bluuebunny/crossref_metadata_2025 huggingface dataset:
The Venous Drainage of the Apical Segment of the Right Lower Pulmonary Lobe
Authors: Maciejewski R.
Published: July 2008

Fifty right lungs taken from dead human bodies of both sexes (30 male, 20 female), whose ages ranged from 16 to 81 years, were studied. The left atrium, pulmonary veins and right main bronchus were injected with a 65% solution of Duracryl and then digested in sulphuric acid. The specimens were examined to determine the number and tributaries of the apical segmental veins of the lower lobe. Their length was 36 mm at the most and their diameter 8 mm. Four atypical kinds of tributaries from other segments were distinguished in every fourth case examined, and 5 kinds of accessory veins opening into the immediate veins were present, likewise in every fourth case examined.
The Sesamoid Bone of Musculus abductor pollicis longus (Os radiale externum or Prepollex) in Primates
Authors: Le Minor J.M.
Published: July 2008

The sesamoid bone of the musculus abductor pollicis longus has been investigated in a series of 276 nonhuman primates representative of 37 genera, and in a series of 300 radiographs of human subjects. The presence of this ossicle in primates is a primitive characteristic. It is present in all nonhuman primates, and is generally articulated with both the scaphoid and trapezium. Modifications of the general mammalian pattern exist only in Gorilla gorilla, where the sesamoid bone is observed in about half of the individuals, and in Homo, where this ossicle is normally absent.
How Repair Cementum Becomes Attached to the Resorbed Roots of Human Permanent Teeth
Authors: Bosshardt D.D. , Schroeder H.E.
Published: July 2008

Human premolars extracted for orthodontic reasons were fixed with a mixture of formaldehyde and glutaraldehyde and processed for light and transmission electron microscopy. About 15% of all available teeth showed signs of superficial root resorption. Quantitatively, the resorption lacunae were more frequent at the apical third of the root, when compared to the mid-root and the cervical levels. Qualitatively, the resorption areas appeared as shallow irregular concavities. The degree of resorption and/or repair varied considerably both within and between sites, ranging from arrested resorption to advanced repair. An about 1- to 2-µm-thick seam of exposed collagen fibrils of the residual dentinal matrix lined the resorbed root surfaces in the arrested stage of resorption. A particular class of mononuclear cells repopulated these surfaces and commenced to attach newly produced collagenous matrix fibrils to the exposed dentinal matrix. Increasing fibril formation and bundling resulted in a collagenous fiber fringe oriented perpendicular to the bottom of Howship’s lacunae. Following the implantation and establishment of this initial fiber fringe, the junctional zone between the two matrices and further portions of the repair matrix became progressively obscured by a fine granular and electron-dense material, indicating the advancing front of mineralization. In addition, the junctional zone later attained a high degree of electron density and basophilia. Subsequently formed matrix derived from cementoblasts was structurally heterogeneous and resembled cellular intrinsic fiber cementum (CIFC). It is suggested that the initially produced matrix along resorbed root surfaces closely resembles that seen during initial formation of acellular extrinsic fiber cementum (AEFC), whereas further apposition results in a tissue with the characteristics of CIFC.
Short- and Long-Term Effects of Streptozotocin-lnduced Diabetes on the Dorsal Motor Nucleus of the Vagus Nerve in the Rat
Authors: Tay S.S.W. , Wong W.C.
Published: July 2008

The present study describes ultrastructural changes in the dorsal motor nucleus of the vagus nerve of male Wistar rats after induction of diabetes by streptozotocin. During the acute phase (3–7 days), degenerating electron-dense dendrites and axon terminals were dispersed in the neuropil. Degenerating dendrites were characterized by an electron-dense cytoplasm containing short segments of dilated rough endoplasmic reticulum, swollen mitochondria and scattered ribosomes, while degenerating axon terminals were characterized by an electron-dense cytoplasm, clustering of small spherical agranular vesicles and swollen mitochondria. Some of these degenerating axon terminals formed axodendritic synapses with seemingly normal as well as degenerating dendrites. During the mid phase (1–6 months), most of the degenerating neuronal profiles had been engulfed or removed by macrophages that infiltrated the neuropil. During the late phase (9–12 months), a second wave of degeneration occurred in the dorsal motor nucleus of the vagus nerve, similar to that of the acute phase. In addition to the degenerating dendrites and axon terminals, several neuronal cell bodies with electron-dense cytoplasm were observed. Numerous macrophages containing degenerating debris were also present in the neuropil. It is concluded that the ultrastructural changes in the dorsal motor nucleus of the vagus nerve are the result of streptozotocin-induced diabetes.
A Biomechanical Perspective on Spinal Mechanisms of Coordinated Muscular Action: An Architecture Principle
Authors: Nichols T.R.
Published: July 2008

