bluuebunny/crossref_metadata_2025 huggingface dataset:
The microfibrils of connective tissue: II. Immunohistochemical detection of the amyloid P component
Authors: Inoué S. , Leblond C. P. , Grant Derrick S. , Rico Philippe
Published: February 2005

Immunohistochemical methods were used for the detection of the amyloid P component in the microfibrils of two regions: the zonule of the eye and the connective tissue of the foot pad in 20‐ to 50‐gm mice. Following fixation by immersion in 4% formaldehyde, the eyes and foot pads were embedded in paraffin, and sections were immunostained for light microscopy by using antiamyloid P component antiserum followed by peroxidase‐antiperoxidase procedure. For electron microscopy, formaldehyde‐fixed tissues were immunostained for the amyloid P component with protein A‐gold by using either thin Lowicryl sections or frozen sections which were then embedded in Epon for thin sectioning.

In the zonule of the eye, the light microscope showed that zonular fibers were strongly immunostained for the amyloid P component; there was also weak staining of the nonpigmented ciliary epithelium at the distal end of the fibers and of the zonular lamella at their proximal end. The electron microscope revealed clear‐cut immunolabeling of the microfibrils making up zonular fibers as well as of individual microfibrils. In the foot pad, the light microscope detected a weak diffuse staining of connective tissue, whereas the electron microscope showed immunolabeling restricted to microfibrils. It was concluded that the amyloid P component was present in, or associated with, microfibrils.

Purified amyloid P component was prepared and examined in the electron microscope after either negative staining or routine processing. After negative staining, it appeared as flat pentagonal units, frequently associated into columns. After routine processing, the units looked like cross sections of microfibrillar tubules. The dimensions of the units matched those of the hypothetical segments of the tubules. It was concluded that this tubule consisted of a column of amyloid P units. The cohesion of the units within the column was likely to be reinforced by the bands present at the surface of microfibrils.
Transitional epithelial zone of the bovine nasal mucosa
Authors: Adams Donald R.
Published: February 2005

To determine the extent and ultrastructure of epithelium lining the transitional nasal mucosa of the neonate, gnotobiotic calf tissues were prepared for scanning and transmission electron microscopy. Stratified cuboid epithelium of the rostral 40% of the nasal cavity contained few ciliated cells; the next caudal 10–15%, although ciliated, had extensive nonciliated areas. The predominant type of surface cell was nonciliated, had short microvilli, and contained a multilobate nucleus and numerous pinocytotic vesicles. In some areas the surface of these cells presented a cobblestone appearance. Basal cells contained numerous bundles of filaments, ribosomes, and basal vesicles. Caudally, nonciliated columnar cells included a cell type similar to the more rostral cuboid cell, as well as brush cells and immature secretory and ciliated cells. Goblet cells were infrequently observed. Intraepithelial nerve terminals were abundant. Other intraepithelial cells, often difficult to identify owing to varying characteristics, included lymphocytes. Based upon comparisons of this neonatal epithelium with mature epithelium, observed in earlier studies of other mammalian species, the transitional mucosa is believed normally to occupy an extensive area of the nasal cavity.
EMG of scapulohumeral muscles in the chimpanzee during reaching and “arboreal” locomotion
Authors: Larson Susan G. , Stern Jack T.
Published: February 2005

Current views on the function of the deltoid and rotator cuff muscles emphasize their roles in arm‐raising as participants in a scapulohumeral force “couple.” The acceptance of such a mechanism is based primarily on a 1944 EMG study of human shoulder muscle action. More recently, it has been suggested that shoulder joint stabilization constitutes a second and equally important function of the cuff musculature, especially in nonhuman primates which habitually use their forelimbs in overhead postural and locomotor activities. Few comparative data exist, however, on the actual recruitment patterns of these muscles in different species. In order to assess the general applicability of a scapulohumeral force couple model, and the functional significance of the differential development of the scapulohumeral musculature among primate species, we have undertaken a detailed study of shoulder muscle activity patterns in nonhuman primates employing telemetered electromyography, which permits examination of unfettered natural behaviors and locomotion. The results of our research on the chimpanzee, Pan troglodytes, on voluntary reaching and two forms of “arboreal” locomotion reveal four ways in which previous perceptions of the function of the scapulohumeral muscles must be revised: (1) the posterior deltoid is completely different in function from the middle and anterior regions of this muscle; (2) the integrity of the glenohumeral joint during suspensory postures is not maintained solely by osseoligamentous structures; (3) the function of teres minor is entirely different from that of the other rotator cuff muscles and is more similar to the posterior deltoid and teres major; and (4) each remaining member of the rotator cuff plays a distinct, and often unique, role during natural behaviors. These results clearly refute the view that the muscles of the rotator cuff act as a single functional unit in any way, and an alternative to the force couple model is proposed.
Structural and histochemical aspects of epidermis development of fetal porcine skin
Authors: Meyer Wilfried , Görgen Sabine , Schlesinger Christa
Published: February 2005

