bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructure of the submandibular gland in the African multimammate rodent, Praomys natalensis
Authors: Toyoshima Kuniaki , Tandler Bernard 
Published: February 2005

AbstractPraomys natalensis, an African rodent that is phenotypically and cytogenetically intermediate to rats and mice, possesses a submandibular gland that is histologically similar to that in both of these near relatives, but is ultra‐structurally unique. Acinar cells, which are seromucous in nature, contain secretory granules that often contain a perfect “bull's eye” inclusion (or some variant of this configuration) suspended in a dense matrix. The Golgi apparatus in these cells has an unusual structure, with the Golgi saccules often being doubled over, so that the outermost saccule also is the innermost. This peculiar architecture apparently arises fairly late in the secretory process, i.e., a Golgi apparatus of conventional structure gives rise to a nascent granule (condensing vacuole), then its saccules secondarily fold over. Intercalated ducts are preceded by a ring of specialized cells that have a number of serous‐type granules, the duct cells themselves being devoid of such granules. Granular convoluted tubules (GCT) contain large dense granules that appear to be spontaneously involved in chain exocytosis. These GCT granules probably are the repositories of nerve growth factor, which is particularly abundant in Praomys. Striated ducts for the most part are typical in appearance, but they and, to a lesser extent, GCTs contain prominent, membrane‐bound crystalloids with a periodicity of about 15 nm.
Rat small intestinal mucins: A quantitative analysis
Authors: Kemper Abbie C. , Specian Robert D. 
Published: February 2005

AbstractAlthough much is known about the qualitative distribution of mucin‐secreting goblet cells in the small intestine, the quantitative distribution of stored mucins remains undefined. The purpose of this study was to determine the distribution of neutral stored mucin in the rat small intestine by using morpho‐metric techniques and once established, to verify that this methodology could detect secretion in animals exposed to a known mucin secretagogue. Twelve male Wistar rats (five baseline, five pilocarpine‐treated, and two vehicle controls) were fixed by vascular perfusion. After a brief fixation the intestine was removed, cut into 10 equal segments, sliced, and fixed overnight. Methacrylate sections from each segment were stained with periodic acid‐Schiff and toluidine blue. For mor‐phometry, the volume of epithelium per surface area of epithelial basal lamina was calculated with a Merz grid. The volume density of stored mucin per epithelium was determined by point‐counting on a square lattice grid. Volumes were related to either surface area of epithelial basal lamina or mucosal surface area. Due mostly to contributions by villus stored mucin, the total amount of product was found to increase proximally to distally in the small bowel, with the most dramatic increases occurring in the first three segments. When subjected to pilocarpine, a massive secretory response was evoked, resulting in a near total depletion of crypt stored mucin at all levels of the small bowel. Secretion of villus stored mucin also occurred throughout the small intestine, however reaching levels of significance at only a few points. This study describes the distribution of stored mucin in the small intestine under baseline and accelerated secretory conditions.
Regeneration of skeletal muscle in streptozotocin‐induced diabetic rats
Authors: Gulati Adarsh K. , Swamy M. S. 
Published: February 2005

AbstractThe present study analyzes the regeneration of skeletal muscle in diabetic rats. Intravenous injection of streptozotocin (STZ) was used to induce diabetes. Six weeks later the extensor digitorum longus (EDL) muscles from diabetic rats were either transplanted into diabetic or normal hosts to initiate regeneration. Normal EDL muscle transplants in normal and diabetic hosts were also performed for comparison. One, 2, 4, and 12 weeks after transplantation, the EDL regenerates were morphologically analyzed. Regeneration and formation of neuromuscular junctions were observed in all transplants, including diabetic regenerates in diabetic hosts. The overall mass and myofiber size of the diabetic EDL regenerate in the diabetic host was significantly reduced in spite of complete regeneration. Recovery of the diabetic muscle mass and the myofiber size was observed after transplantation into normal hosts. A reduction in mass and myofiber size was observed in normal EDL muscles transplanted into diabetic hosts. It is concluded that poor recovery of diabetic muscle is related to metabolic and structural alterations in the diabetic host, rather than to innate capacity of the muscle to per se undergo regeneration and reinnervation. The observed enhancement in recovery of diabetic muscle after transplantation in a normal host and deterioration of normal muscle after transplantation in a diabetic host shows that the host environment determines the success of muscle regeneration.
Two‐phase in vitro culture of explanted chick embryos
Authors: Flamme Ingo , Albach Karin , Müller Stefan , Christ Bodo , Jacob Heinz Jürgen 
Published: February 2005

