bluuebunny/crossref_metadata_2025 huggingface dataset:
A new technique for explantation and in vitro cultivation of chicken embryos
Authors: Dugan John D. , Lawton Michael T. , Glaser Bert , Brem Henry
Published: February 2005

A technique is described for explanting and cultivating chicken embryos in plastic drinking cups which have been modified with plastic wrap to reproduce the geometry and dimensions of the egg shell. Successful explantation rates of 97% are possible with a double‐window technique, and survivability in cups exceeds that achievable in other in vitro systems (i.e., petri dishes). Longterm survival to the 21st day of incubation is seen routinely. This system with cups is less expensive than that with petri dishes, and simpler than that with plastic wrap/tripods. Thus, this new method of in vitro cultivation of chicken embryos improves upon explantation rate, survivability and system design, and has a wide range of applications in developmental biology, angiogenesis, cancer, and pharmacology research.
The effects of age on atrophy and recovery in denervated fiber types of the rat nasolabialis muscle
Authors: White Ketti K. , Vaughan Deborah W.
Published: February 2005

This study investigates the effects of advancing age on responses of nasolabialis muscle fibers to denervation and reinnervation. The nasolabialis is innervated by the facial nerve and is responsible for the whisking movement of the animal's large vibrissae. In young adult (3‐month) and middle‐aged (15‐month) rats the muscle on one side of the head was denervated by crushing the facial nerve. At specific days postcrush, animals were sacrificed and thick sections of muscle were incubated to demonstrate cytochrome oxidase activity, a mitochondrial enzyme, which differentiated between red, white, and intermediate fiber types. The rate and extent of atrophy and recovery were evaluated using light microscope morphometric methods for which transverse fiber areas were measured and compared to fibers on the contralateral control side. There was an age‐related delay in the time of functional return since older animals resumed normal whisking behavior 6 days later than the younger animals. In both age groups, white and intermediate fibers atrophied to the greatest extent and red fibers showed least atrophy. Despite the different responses of the fiber types to denervation, there was no age difference in the maximum degree of fiber atrophy within each fiber type. Age differences did occur in the rate of the denervation response since the middle‐aged fibers consistantly showed a more rapid significant atrophy than the young adult fibers. During recovery, older fibers may be limited in their ability to attain the size of fibers on the control side. The results indicate that through middle age, the process of advancing age increases the susceptibility of the nasolabialis muscle to denervation but does not alter the maximum extent of atrophy. The ability to recover to normal fiber size, at least 2 months after denervation, is also age‐related.
Fiducial points for three‐dimensional computer‐assisted reconstruction of serial light microscopic sections of umbilical cord
Authors: Ongaro Ivano , Sperber Geoffrey H. , Machin Geoffrey A. , Murdoch Colleen A.
Published: February 2005

Fascicles of human sural (peripheral sensory) nerve were used as external fiducial points (FP) for accurate registration of serial light microscopic sections in three‐dimensional reconstruction of human umbilical cord. This paper describes a method for embedding the FPs within the paraffin wax block simultaneously with the specimen to be sectioned. Using a new design of embedding box, the FPs are embedded close to the specimen and are transferred to the slides as part of the tissue sections. Three to four FPs were used to align and scale the serial tissue sections for digitization and computerized reconstruction, using a commercially available software program on IBM‐compatible 80386 hardware. A three‐dimensional solid surface graphic model of a segment of human umbilical cord was generated.
Rearrangement of the metaphyseal vasculature of the rat growth plate in rickets and rachitic reversal: A model of vascular arrest and angiogenesis renewed
Authors: Hunter William L. , Arsenault A. Larry , Hodsman Anthony B.
Published: February 2005

The morphology of the metaphyseal microvasculature at the epiphysis was examined at both the light and electron microscopic level in rickets and rachitic reversal. The animals studied were normal, rachitic, and rachitic reversed at 8, 24, and 96 hours post‐vitamin D administration. The overall architecture of the metaphyseal vessels was significantly altered throughout the intervals examined. In the rachitic animal, arterioles, venules, and capillaries were found adjacent to the growth plate, either directly apposed to the hypertrophic chondrocytes or separated from them by bone‐forming cells. These vessels are in many ways similar to the larger arterioles and venules that normally supply the metaphyseal capillary sprouts, but in the normal growing animal are usually located 350–500 μm from the epiphyseal cartilage. The rachitic capillaries appear relatively well differentiated with a partial basement membrane and a perivascular cell lining. In early rachitic reversal, small vascular projections are induced to grow from the large diameter venules that border upon the hypertrophic chondrocytes. These vascular sprouts that invade the epiphyseal cartilage are quite undifferentiated, with no basement membrane or pericyte lining at the sprout apex and occasional abluminal endothelial cell projections. Within 96 hours, the metaphyseal microvasculature has returned to an apparently normal state with only capillaries at the cartilage‐vascular interface and larger vessels (arterioles and venules) located several hundred microns deeper into the metaphysis. The sequential processes of differentiation and cessation of capillary growth followed by dedifferentiation and reinitiation of microvascular growth make the rachitic system a unique one in which to study angiogenesis.
Spatiotemporal pattern of type X collagen gene expression and collagen deposition in embryonic chick vertebrae undergoing endochondral ossification
Authors: Iyama Ken‐Ichi , Ninomiya Yoshifumi , Olsen Bjorn R. , Linsenmayer Thomas F. , Trelstad Robert L. , Hayashi Masando
Published: February 2005