Epidermal development of fetal porcine skin was studied in fetuses from 41 days of gestation until birth with scanning and electron microscopy techniques as well as histochemical methods, including immunohistochemistry. The porcine fetus develops a relatively thick and solid multilayered cover of epidermal cells, which is not lost before birth. It consists of tightly packed cells of the periderm and the stratum intermedium. The periderm cells are totally filled with filamentous proteins; in the intermediate cells, the filamentous proteins are concentrated in the cell periphery, forming a thick marginal zone. Immunohistochemically, the cytofilaments could be identified as cytokeratins of lower and higher molecular weights. The first thin stratum corneum lamellae are formed below the stratum intermedium at about 80–85 days of gestation.
Immunocytochemical analysis of prolactin cells in the adult rat adenohypophysis: Distribution and quantitation relative to sex and strain
Authors: Phelps Carol J.
Published: February 2005

Prolactin immunocytochemistry was conducted (1) in serial sections of whole fixed pituitaries, for cell distribution analysis; and (2) on preparations of enzymatically dispersed anterior pituitary cells maintained for 1–4 days in vitro, for quantitation of the relative population of prolactin (PRL) cells. Both types of analysis were conducted on glands from young adult rats of both sexes in Long‐Evans, Sprague‐Dawley, and Fischer 344 strains. Cell quantitation results were compared with serum levels, intracellular content, and in vitro release of prolactin, for individual cell preparations. The results show that both PRL cell distribution and relative population numbers are similar between sexes in all three rat strains. Average percentages ranged from 25.9% to 32.1% in all young males and diestrous females. Prolactinpositive numbers of cells correlated positively with intracellular hormone content but not with serum or medium PRL levels. The prolactin cell population was significantly larger in aged Fischer 344 males but was not correlated with intracellular PRL levels. The prolactin cell population was heterogeneous in staining intensity and distribution in both sexes of all three strains.
Tridimensional structure of the Golgi apparatus in type A ganglion cells of the rat
Authors: Rambourg A. , Clermont Y.
Published: February 2005

The three‐dimensional structure of the whole Golgi apparatus and of its components in type A ganglion cells was examined in thin and thick sections by low‐ and high‐voltage electron microscopy. At low magnification, in 10‐μm‐thick sections of osmicated cells, the Golgi apparatus formed a broad, continuous perinuclear network. At higher magnification and in thinner sections of cells impregnated with uranyl acetate‐lead‐copper citrate or postfixed in K‐ferrocyanide‐reduced osmium, the Golgi apparatus appeared as a heterogeneous structure in which saccular regions characterized by stacks of saccules alternated with intersaccular regions made up of branching membranous tubules which bridged the saccules of adjacent stacks. The saccular regions consisted of the following superimposed elements: (1) a cis‐osmiophilic element made up of anastomosing tubules; (2) two or three saccules negative for the phosphatases tested (i.e., nicotinamide adenine dinucleotide phosphatase = NADPase, thiamine pyrophosphatase = TPPase, and cytidine monophosphatase = CMPase); (3) two saccules showing TPPase activity; and (4) one to three trans‐sacculotubular elements showing a “peeling‐off” configuration, one of which showed CMPase activity. The saccules (phosphatase‐negative) on the cis‐side of the Golgi stacks showed, in addition to small circular pores, larger perforations in register. The cavities thus formed in the stacks of saccules, called “wells,” always associated with small 80‐nm vesicles, had a pan shape with the mouth directed toward the cis‐face and the bottom closed by a TPPase‐positive saccule. In face views of the saccules, the smallest of these perforations showed either a crescent shape, due to the presence of a bud on one side of the perforation, or a circular shape with a single small 80‐nm vesicle in the center which was occasionally attached to the saccule by a filiform stalk. Such smaller cavities were considered as the precursors of the larger perforations and eventually of the wells. The small 80‐nm vesicles seen in the small cavities or in the wells appeared to form in situ and possibly migrate toward the cisternae of endoplasmic reticulum seen proximal to the cis‐face of the stack of saccules. Small 80‐nm vesicles were also numerous in the intersaccular regions, along the lateral‐ and trans‐aspects of the Golgi stacks, while larger, 150‐to 300‐nm vesicles, coated and uncoated, were seen only on the trans‐face of the Golgi stacks in proximity to the trans‐sacculotubular elements which appear to “peel off” from the Golgi stacks.
Association of mesenchyme with attenuated basement membranes during morphogenetic stages of newt limb regeneration
Authors: Neufeld Daniel A. , Aulthouse Amy Lynn
Published: February 2005