AbstractThe present study describes a method of culturing chick embryos together with their surrounding area vasculosa on two different culture media in succession. Embryos in the 2nd day of incubation (stages 13, 14, 15 according to Hamburger and Hamilton, 1951) were explanted from the yolk with the aid of a ring of filter paper and transferred dorsal side up to a silicone culture dish containing the first culture medium (89.5 % L‐15, 10 % fetal calf serum, 0.5 % Antibiotics). The paper ring was clamped onto the wall of the culture dish by a steel ring so that the embryo was fixed for the culture period. After 4 ± 1, 8 ± 1, 12 ± 1 hrs, the embryos were taken from the culture dishes and transferred to others containing a yolk‐albumen mixture as culture medium; 81.2 % of embryos survived the first phase of culture. On the second medium 50.3 % of explanted embryos were still alive at stage 20 (HH), and 7.9% of them reached the 5th day of development (St 25 HH).The average length of survival in vitro was found to be influenced by both the length of the first culture phase and the stage at which embryos were explanted.This culture method may be useful for teratological tests, since in the first phase of culture, concentrations of test substances and the time of exposure can be exactly adjusted, and in the second phase, the embryo is allowed to develop quite normally, under conditions similar to those in ovo.
Ultrastructure of the sublingual gland in the African multimammate rodent
Authors: Toyoshima Kuniaki , Tandler Bernard 
Published: February 2005

AbstractThe sublingual gland of Praomys natalensis, an African rodent that is phenotypically and cytogenetically intermediate to mice and rats, is a mixed gland, consisting of mucous acini that are capped by serous demilunes, of intercalated ducts, and of some short striated ducts that quickly become excretory ducts. The mucous cells are typical in appearance, with lucent granules that contain an assortment of scattered vermiform or particulate densities. The serous cells display an array of secretory granules with a highly unusual substructure. Rather than a pattern based on the manner in which light and dark regions are disposed in their matrix, these granules contain packets—some furled, some flat—of membranes that exhibit a pronounced axial periodicity of ∼5 nm. Intercalated ducts are simple in structure, with no obvious morphological specializations. Striated ducts resemble those in the salivary glands of less exotic rodents, but they and the excretory ducts often have clusters of cytoplasmic crystalloids consisting of linear densities that intersect at right angles and that have a periodicity in both directions of ∼ 12 nm.
Three‐dimensional structure of dense bodies in rabbit renal artery smooth muscle
Authors: McGuffee Linda J. , Mercure Juanita , Little Sally A. 
Published: February 2005

AbstractIn this report, we present a three‐dimensional computer assisted reconstruction study from serial thin sections through a rabbit renal artery smooth muscle cell. In a series of 32 consecutive thin (100‐nm) sections, one longitudinally oriented cell was followed and photographed in alternating sections. The profiles of the cell surface and dense bodies were reconstructed from these 16 planes and the distribution, size, shape, and spatial relationships among these components was examined. The reconstructed images showed that the cell decreases in diameter from its widest region in the center to the two ends in a step‐wise taper. Within the cell, dense bodies are numerous. Relative to the cell axes, a membrane associated dense body (MDB) can be ≤3.5 μm long, 0.25 μm wide, and may extend up to 2 μm in depth. While the MDB profile in one section may be aligned with the long axis of the cell, in an adjacent section the same dense body may appear almost circular or wedge shaped. The same is true of cytoplasmic dense bodies (CDBs). Compared with MDBs, CDBs are smaller in all dimensions. Some, but not all, CDBs line up in strings oriented with the long axis of the cell. The continuity of dense bodies over considerable cell depth and their change in shape may have important implications for integration of contractile activity and for transmitting passive tension to the extracellular matrix.
Kinetics of the tingible body macrophage response in mouse germinal center development and its depression with age
Authors: Smith J. P. , Lister A. M. , Tew J. G. , Szakal A. K. 
Published: February 2005