We examined the spatio‐temporal pattern of type X collagen mRNA and its protein in the embryonic chick vertebrae undergoing ossification by in situ hybridization and immunohistochemistry. Hypertrophic chondrocytes, producing type X collagen, were developed as islands of cells in a few vertebral body segments of stage 36 embryos. These cells were increased in number at stages 37 and 38 and they expressed high levels of type X collagen mRNA and deposited its protein in the matrix. Blood vessels entered from the perichondrium at stage 37 and invaded deeply into hypertrophic cartilage at stage 38. As the vertebrae grew further at stage 40, the leading front of active hypertrophic chondrocytes with high levels of type X mRNA shifted from the midvertebral perivascular area towards intervertebral borders, while the perivascular area retained a number of inactive hypertrophic chondrocytes with low levels of type X mRNA. Type X collagen was found in large amounts throughout the matrix areas containing both active and inactive hypertrophic chondrocytes. Calcium was detected by von Kossa's technique in hypertrophic cartilage matrix in a small amount at stage 37, in parts of the matrix with type X collagen deposition in succeeding stages, and finally in almost the entire area of type X collagen deposition at stage 45. The vertebral segments of stage 45 embryos also showed a clearly reversed pattern of expression between type X collagen mRNA and types II and IX collagen mRNAs. The results demonstrate that the production of type X collagen by hypertrophic chondrocytes precedes both vascular invasion and mineralization of the matrix, suggesting that hypertrophic chondrocytes have an important role in regulating these events.
Ultrastructure of the turtle spermatozoon
Authors: Hess Rex A. , Thurston Ronald J. , Gist Daniel H.
Published: February 2005

The turtle spermatozoon is vermiform in shape with a narrow pointed head that is curved. In general, the turtle sperm contains a typical head, midpiece and tail, similar in morphology to that of birds, amphibians and other reptiles. However, several structures are unique. These unusual features include (1) a perforatorial cap over the proximal end of the nucleus, which contains 2–3 rods that are contiguous with intranuclear tubules; (2) a connecting collar of dense material that surrounds the base of the nucleus; (3) a distal centriole containing central microtubules that extend its entire length and having outer triplicate microtubules that open toward the central cavity of the centriole; and (4) unusual spherical mitochondria containing 7–8 outer laminated membranes.
Ultrastructure of lingual salivary glands in the American chameleon: Anolis carolinensis
Authors: Rabinowitz Terry , Tandler Bernard
Published: February 2005

That portion of the dorsal surface of the tongue of Anolis carolinensis that is covered by plumose papillae is underlaid by a series of tubular salivary glands that open between the papillae; glands persist into the posterior zone of the tongue, where they open between cylindriform papillae. Anterior glands are serous in nature—they consist of simple columnar epithelial cells that contain abundant secretory granules exhibiting a variety of substructural patterns. The Golgi apparatus is large and of unusual appearance, with numerous closely packed terminal dilatations and condensing vacuoles. Near the posterior border of the lingual zone covered by plumose papillae, mucous cells begin to appear in the glandular epithelium. More posteriorly, the apical portions of the glands consist entirely of mucous cells, whereas the blind ends of the glands are composed of serous cells. The most posterior glands are of the pure mucous variety. The glands finally disappear a short distance posterior to the cylindriform papillae. The functions of the abundant and highly differentiated salivary glands of the Anolis tongue remain obscure.
Identification of sugar residues in secretory glycoconjugates of olfactory mucosae using lectin histochemistry
Authors: Foster James D. , Getchell Marilyn L. , Getchell Thomas V.
Published: February 2005

Lectin histochemistry at the light microscope level was used to determine the distribution of sugar residues in secretory cells of the olfactory mucosae of salamander, hamster, and mouse. Differences in sugar composition and distribution of glycoconjugates found in sustentacular cells and acinar cells of Bowman's glands of these three animals were characterized.

Oligosaccharides in secretory products of sustentacular cells in salamander olfactory mucosa contained sialic acid, galactose (Gal), N‐acetylgalactosamine (GalNAc), N‐acetylglucosamine (GlcNAc), fucose, and mannose residues. Glycoconjugates of these cells lacked terminal galactosyl‐β‐(1,3)N‐acetylgalactose (Galβ1,3GalNAc) residues. The sequences Galβ1,3GalNAc, N‐acetyllactosamine (Galβ1,4GlcNAc), and GalNAc were penultimate to sialic acid residues. Sustentacular cells of mouse and hamster did not appear to contain O‐linked oligosac‐charides but stained for mannose‐containing N‐linked oligosaccharides.