The interface between epithelium and mesenchyme may be involved in inductive interactions which occur during development. This interface within the growth bud, or blastema, of a regenerating limb has been examined to determine whether changes in basement‐membrane structures are visible in regions of putative epithelial‐mesenchymal inductive interaction. Regenerating forelimbs of adult newts were fixed by perfusion with osmotically balanced aldehydes. Late‐bulb to early‐digit stage regenerates were collected and processed either for light and transmission electron microscopy or for scanning electron microscopy. Light microscopy confirmed that regions characterized by increased numbers of subepithelial mesenchymal cells were covered by a diffusely stained basement membrane. Transmission electron microscopy of these regions revealed two structural components of the basement membrane. The thin basal lamina was continuous in all regions of all stages examined, but it was attenuated apically in areas of mesenchymal cell accumulation. The thicker underlying reticular lamina was markedly attenuated in these regions near the blastemal apex. Scanning electron microscopy of de‐epithelialized blastemas revealed that, apically, the reticular lamina formed only a delicate lacelike network. On the base of the blastema, it formed a dense fibrillar meshwork which was further organized into a geometric pattern in the adjacent stump skin. Cumulatively, these observations suggest that physical contact between epithelial and mesenchymal cells is not essential at these stages, but that regions of putative epithelial‐mesenchymal interaction are characterized by a distinctly diminished reticular lamina. Structural changes in basement‐membrane components may be related to termination of local inductive events.
The ultrastructure of the rat primary decidual zone
Authors: Parr Margaret B. , Tung H. N. , Parr Earl L.
Published: February 2005

The rat primary decidual zone (PDZ) is a transitory, avascular region of transformed fibroblasts surrounding the implanting embryo. Tracer studies have indicated that the PDZ is selectively permeable to macromolecules, permeability decreasing with increasing molecular weight of the tracer. To clarify the morphological basis of the permeability barrier, we have studied the ultrastructure of the PDZ with particular emphasis on the intercellular features and cellular junctions. The cells of the PDZ were large and tightly packed; their apposed membranes showed extensive interdigitations in some regions, but elsewhere they were relatively straight. Tight junctions, gap junctions, and desmosomelike junctions were observed between decidual cells. The tight junctions usually consisted of one or two points of membrane fusion, and they were oriented both parallel and perpendicular to the long axis of the PDZ. These junctions were frequently associated with gap junctions. Scattered pockets of dilated extracellular space between decidual cells contained collagen fibrils and an amorphous, dense material. These extracellular components were also sequestered by the decidual cells in deep invaginations of the cell surface that were continuous with the extracellular space. Decidual cells also exhibited flangelike processes that penetrated the basal laminae of the adjacent epithelium and capillary endothelium. Our present observations indicate that decidual cells are connected by tight junctions, and a previous study demonstrated that macromolecules up to 40 kDa readily cross the PDZ; hence, the tight junctions appear to be discontinuous. We suggest that the structures restricting the movement of large macromolecules (66 kDa and larger) across the PDZ from blood vessels to the embryo may include discontinuous tight junctions, membrane interdigitations, and amorphous intercellular material.
The structure of the osteoderms in the gekko: Tarentola mauritanica
Authors: Levrat‐Calviac V. , Zylberberg L.
Published: February 2005

Histological and cytological analysis reveals that the osteoderms of Tarentola mauritanica are composed of an outer part superimposed on a basal region. The structure of both parts can be related to that of the surrounding dermis. The basal part of the osteoderms, inserted in the dense dermis, is made up of abundant closely packed collagen fibrils that orient the mineral deposit. The outer part, located in the superficial loose dermis, is crossed by few bundles of mineralized collagen fibrils arising from the basal part. These bundles connect the osteoderm to the overlying loose dermis. The outer superficial part is characterized by the presence of mineralized globules surrounding the mineralized collagen bundles. In these globules, the crystals are deposited on a microfibrillar matrix rich in acidic mucosubstances and composed of radially oriented, tangled microfilaments that lie among the collagen bundles. The two different mineralizing systems in the osteoderms of Tarentola mauritanica may reflect two different organic matrices. The mineral is deposited in a preexisting dermal tissue, as a “metaplastic ossification,” and is another expression of the potential retained by the reptilian dermis to form mineralized structures.
Development of aortic and mitral valve continuity in the human embryonic heart
Authors: Teal Sharon I. , Moore G. William , Hutchins Grover M.
Published: February 2005

The anatomic relationship of the aortic and mitral valves is a useful landmark in assessing congenital heart malformations. The atrioventricular and semilunar valve regions originate in widely separated parts of the early embryonic heart tube, and the process by which the normal fibrous continuity between the aortic and mitral valves is acquired has not been clearly defined. The development of the aortic and mitral valve relationship was studied in normal human embryos in the Carnegie Embryological Collection, and specimens of Carnegie stages 13, 15, 17, 19, and 23, prepared as serial histologic sections cut in the sagittal plane, were selected for reconstruction. In stage 13, the atrioventricular valve area is separated from the semilunar valve area by the large bend between the atrioventricular and outflow‐tract components of the single lumen heart tube created by the left interventricular sulcus. In stages 15 and 17, the aortic valve rotates into a position near the atrioventricular valves with development of four chambers and a double circulation. In stage 19, there is fusion of aortic and mitral endocardial cushion material along the endocardial surface of the interventricular flange, and this relationship is maintained in subsequent stages. Determination of three‐dimensional Cartesian coordinates of the midpoints of valve positions shows that, while there is growth of intervalvular distances up to stage 17, the aortic to mitral distance is essentially unchanged thereafter. During the period studied, the left ventricle increases in length over threefold. The relative lack of growth in the saddle‐shaped fold between the atrioventricular and outflow tract components of the heart, contrasting with the rapid growth of the outwardly convex components of most of the atrial and ventricular walls, may be attributed to the different mechanical properties of the two configurations. It is postulated that the pathogenesis of congenital heart malformations, which characteristically have failure of development of aortic and mitral valve continuity, may involve abnormalities of rotation of the aortic region or malpositioning of the fold in the heart tube.
Adenohypophysis of the elephant seal (Mirounga leonina): Morphology and seasonal histological changes
Authors: Griffiths D. J. , Bryden M. M.
Published: February 2005