AbstractAlthough tingible body macrophages (TBM) have been recognized in germinal centers for over 100 years, their role in the germinal center response is not clear. In this study, the kinetics of the TBM response was quantitatively assessed and correlated with the kinetics of germinal center development in young mice. The TBM response in old mice (which have an age‐related depression of germinal center development; Szakal et al., 1990) was analyzed for comparison. Young and old immune mice were challenged with human serum albumin and 0, 1, 3, 5, 7, 10, and 14 days later the popliteal and axillary lymph nodes were evaluated. Germinal centers were localized histochemically in alternate serial sections using horseradish peroxidase conjugated peanut agglutinin. TBM numbers were determined per germinal center on adjacent sections by the presence of tingible bodies or histochemically by using the monoclonal antibody Mac‐2. Analysis of lymph nodes from young mice showed that TBM numbers decreased with the dissociation of preexisting germinal centers. TBM reappeared 5 days after challenge and the TBM kinetics paralleled the increase in size of de novo germinal centers. In fact, a constant ratio of one TBM to every 350–450 B cells was maintained from day 5 to day 10. In old lymph nodes, TBM were generally absent throughout germinal center development. The lack of TBM prior to germinal center development and their absence in aged mice are inconsistent with the concept that TBM are required for the induction of the germinal center reaction. However, the data are consistent with a role for TBM in regulating the magnitude of the germinal center reaction.
Implementing Boissonnat's method for generating surface models of craniofacial cartilages
Authors: Lozanoff Scott , Deptuch John J. 
Published: February 2005

AbstractSurface modeling of embryonic craniofacial morphology typically is accomplished using data derived from planar contours. Methods currently available for reconstructing embryonic craniofacial anatomy from contour data rely on shortest‐path algorithms in order to interpolate surfaces. However, these techniques either fail or require a considerable amount of user interaction when complex surfaces are modeled since foramina and structural divisions cannot be interpolated properly. Recently, a new approach has been described by Boissonnat that constructs a polyhedral volume between sets of planar contours. Surfaces are interpolated by identifying the planes formed when the contours intersect the polyhedron. The purpose of this study is to determine whether craniofacial cartilages from embryonic mice can be reconstructed in an accurate and reliable fashion using this method. Embryonic mice were collected and processed for routine histological sectioning. Serial sections of the anterior cranial base and nasal capsule were obtained, subjected to videomicroscopy, and modeled. Reconstructions of the anterior cranial base and nasal capsule from embryonic mice were compared to the same structures in age‐matched specimens that were processed with whole‐mount staining procedures. The models compared well with the whole‐mount preparations. In addition, the reconstruction technique accurately rendered complex surface features of the embryonic anterior cranial base and nasal capsule including foramina and structural branches.
The subdural space interpreted as a cellular layer of meninges
Authors: Frederickson Richard G. 
Published: February 2005

AbstractThe subdural region within the cranial meninges is examined in guinea pigs by electron microscopy. The fine structures of the arachnoid membrane and dura are described separately in specimens that have been isolated from each other during removal from the cranial cavity. In addition, the fine structure of the intact dura‐arachnoid is described, where the subdural space would be present in an undisrupted state. Lastly, the inner surface of the dura and the outer surface of the arachnoid membrane are examined at the point of separation between the two specimens where the dura is reflected from the arachnoid by experimental dissection. From these observations morphologic criteria are established for identifying the constituents and boundaries of the subdural space and for explaining mechanisms in the histogenetic process of “opening” or enlarging this space.The morphologic identity of the classic subdural space is reinterpreted in light of the findings. The subdural space, traditionally described as a fluid‐filled potential cavity existing in an extracellular compartment, is not apparent in the guinea pig. Instead, fragile cells designated as light cells occupy the compartment between the dura and arachnoid, with very little extracellular space available. Experimental opening of the subdural space occurs, significantly, along pathways extending by fracture through the cytoplasm and intercellular separation of these light cells rather than by enlargement of a preexisting mesothelial‐lined intercellular space between these cells and the true arachnoid cells. Cytoplasmic fine structure of light cells suggests a close kinship with cells in the meningeal layer of the dura. The functional significance of the light cells and their possible role in subdural hematomas is discussed.
Distribution and morphological characteristics of axons in the periodontal ligament of cat canine teeth and the changes observed after reinnervation
Authors: Loescher A. R. , Holland G. R. 
Published: February 2005