Glycoconjugates of acinar and duct cells of Bowman's glands in the salamander, hamster, and mouse contained variable amounts of β(1,4)GlcNAc residues, and terminal N‐acetyllactosamine, Galβ1,3GalNAc, and GalNAc residues. In the salamander, glycoconjugates of acinar cells possessed terminal GlcNAc residues but were not sialylated, while those of hamster and mouse generally stained for sialic acid but did not possess terminal GlcNAc residues. Secretory products of a subpopulation of rodent acinar cells also contained penultimate Galβ1,3GalNAc residues. Staining for sialic acid, Gal, GalNAc, and GlcNAc in glycoconjugates of rodents was often limited to a sub‐population of Bowman's glands. This was especially noticeable in the mouse.
Anatomy of the rat knee joint and fibre composition of a major articular nerve
Authors: Hildebrand C. , Öqvist G. , Brax L. , Tuisku F.
Published: February 2005

Several recent reports discuss the role of joint nerves in arthritis. Many of these are based on studies in the rat. The aim of this study is to examine the anatomy of the rat knee joint, in search for a primary articular nerve, and to analyze the fibre composition of that nerve. The results show that the structure of the joint differs in some respects from the human knee. At the upper end of the bony patella a cartilaginous patella extends proximally, forming the anterior wall of the suprapatellar bursa. Distinct collateral ligaments are integrated in the joint capsule. The extensor digitorum longus muscle bridges the knee joint, originating from the lateral femoral epicondyle. The well‐developed menisci contain pyramid‐shaped ossicles. The cruciate ligaments are arranged like in the human knee. A large posterior (PAN) and a small medial (MAN) articular nerve can be indentified. The PAN is composed of some 400 axons, about 80% of which are unmyelinated. All myelinated fibres are sensory. They present a unimodal size spectrum with a size range of 1–8 μ, and a predominance of small fibres. Specific denervations indicate that about 1/3 of the unmyelinated axons represent afferents, and some 2/3 are sympathetic efferents. Interestingly, neonatal capsaicin treatment did not influence the number of unmyelinated PAN axons. The functional significance of the numerous unmyelinated sympathetic and sensory PAN axons in the normal knee joint remains to be elucidated.
Subdural compartment in pig: A morphologic study with blood and horseradish peroxidase infused subdurally
Authors: Orlin Jan R. , Osen Kirsten K. , Hovig Torstein
Published: February 2005

The dura‐arachnoid junction is examined in normal animals and in animals subjected to subdural infusion of blood immediately prior to death, simulating acute subdural hemorrhages. The Norwegian landrace pig is used as the experimental animal. Horseradish peroxidase (HRP) has been added to the injected blood to serve as a macromolecular tracer. The material is studied by light and electron microscopy. Special attention is given to the level of the induced subdural cleavage plane, the total distribution of the infused blood, and the natural sites of drainage.

The dura‐arachnoid junction, identified here as the subdural compartment (the dural border layer of others), consists of an avascular tissue with flake‐like, relatively electron‐lucent cells stacked upon each other in several layers with narrow intercellular clefts. Under normal conditions there is no evidence of a so‐called “subdural space.” When under the present experimental conditions bleeding takes place into this cellular tissue, it splits without any particular, predestined cleavage plane, although most often close to the fibrous matter of the dura. The bleeding extends throughout the cerebral and spinal parts of the compartment and also along the spinal nerve roots. Contamination of the subarachnoid space occurs only in some cases subjected to large infusions and apparently only at spinal levels. The HRP diffuses into the dura, but does not traverse the arachnoid barrier layer.
Studies of variant palatal rugae in normal and corticosteroid‐treated mouse embryos
Authors: Sakamoto Michiko K. , Nakamura Kosho , Handa Jun , Kihara Takahide , Tanimura Takashi
Published: February 2005

Fourteen‐ and 15‐day mouse embryos treated with triamcinolone on day 11 of gestation were examined for the presence of variant rugae. Nontreated mouse embryos served as controls. Variant rugae found were classified into five types. All five types of variations (bifurcation, division, supernumerary, shortness and cross) were observed in triamcinolone‐treated embryos, and shortness was most frequently seen. Supernumerary, bifurcation and division were ranked next, following by cross. Variant, rugae, except the cross, were also observed in nontreated embryos in low frequencies, but more than one‐half of them were the bifurcation of the second ruga. Divided rugae ranked next, and supernumerary and shortness were found occasionally. Except for the bifurcated and supernumerary rugae, the greater part of the variant rugae were found in the fifth and fourth ruga in the triamcinolone‐treated groups and in the fifth ruga in the nontreated groups. As the incidence of variant rugae in the triamcinolone‐treated embryos was significantly higher than that in the nontreated, it was regarded as one of the changes induced by the corticoid. Based on the characteristic features of the rugal region, it is speculated that the formation of variant rugae is associated with the disturbance of normal epithelial‐mesenchymal interaction which may be controlled by the nerve fibers appearing at the time of rugal formation. The relationship between the increased appearance of variant rugae and the failure of palatal shelf elevation was examined, but no direct evidence was obtained.
Differential expression of calbindin‐D 28 kDa in rat incisor ameloblasts throughout enamel development
Authors: Berdal A. , Nanci A. , Smith C. E. , Ahluwalia J. P. , Thomasset M. , Cuisinier‐Gleizes P. , Mathieu H.
Published: February 2005

