamster were examined at each day of the estrous cycle. The lymphatic passage from the ovarian bursa to a para‐aortic lymph node was stained black by india ink injected into the bursal cavity. This suggests that bursal fluid drains from the cavity via lymphatic vessels. Lymphatic stomata connecting the bursal cavity with the lymphatic lumen were consistently present throughout the cycle. However, the stomata were more frequently observed in the bursae on day 1 than on day 4 of the cycle. Also, they were more frequently observed in the bursae injected with 5 μl of chick erythrocytes than in the contralateral (not injected) bursa in hamsters on day 4 of the cycle. These results suggest that the stomata are openings the patency of which varies in response to changes in the bursal cavity. There were regions where the lymphatic lumen was separated from the bursal cavity only by lymphatic lumen was separated from the bursal cavity only by lymphatic endothelial cells. These regions were present throughout the estrous cycle. They may be patent stomata; dehiscence of junctions between the endothelial cells may give rise to stomata or widen the stomata orifices that are already present.
Cellular and subcellular colocalization of nerve growth factor and epidermal growth factor in mouse submandibular glands
Authors: Watson Ann Y. , Anderson Jacqueline K. , Siminoski Kerry , Mole John E. , Murphy Richard A.
Published: February 2005

Immunocytochemical methods have been used to compare the cellular and subcellular distribution of nerve growth factor (NGF) and epidermal growth factor (EGF) in mouse submandibular glands. Rabbit antisera raised against purified proteins were characterized by immunoblot methods and were used to stain sections of salivary glands embedded in plastic. For light microscopy, antibodies were visualized by indirect immunofluorescence. For electron microscopy, thin sections were treated simultaneously with IgG against NGF and EGF coupled to colloidal gold particles of different size. Data indicate that NGF and EGF are present in all granular convoluted tubule cells and in no other cell type within the salivary gland. Ultrastructural analyses indicate that NGF and EGF are evenly distributed together within mature secretory granules, although a population of small granules was identified that is not immunoreactive for either protein. Taken together, the data suggest that granular convoluted tubule cells are homogeneous in the production and storage of NGF and EGF.
Immunochemical localization of vitamin D‐dependent calcium‐binding protein in mouse placenta and yolk sac
Authors: Bruns M. Elizabeth H. , Kleeman Ellen , Mills Stacey E. , Bruns David E. , Herr John C.
Published: February 2005

A 10,000‐dalton calcium‐binding protein (10‐kd CaBP) has been described in the placentae and yolk sacs of rats and mice. This protein is similar or identical to vitamin D‐dependent intestinal CaBP and these proteins have been implicated in the molecular mechanisms of intestinal calcium absorption and transplacental calcium transport. Using an antiserum to the purified 10‐kd rat intestinal CaBP, the localization of CaBP in the 16–17‐day mouse yolk sac and placenta was studied immunocytochemically with peroxidase‐antiperoxidase labelling and quantified by radial immunodifussion. A high concentration of immunolabelling was observed in the endodermal cells of the intraplacental yolk sac lining the sinuses of Duval. The columnar endodermal cells lining one side of the endodermal sinuses adjacent to fetal vessels contained most of the immunoreactive label. Quantitation by radial immunodiffusion demonstrated a 5.5‐fold higher concentration of CaBP in the portion of the placenta containing most of the intraplacental yolk sac than in the maternal half of the placenta. This demonstration of a 10‐kd CaBP within the intraplacental yolk sac suggests this protein functions to facilitate placental calcium transport and is the first study which directly supports the hypothesis of a functional role for the sinuses of Duval in calcium transport.
Mitochondrial morphometrics of histochemically identified human extraocular muscle fibers
Authors: Carry Michael R. , Ringel Steven P. , Starcevich Jill M.
Published: February 2005