Changes in adenohypophyseal cell populations over a 12‐month period were studied in the seasonally breeding elephant seal (24 adult males, 3 adult females, and 5 neonates) at Macquarie Island. The glands were weighed and fixed in formol sublimate. Selected sections were stained with the oxidation‐alcian blue‐periodic acid Schiff‐orange G technique. Gonadotropic, thyrotropic, lactotropic, and somatotropic cells were readily identifiable; whilst corticotropes, inactive secretory cells of all types, and stellate cells were not stained and were counted collectively as chromophobic cells. Hypophyseal weight was low throughout autumn and winter, but increased significantly during the spring breeding season and the summer. Thyrotropes were distributed evenly throughout the pars distalis, but the other secretory cells showed areas of concentration. Acidophils were common peripherally, particularly lactotropes, while gonadotropes were largely confined to the ‘basophilic wedge,’ a narrow, central superior zone. In males, lactotropic and gonadotropic cells showed significant seasonal changes in number. Gonadotropes were more common in sexually active males than sexually quiescent ones, while lactotrope numbers were much greater at midsummer than midwinter. This lactotrope cycle appeared to be related to photoperiod but unrelated to breeding.
Proliferation of arteriovenous anastomoses in the developing rabbit ear is enhanced after denervation
Authors: Morris Judith L. , Bevan Rosemary D.
Published: February 2005

The innervation of the rabbit ear vasculature by noradrenergic and substance P‐immunoreactive (SP‐IR) nerves was investigated in both young and adult animals. All vascular segments were supplied by both noradrenergic and SP‐IR nerves. In the ear margins, the arteriovenous anastomoses (AVAs) were more densely innervated than other vessels. In general, the density of both noradrenergic and SP‐IR nerves increased with age until 10–12 weeks postnatum. The ear vasculature was denervated in young rabbits to test whether the normal proliferation of AVAs in the growing ear was altered in the absence of nerves. Surgical resection of all auricular nerve trunks except the auricular branch of the auriculo‐temporal nerve, and removal of the ipsilateral superior cervical ganglion in 10‐ to 12‐day‐old rabbits left the ear devoid of both noradrenergic and SP‐IR nerves for at least four weeks. Repeated administration of 6‐hydroxydopamine (6‐OHDA) to young rabbits produced degeneration of noradrenergic terminal axons, but preterminal nerve trunks survived. SP‐IR nerves did not appear to be affected by 6‐OHDA. These denervaton regimes resulted in a 1.5‐ to 2‐fold increase in the number of AVAs formed in the growing ear. Surgical denervation and 6‐OHDA treatment also led to retarded growth of the media of the central ear artery, but this effect of 6‐OHDA was probably not due to a specific action on vascular smooth muscle. Surgical resection of most of the dorsal auricular nerves in adult rabbits did not affect AVA density. Large differences in AVA density were apparent between groups of control animals from different parts of the country, or groups examined at different times of the year. These results demonstrate that the labile nature of AVAs in the rabbit ear can result in considerable variability in the absolute number of AVAs and suggest that both intrinsic and extrinsic factors may influence development of the microvasculature.
Somitic‐vertebral correlation and vertebral levels in the human embryo
Authors: Müller Fabiola , O'Rahilly Ronan
Published: February 2005

Somitic and vertebral interrelationships and levels were studied in 84 human embryos of stages 9–23 (3–8 postovulatory weeks). The first four somites are occipital, the occipitocervical junction is at somites 4/5, and eight somites are involved in the cervical region: X, Y, Z, and C. 3–7. By stage 17 the total number of occipitovertebral “units,” namely 38 or 39, is attained. Resegmentation (Neugliederung) of sclerotomes is not supported. A new scheme of somitic/vertebral correlation is proposed in which somites and centra are in register. Differential growth of the regions of the vertebral column was calculated, and it was found that the percentages of the total column occupied by the various regions vary from one stage to another. The cervical and coccygeal regions decrease, the thoracic and lumbar regions increase, and the sacral region remains more or less constant during embryonic development. The following structures descend with reference to the vertebral column during the embryonic period proper: roots of lower limbs, thyroid gland and thymus, tracheal bifurcation, lungs, heart, diaphragm, abdominal arteries, mesonephroi, and suprarenal glands. The gonads may descend slightly. The scapulae and the separation point between the trachea and the esophagus remain at a fairly constant level. The metanephroi ascend. The migration of many of these structures (e.g., the heart, diaphragm, and metanephroi) is much more marked in the embryonic period than later although it continues during the fetal and postnatal periods. The conus medullaris ascends during the fetal period. Anomalies of migration that affect such organs as the thyroid gland, gonads, and metanephroi are discussed.
Immunocytochemical localization of a developmentally regulated, isoproterenol‐inducible protein (LM protein) in rat submandibular gland
Authors: Yagil Chana , Naito Yukio , Barka Tibor
Published: February 2005