Calbindin‐D 28 kDa (CaBP 28 kDa), a vitamin D‐dependent calcium‐binding protein, has been associated with calcium handling by cells. We have investigated the expression of this protein in the rat incisor enamel organ, an epithelium interposed between a mineralizing matrix and connective tissue rich in blood vessels, by radioimmunoassay (RIA), Western blotting, and quantitative protein A‐gold immunocytochemistry with antibodies to rat kidney CaBP 28 kDa. RIA of cytosolic extracts showed that enamel organs contained relatively high concentrations of CaBP 28 kDa (compared to kidney; see review by Christakos S., C. Gabrielides, and W.B. Rhoten 1989 Endocr. Rev., 10:3–25). Immunoblotting of proteins extracted from enamel organ strips revealed an intensely‐stained band near 28 kDa throughout amelogenesis following ameloblast differentiation. Immunocytochemically, CaBP 28 kDa was localized exclusively within ameloblasts. The density of labelling increased from the presecretory stage to the secretory stage and fluctuated across the maturation stage in relation to ameloblast modulation. Ruffle‐ended ameloblasts consistently showed the most intense immunoreaction. Gold particles were present throughout the cytoplasm and nuclei of ameloblasts but regions rich in rough endoplasmic reticulum or cell webs showed a higher immunolabelling. Some gold particles were also associated with the external face of the rough endoplasmic reticulum. Multivesicular bodies in maturation stage ameloblasts were occasionally immunoreactive. These data suggest that the intracellular concentration of CaBP 28 kDa is regulated throughout amelogenesis reflecting a stage‐specific control of calcium homeostasis in ameloblasts.
Rapid determination of cancellous bone mineral loss in ovariectomized rats by a subtraction technique
Authors: Eskandar Enass , Kimmel Donald B. , Wronski Thomas J.
Published: February 2005

We present a rapid technique for determining cancellous bone mineral changes in small experimental animals. We used the distal centimeter of the right femur from ovariectomized (OX) (N = 30) and shamovariectomized (ShOX) (N = 28) rats, aged 90 days at surgery and killed at times from 125–540 days postsurgery. We used dual photon absorptiometry to scan the segment three times: intact, after parasagittal splitting, and after removing all cancellous bone. We equated the difference between the second and third scans to cancellous bone mineral content (Cn.BMC). To validate this, we compared it with histomorphometrically determined bone volume (BV/TV) of the proximal tibial metaphysis of the same rat. Parasagittally splitting the segment removed no detectable mineral. OX rats had 40% less Cn.BMC than ShOX rats. However, OX rats had 80% lower BV/TV than ShOX rats. The subtraction technique not only makes a rapid, reasonable assessment of cancellous bone loss in OX rats but permits a smaller sample size than histomorphometry. The histomorphometric technique finds a greater difference between OX and ShOX rats because it examines a region where cancellous bone loss is more marked than does the scanning technique. The current technique measures bone of not only the central secondary spongiosa but also the juxtacortical region and the primary spongiosa, where OX‐related differences are less prominent. The principles of this subtraction technique proved workable. However, for the future, we recommend a two‐scan technique using a dual energy X‐ray scanner. It is likely to take only 20–30 min per specimen to assess cancellous bone mineral.
Fibronectin filaments and actin microfilaments are organized into a fibronexus in Dupuytren's diseased tissue
Authors: Tomasek James J. , Haaksma Carol J.
Published: February 2005

The fibronexus is a close transmembrane association between fibronectin filaments and actin microfilaments. It has been found at the surfaces of fibroblasts in tissue culture, as well as within contracting granulation tissue. This specialized connection has been proposed to play an important role in the adhesive properties of fibroblasts. The purpose of this study is to determine whether the fibronexus is present in other contracting tissues besides granulation tissue, specifically in Dupuytren's diseased tissue. Dupuytren's disease is a pathologic condition in which the palmar aponeurosis becomes shortened leading to irreversible flexion of the digits. Shortening of the aponeurosis is believed to be an active cellular process. Extracellular filaments and actin microfilaments form close transmembrane associations at the surfaces of actin‐rich fibroblasts in Dupuytren's disease. Extracellular filaments extend from the cell surface into the surrounding tissue connecting fibroblasts with collagen fibrils and adjacent cells. In this study we have used immunoelectron microscopy to demonstrate that the extracellular filaments that participate in these close transmembrane associations contain fibronectin. High voltage electron microscopy has been used to examine the three‐dimensional relationships between the cytoskeleton and fibronectin filaments in Dupuytren's diseased tissue. We propose that the fibronexus is a dominant adhesive structure at the surface of fibroblasts in Dupuytren's diseased tissue. The fibronexus, by mediating cell‐to‐cell and cell‐to‐matrix attachments, may serve to transmit contractile forces generated by actin microfilaments in these cells throughout the diseased tissue.
Effect of tunicamycin, an inhibitor of protein glycosylation, on testicular cord organization in fetal mouse gonadal explants in vitro
Authors: Kanai Yoshiakira , Hayashi Yoshihiro , Kawakami Hayato , Takata Kuniaki , Kurohmaru Masamichi , Hirano Hiroshi , Nishida Takao
Published: February 2005

The effect of tunicamycin (TM) on testicular cord organization in the fetal mouse was examined in vitro at light and electron microscopic levels, with special reference to the glycoprotein functions during Sertoli cell differentiation.

In testicular explants treated with TM, testicular cord organization was inhibited. TM treatment affected basal lamina formation by Sertoli cells, resulting in a discontinuous basal lamina or none at all in certain areas. The disorganized Sertoli cells were amorphous in shape, exhibited poor epithelial polarity, and were irregularly arranged in the testicular parenchyma. Extracellular matrix and collagen fibers were often observed in the intercellular spaces between the disorganized Sertoli cells. Lectin histochemical observation revealed that the number of wheat germ agglutinin binding sites on the plasma membrane and basal lamina of disorganized Sertoli cells was significantly decreased by TM treatment. However, junctions were normally observed in the plasma membrane between disorganized Sertoli cells. Leydig cells showed a normal differentiation in the testicular parenchyma in the presence of TM.