Three fiber types—coarse, granular, and fine—were readily identified in histochemical cryostat sections of human extraocular muscle (EOM). The cryostat retrieval method was utilized to identify these three fiber types in serial electron microscopic thin sections. Using morphometric techniques, five mitochondrial variables (mitochondrial volume fraction, mitochondrial profile size, mitochondrial profile density, and clusters of two or of three or more mitochondrial profiles) were determined for a total of 162 histochemically identified fibers from two regions (orbital and global zones) from six EOMs. Coarse fibers had numerous large‐sized mitochondrial profiles, often occurring in clusters. Granular fibers had fewer and smaller‐sized profiles scattered across the fiber. Fine fibers had the most numerous, but smallest‐sized mitochondrial profiles. Despite significant differences in group (fiber types) means for the mitochondrial variables, no single variable was sufficient for separating fiber types into distinct populations. Although a scattergram plot of two variables was sufficient to separate orbital zone fibers, a computer‐generated, multivariate discriminant analysis was needed to separate the global zone fibers into distinct populations. These results will aid future studies on normal and pathological human EOM by providing a morphometric basis for identifying fiber types in the orbital and global zones.
Incorporation of 3H‐fucose and the secretion of glycoproteins in the coagulating gland of the mouse
Authors: Samuel Lynn H. , Flickinger Charles J.
Published: February 2005

The coagulating gland of rodents, which is part of the prostatic complex, secretes components of semen. Although possessing some ultrastructural features of other exocrine glands, the mechanism of secretion by these cells has been problematic. In the present study the pathway, kinetics, and mode of secretion in the coagulating gland of the mouse were studied by light and electron microscope autoradiography at intervals between 10 minutes and 3 hours after injection of 3H‐fucose. The majority of silver grains overlay the Golgi apparatus at the initial interval, but in addition, more than a third of the grains were associated with extremely distended cisternae of the rough endoplasmic reticulum. At later intervals, radioactivity of the Golgi apparatus and the endoplasmic reticulum declined, while labeling of secretory granules increased greatly. Luminal contents became labeled 1 hour after administration of precursor. The results indicate that the pathway for secretion of glycoproteins proceeds through the Golgi apparatus to secretory granules and the glandular lumen, as in many other cells. In particular, heavy labeling of secretory granules at later intervals indicates that merocrine secretion is the most likely mechanism in the coagulating gland. However, the unusual observation that a significant proportion of grains overlay the rough endoplasmic reticulum at the initial interval raises the possibility that some fucose is incorporated into glycoproteins in the endoplasmic reticulum, as has been reported for other cell types with similarly configured endoplasmic reticulum.
Concomitant analysis of osteoblastlike cell migration and proliferation on a serum‐enriched growth surface
Authors: Zuk Anna , Wezeman Frederick H.
Published: February 2005

Osteoblastlike cell migration and accompanying proliferation on a growth surface precoated with fetal calf serum (FCS) was quantified using a modification of the chemotactic model of Alessandri et al. (1983) and autoradiography. Culture dishes were precoated with 1%, 10%, or 100% FCS and were overlaid with agar. Three‐millimeter‐diameter wells were cut and first‐passage osteoblastlike cells in serum‐free medium were seeded into the wells. At 12 and 48 hours, outward migration was quantified by measuring (1) the distance osteoblastlike cells had migrated peripheral to the well margin, and (2) the number of osteoblast‐like cells peripheral to the well margin. The data indicated that the migration of osteoblast‐like cells was related to time and FCS concentration. More cells migrated a further distance at 48 hours than at 12 hours. In addition, with greater FCS concentrations, osteoblastlike cell migration increased; 3H‐thymidine pulse labelling showed no incorporation of label into osteoblastlike cells at 12 hours. However, pulse labelling after 48 hours demonstrated that a small number of nuclei peripheral to the well margin were labelled. The data suggest that proliferation contributes negligibly to the population of osteoblastlike cells peripheral to the well margin. The appearance of osteoblastlike cells peripheral to the well margin is due primarily to migration.
In vivo demonstration by radioautography of binding sites for insulin in liver, kidney, and calcified tissues of the rat
Authors: Martineau‐Doizé B. , McKee M. D. , Warshawsky H. , Bergeron J. J. M.
Published: February 2005

An in vivo binding assay using radioautography was employed to visualize insulin receptors in rat tissues. Two and one‐half minutes after the intravenous injection of 125I‐insulin, free hormone was separated from bound hormone by whole body perfusion with lactated Ringer's solution followed by perfusion with glutaraldehyde. The localization of bound hormone, fixed in situ by perfusion with glutaraldehyde, was determined. Nonspecific binding of labeled insulin was noted in the proximal convoluted tubules of the kidney cortex, prebone and adjacent bone, predentin and adjacent dentin, and enamel. Specific binding sites were observed at the periphery of hepatocytes, over osteoblasts, and in relation to the endothelial cells of fenestrated capillaries within the papillary layer of the maturation zone of the incisors.
Unmyelinated axons in the feline trigeminal motor root
Authors: Risling Mårten , Fried Kaj , Hildebrand Claes , Cukierman Anna
Published: February 2005