Administration of the β‐adrenergic drug isoproterenol (IPR) produces hyperplastic and hypertrophic enlargements of the submandibular gland of the rat and induces the synthesis of specific proteins in this organ. One of these proteins, the LM (large mobile) protein, was demonstrated immunocytochemically in the submandibular glands of developing untreated and IPR‐treated rats. Immunoreactive LM protein was absent in the glands of 20‐day‐old fetuses and 1‐ and 2‐day‐old rats. It was localized in the proacinar and immature acinar cells in the glands of 6‐ to 21‐day‐old animals, but it was undetectable at 28 days of age. In the glands of adult rats, secretory granules of the granular convoluted tubule cells showed immunostaining for the LM protein which was also present in trace amounts in the acinar cells. Daily administration of IPR for 5 days to newborn or 8‐ or 15‐day‐old rats caused an apparent acceleration of proacinar/acinar cell differentiation, and consequently it increased the frequency of cells immunostained for the LM protein as well as the amount of immunoreactive material in these cells. Thus, the expression of LM protein in the submandibular gland is developmentally regulated, and it is restricted to the stage of differentiation of proacinar cells from terminal tubule cells. IPR is capable of inducing this protein in fully differentiated acinar cells in 3‐week‐old or older animals.
Restriction of exogenous transthyretin (Prealbumin) by the endothelium of the rat choriocapillaris
Authors: Pino Richard M.
Published: February 2005

The endothelium of the choriocapillaris has been shown to restrict molecules with Einstein‐Stokes radii ≥ 3.2 nm which correspond to minimal molecular weights of approximately 64,000–68,000 daltons. The present study was undertaken to determine if the endothelium restricts exogenous transthyretin (prealbumin), a 55,000‐dalton carrier of retinol‐binding protein. Rats were injected with human 125I‐transthyretin which was allowed to circulate for 15 and 30 min. Chromatographic analysis demonstrated that the human transthyretin did not bind to rat blood proteins. Eye tissue from injected rats was prepared for light and ultrastructural autoradiographic analysis. Autoradiographic grains were confined to areas over the lumen of the choriocapillaris with few present on Bruch's membrane, the basement membrane common to the endothelium of the choriocapillaris and the retinal pigment epithelium. These findings demonstrate that the choriocapillaris can restrict transthyretin and suggest a possible role of its endothelium in the metabolism of retinol‐carrier molecules.
Ultrastructural localization of concanavalin A‐binding sites in the Golgi apparatus of various types of neurons in rat dorsal root ganglia: Functional implications
Authors: Malchiodi F. , Rambourg A. , Clermont Y. , Caroff A.
Published: February 2005

The localization of concanavalin A (con A) binding sites has been determined at the electron‐microscopic level in the six types of neurons (A1, A2, A3, B1, B2, C) of rat dorsal root ganglia. In all ganglion cells, con A stained the plasma membrane, the nuclear envelope, the cisternae of the rough endoplasmic reticulum, and the matrix of some multivesicular bodies. In contrast, the con A reactivity of the Golgi apparatus varied according to cell type. In type B1 and B2 cells and possibly in type A3 cells, the lectin was exclusively located in three or four saccules on the cis side of the Golgi stacks, whereas the TPPase‐positive saccules and the trans sacculotubular elements were unstained with con A. In type A1, A2, and C neurons, all Golgi saccules as well as the trans sacculotubular elements were stained with the lectin. These results suggest that different types of glycoproteins were produced in these two groups of neurons. In the type A1, A2, and C cells, the persistence of the lectin reactivity in the TTPase‐positive saccules or sacculotubular elements on the trans side of the Golgi stacks suggests the presence of glycoproteins with oligosaccharide side chains rich in α‐D‐mannosyl residues in terminal positions. In contrast, the disappearance of the con A reactivity in equivalent elements of the Golgi stacks in type B1, B2, and A3 cells suggests the addition at this level of other sugar residues characteristic of complex oligosaccharide side chains. The majority of the vesicular elements associated with the Golgi apparatus, as well as lysosomes, were unstained with con A.
Late skeletal development at the articulation between upper pharyngeal jaws and neurocranial base in the fish, Astatotilapia elegans, with the participation of a chondroid form of bone
Authors: Huysseune A.
Published: February 2005