A principle of organization of spinal circuitry which emerges from the studies reviewed here is that the structure of the distributed network of pathways in the spinal cord contains a detailed representation of the corresponding three dimensional architecture of the musculoskeletal system. The pertinent architectural features for a given muscle include (1) the number and identity of spanned joints, and (2) the line of action at a joint with respect to the torque directions of other muscles and to the gravity vector. In accordance with established ideas, muscles with common primary actions (synergists) at the ankle are linked by excitatory, length-dependent pathways. Those muscles which have opposite actions are linked by reciprocal inhibition, although muscles which are not principally involved in postural control are not connected in this way. Among anti-gravity and stabilizing muscles, force-dependent, inhibitory pathways link (1) muscles crossing different joints, and (2) members of different synergistic groups which exert torques in different directions. Therefore, each muscle has a unique set of actions in terms of joints spanned and line of action, and each muscle receives a unique combination of reflex inputs. The cross-joint coordination resulting from actions of force-dependent pathways becomes stronger at higher forces with a consequent reduction in degrees of freedom of the musculoskeletal system. Length-dependent pathways link muscles which share some, but not all, mechanical actions at a joint and may have different patterns of activation during locomotion. Length-dependent pathways appear to coordinate muscle responses to postural disturbances and enhance joint stiffness.
Development of the Anal Fin Appendicular Support in the Western Mosquitofish, Gambusia affinis affinis (Baird and Girard, 1854): A Reinvestigation and Reinterpretation
Authors: Rosa-Molinar E. , Hendricks S.E. , Rodriguez-Sierra J.F , Fritzsch B.
Published: July 2008

Development of the sexually dimorphic anal fin appendicular support of an internal fertilizing bony fish Gαmbusia affinis affinis was investigated by staining whole-mounted embryos, immature, and adult female and male G. a. affinis with alizarin red S and alcian blue. The tissue was examined histologically to assess development of the amphicelous centrum and to verify specificity of the stains. Our data confirm earlier claims about the development of the male and female characteristics in this species, and we provide for the first time direct embryonic evidence suggesting that development of the sexually dimorphic anal fin appendicular support is biphasic: (1) anteriorization of the most anterior caudal segments, and (2) growth and elongation of hemal arches of vertebrae 14-16. The first process involves a sequential homeotic transformation of hemal arches of vertebrae 11-13 through resorption of mineralized connective tissue, thus forming parapophyses that bear pleural ribs. This process begins in undifferentiated embryos and proceeds similarly in postnatal males and females. During the same period, the second process, likely induced by male gonadal hormones, causes the addition of mineralized connective tissue at the hemal arches of vertebrae 14-16. This second process, which occurs only in males, elongates the hemal arches of vertebrae 14-16 anteriorly. This elongation apparently translocates the anal fin appendicular support (including parts of the hemal spine of the hemal arch of vertebra 13) to the level of vertebra 11. It appears that the developmental programs of both female and male G. a. affinis create an area of 6 vertebrae which are markedly different from any vertebrae anterior to 11 and posterior to 16. We propose to term the area including these vertebrae and the associated anal fin, the genital area. We also propose that the first process, homeotic transformation of caudal into precaudal segments, is regulated by differential expression of control genes, such as homeobox genes, whereas the second process is regulated by gene expression under the control of male gonadal hormones. Conflicting data in the literature can be resolved with this model. Appropriate tests of the model are proposed.
Observations on the Vomeronasal Organ of the Colugo Cynocephalus (Mammalia, Dermoptera)
Authors: Bhatnagar K.P. , Wible J.R.
Published: July 2008

This paper presents the first description of a functional vomeronasal organ in the colugo or ‘flying lemur’ Cynocephalus, the sole living representative of the order Dermoptera (Mammalia). The vomeronasal organ complex comprises patent nasopalatine and vomeronasal ducts, a 10-mm-long epithelial tube consisting of an 8- to 10-cell thick, 65-µm-tall neurosensory epithelium, the vomeronasal nerve, and the accessory olfactory bulb. The vomeronasal glands are sparse. Among mammals, the vomeronasal organ of the colugo is one of the relatively longest, at nearly 48% of nasal cavity length. It is exceeded among archontans (colugos, bats, primates, and tree shrews) only by that of the strepsirhine primate Microcebus murinus.
Changes in the Distribution and Intensity of Alkaline Phosphatase Activity in Rat Lymph Node and Spleen Cells after Antigen Stimulation
Authors: Tokuda N. , Fujikura Y. , Sawada T. , Ohba Y. , Fukumoto T.
Published: July 2008

We investigated the reaction of the popliteal lymph nodes (PLN) to the injection of two antigens, keyhole limpet hemocyanin (KLH) and lipopolysaccharide (LPS), into the footpads of rats, as well as the changes occurring in the PLN after allogeneic cell stimulation. Changes in alkaline phosphatase (ALP) activity of the lymph nodes were examined enzyme histochemically. Paralleling with PLN weight gain, increased ALP activity was observed in the medullary regions of the lymph nodes of stimulated rats. ALP reactivity in the stimulated lymph nodes was observed to be weak in the germinal centers and strong in the medullary regions. The spleens of rats subjected to systemic graft-vs.-host (GVH) reaction were examined in a similar fashion. The ALP-positive areas of the GVH spleens increased in size as compared with normal spleens. These positive areas of lymph node and spleen appear to correspond mainly to areas containing OX12-positive cells. These results suggest that enzyme-histochemical analysis of ALP activity together with immunohistochemical analysis of lymphocyte phenotypes may be a useful method for examining lymph node and spleen reactions to soluble and cellular antigens in rats.
Formation of Cartilaginous Nodules and Heterogeneity in Clones of HH 17 Mandibular Ectomesenchyme from the Embryonic Chick
Authors: Ekanayake S. , Hall B.K.
Published: July 2008