These observations suggest that basal lamina formation of Sertoli cells and/or the expression of their cell surface glycoconjugates may be crucial for the establishment of Sertoli cell polarity and/or the Sertoli‐Sertoli cell interactions required for proper testicular cord formation. Sertoli cell organization into testicular cords and Leydig cell differentiation may be controlled by different regulatory mechanisms.
The restraining function of the cruciate ligaments on hyperextension and hyperflexion of the human knee joint
Authors: Fuss Franz K.
Published: February 2005

Each of the cruciate ligaments contains functionally different fiber groups; one fiber bundle is always taut; numerous others are taut in intermediate or extreme positions. The bulk of the fibers of the anterior cruciate ligament (ACL) is taut in maximal extension, while that of the posterior cruciate ligament (PCL) is taut in the intermediate positions and in maximal flexion. Fibers taut in extreme positions serve as restraints: during hyperextension, the ACL restrains forward migration of its tibial attachment, while the PCL interacts with other structures to prevent posterior opening of the joint. The inverse situation occurs in hyperflexion. Cruciate fibers are dissimilar in length and angular arrangement so that, when movements are restrained, they lengthen to different extents. To define this phenomenon in quantitative terms, the term isokolyons was coined for lines from which fibers showing identical elongation in percentage on exposure to a force take their origin.
Changes in immunoreactivity for cathepsin H in rat type II alveolar epithelial cells and its proteolytic activity in bronchoalveolar lavage fluid over 24 hours
Authors: Ishii Yukio , Hashizume Yutaka , Kominami Eiki , Uchiyama Yasuo
Published: February 2005

Variations in immunoreactivity for cathepsin H in rat type II alveolar epithelial (type II) cells and in its proteolytic activity in bronchoalveolar lavage fluid (BALF) were examined at six evenly spaced times over 24 hr (light period: 0600–1800 hr). Ring‐shaped immunodeposits for cathepsin H were detected in type II cells (lamellar bodies), their sizes varying over 24 hr. The large ring‐shaped immunodeposits increased during the light period, decreasing rapidly from 2000 to 0000 hr. Small intense immunodeposits abundantly appeared in the cells at 0000 hr. The area densities of immunodeposits in type II cells and their optical densities also varied with the time of day; both densities were high during the dark period, peaking at the mid dark period, whereas they were decreased during the light period. Proteolytic activities of cathepsin H in BALF (6 ml/rat) examined at each time revealed a distinct variation over 24 hr, corresponding to the variation in the immunoreactivity in type II cells. The activities in BALF were high from 1600 to 0400 hr and low at 0800 hr. These results suggest that the variation in immunoreactivity for cathepsin H in type II cells over 24 hr reflects the intracellular growth of lamellar bodies and secretory activity of the cells. Similar variations in the immunoreactivity and proteolytic activity of cathepsin H in the cells and BALF indicate its cosecretion with surfactants.
Occurrence of epidormal growth factor‐binding sites during differentiation of cementoblasts and periodontal ligament fibroblasts of the young rat: A light and electron microscopic radioautographic study
Authors: Cho Moon‐Il , Lin Wen‐Lang , Garant Philias R.
Published: February 2005

Occurrence of epidermal growth factor (EGF)‐binding sites during differentiation of cementoblasts and periodontal ligament (PDL) fibroblasts was investigated using radioautography after I. V. injection of 125I‐EGF to 14‐day‐old rats. During differentiation of cementoblasts, a very low level of EGF‐binding sites was present on the mesenchymal cells in dental follicle proper, precementoblasts, and cementoblasts. On the other hand, during differentiation of PDL fibroblasts, numerous EGF‐binding sites were observed on the undifferentiated paravascular cells and on the perifollicular mesenchymes representing the major source of PDL fibroblast precursor cells. Also heavy labeling was observed throughout their differentiation to PDL fibroblasts, as well as during full synthetic activity as mature cells. Quantitative analysis of the light microscopic radioautographs revealed that these cells demonstrated approximately 4 grains per 100μm2 of cell area. These results suggest that EGF plays an important role in differentiation of PDL fibroblasts, but not in that of cementoblasts. Furthermore, the well‐known in vivo effect of EGF in producing precocious eruption of teeth may be a consequence of a more extensive effect of EGF throughout differentiation of PDL fibroblasts as well as during full synthetic activity as mature cells.
Apical mitochondria‐rich cells in the human epididymis: An ultrastructural, enzymohistochemical, and immunohistochemical study
Authors: Palacios Jose , Regadera Javier , Nistal Manuel , Paniagua Ricardo
Published: February 2005