This paper presents light‐microscopical details of the late development of skeletal tissues at the joint between upper pharyngeal jaws (UPJs) and neurocranial base (parasphenoid and basioccipital bones) in the acellular‐boned teleost Astatotilapia elegans. On each of the supporting elements, a bone tissue (AB) is deposited that is anomalous because of its retention of cells within the matrix. Later, this layer is gradually replaced by the anomalous large‐celled chondroid kind of bone (CB). Both AB and CB probably grow by apposition from the overlying fibrous layer. Osteoblastlike cells secrete osteoid, which soon calcifies and traps the cells. As in young cellular membrane bone, cells in the AB have a wide, elongate shape and lie amidst sparse, calcified, bonelike matrix but lack a canalicular system. Later generations of enclosed cells have a more vesicular shape, with at least some cells remaining alive in the calcified matrix. Appositional growth of the chondroid bone at its articular side is matched from a certain stage onward by erosion at its basal side. On the upper pharyngeal jaws this resorption is clearly related to the development of new teeth. Although in older stages and adults the chondroid tissue resembles a secondary cartilage, the term chondroid bone (CB) was preferred because of (1) the continuing formation by osteoblastlike cells; (2) the staining affinities of its matrix with that of bone; and (3) its formation both on cartilage bone (the infrapharyngobranchials III‐IV and basioccipital bone) and on membrane bone (the parasphenoid bone).
Enzymatic heterogeneity of the capillary bed of rat skeletal muscles
Authors: Mrázková Olga , Grim Miloš , Carlson Bruce M.
Published: February 2005

This study of the capillaries in rat skeletal muscle involved the use of a histochemical method that allows one to distinguish between arterial and venous portions of capillaries. Under controlled staining conditions, the arterial portion of the capillary bed reacts positively for alkaline phosphatase (AP) activity, and the venous portion is positive for dipeptidylpeptidase IV (DPP IV) activity. A short transitional capillary segment is positive for the activity of both enzymes. Capillaries of the normal soleus muscle and the red and white portions of the sternomastoid muscle have been quantitatively analyzed. Quantitative data demonstrated differences in capillary dimensions among the muscles studied. Capillaries of the white part of the sternomastoid were the longest, and they had the shortest DPP IV‐positive segment (8% of the total capillary length). Capillaries of the soleus muscle were the shortest, and they also had short DPP IV‐positive segments (16%). In contrast, the DPP IV‐positive segments of the red part of the sternomastoid occupied 60% of the total capillary length. Survey cross sections reveal a mosaic distribution of patches of capillaries stained for AP and DPP IV activity. This study reveals that within given bundles of muscle fibers, the capillaries that run parallel to the muscle fibers are aligned relative to one another in such a manner that their arterial and venous segments are in register.
Measuring histological form change with finite element methods: An application using diazo‐oxo‐norleucine (DON)‐treated rats
Authors: Lozanoff Scott , Diewert Virginia M.
Published: February 2005

Analyses of drug‐induced anatomical malformations routinely rely on linear measurements as a data base. Morphometric approaches utilizing these measures become inappropriate at the histological level at which a constant external referencing system is impossible to achieve. The purpose of this study was to quantify anatomical form change in the craniofacial region of late embryonic rats induced by a known teratogen, diazo‐oxo‐norleucine (DON), independent of any global referencing system. A sample of 17 untreated specimens of 17‐day gestation served as the control. A second group, equivalent in number and age, received 2.0 mg DON on day 15. Homologous landmarks were identified in each specimen and craniofacial regions were partitioned with respect to these bounding nodes into nasal, oral, and mandibular elements. Form change was viewed as the continuous deformation of a reference craniofacial region from a 15‐day untreated specimen into each final 17‐day geometry. An interactive graphics program generated spatially invariant measures of form change through finite element methods. A local coordinate system was established for each element. A point within each region of the 15‐day reference specimen was selected and the spatial relationship between this point and bounding nodes was quantified through interpolation functions. Size and shape variables were derived from a Lagrangian strain tensor, and values were compared between groups. Results showed that all three craniofacial regions were smaller in size among DON‐treated specimens, but only oral and mandibular region shapes were different from controls. The finite element approach was considered superior to other histological morphometric techniques since an entire geometry was described and a visual description of form change as well as spatially invariant measures of size and shape change were derived.
Gill ultrastructure of the pacific hagfish Eptatretus stouti
Authors: Mallatt Jon , Paulsen Charles
Published: February 2005