In vitro cloning of embryonic cells is a powerful tool for understanding the mechanism and timing of cell differentiation during development. Although in vitro mass culture of chondrogenic mesenchymal cells and clonal culture of already differentiated chondrocytes have been reported, clonal culture of chondrogenic ectomesenchymal cells at a postmigratory stage but prior to chondrogenic cell condensation has not been reported, nor have cartilage nodules been obtained in clonal culture. We cloned chick mandibular ectomesenchymal cells from HH stage 17 chick embryos. These cells produced clones that underwent chondrogenesis as determined by the presence of alcian blue-staining extracellular matrix and immunohistochemical visualization of type II collagen. Chondrogenic clones formed three-dimensional cartilaginous nodules. This postmigratory mandibular ectomesenchyme is heterogeneous, containing two different types of unipotential cells that give rise to chondrogenic and nonchondrogenic cells, plus bipotential cells that give rise to both chondrogenic and nonchondrogenic cells.
Fibre Type Distribution, Capillarization and Enzymatic Profile of Locomotor and Nonlocomotor Muscles of Horses and Steers
Authors: Karlström K. , Essén-Gustavsson B. , Lindholm A.
Published: July 2008

Samples were taken at slaughter from heart and both locomotor and nonlocomotor muscles from animals of similar body weight but adapted to different levels of activity: three horses and three steers. All samples were analyzed biochemically to measure the activity of key metabolic enzymes. The skeletal muscles were analyzed histochemically for fibre type composition, fibre area and capillary supply. The general pattern of differences in fibre type composition and metabolic profile between muscle groups was similar in both horses and steers. The hearts of both species had high citrate synthase (CS), 3-OH-acylCoA-dehydrogenase (HAD) and hexokinase (HK) and low lactate dehydrogenase (LDH) activities. In both species, deep portions of muscles and muscles localized deeper in the body had a more oxidative metabolic profile than superficial portions and muscles. Taking all muscles into account, it was found that CS and HAD were higher and LDH lower in horse than in steer muscles. Horse muscles contained more type ΠA fibres and had a higher capillary supply than steer muscles. There was no difference between the two species regarding mean fibre area. The adaptation of the horse to a higher level of activity in comparison with steers was reflected in a higher oxidative capacity, better vascularization and a larger proportion of type IIA fibres. It was also obvious from these results that the ATPase fibre-typing system does not reflect the metabolic profile of a muscle.
A Study of General Innervation of the Human Adrenal Cortex Using PGP 9.5 Immunohistochemistry
Authors: McNicol A.M. , Richmond J. , Charlton B.G.
Published: July 2008

Immunohistochemical detection of the neurone-specific ubiquitin hydrolase protein gene product 9.5 (PGP 9.5) has been applied to the normal adult human adrenal cortex to define overall patterns of innervation. Three distinct types of nerve morphology were noted in the cortex: large nerve trunks traversing the cortex to the medulla, a complex, branching network of slender nerve bundles and individual nerve fibres. These were more abundant in the head and body than in the alae and tail. Varicosities suggested local neurotransmitter release. Nerve fibres were also identified in the muscular wall of the central vein, which are apparently neither noradrenergic nor cholinergic. These data are in support of a direct role for nerves in the control of adrenocortical function and/or vascular responses in man.
Reinnervation by Axon Collaterals from Single Facial Motoneurons to Multiple Muscle Targets following Axotomy in the Adult Guinea Pig
Authors: Ito M. , Kudo M.
Published: July 2008

To study the process of recovery from facial palsy experimentally, the location of cranial motoneurons supplying the posterior belly of the digastric muscle (PDG) and the extratemporal portion of the facial nerve trunk was examined in a double-labeling paradigm using two retrograde tracers in the adult guinea pig of which the facial nerve had been surgically injured. In different stages after the induced facial palsy had recovered functionally (4-13 weeks after the surgical operation), wheat germ-agglutinated horseradish peroxidase (WGA-HRP) was injected into the PDG and Fluoro-Ruby (FR) was applied to the proximal cut end of the extratemporal portion of the facial nerve trunk. Distribution of neurons retrogradely labeled with WGA-HRP and/or FR was plotted in the brainstem and compared with that of the controls. In the intact cases, HRP-labeled neurons were restrictedly seen in the accessory facial nucleus (Acs7), while FR-labeled neurons were found within the main facial nucleus (FMN). In the axotomized cases: (1) HRP-labeled neurons were seen diffusely in the Acs7 as well as in the FMN, where normal myotopical representation no longer seemed to be maintained. (2) FR-labeled neurons were also observed diffusely in the FMN and the Acs7. (3) A considerable number of neurons were doubly labeled with WGA-HRP and FR in both the Acs and the FMN in cases with shorter survival periods (4-7 weeks), but not in cases with longer survival periods (12-13 weeks). Thus, new findings show that connections are temporarily maintained by single, facial motoneurons with axon collaterals to multiple muscle targets in adult mammals. These transient projections may also serve as an ideal model to study the mechanisms of the regeneration occurring in the process of facial palsy recovery.
Mesotendons of the Flexor pollicis longus Muscle
Authors: Zbrodowski A. , Gajisin S. , Bednarkiewicz M.
Published: July 2008