An ultrastructural, enzymohistochemical, and immunohistochemical study of the ductus epididymis in normal men was undertaken to investigate the characteristics of the apical mitochondria‐rich cells (AMRCs). These cells, which differ morphologically from the principal cells (PCs), appear in isolation in the caput epididymidis (5.8 ± 1.7 cells per cross‐sectional duct) and only occasionally in the corpus epididymidis. The morphologic appearance of AMRCs varies from slender cells extending from the basement membrane to the lumen to apical cells without apparent contact with the basement membrane. The former display a round pale nucleus located in the middle of the epithelium; the apical cells have a dark nucleus, which, surrounded by a narrow cytoplasmic band, protrudes into the lumen. The cytoplasm of AMRCs is electron‐dense and contains numerous mitochondria surrounded by rough endoplasmic reticulum cisternae. In the apical portion, there are lysosomes, vesicles with an electron‐dense granule, and vacuoles showing a variable size and content. The stereocilia are shorter and less numerous than those of the PCs. The AMRCs are similar to the PCs in the intensely positive reaction for the enzymatic activity acid phosphatase, as well as in the lack of reaction for alkaline phosphatase and phosphorylase activities. AMRCs differ from PCs in: (1) a more intense reaction to the enzymatic activities ATPase, NADP, and succinic dehydrogenease, (2) a more intense immunostaining by AE1/AE3 and Ks4.62 anti‐cytokeratin antibodies, and anti‐estradiol receptor protein (D5) antibodies, and (3) a lower staining affinity for epithelial membrane antigen (EMA) antibodies. No positive immunostaining for the anti‐cytokeratin Ks8.6 antibodies was observed in either AMRCs or PCs.
Characterization of the functional stages of osteoclasts by enzyme histochemistry and electron microscopy
Authors: Fukushima Osamu , Bekker Petrus J. , Gay Carol V.
Published: February 2005

To investigate the functional stages of osteoclasts, the ultrastructural histochemical distribution of the lysosomal enzymes [acid phosphatase (tartrate‐sensitive) and neutral phosphatase], the plasma membrane enzymes [alkaline phosphatase, Ca++‐ATPase, and alkaline ouabain‐insensitive p‐nitrophenylphosphatase (alkaline p‐NPPase)], and the mitochondrial enzyme (cytochrome C oxidase) was evaluated in the chicken tibial metaphysis.

Both active‐appearing and detached (resting) osteoclasts were studied. Serial sectioning was used to identify detached osteoclasts which were present in the perivascular space. The ultrastructure of detached osteoclasts was similar to that of active osteoclasts, except for the lack of a ruffled border and clear zone, and an altered distribution pattern of small vesicles. Small vesicles were uniformly distributed in the cytoplasm of resting osteoclasts, whereas they were concentrated beneath the ruffled border of active osteoclasts. Alkaline p‐NPPase, a marker enzyme for the basal ruffled border, was also apparent on the membrane of small vesicles. However, the vesicles did not possess Ca++ ‐ATPase, a marker enzyme for the apical plasma membrane. These findings support the concept that small vesicles serve as a membrane reservoir for the ruffled border membrane.

Pre‐osteoclasts contained abundant mitochondria and lysosomes, prominent Golgi complexes, moderately developed endoplasmic reticulum, and lacked small vesicles. Pre‐osteoclasts appear to fuse with osteoclasts which are attached to the bone surface, but not with detached osteoclasts. The small vesicles, from which the ruffled border arises, are absent from pre‐osteoclasts, suggesting that they develop after fusion with pre‐existing osteoclasts or after attachment to the bone surface. Alkaline p‐NPPase appears to be a marker for differentiation of pre‐osteoclasts to mature osteoclasts.
Pars distalis vasculature: Discovery shuttle STS‐29 rats compared to ground‐based antiorthostatic rats
Authors: Pattison Amy , Pattison Tim , Schechter Joel
Published: February 2005

The anterior pituitary glands of male, adult Long Evans rats carried 5 days in the Space Shuttle Discovery (STS‐29) have been compared with two groups of ground‐based controls. All of the animals were part of a study (SE82‐08) into the effects of gravity versus a microgravity environment on fracture healing. All had sustained a right, mid‐shaft fibular osteotomy. The duration of the study was 10 days, and animals in all groups were weight bearing for the 5 days prior to shuttle lift off. The three experimental groups consisted of four rats each: flight (F) and two ground‐based control groups, weight bearing (WB) and suspended (S). The suspension group was in a Holton/Sweeney head‐down suspension apparatus (antiorthostatic) for the final 5 days of the study. The anterior pituitary glands of F and WB rats were essentially identical. The vasculature and parenchymal cells appeared unaffected in both instances. However, the anterior pituitary glands of S rats were dramatically altered. The vasculature was widely expanded with proteinaceous deposition covering the lumenal endothelial surfaces, and entrapping numerous platelets and aggregates of red blood cells. Parenchymal cells were highly vacuolated, occasionally with membranous vacuoles, but most often revealing large, clear cytoplasmic zones unlined by any membranes. Whereas profiles of exocytosis were numerous in F rats, and present in WB rats, they were essentialy absent in S rats. These results indicate that weightlessness over a 5‐day flight period does not influence the structural integrity of the anterior pituitary gland and may in fact promote secretory granule release. However, the head‐down tilt model, frequently used to study fracture repair under conditions that mimic weightlessness, has a profound impact on the vasculature of the anterior pituitary gland which then affects the structural and functional characteristics of the parenchymal cells.
Formation of secretory granules in the Golgi apparatus of prolactin cells in the rat pituitary gland: A stereoscopic study
Authors: Rambourg A. , Clermont Y. , Chrétien M. , Olivier L.
Published: February 2005