AbstractThe distribution and morphological characteristics of myelinated and non‐myelinated axons innervating the lower canine periodontal ligament (PDL) in adult cats have been analysed. After perfusion fixation and decalcification, the teeth were slit transversely, divided into segments, and embedded in plastic. Ultrathin sections of each segment were examined in the electron microscope and used to reconstruct the whole PDL at 1, 4, 7, and 9 mm from the tooth apex. One millimeter from the tooth apex there were a mean of 920 myelinated axons and 1,415 non‐myelinated axons. The numbers of axons declined toward the tooth crown. Bundles of myelinated and small non‐myelinated axons lay adjacent to the blood vessels midway between the bone and cementum. Isolated myelinated axons appeared to have split away from these main nerve bundles and entered the avascular zone of the ligament, where they lost their myelin sheaths to become large non‐myelinated axons rich in mitochondria. These non‐myelinated axons sometimes appeared to be linked to collagen fibres and were thought to be the mechanoreceptor terminals.Twelve weeks after sectioning and inferior alveolar nerve, the total number of axons innervating the periodontal ligament was 50% of that found in the contralateral controls. The large non‐myelinated axons had smaller mean diameters and contained fewer mitochondria, a change which may be consistent with a reduction in mechanoreceptor excitability.
Parasympathetic postganglionic cells in the glossopharyngeal nerve trunk and their relationship to unmyelinated nerve fibers in the fungiform papillae of the frog
Authors: Inoue Katsuhiro , Kitada Yasuyuki 
Published: February 2005

AbstractThe glossopharyngeal nerve of the frog is made up of afferent nerve fibers and efferent, parasympathetic and sympathetic nerve fibers. The precise origin and course of the parasympathetic efferent nerve fibers in the fungiform papillae of the frog's tongue were investigated. We found the ganglionic cells in the lingual branch of the frog glossopharyngeal nerve. The surface of the ganglionic cell bodies was partly covered by synaptic endings that impinged upon it. Synaptic endings contained clear synaptic vesicles and large dense‐cored vesicles. After cutting of the glossopharyngeal nerve proximal to the jugular ganglion, synaptic endings were found to show definite signs of degeneration. These findings led us to the conclusion that the ganglionic cells in the lingual branch of the glossopharyngeal nerve are the parasympathetic postganglionic cells. After cutting of the glossopharyngeal nerve distal to the jugular ganglion, some unmyelinated nerve fibers in the fungiform papillae and postganglionic cells in the lingual branch remained intact. These results strongly suggest that the origin of some of the unmyelinated nerve fibers is the parasympathetic postganglionic cell in the lingual branch.
Potentiation of cochlear hair cell loss by acoustic stimulus and gentamicin in the guinea pig
Authors: Bhattacharyya Tapan K. , Dayal Vijay S. 
Published: February 2005