A study of 100 upper extremities from fresh human cadavers injected with colored latex or india ink and gelatin revealed the vascularization of the flexor pollicis longus muscle (FPL) tendon. This tendon was found to be vascularized from four different sources with anastomoses between them. Very rich anastomoses were observed between the terminal segments of the arterial branches which form the intratendineal network of the tendon itself.
Direct vs. Indirect Effects of Trypan Blue on the Ectodermal Cells of the 11.5-Day Rat Embryo?
Authors: Mensah-Brown E.P.K.
Published: July 2008

The effect of trypan blue on the 11.5-day rat conceptus after intravitelline vessel administration is described. For comparison, conceptuses injected with varying volumes of Hanks’ BSS have also been studied. Trypan blue significantly retarded the growth and development of conceptuses after 6 hours incubation in vitro. The SEM revealed rounded ectodermal cells, some of which appeared disrupted. These cells seemed to cause some of the intersomitic grooves to disappear, making a number of the somites indistinct from the outside. Unlike cells of uninjected embryos, the surfaces of the affected ectodermal cells lacked microvilli and their perimeters were lined with microvilli-like structures which appeared matted together. It was concluded that trypan blue affected the embryo directly probably by disturbing its fluid and ionic balance.
Dendritic Arbor Alterations in the Medial Superior Olivary Neurons of Neonatally Underfed Rats
Authors: Salas M. , Torrero C. , Regalado M. , Martínez-Gómez M. , Pacheco P.
Published: July 2008

Golgi-Cox-stained bipolar cells of the medial superior olive (MSO) were analyzed in control and undernourished Wistar strain rats at 12, 20, 30 and 40 days of age. Undernutrition significantly reduced the number of dendrites and the extension of ipsilateral dendritic prolongations, with no effects upon the cross-sectional somal area and minimal alterations in the corresponding contralateral dendritic branches. The data suggest that in underfed rate, afferents from the receptors projecting to the MSO via the anteroventral cochlear nuclei may cause an imbalance in the binaural interactions which occur between the axon terminals and the ipsilateral and contralateral dendritic arbors of MSO neurons.
Fine Structural Distinction between Ganglia of the Outer and Inner Submucosal Plexus in Porcine Small Intestine
Authors: Brehmer A. , Stach W. , Addicks K.
Published: July 2008

Ultrastructural differences between ganglia of the plexus submucosus internus (Meissner; PSI) and plexus submucosus externus (Schabadasch; PSE) are described. Comparison revealed a different glia index (ratio glia per neuron) between the PSE (3:1) and the PSI (1:1), the arrangement of PSI neurons in compartments and the appearance of broad membrane-to-membrane appositions inside the compartments of the PSI. Structural and immunohistochemical differences between the two plexuses are discussed. In general, PSE neurons show a wider variety in size and shape than most of the PSI neurons.
Decreased Proliferation of Pituitary Cells of Streptozotocin- Induced Diabetic Rats in Response to Estradiol-17-Beta
Authors: Takahashi S. , Osawa T.
Published: July 2008

Insulin is involved in the proliferation of fibroblasts, hepatocytes and certain other lines of cultured cells. In the present study an attempt was made to clarify the role of insulin in the proliferation of rat pituitary cells. Adult male rats of the Wistar/Tw strain were given intraperitoneal injections of streptozotocin (STZ) at a dose of 32.5 mg/kg. STZ-treated rats developed high blood glucose levels and low serum insulin levels. Proliferation of cells was examined by monitoring the cell uptake of bromodeoxyuridine (BrdU). Estradiol-17β (50 μg) was given to stimulate the proliferation of pituitary cells. The number of BrdU-containing cells was lower in STZ-treated rats than in controls. The responsiveness to estrogen in terms of cell proliferation was lower in STZ-treated rats than in controls. Treatment of STZ-treated rats with insulin increased the number of BrdU-containing cells and restored the responsiveness to estrogen. Insulin stimulated the proliferation of prolactin-secreting cells and growth hormone-secreting cells in estrogen-treated rats. These results suggest that insulin is necessary for the proliferation of pituitary cells.
Ultrastructure of the Intramuscular Connective Tissue in Bovine Skeletal Muscle
Authors: Nishimura T. , Hattori A. , Takahashi K.
Published: July 2008

The three-dimensional arrangement of intramuscular connective tissues in bovine semitendinosus muscle was investigated using the cell-maceration method for scanning electron microscopy, by which cellular elements were eliminated and collagen fibrils and fibers were exposed. The 60-100 µm diameter honeycomb structures of the endomysium housing individual muscle fibers were clearly observed. The sheath of endomysium was membranous and consisted of tightly arranged collagen fibrils 30-70 nm in diameter. The perimysium was composed of several layers of 100–200 µm-thick sheets surrounding the sheaths of the endomysium. The sheets of the perimysium were wavy and consisted of collagen fibers made up of tightly bundled fibrils. The epimysium was composed of two distinct layers of thick sheets. The inner layer consisted of thousands of collagen fibers lying in an extremely regular wavy pattern parallel to the axis of the muscle fiber. The outer layer of epimysium was composed of several wavy sheets of collagen fibers which ran transversely to the axis of the muscle fiber. In a region of the epimysium, there was a thick wall of about 1 mm thickness, where fiber bundles of 200-300 µm in diameter ran longitudinally parallel to the axis of muscle fiber.
The Function of Discomuscular Relationships in the Human Temporomandibular Joint
Authors: Bade H. , Schenck C. , Koebke J.
Published: July 2008