The mode of secretory granule formation in prolactin cells was analyzed in thin or thick sections of pituitary glands from non‐lactating or lactating female as well as from male rats. In all these animals, the Golgi apparatus of prolacting cells consists of a continuous twisted ribbon‐like structure that branches and anastomoses to form a hollow sphere located in the juxtanuclear area. The early signs of secretory granule formation are observed along the trans‐aspect of the Golgi ribbon where progranules appear as focal distensions simultaneously occurring anywhere in the last trans thiamine pyrophosphatase (TPPase)‐containing Golgi element. In the transmost Golgi saccule, such dilatations usually contain several nodular masses of electron opaque material which are separated from each other and from the saccular membrane by a less intensely stained material. While this transmost saccule becomes more fenestrated, its focal polynodular distensions seemingly yield polynodular tubular progranules which are initially closely apposed and usually parallel to the trans face of the Golgi ribbon. Subsequently, these progranules, which frequently show small membranous tubules or tubular networks attached to them, are seen some distance from the Golgi stacks and progresively transform into the more compact polymorphous granules characteristic of prolactin cells. These observations suggest that the polynodular tubular progranules arise by fragmentation of portions of the trans‐Golgi elements rather than by fusion of small uninodular granules budding from the edges of a trans‐Golgi saccule. Once the progranules have been liberated, the rest of the transmost Golgi element appears to break down into small residual networks, tubules, and vesicles. Thus, in prolactin cells as in other glandular cells, the whole transmost Golgi element would fragment during formation of prosecretory granules.
Glomerular number and size in relation to age, kidney weight, and body surface in normal man
Authors: Nyengaard J. R. , Bendtsen T. F.
Published: February 2005

The number and size of glomeruli in normal, mature human kidneys were estimated by a direct and unbiased stereological method, the fractionator. The number was 617,000 on average, and the mean size 6.0 M μm3. Both glomerular number and size showed significant negative correlation to age and significant positive correlation to kidney weight. Apparently, humans loose glomeruli with age.

Body surface area correlated positively to kidney weight and total glomerular volume but not to number of glomeruli. Body surface area correlates significantly with metabolic rate (Robertson and Reid, Lancet, 1: 940–943, 1952). Thus, intraspecies adaptation of kidney filtration capacity to the metabolic demand is performed by changing the size of glomeruli, i. e., the number of glomeruli in individuals of a given species is independent of the metabolic rate.
Identifying and counting epithelial cell types in the “corpus” of the mouse stomach
Authors: Karam Sherif M. , Leblond Charles Philippe
Published: February 2005

The epithelial cells lining the oxyntic mucosa in the stomach “corpus” were identified, localized, and counted in 2‐month‐old male C57BL‐6 mice, using glutaraldehyde‐formaldehyde fixation and osmium tetroxide postfixation for studies in the light microscope (LM) while adding tannic acid to the fixative and postfixing in ferrocyanide‐osmium for studies in the electron microscope (EM).

The cells form a single epithelium, which invaginates into blind tubular units. Each unit is divided into four successive regions: pit, isthmus, neck, and base. On the average, a unit contains 194.2 cells. The cells have been classified into three groups totaling 11 types, listed with their mean number per unit. The first group is composed of three well‐characterized cell types, each restricted to a region: (1) 37.0 surface mucous cells, hereafter called pit cells, in the “pit” region, (2) 12.6 mucous neck cells, simply called neck cells, in the “neck” region, and (3) 67.4 zymogenic cells in the “base” region.

The second group is also composed of three well‐characterized cell types, distributed over the four regions: (1) 26.0 parietal cells, (2) 13.2 entero‐endocrine cells, and (3) 0.6 caveolated cell.

The third group consists of five cell types, which have been little or not characterized in the past. Four are located in the “isthmus” region and show EM features indicative of immaturity, that is, a nucleus with mainly diffuse chromatin and large reticulated nucleoli, and a scanty cytoplasm rich in free ribosomes: (1) 17.2 cells are the least differentiated in the epithelium; they are devoid of secretory granules and accordingly named granule‐free cells, (2) 10.0 cells contain a few dense secretory granules smaller than, but otherwise similar to, those in pit cells; they are referred to as pre‐pit cells, (3) 1.8 cells possess a few marbled secretory granules that often exhibit a pale core and are smaller than, but otherwise similar to, those in neck cells; they are called pre‐neck cells, (4) 0.6 cells display long microvilli and/or small canaliculi similar to those in parietal cells; they are named pre‐parietal cells, and (5) 5.6 cells restricted to the base region are characterized by secretory granules with features intermediate between those of neck and zymogenic cells; they are named pre‐zymogenic cells.

The observations suggest the following hypothesis on cell filiation. The granulefree cells would function as stem cells and give rise to pre‐pit, pre‐neck, and preparietal cells, which would, respectively develop into pit, neck, and parietal cells; neck cells would then transform into pre‐zymogenic cells, which would finally become zymogenic cells. Entero‐endocrine and caveolated cells would come directly from the postulated stem cell.
The morphological basis of folded‐wing posture in the American Kesrel, Falco sparverius
Authors: Meyers Ron A.
Published: February 2005