The trigeminal motor root was studied in the electron microscope at different proximodistal levels in eight adult cats. Counts at a level halfway between the trigeminal ganglion and the pontine junction showed that the root contains about 9% (n = approximately 300) unmyelinated axon profiles at this level. Small groups of unmyelinated axons occur on both sides of the PNS‐CNS border, in the surrounding pia mater, and in perivascular spaces of the CNS compartment. Examination of serial sections from the PNS‐CNS transitional region showed that some unmyelinated axons actually cross the PNS‐CNS border. The functional significance of these fibres remains unknown.
Changes in the extracellular matrix and glycosaminoglycan synthesis during the initiation of regeneration in adult newt forelimbs
Authors: Mescher Anthony L. , Munaim Syeda Iffat
Published: February 2005

The extracellular matrix (ECM) of the distal tissues in a newt limb stump is completely reorganized in the 2–3‐week period following amputation. In view of numerous in vitro studies showing that extracellular material influences cellular migration and proliferation, it is likely that the changes in the limb's ECM are important activities in the process leading to regeneration of such limbs. Using biochemical, autoradiographic, and histochemical techniques we studied temporal and spatial differences in the synthesis of glycosaminoglycans (GAGs) during the early, nerve‐dependent phase of limb regeneration. Hyaluronic acid synthesis began with the onset of tissue dedifferentiation, became maximal within 1 week, and continued throughout the period of active cell proliferation. Chondroitin sulfate synthesis began somewhat later, increased steadily, and reached very high levels during chondrogenesis. During the first 10 days after amputation, distributions of sulfated and nonsulfated GAGs were both uniform throughout dedifferentiating tissues, except for a heavier localization near the bone.

Since nerves are necessary to promote the regenerative process, we examined the neural influence on synthesis and accumulation of extracellular GAGs. Denervation decreased GAG production in all parts of the limb stump by approximately 50%. Newt dorsal root ganglia and brain‐derived fibroblast growth factor each produced twofold stimulation of GAG synthesis in cultured 7‐day regenerates. The latter effect was primarily on synthesis of hyaluronic acid. The results indicate that the trophic action of nerves on amphibian limb regeneration includes a positive influence on synthesis and extracellular accumulation of GAGs. Since the ECM exerts a major influence on cellular proliferation and migration, the effect of nerves on GAG metabolism may have considerable importance for growth and development of the early regenerate.
Peritubular myoid cells of human and rat testis are smooth muscle cells that contain desmin‐type intermediate filaments
Authors: Virtanen I. , Kallajoki M. , Näurväunen O. , Paranko J. , Thornell L.‐E. , Miettinen M. , Lehto V.‐P.
Published: February 2005

We studied the cytoskeletal composition of human and rat testicular myoid cells by using immunofluorescence microscopy with polyclonal and monoclonal antibodies. In adult human and rat testis, the peritubular myoid cell layer was brightly positive for desmin, the muscle type of intermediate filament protein, and a faint reaction was also seen with antibodies to vimentin, the intermediate filament protein of fibroblasts and diverse other mesenchymal cells. The desmin‐positive myoid cell layer could already be identified in newborn rat testis but was more compact in appearance 23 days after birth. Both squash preparations and cultured cells from adult rat seminiferous tubules revealed distinct cell populations positive for desmin. The adult myoid cells of both species also showed a strong reaction with antibodies to myosin and p230, a nonerythroid avian α‐spectrin analogue. The immunostaining results could be confirmed by the western blotting technique: Experiments with isolated seminiferous tubules showed a specific reaction with a 55,000‐dalton and a 58,000‐dalton polypeptide when desmin and vimentin antibodies were used, respectively.