The aim of this morphological study was to investigate whether muscle tissue attaches directly to the discus articularis of the human temporomandibular joint (TMJ) and to indicate the probable significance of such attachments for the function of this articulation. The macroscopic and microscopic findings were derived from fixed and unfixed human TMJ of varying ages and genders, whereby the functional maturity of the masticatory apparatus was taken into consideration. To date, the results of this study show that aside from fibers originating from the superior venter of the m. pterygoideus lateralis, additional muscle or connective tissue fibers from the perimysium of the m. masseter insert to varying extent in the disc. The same is true for the m. temporalis, which is also directly connected to the disc via muscular or fibrous elements, or indirectly via fibers from the m. masseter. The insertion of the m. pterygoideus lateralis is always in the medial portion of the discus articularis and those of the mm. temporalis and masseter, respectively, in the middle and lateral portions of the disc. It is highly probable that a direct force transfer through the mm. temporalis and masseter to the articular disc takes place, and that these muscles contribute to the movement of the disc during jaw movement, whereas the size and form of the muscle insertions are subject to a great deal of individual variation. Differences were observed between immature and mature TMJ as well as between partly and fully toothed masticatory apparatuses.
Immunohistochemical and Radioimmunological Assessment of Thyrotrophs in the Pituitary of Aging Rats
Authors: Cónsole G.M. , Gómez Dumm C.L.A. , Goya R.G.
Published: July 2008

Thyrotrophs were studied by quantitative immunohistochemistry in the pituitary gland of young (4 months), old (20 months) and very old (29 months) male rats. An attempt was also made to correlate morphometric parameters with serum levels of thyrotropin (TSH), thyroxine (T4) and triiodothyronine (T3). Cells were immunostained by the peroxidase-antiperoxidase method and hormones were measured in serum by specific radioimmunoassays. There was a marked age-related reduction in TSH cell number, volume density and surface density but a significant increase in TSH cell area and perimeter. Basal serum levels of TSH increased, T4 decreased and T3 remained unchanged with age. There was a highly significant (p < 0.001) negative correlation between serum TSH and T4, but no significant correlation was found between TSH and morphometric parameters. The present results suggest that aged rats possess a reduced but functionally preserved thyrotrophic cell population. The coexistence of high circulating levels of TSH with reduced serum T4 suggests that aging brings about a progressive desensitization of the thyroid to TSH.
Hip Joint Position and Architecture of Rat Semimembranosus Muscle: Implications for Length-Force Characteristics
Authors: Willems M.E.T. , Huijing P.A.
Published: July 2008

Alteration of hip joint angle, while keeping the knee position constant, changes the orientation of the biarticular rat semimembranosus lateralis muscle with respect to the bony origin at the pelvis. Geometrical and length-force characteristics of the muscle were determined in two experimental groups, each with a different orientation: angles between the muscle and line of origin were set at 68.1 ± 5.3° (condition 68) and 121.9 ± 9.1 ° (condition 122). For muscles of condition 68 and condition 122, the number of sarcomeres in series was similar in both proximal fibers (11,436 ± 356 and 11,555 ± 175, respectively) and distal fibers (12,585 ± 844 and 12,787 ± 288, respectively). At similar distal fiber lengths, the sarcomere length in proximal fibers was higher in condition 122 than in condition 68, indicating a change in heterogeneity of fiber sarcomere lengths in the muscle. Hence, length-force relationships of proximal and distal sarcomeres were more scattered with respect to muscle length in condition 122 than in condition 68. Range of distal fiber length between optimum and zero muscle force was increased by 2.7 mm (13%) in condition 122. These data indicate that biarticular muscles with bony origins can exhibit different length-force characteristics at similar distal fiber lengths. During hip joint movements and fiber shortening, muscle fibers of such biarticular muscles use shifting fiber length-force relationships with respect to muscle length.
The Basement Membrane and Its Involvement in Carcinoma Cell Invasion
Authors: Flug M. , Köpf-Maier P.
Published: July 2008

During the development of invasive cancer, carcinoma cells have to penetrate the extracellular matrix including the basement membrane (BM). This is a usually continuous layer composed of a dense meshwork of collagens, glycoproteins and proteoglycans. It normally underlies epithelia and lacks any pores large enough to allow epithelial cells to pass through them. In consequence, the invasion of carcinoma cells through the BM must be either an active process effected by the carcinoma cells themselves or is mediated by structural alterations of the BM occurring during carcinogenesis and cancer progression. It was supposed by many authors that invading and metastasizing carcinoma cells are able to degrade actively the continuous, uninterrupted BM by secreting type IV collagenase and other proteolytic enzymes. Although there is a wealth of experimental evidence which fits the concept that the active degradation of the BM is an essential requirement for carcinoma cell invasion and metastasis, certain data do not agree with this hypothesis. Thus, it is still doubtful whether active lysis of the BM by carcinoma cells is actually a prerequisite for invasion and metastasis or whether there are alternative and/or additional mechanisms favoring the invasion of carcinoma cells.
Differential Expression of Cytokeratin mRNA in Hamster Squamous Epithelia as Observed by in situ Hybridization Using Human Cytokeratin cRNA Probes
Authors: Baert J.H. , Viaene A.I. , Veys R.J.
Published: July 2008