AbstractWe explored the possibility of synergism between a pure‐tone stimulus and gentamicin in causing cochlear injury by analyzing hair cell loss. Guinea pigs receiving daily injections of gentamicin (200 mg/kg body wt.) for 1 week were exposed to a 2 kHz tone (95 dB SPL, 2 hours daily). Surface preparations of the spiral organ were studied by phase contrast microscopy, and the extent of hair cell loss in the entire organ of Corti was recorded in cytocochleograms.Gentamicin by itself was slightly ototoxic, damaging the innermost row of outer hair cells, whereas exposure to sound alone caused no hair cell loss. Combined antibiotic and acoustic exposure produced extensive cochlear damage. A few animals showed massive hair cell degeneration and collapse of the organ of Corti, except in the apical turn. The site of damage was possibly determined by the frequency of the sound stimulus. Thus, an intermittent tonal stimulus such as that used in the present experiment can be harmless by itself, but causes injury to cochlear hair cells in guinea pigs when administered in combination with gentamicin.
Changes in actin distribution during sperm development in the opossum, Monodelphis domestica
Authors: Olson Gary E. , Winfrey Virginia P. 
Published: February 2005

AbstractThe distribution of actin in spermatogenic cells and epididymal spermatozoa of the opossum, Monodelphis domestica, was examined by immuno‐fluorescence microscopy to identify its potential function in the major structural events of sperm development. In spermatogenic cells actin was located at the site of initial interaction between the nucleus and acrosome and remained present through subsequent acrosome morphogenesis. Actin was also associated both with the posterior pole of the nucleus, at the site of flagellar attachment, and with the manchette. Thus actin may play a role in establishing the specific associations of spermatid organelles and in the streamlining of the cells' architecture. In epididymal spermatozoa two sites of actin localization are present. The first site is surrounding the connecting piece where it may participate in the characteristic 90° rotation of the head. The second site was a ring of actin surrounding the lateral boundary of the acrosome where it may play a role in the sperm pairing process which also occurs in the epididymis.
Cytoplasmic distribution of poly(A)‐containing RNA in developing Necturus maculosus oocytes with reference to annulate lamellae
Authors: Ganion L. R. 
Published: February 2005

AbstractThe cytoplasmic distribution of poly(A)+ mRNA and its relationship to annulate lamellae were examined in developing Necturus maculosus oocytes by in situ hybridization with [3H]poly(U). The specificity of [3H]poly(U) binding was tested by incubating control ovarian sections with either KOH or RNase A before in situ hybridization. In both experiments, the silver grain densities were markedly reduced. Poly(A)+ RNA is uniformly distributed in the cytoplasm until the mid‐growth phase and then later in vitellogenesis becomes localized in the subcortical ooplasm. The silver grain density in the cytoplasm varied during oogenesis and was greatest in previtellogenic oocytes. Annulate lamellae commonly are observed with the light microscope in oocytes prior to vitellogenesis. In such oocytes, the labeled mRNA probe is observed over cytoplasmic regions of annulate lamellae. The results suggests that a differential localization of messenger RNA occurs during oogenesis in Necturus maculosus. Furthermore, poly(A)+ RNA is present in cytoplasmic regions of annulate lamellae.
Prenatal and postnatal development of the large intestine in the insectivore Suncus murinus, the laboratory shrew
Authors: Kiso Yasuo , Oku Kazuomi , Matsuda Hiroshi , Yamauchi Shoji 
Published: February 2005

AbstractDevelopment of the large intestine in the insectivore Suncus murinus (the laboratory shrew) was investigated from day 21 to 30 of gestation and from birth to 20 days of age. Two days before birth, the stratified epithelium in the large intestine changed into a single layer. Although neither villi nor villus‐like structures were ever present, fissures, corresponding to openings of the crypts, appeared on the mucosal surface before birth. These increased in number as well as in width and depth, connected with each other, and gave the mucosal surface a ridge‐like appearance by 20 days of age. An elevation containing submucosae appeared shortly after birth and formed a large circular fold during the neonatal period. Goblet cells were the predominant epithelial cell type. Individual epithelial cells were mature‐looking a few days before birth; goblet cells contained numerous mucous globules and absorptive cells possessed well‐developed organelles. However, although goblet cells increased in number and exhibited active mucous‐releasing forms after birth, absorptive cells never showed morphologic evidence of active endocytosis, such as apical endocytotic complexes and large supranuclear vacuoles. Each epithelial cell was similar in ultrastructure to that of the adult shortly after birth.