The present results show that the peritubular myoid cells are genuine smooth muscle cells with desmin‐type intermediate filament cytoskeleton and suggest that these cells can be identified by this feature before their ultrastructural maturation.
Assessment of cortical and trabecular bone distribution in the beagle skeleton by neutron activation analysis
Authors: Parks N. J. , Jee W. S. S. , Dell R. B. , Miller G. E.
Published: February 2005

The distribution of bone calcium between morphologically identifiable cortical and trabecular bone obtained by dissection and quantitated by neutron activation analysis (NAA) is described. The skeleton of a female beagle dog was dissected into approximately 400 pieces and assayed for 49Ca produced in the University of California, Irvine TRIGA reactor. For each of the skeletal sections, we give the initial weight of the alcohol‐fixed tissue, which includes cortical bone, trabecular bone, marrow, and cartilage, and a final tissue weight after the marrow and trabecular bone have been dissected away; total section and cortical section calcium weights are reported. The level of detail is represented, for example, by the vertebrae, which were divided into three parts (body, spine, and transverse processes) and by the long bones, which were divided into 10–12 parts such that characterization of the epiphysis, metaphysis, and diaphysis was accomplished. The nedian percentage cortical calcium values for cervical, thoracic, and lumbar vertebrae were 82%, 56%, and 66%, respectively; however, variation within these groups and among individual vertebral sections was about a factor of 2. For long bones, the median percentage cortical calcium varied from 90–100% in the midshaft to below 50% in the proximal and distal sections. The final calculated cortical tissue‐to‐calcium mass ratio (TCR) varied from about 4.5 for midshafts of the long bones to about 9 for thoracic vertebral bodies and indicated that the mineral fraction of cortical bone is not constant throughout the skeleton. The ratio of cortical to trabecular calcium in the skeleton was 79.6:20.4.
Pituitary lactotroph sedimentation profiles and in vitro secretory activity after ablation of the medial basal hypothalamus
Authors: Phelps Carol J. , Hymer Wesley C.
Published: February 2005

Pituitary cells from adult male rats subjected to chronic (6 and 10 weeks) medial hypothalamic ablation (MHA) were analyzed by unit gravity sedimentation to assess distribution of size and density of lactotrophs, and for subsequent in vitro prolactin (PRL) release in primary culture. Tinctorial staining (Herlant's tetrachrome) showed that initial preparations of cells from MHA rats were small and relatively undifferentiated. MHA cells did not sediment as far into the gradient as did cells from intact control pituitaries. Intracellular PRL content was lower in all gradient fractions of MHA cells. At 6 weeks after surgery, peak recovery of PRL was also in the upper portions of the gradient. In the 10‐weeks group, however, peak PRL recovery from MHA cells was in a population that sedimented further, but more restrictedly, in comparison with control cells. At both postsurgical intervals, the majority of tinctorially or immunocytochemically identified lactotrophs from lesioned rats were lower in the gradient, indicating enlarged and denser cells. Relative numbers of lactotrophs (per pituitary) were increased 10 weeks after MHA. In vitro PRL release, over a maximum of 21 days culture, was comparable for cells from MHA rats and intact controls, according to daily per cell secretion rates and “production index” (hormone released/initial hormone content). By comparison, luteinizing hormone (LH) release was suppressed in culture compared to intact controls, and LH was recovered from gradient fractions of smaller cells. The results indicate that chronic removal of hypothalamic influence results in gradual prolactin cell hypertrophy and decreased hormone retention and in relative increase in numbers. Since PRL release in vitro proceeded at a normal rate, the primary effect of such a lesion appears to be increased hormone turnover. The data also emphasize the autonomous capacity of lactotrophs, relative to other pituitary cell types, to adjust cellular mechanisms in order to continue secretory function in the absence of hypothalamic influence.
Tridimensional observation of fluorescent granular perithelial (FGP) cells in rat cerebral blood vessels
Authors: Mato Masao , Aikawa Eizo , Mato Takashi K. , Kurihara Kyouichi
Published: February 2005

The tridimensional appearance and distribution of FGP (fluorescent granular perithelial) cells was studied by means of light and scanning electron microscopy. In young rats they first appeared as hexagonal cells in that were closely associated; later they transformed into slender forms and were loosely arranged. Scanning electron microscope observation gave a general view of FGP cells, their globular vacuolated inclusions, and their hypertrophied protrusion into the luminal surface of blood vessels. The nodular protrusions may be related to the limitation of blood flow in small cerebral blood vessels.
Regional differences in myocyte size in normal rat heart
Authors: Gerdes A. Martin , Moore Jo A. , Hines Joseph M. , Kirkland P. A. , Bishop Sanford P.
Published: February 2005

Three independent methods were evaluated in an effort to obtain reliable values for myocyte size in adult Sprague‐Dawley rats. Cell volume was determined from isolated myocytes by a Coulter Channelyzer system. Cell volume was also determined from the product of length and cross‐sectional area of isolated myocytes. Additionally, myocyte cross‐sectional area was measured morphometrically from electron micrographs of whole perfusion‐fixed tissue. A major goal was to determine if anatomical methods used to measure cell volume produce values comparable to the more expeditious and objective Coulter Channelyzer method. The results of these experiments showed that myocyte dimensions obtained from all three techniques were similar.