In this hybridohistochemical study, we investigated the expression of cytokeratin (CK) mRNA in the keratinizing squamous epithelium of hamster cheek pouch and esophagus, using eight different digoxigenin-labelled RNA probes complementary to human CK mRNAs. CK 4, CK 6, CK 8, CK 14, and CK 15 RNA probe obviously hybridized with hamster counterpart mRNA(s) in the cheek pouch as well as in the esophageal epithelium. However, using the CK 10-specific RNA probe, only the cheek pouch epithelium exhibited a positive reaction. We were not able to detect any positive signal for the CK 18 or for the CK 19 RNA probe. We observed three different CK mRNA distribution patterns in the cheek pouch epithelium, and four in the esophageal epithelium. The differences in expression and distribution pattern of CK mRNAs between the two types of epithelia suggest that the hamster CK polypeptide family comprises at least six different species. We also conclude that human cRNA probes for CK mRNAs may provide a way to detect changes in CK expression and distribution during induced non-neoplastic and neoplastic changes in the hamster cheek pouch model. This may also help to elucidate the molecular pathogenesis of squamous-cell carcinoma.
Microsurgical Anatomy of Arteries Related to the Internal Acoustic Meatus
Authors: Brunsteins D.B. , Ferreri A.J.M.
Published: July 2008

The distribution and location of the labyrinthine arteries (LA) have been investigated in 6 adults and 15 human fetuses using microdissection. The LA is a single or double artery that penetrates the internal acoustic meatus (IAM) extending to the arachnoidal, dural, temporal and neural branches and ending at the fundus of the IAM in three terminal branches, namely the anterior vestibular artery (AVA), the vestibulocochlear artery (VCA) and the cochlear artery (CA). When the LA is a single artery, it is located on the cochlear nerve, under the facial nerve, and ends in the hiatus between the cochlear and the vestibular nerves. In cases with a biarterial system, the inferior LA passes under the nerves and becomes the VCA at the fundus of the IAM. The location of the superior LA is similar to that of the LA in the monoarterial system and the superior LA terminates at the cochlear artery and the VCA. The nomenclature, distribution and surgical importance of the two arterial patterns are analyzed.
Mammary Phenotypic Expression Induced in Epidermal Cells by Embryonic Mammary Mesenchyme
Authors: Cunha G.R. , Young P. , Christov K. , Guzman R. , Nandi S. , Talamantes F. , Thordarson G.
Published: July 2008

The goal of this research was to establish methods for inducing mammary epithelial differentiation from nonmammary epithelium. For this purpose, mid-ventral or dorsal epidermis (skin epithelium; SKE) from 13-day rat or mouse embryos was associated with 13-day embryonic mouse mammary mesenchyme (mammary gland mesenchyme; MGM) (mouse MGM + rat or mouse SKE). The resultant MGM + SKE recombinants as well as controls (homotypic mouse mammary recombinants, homotypic mouse skin recombinants and mouse mammary mesenchyme by itself) were grafted under the renal capsule of syngeneic or athymic female nude mouse hosts. Most female hosts were induced to undergo lactogenesis by grafting an adult pituitary which elicited a state of hyperprolactinemia. Tissue recombinants of mouse MGM + rat or mouse SKE grown for 1 month in vivo formed a hair-bearing keratinized skin from which mammary ductal structures extended into the mesenchyme. The ducts were composed of columnar luminal epithelial cells as well as basal, actin-positive myoepithelial cells. When grown in pituitary-grafted hosts, the ductal epithelial cells expressed casein and α-lactalbumin as judged by immunocytochemistry. The expression of caseins in MGM + SKE recombinants was confirmed by Western blot. The epithelial cells in mouse MGM + rat SKE recombinants expressing milk proteins were shown to be rat cells while the surrounding connective tissue was composed of mouse cells based upon staining with Hoechst dye 33258. Using mammary-specific markers, these studies confirmed the earlier morphological studies of Propper and unequivocally demonstrated for the first time that embryonic mammary mesenchyme can induce morphological and functional mammary differentiation from nonmammary epithelium.
Adhesion and Fusion of Ependyma in Rat Brain
Authors: Kawamata S. , Stumpf W.E. , Bidmon H.J.
Published: July 2008

Changes of the ependyma of the rat brain from 2 days after birth to 1 year were studied. In neonatal rats, the ependyma of the lateral ventricle extended medially to cover the hippocampus. The ependyma above the hippocampus disappeared with age in two ways: (1) a zipper-like withdrawal of the medial portion of the ventricle towards the lateral direction, and (2) adhesion and fusion of the ependyma in the lateral region. The zipper-like closure and fusion, which resulted in disappearance of the ependyma, took place in almost all rats within 2 or 3 weeks after birth. Initially, ependymal cells retained their cell polarity with regular organization at adhesion sites as a two-cell-layer seam. Subsequently, their polarity became disorganized in the fusion areas with convergence of the two-cell-layer seam into a one-cell-layer seam, followed by disruption. The ciliary bundle of individual ependymal cells became randomly oriented, sometimes in two or more directions. At the sites where fusion had occurred, fragmentary ependymal seams remained detectable (more than 50%) among the neuropil even in adults. These ectopic seams often contained cystic ependymal cells. In the third ventricle, adhesion was observed but fusion was not. The results indicate that adhesion and fusion of the ependyma occur in select areas during brain development, during which ependymal cells lose their cell polarity.
Three-Dimensional Architecture of Collagen Fibrils in the Mouse Corpus cavernosum penis
Authors: Nakano T.
Published: July 2008