At the gross anatomical level, hagfish gills show unusual features not seen in any other fish gills. Our study was undertaken to determine if peculiarities also characterize the microscopic anatomy and ultrastructure of hagfish gills. To the contrary, branchial respiratory lamellae of Pacific hagfish were found to resemble the lamellae of lampreys, elasmobranchs, and teleosts, often down to the finest subcellular details. As in other fish, hagfish lamellae are lined by epithelium containing pavement cells with organelles indicative of a secretory function, basal cells showing undifferentiated cell features, and branchial ionocytes. The ionocytes are identical to chloride cells of teleosts in cytostructure, distribution, and abundance. There are pillar and marginal capillaries in hagfish gill lamellae. Pillar cells contain bundles of 5‐nm microfilaments, and they associate with collagen collagen columns as in other fish. Hagfish pillar cells do exhibit odd features, however: They cluster (groups of up to nine were seen), and their extracellular collagen columns are rarer than in other fish gills (averaging only two columns per three pillar cells). Other special features of hagfish gills are the following: (1) lipid droplets and smooth endoplasmic reticulum are well developed in all cell types; (2) pavement cells secrete a lipomucous product (stains with periodic acid‐Schiff, Alcian blue, and Sudan black B); and (3) goblet cells are absent. The presence of “chloride cells” in hagfish is puzzling, as hagfish body fluids are iso‐osmotic to seawater and there is no need to osmoregulate for sodium chloride; the ionocytes contain carbonic anhydrase, suggesting a function in acid/base regulation.
A description of caudal migration during growth leading to the formation of the pericardial and pleural coeloms, to caudal movement of the aortic arches, and to development of the shoulder
Authors: Searls Robert L.
Published: February 2005

Formation of the shoulder in the chick embryo results from movement of cells into the base of the wing from more cranial regions. Between stage 23 and stage 27, the lateral body wall overlying the pleural coelom is caused to move into the base of the wing because the cranial margin of the pleural coelom moves from the level of the tenth somite to the level of the 16th somite. Thus, formation of the shoulder is related to the formation of the pleural coelom. Textbook descriptions of the formation of the pleural coelom did not permit this relationship to be delineated. Therefore, investigation of the relationship between the formation of the shoulder and the formation of the pleural coelom seemed warranted. At stage 12 the coelom is lateral to the gut from the level of the second somite to the level of the 16th somite and is continuous with the extraembryonic coelom. During stage 13 the coelom obtains a ventral margin at the level of the third and fourth somites as the heart fuses with the lateral body wall to form the lateral mesocardium. Between stage 16 and stage 23, the second (cervical) flexure develops, causing the lateral mesocardium to form a ventral margin of the coelom from the level of the first to the 17th somites. Between stage 16 and stage 23, the coelom becomes ventral to the pharynx and lung to the level of the ninth somite. From stage 23 to stage 27, the lateral body wall from the cranial margin of the lung to the caudal margin of the hyoid arch moves in a caudal direction. During stage 27, the lateral body wall fuses with the lateral mesocardium to form the pleuro‐pericardial membrane. The wing remains ventral to the 16th to 19th somites, causing a pileup of cells at the cranial base of the wing, the shoulder.
The ontogeny of the mouse estrogen receptor: The pelvic region
Authors: Holderegger C. , Keefer D.
Published: February 2005

The appearance of estrogen receptors was examined during the course of fetal and neonatal development in the pelvic region of the mouse; 3H‐diethylstilbestrol (DES) was administered via the maternal circulation to developing mice on days 4, 7, 10, 13, 14, 15, and 17 of gestation or to neonates on the day of birth. Localization of the ligand was monitored autoradiographically. The earliest appearance of estrogen receptors occurred in the mesenchyme around the genital ducts on day 13 of pregnancy. On subsequent days, estrogen‐concentrating cells appeared in certain mammary‐gland cells, connective‐tissue strands, in perichondrium associated with specific developing bones, skin, interstitial tissue of the testis, in a sheath of cells surrounding the colon, and in the urethra. The significance of cells containing estrogen receptors in these locations is discussed in reference to a transplacental action of estrogens and the clinical ramifications of DES.
Distribution of hyaluronic acid and sulfated glycosaminoglycans during blood‐vessel development in the chick chorioallantoic membrane
Authors: Ausprunk Dianna H.
Published: February 2005

This study uses histochemical methods to determine the ultrastructural distribution of specific glycosaminoglycans (GAGs) during the development of blood vessels in the chick chorioallantoic membrane (CAM) and to correlate changes in GAG composition with the significant structural events in the development of these vessels. Tissues were stained with tannic acid, ruthenium red, and high iron diamine and digested in various GAG‐degrading enzymes to identify specific GAGs. The results are consistent with a role for hyaluronic acid in the formation, alignment, or migration of the capillary plexus of the CAM and a role for sulfated GAGs (heparan sulfate, chondroitin sulfate, dermatan sulfate) in the differentiation and development of arterial and venous vessels of the chorioallantoic membrane.
Mapping of the rat liver endothelial membrane with lectins and glycosylated ferritins
Authors: Irie Seiji , Tavassoli Mehdi
Published: February 2005