The second major objective was to use the above‐mentioned techniques to evaluate regional differences in myocyte size. Myocyte cross‐sectional area and volume were significantly larger in the endomyocardium than in the epimyocardium of the left ventricle. Right ventricle myocytes had significantly smaller volumes and crosssectional areas than did left ventricle myocytes. There were no regional differences in cell lengths.

We conclude that (1) the Coulter Channelyzer system gives values for isolated myocyte volume that are similar to values obtained with histometric techniques; (2) values for isolated myocyte cross‐sectional area were representative of values obtained from myocytes in whole‐sectioned tissue; (3) significant regional differences in myocyte size are present in adult rat hearts; and 4) regional variations in myocyte size are due to differences in myocyte cross‐sectional area rather than cell length.
Venous distribution of superficial cervical region in rhesus (Macaca mulatta) monkey
Authors: Al‐Lami Fadhil , Poole Melanie
Published: February 2005

The superficial veins of the cervical region in over 50 Macaca mulatta monkeys were studied. We found, in addition to the external jugular vein, another major vein, which we have termed jugular accessory. It is comparable in size and runs ventral to the external jugular vein. It commenced at the angle of the mouth, ran in a groove on the dorsal aspect of the submandibular gland, and descended on the surface of the sternocleidomastoid muscle where it was connected to the external jugular vein by a short transverse twig. It then descended toward the clavicle, crossed it ventrally, and immediately joined the cephalic vein. The resultant common vein pierced the thoracic wall between the clavicle and first rib and joined the external jugular and axillary veins, producing the subclavian vein. It was the jugular accessory and the external jugular, being connected as described, that formed an “H”‐shaped system.
Morphological evaluation of vascular smooth muscle cell: Length and width from a single scanning electron micrograph of microvessels
Authors: Miller Bryan G. , Gattone Vincent H. , Overhage J. Marc , Bohlen H. Glenn , Evan Andrew P.
Published: February 2005

Accurate three‐dimensional data on the structure of vascular smooth muscle cells is essential for understanding the microvascular system in both normal or disease conditions. The laborious serial reconstruction methods have limited the amount of data collected on the structure of individual vascular smooth muscle (VSM) cells. The circumferential viewing of whole vessel segments via scanning electron microscopy provides an alternative approach, but even this technique is highly specialized and tedious. This study presents a simplified method to determine the average cell length and width of individual VSM cells by using only one view of a microvessel (single view). The vessels do not have to be isolated for circumferential viewing and can be left in their host tissue if desired. Values for the average VSM cell length and width were obtained by both circumferential‐ and single‐view approach on the same vessels. The average cell length and width obtained from the single‐view method (using one‐third circumference) duplicated the mean length and width measurements obtained by circumferential viewing.
Determination of the lengths of nonisotropic linear features in micrographs
Authors: Harvey R. J.
Published: February 2005

The method described was devised to facilitate rapid and reasonably accurate estimations of the length of a nonisotropic linear feature in a micrograph. It arose from studies in which we were determining the length of the Purkinje cell layer in each of a set of serial sections through the rat cerebellum. The Purkinje cell layer appears as a linear feature in such sections and the simplest and most rapid method of estimating the length of this type of feature is to count the number of intersections that it makes with a series of equally spaced parallel test lines (see, e.g., Weibel, E.R., 1979: Stereological Methods Vol. 1, Practical Methods for Biological Morphometry). In many sections, the Purkinje cell layer was markedly nonisotropic, and the length obtained by this method varied very considerably depending on the orientation of the section relative to the test lines. The present method employs two orthogonal sets of parallel test lines, and the length of the feature is estimated from the square root of the sum of the squares of the counts of the number of intersections with each of the two sets of lines. The result obtained varies very little with the relative orientations of the feature and the test grid and a good estimate of the length can be obtained from the counts from a single random placement of the grid on the section. It has been found that the technique can be carried out efficiently and reliably by relatively inexperienced personnel, and the results are obtained more rapidly than when alternative methods for estimating dimensions of nonisotropic features are used.
Ultrastructural location of complex carbohydrates in developing rat incisor enamel
Authors: Goldberg M. , Septier D.
Published: February 2005