The three-dimensional architecture of the collagen fibrils in the corpus cavernosum penis of the mouse was studied after digestion of cellular and some extracellular elements by NaOH. The tunica albuginea was made up of undulating bundles of collagen fibrils which were arranged in outer longitudinal and inner circular layers. In both layers, several bundles were successively stacked to show the conspicuous lamellar arrangement. On the outer surface of the tunica, the collagen fibrils were interwoven like lacework. The trabecula appeared as a group of collagen bundles which extended from the inner circular layer of the tunica and showed a wavy arrangement. The grouped bundles in the trabecula were covered with a delicate sheath of collagen fibrils. These architectural features of the collagen fibrils appear to be related to fluctuations in the diameter and shape of the corpus during erection and detumescence.
Temporal and Spatial Factors in Diethylstilbestrol-lnduced Squamous Metaplasia in the Developing Human Prostate. II. Persistent Changes after Removal of Diethylstilbestrol
Authors: Yonemura C.Y. , Cunha G.R. , Sugimura Y. , Mee S.L.
Published: July 2008

To determine if the metaplastic effects of diethylstilbestrol (DES) on prostatic development are reversible, human fetal prostates (obtained from abortus specimens 6-22 weeks old) were bisected mid-sagittally; one half was grafted under the renal capsule of untreated, athymic, male nude mice and the contralateral half was similarly grafted into DES-treated hosts. Severe squamous metaplasia seen in the prostatic ducts after 1 month of continuous DES exposure either disappeared entirely or became reduced in extent and degree after retransplantation of the DES-treated specimens to untreated, intact male hosts and 2 additional months of growth. However, 14 of 21 DES-treated prostates harvested after a 2-month recovery period without DES revealed ductal dilatation (ectasia) and persistent distortion of ductal architecture. Ectasia was most severe in the proximal ducts near the urethra and in prostates 17 weeks or older at the end of 1 month of DES treatment. The clinical consequences of early alteration of prostatic ductal architecture and development are potentially deleterious, as men who were prenatally exposed to DES may be at increased risk for the development of prostatic disease.
Differential Expression and Localization of Integrins and CD44 in the Membrane Domains of Human Uterine Epithelial Cells During the Menstrual Cycle
Authors: Albers A. , Thie M. , Hohn H.-P. , Denker H.-W.
Published: July 2008

Human uterine epithelium displays a distinctly polarized organization with basal, lateral, and apical plasma membrane domains. Although nonadhesive throughout most of the menstrual cycle, uterine epithelial cells allow attachment of trophoblast cells to their apical pole during embryo implantation. Development of the receptive state might involve expression of cell adhesion molecules and/or redistribution of such molecules with respect to their localization at the basal, lateral, and apical membrane domains of cells. Expression and distribution of α1-, α3-, α5-, α6-, β1-, β3- and β4-integrin subunits as well as of CD44 were examined in the luminal epithelium of human endometrium by immunohisto-chemistry in different phases of the menstrual cycle. The luminal epithelium was found to express αl-, α3-, α6-, β1-, β4-integrin subunits and CD44. α6-integrin subunits and CD44 displayed cycle dependency. The oc6-integrin subunits were detected in the basal membrane domains in all phases. However, in correlation with increasing expression during the secretory phase of cycle, these subunits newly appeared in the lateral membranes of epithelial cells. CD44 showed increased expression in the secretory phase but was always restricted to the lateral membranes. The conspicuous behavior of α6-integrin subunits and CD44 is discussed with respect to its possible functional significance for embryo implantation, and in relation to a hypothesis postulating that steroid-controlled master genes direct the acquisition of the receptive state of the luminal uterine epithelium by changing elements of the apicobasal polarity of these cells.
Mild Age-Related Changes in the Dentate Gyrus of Adult Rhesus Monkeys
Authors: Tigges J. , Herndon J.G. , Rosene D.L.
Published: July 2008