Gross dissection and histochemical analysis of the shoulder musculature of the American kestrel, Falco sparverius, revealed that four muscles are specialized for slow contraction and may function in the postural control of the folded wing. Mm. latissimus dorsi pars cranialis, scapulohumeralis cranialis, and brachialis were found to contain > 95% tonic fibers, whereas M. deltoideus minor was found to possess a relatively even mix of fast‐twitch and tonic muscle fibers. M. latissimus dorsi pars cranialis, M. scapulohumeralis cranialis, and M. brachialis crosses the elbow joint on the ventral surface of the forearm. This paper suggests postural muscles have largely been ignored in studies of avian musculature, and the need to consider a variety of possible muscle functions when analyzing locomotor muscle functions.
Macrophage development: II. Early ontogeny of macrophage populations in brain, liver, and lungs of rat embryos as revealed by a lectin marker
Authors: Sorokin Sergei P. , Hoyt Richard F. , Blunt Dana G. , McNelly Nancy A.
Published: February 2005

Earliest origins of macrophage populations in the central nervous system, the liver, and the lungs were studied in rat embryos aged between 10.5–11 days and 14 days of gestation, based on light and electron microscopic identification of macrophages using peroxidase‐coupled isolectin B4 of Griffonia simplicifolia (GSA I‐B4), which recognizes alpha‐D‐galactose groups on the cell membrane. During embryonic life macrophages and their precursors are GSA I‐B4‐positive and generally bereft of peroxidase‐positive granules. At 10.5 days the yolk sac and embryonic circulations have just become joined, the brain has five vesicles but nerve cells are little differentiated, the liver exists as a diverticulum of the gut with fingerlike extensions of hepatocytes, and the lungs as a laryngotracheal groove. Macrophages and/or their precursors occurred in small numbers in embryonic mesenchyme and blood vessels but showed no special affinity for either liver or lung rudiments. The developing brain was the first organ to be colonized, beginning on prenatal day 12. The liver followed between days 12 and 13 and was succeeded by the lungs, beginning between days 13 and 14. Dividing macrophages were present in these organs at the outset of colonization and throughout the duration of the embryo series, indicating that from the beginning, replication of resident cells contributes to growth of the local population. Granulocyte precursors were first apparent in the liver around day 13; they are also GSA‐positive but are distinguished from macrophages by their content of peroxidase‐positive granules. Organ cultures of 13‐day liver and lungs, and 14‐day brain tissue, indicate that whereas isolated liver fragments support the formation of both granulocytes and macrophages, only the latter develop in brain or lung cultures. A resident population of macrophages evidently is set up very early in these organs, well before white cells colonize the spleen, bone marrow, and other future blood forming regions. The events outlined are seen as stages in an embryo‐wide process that leads to establishment of macrophage populations in various organs.
Differentiation of bursal secretory‐dendritic cells studied with anti‐vimentin monoclonal antibody
Authors: Olah Imre , Kendall Cyndy , Glick Bruce
Published: February 2005

Embryonic and posthatched differentiation of bursal secretory dendritic cells, which express vimentin intermediate filaments, were studied with anti‐vimentin (clone 3B4) and anti‐cytokeratin (clone Lu5) monoclonal antibodies. Anti‐cytokeratin staining revealed that medullary reticular epithelial cells formed a continuous network at every age, whereas the vimentin positive cells were single and showed dendritic appearance. On the basis of location, number, shape, polarized appearance, and Ia staining, the vimentin‐positive cells and secretory dendritic cells appeared to be the same cell.

Secretory dendritic cell precursors entered the bursal epithelium between 11 and 13 days of embryogenesis. The first vimentin positive cell appeared in the bud of 14‐day embryos. Bud formation preceded the appearance of vimentin‐positive cells. These observations suggested that the secretory dendritic cell precursor did not express vimentin when it entered the epithelium. Between 15 days of embryogenesis and 2 weeks of posthatch development, the changes in vimentin staining pattern revealed a cytological differentiation of the vimentin‐positive cell. During rapid bursal growth, the number of secretory dendritic cells (vimentin‐positive cells) increased about 18 times possibly by proliferation of vimentin‐negative precursors in the epithelial arches of the corticomedullary border. © 1992 Wiley‐Liss, Inc.
The neuroepithelial cells of the fish gill filament: Indolamine‐immunocytochemistry and innervation
Authors: Bailly Y. , Dunel‐Erb S. , Laurent P.
Published: February 2005

The neuroepithelial cells (NECs) of the fish gill filament share several morphofunctional features with the cells of the neuroepithelial bodies in the lungs of air‐breathing vertebrates. In the present study, a detailed indolamineimmunocytochemical analysis of the branchial neuroepithelial cells and nerves was undertaken in non‐teleost and teleost species, with particular emphasis on the latter. In the rainbow trout, Oncorhynchus mykiss, the chemical degeneration of either catecholaminergic (by 5‐ and 6‐hydroxydopamines) or indolaminergic (by 5,6‐dihydroxy‐tryptamine) innervations associated with the NECs was studied using electron microscopy.

In teleosts, the NECs are located primarily on the distal half of the filament. In the trout particularly, these cells are innervated mainly by non‐indolaminergic nerves taking up sympathetic neurotoxins. The proximal half of the filament contains isolated NECs innervated additionally by intrinsic indolaminergic neurons.

Serotonin‐like immunoreactivity of the NECs is evident in the granular vesicles packed within the basal soma and processes which surround non‐vascular and vascular smooth muscles in the filament. Apical processes from the neuroepithelial cells occasionally contact the water on the surface of the filament epithelium. The secretory function of the NECs is discussed with reference to the probable involvement of serotonin in the modulation of fish gill function. In addition, their connections with both central and branchial nervous system suggest a possible chemoreceptor role. © 1992 Wiley‐Liss, Inc.