The ultrastructural distribution of complex carbohydrates in an early formation stage of rat incisor enamel was investigated by staining with the periodic acid‐thiocarbohydrazide‐silver proteinate reaction (PA‐TCH‐SP) for vicinal glycol‐containing glycoconjugates, the phosphotungstic acid‐chromic acid mixture (PTA) for glycoproteins, and the cationic dyes alcian blue or bismuth nitrate for sulfated glycoconjugates. In order to remove selectively sulfated complex carbohydrates, half of the serial sections obtained were digested with a bovine testicular hyaluronidase prior to staining.

Far fewer electron‐dense deposits were observed with the PA‐TCH‐SP method on hyaluronidase‐treated sections, especially those subsequently treated for 48 hours with TCH. On the other hand, the minimal staining obtained with PTA was much more intense on sections treated with hyaluronidase where linear fiberlike structures were observed. With cationic dyes, staining of dotlike alignment structures and ground substance was obtained but was completely abolished by hyaluronidase treatment. Cuprolinic blue in a critical electrolyte concentration, ruthenium hexamine trichloride used with aldehyde during fixation, as well as rapid‐freezing followed by freeze‐substitution validate that this dotlike distribution is not an artefact of processing.

The staining results demonstrated that the glycoproteins and sulfated complex carbohydrates in developing rat incisor enamel each display a specific distribution pattern. The glycoproteins were present as fiberlike structures and the sulfated carbohydrates appeared as dotlike formations located close to the surface of the fiberlike structures, and/or in the spaces between them.
Stereological investigations on human gastric mucosa: I. Normal oxyntic mucosa
Authors: Helander Herbert F. , Leth Robert , Olbe Lars
Published: February 2005

Quantitative morphological data on normal human oxyntic mucosa were obtained from endoscopic biopsies in ten healthy male volunteers. Corpus mucosa was biopsied in the resting state and during maximal acid secretion and then processed for light and electron microscopy. Stereological analyses were carried out on sections comprising the entire thickness of the epithelial layer. About one‐third of the mucosal volume was taken up by lamina propria and 15% by parietal cells. Counts of cells that displayed their nucleus in the sections revealed that an average of 12% of the epithelial cells were parietal cells, 43% were mucous cells, 40% were zymogen cells, and 4% were endocrine cells. Parietal cells displaying two nuclei were twice as large as those with only one nucleus. Six percent of the parietal cell volume was taken up by the nucleus, and 33% of the cytoplasmic volume was occupied by mitochondria. Stimulation of acid secretion resulted in a 76% increase in the secretory surface density; simultaneously there was a slight decrease in the mean size of the parietal cells and an increase in the relative volume of the nucleus. During maximal stimulation of acid the parietal cells from the superficial mucosal layers displayed a 40% larger secretory surface than those from the deeper parts of the mucosa.

The data, which will serve as a basis for studies of pathological mucosae, are compared with those obtained in other species.
Diameters of arteries, veins, and airways in isolated dog lung
Authors: Horsfield Keith , Kemp Wendy , Phillips Sally
Published: February 2005

Triple resin casts were made of the pulmonary arteries, veins, and airways from six dog lungs. The airways were cast at a pressure of 25 cm resin in all six. In the first three, both vessels were cast at a pressure of 30 cm resin, and in the second three, arteries were at 10 cm resin and veins at 5 cm resin. Measurements were made of luminal airway diameters down to 1 mm and of the luminal diameters of the corresponding segments of the vascular trees. The relation of one to the other was shown by calculating the regression lines for the corresponding diameters. Intrapulmonary arteries and veins are of approximately equal diameter when cast at 30 cm resin, while the veins are 20% larger than the arteries when cast at 5 cm and 10 cm of resin, respectively. Both vessel diameters are 75% of bronchial at the higher pressure, while at the lower pressures arteries are 59%, and veins 71% of bronchial. In any individual, vessel diameters are a relatively constant proportion of airway diameter. This constant of proportionality varies considerably between dogs, its value ranging from 0.48 to 1.03. It is concluded that in any individual all three trees have similar diameter ratios—that is, the ratio between mean diameters of branches in successive orders.
Toward computerized morphometric facilities: A review of 58 software packages for computer‐aided three‐dimensional reconstruction, quantification, and picture generation from parallel serial sections
Authors: Huijsmans D. P. , Lamers W. H. , Los J. A. , Strackee J.
Published: February 2005

This review gives an inventory of 58 computer‐aided three‐dimensional reconstruction applications in the domain of biomedical research. It is devoted to the formulation of a set of recommendations thought to be necessary for improved performance of software packages in this field. These recommendations can be used to select packages and to guide future developments of existing reconstruction systems.