Memory and cognitive performance decline with advancing age in humans. Rhesus monkeys show a similar age-related memory deficit. Since the functional neuroanatomy of the temporal lobes in the two species is similar, and since the circuits of the temporal lobes are known to be involved in memory function, we undertook a study of the anatomical characteristics of synapses in the dentate gyrus of the rhesus monkey throughout the adult life span. Light- and electron-microscopic examinations were carried out on the dentate gyrus of 10 adult rhesus monkeys (4-35 years) to determine the effect of age on the thickness of the molecular layer and on axon terminals in the outer portion of the molecular layer. The thickness measurements were made on 100-µm-thick Vibratome sections and on 1-µm-fhick Araldite-embedded sections. A total of 100 electron micrographs covering a test area of 3,600 µm2 for each monkey were taken in the outer portion of the molecular layer. Counts of axon terminals synapsing with dendritic spines or shafts, measurements of the cross-sectional area of these terminals, and the length of the postsynaptic density were taken on enlarged prints. The thickness of the molecular layer remained unchanged throughout adulthood. Statistical analysis revealed no overall age-associated loss of synapsing axon terminals or shrinkage of the cross-sectional areas of their profiles. Further, there was no loss in the total number of synapses (axospinous plus axodendritic) or any change in the lenghts of their postsynaptic membrane densities. However, when axodendritic (shaft) synapses (which constitute 13% of the total) were considered separately, a statistically significant age-related loss was detected. Qualitative observations revealed that older monkeys had a moderate number of dystrophic myelinated axons and corpora amylacea located in astrocytic processes in the outer portion of the molecular layer, features not present in young monkeys. Also, glial cells and pericytes showed age-associated accumulation of lipofuscin-like inclusions. A single occurrence of a structured inclusion body in a dendrite was observed in a 10-year-old monkey. In conclusion, most synaptic measures in the dentate gyrus remain stable throughout adulthood of rhesus monkey and there are relatively few other age-related changes. The small age-associated loss of axodendritic synapses is only apparent following separate statistical treatment of these synapses. The functional significance of this loss is unclear since it would result in only 3% reduction in total synapses (shaft plus spinous) from 4 to 35 years of age, the maximal life span of the rhesus monkey.
Basement Membrane Formation of Fetal Mouse Intestinal Epithelial Cells in Organoid Cultures
Authors: Murata E. , Zimmermann B. , Merker H.-J. , Akita M. , Kaneko K.
Published: July 2008

Basement membrane formation of fetal mouse intestinal epithelial cells was investigated in organoid cultures. Intestinal cells were dissociated with a commercial collagenase/dispase preparation, and the cells were grown at high density on a membrane filter at the interface between the medium and air. This type of culture allows the histotypical reorganization of cells. After 2 days in culture, epithelial cells began to accumulate on the surface, in particular at the periphery of the culture. These cells were usually cuboid, and small vesicles were formed in the center of the culture. Laminin-positive material was observed at peripheral sites. However, no basement membrane could be identified beneath the epithelial cells at the electron-microscopic level. After 3 days, epithelial cells that had gathered at the periphery became columnar in shape. Laminin-positive material extended across the surface of the culture. However, the vesicles formed in the center of the culture were not associated with laminin-positive material. Basement membrane was observed by electron microscopy at some sites beneath groups of epithelial cells, but did not extend continuously beneath these cells. Some epithelial cells made contact with the underlying mesenchymal cells through the discontinuous basement membrane via intercellular contacts. After 5-6 days, the surface of the culture was almost completely covered with epithelial cells and, at some sites, villus-like structures were visible. Laminin-positive material was clearly detectable under epithelial cells, as well as around epithelial vesicles located in the center of the culture. By electron microscopy, basement membrane was clearly visible between the epithelial and mesenchymal cells. After 9 days, villus-like structures were rarely observed. After 3 weeks, the cell mass had become smaller and villi had disappeared. Basement membrane was extensively folded and no basement membrane was visible at some sites. Formation of basement membrane by epithelial cells in monolayer culture occurs in an incomplete and irregular manner. It occurs rapidly in organoid cultures that include mesenchyme and epithelium. The organoid culture used here should be a useful tool for studies of the formation and degeneration of the basement membrane as well as interactions between the epithelium and mesenchyme.
Fine Structure of the Epidermal Basement Membrane of the Lip: Applications of Dithiothreitol Separation and Ultrathin Frozen Sectioning
Authors: Osawa T. , Nozaka Y.
Published: July 2008

The fine structure of the epidermal basement membrane at the electron-microscopic level has already been defined. To obtain more details, two techniques, dithiothreitol separation and ultrathin frozen sectioning, were applied either alone or in combination. Negatively stained ultrathin sections showed a much thicker lamina densa than ordinary plastic-embedded sections. In the lamina lucida, bridging filaments and subbasal dense plates were observed in negative images. After the treatment with dithiothreitol, the lamina densa could be peeled off mechanically from the underlying dermis, and the anchoring fibrils were pulled off the dermis, preserving the connection with the lamina densa. With this specimen, bundles of anchoring fibrils were observed clearly and their lengths could be measured. Negatively stained ultrathin sections of dithiothreitol-separated specimens showed the fine structure of the lamina lucida. Bridging filaments in the lamina lucida were resolved by negative staining.
Accumulation and Massive Cell Death of Polymorphonuclear Neutrophils in the Developing Bone Marrow of the Mouse: A Histological Study
Authors: Sasaki K. , Iwatsuki H. , Suda M. , Itano C.
Published: July 2008

Accumulation and cell death of neutrophils were studied by light and electron microscopy in neonatal mouse bone marrow. At the beginning of bone marrow hematopoiesis, the marrow cavity contained a large number of polymorphonuclear leukocytes. Polymorphs comprised approximately 75% of the total nucleated cells in the hematopoietic compartment of the newborn marrow, the majority being neutrophils. Mature neutrophils were sometimes crossing the endothelium of the marrow blood sinus. Neutrophils in neonatal marrow show features typical of apoptosis, e.g. formation of nuclear pockets and blebs, margination of compact nuclear chromatin to form sharply circumscribed masses, condensation of cytoplasm, and convolution of cell outlines. Dying neutrophils were devoured and digested by phagocytes. The occurrence of large-scale neutrophil death and removal of neutrophils by phagocytes in neonatal bone marrow are discussed in relation to programmed cell death in development of the fetal hematopoietic system.