The survey is restricted to three‐dimensional reconstructions based upon a series of parallel sections of an object. Subjects treated are programming languages, resolution and sampling, input preparation, realignment, local deformation of slices, numerical quantifications, topological complexity, internal representation, display complexity (hidden surfaces, shading, smoothing), structure extraction, descriptive elements, database, data compression, time efficiency of systems and algorithms, hardware configuration, input devices, input media, interactive aids, display devices, and output devices. Information for this survey comes from articles that appeared between 1965 and 1985.
Localization of actin in mammalian spermatozoa: A comparison of eight species
Authors: Flaherty Sean P. , Winfrey Virginia P. , Olson Gary E.
Published: February 2005

The distribution of monomeric and polymeric actin in spermatozoa from the bull, boar, rabbit, human, rat, mouse, golden hamster, and guinea pig has been examined by using a monoclonal antiactin antibody and NBD‐phallacidin. Actin was present in sperm from each species. When the monoclonal antibody was used, there was a species‐specific distribution and intensity of fluorescence, but no generalized pattern. Specific fluorescence was noted in the neck and principal piece of human sperm; in the postacrosomal region, neck, and midpiece of bull and boar sperm; in the postacrosomal region, neck, and principal/equatorial segment border of rabbit sperm; in the neck region of hamster sperm; and in the neck, midpiece, and principal piece of rat, mouse, and guinea pig sperm. Sperm from all eight species displayed no specific fluorescence with NBD‐phallacidin, indicating that actin was present in a nonfliamentous form. SDS extracts of sperm were analyzed by SDS‐PAGE and Western blotting; in sperm from each species, a 42‐kD protein with specific affinity for the monoclonal antibody was present.
Morphometric and cytochemical analysis of lysosomes in rat Peyer's patch follicle epithelium: Their reduction in volume fraction and acid phosphatase content in M cells compared to adjacent enterocytes
Authors: Owen R. L. , Apple R. T. , Bhalla D. K.
Published: February 2005

M cells are specialized epithelial cells over lymphoid follicles in Peyer's patches which take up viruses, bacteria, and antigenic macromolecules from the intestinal lumen. Unlike ordinary enterocytes which sequester pinocytosed material in lysosomes, M cells transport such material across the epithelium to antigen‐processing areas in lymphoid follicle domes, suggesting a difference in lysosomal activity or a different route for movement of endocytic vesicles. Ileal Peyer's patches in rats were examined by electron microscopy to identify lysosomes by acid phosphatase activity. Acid phosphatase was found in dense bodies in enterocytes but not in M cells. Stereological analysis showed the volume fraction occupied by dense bodies in M cells to be 16 times less than in enterocytes (P <.0005), even though the volume fractions of cytoplasm occupied by mitochondria in M cells and enterocytes were not significantly different. The small volume fraction of dense bodies and the absence of acid phosphatase activity in M cells thus correlate with absence of lysosomal degradation of luminal microorganisms during transport into lymphoid follicles by M cells and may provide not only a complete array of microbial antigens for initiation of immune responses, but also a route through the mucosal barrier for microorganisms which can evade local containment mechanisms.
Prolactin causes increased turnover of dopamine in 10‐day‐old rat median eminence
Authors: Silverman William F. , Walsh Raymond J.
Published: February 2005

The present work examines the ability of prolactin to enter the CNS of the rat and effect its feedback stimulation of dopamine release prior to the appearance of prolactin receptors in choroid plexus (i.e., 10 days postnatal). An inhibitor of tyrosine hydroxylase was used to allow the assessment of dopamine turnover separate from synthesis and transport of the amine. Chronic but not acute hyperprolactinemia resulted in increased dopamine release relative to vehicle‐treated controls, as shown by diminished fluorescence intensity in the median eminence. These results indicate that activation of the prolactin short‐loop feedback system occurs by 10 days postnatal, prior to the appearance of prolactin receptors at the choroid plexus.