We explored the luminal surface of liver sinus endothelium for the presence of lectin receptors and lectinlike substances capable of interacting with specific sugars. We used ferritin‐conjugated lectins and glycosylated ferritins as probes. Incubation of small blocks of rat liver with these probes led to the binding of concanavalin A (on A), Ricinus communis (RCA), wheat germ agglutinin (WGA), phytohemagglutinin (PHA) and mannosyl ferritins to the luminal surface of endothelium. Ulex europaeus agglutinin I (UEA), fucosyl, galactosyl, and chitobiosyl‐ferritins did not bind. The binding was patchy and sparse in the case of Con A and mannosyl‐ferritins but uniform for others. Binding density did not correlate with hemagglutinability of lectins, suggesting that the difference in the hemagglutinability of these lectins did not account for the difference in their binding densities. Bindings were all completely inhibited in the presence of excess specific sugar inhibitors, indicating the specificity of binding. The distribution of binding was segregated on the endothelial membrane, being heaviest on luminal pits. To define the functional significance of this segregated distribution, sinus endothelium was compared to portal‐vein endothelium in which endothelial fenestrations are also seen; and these fenestrations as well as pits may be covered by a thin diaphragm. Of interest was the total absence of binding to the diaphragm. The significance of these findings is discussed.
Morphometry of the coronary microvasculature of the canine left ventricle
Authors: Hyde Dallas M. , Buss Daryl D.
Published: February 2005

The objective of this study was to test for the presence of transmural gradients of various components of the coronary microvasculature of the canine left ventricle. In order to achieve study objectives, the heart and coronary circulation were fixed in a reproducible state of myocardial and vascular tone (diastolic cardiac arrest and maximal coronary vasodilation). Morphometric methods which treat the coronary microvasculature as anisotropically arranged structures were applied for quantitative structural analysis. Eight dog hearts were fixed with a glutaraldehyde‐cacodylate‐buffered fixative by retrograde perfusion of the aorta with the heart in diastolic arrest and with maximal coronary vasodilation. Tissue samples were taken from areas near to the anterior and posterior papillary muscles from the subendocardium, subepicardium, and intermediate transmural locations. Morphometric results showed a homogeneously arranged array of microvascular and myocardial components with no significant differences in any of the primary morphometric measurements, down to the ultrastructural level, in myocytes relative to transmural location. The results suggest that transmural differences in coronary blood flow are not due to transmural structural differences but rather are due to physiological regulatory mechanisms of coronary blood flow. Further, the results indicate that failure to correct for anisotropy of myocardial structures can lead to erroneous conclusions concerning the structural basis of function in the heart.
Ultrastructure of alveolar bone during tooth eruption in the dog
Authors: Marks Sandy C. , Cahill Donald R.
Published: February 2005

Previous work from our laboratories has established that eruption of the permanent mandibular premolars in dogs is dependent upon the presence of the dental follicle and that it involves resorption of alveolar bone and the roots of the deciduous predecessor above and formation of alveolar bone below the developing crown. This study illustrates the topography of the bone surfaces of the crypt by scanning electron microscopy and the ultrastructure of the cells on alveolar bone surfaces during tooth eruption. Above the developing crown where the eruption pathway forms, the bone surface is a pitted sheet, the characteristic topographic feature of bone resorption; between the crown and the mandibular canal, the bone surface has numerous interconnecting trabeculae. Transmission electron microscopy of bone cells lining the eruption pathway area of the crypt showed numerous osteoclasts with adjacent mononuclear cells. Both cell types contained specific, membrane‐bound cytoplasmic vesicles shown by the work of others to be characteristic features of osteoclasts and their precursors. Basal trabeculated bone in the crypt was covered by plump osteoblasts. These data show that the metabolic events in alveolar bone associated with tooth eruption have the appropriate cellular and bony surface correlates and that the suspected control of alveolar bone resorption by the dental follicle may be mediated by its recruiting and directing to adjacent bone surfaces the mononuclear precursors of osteoclasts.
Expression of nuclear estrogen‐binding sites within developing human fetal vagina and urogenital sinus
Authors: Taguchi Osamu , Cunha Gerald R. , Robboy Stanely J.
Published: February 2005

An autoradiographic study of nuclear estrogen binding was performed in developing human urogenital sinuses and vaginas derived from first and second trimester specimens. Nuclear estrogen binding was detected in all specimens ≥ 10 weeks of gestation within mesenchymal cells. Nuclear labelling within epithelium was observed only in those specimens whose development and differentiation was advanced. Thus, mesenchyme appears to be the initial estrogen target tissue within the developing human vagina and may play a fundamental role in estrogen‐induced teratogenesis of the human genital tract.
Ultrastructure of the giant cell infiltrate of subcutaneously implanted bone particles in rats and mice
Authors: Popoff Steven N. , Marks Sandy C.
Published: February 2005

The giant cells of soft tissues and those of mineralized tissues (osteoclasts) have distinctly different cell surface receptors and ultrastructural characteristics. Recently, the removal of dead bone particles in a subcutaneous environment has been described as a prototype of bone resorption, and a major issue is whether the giant cells that surround these ectopic bone implants and the processes involved in the disruption of bone surfaces are the same as those in the skeleton. We have compared the cytology and ultrastructure of giant cells recruited to subcutaneously implanted isogeneic bone particles with similar features of osteoclasts in metaphyseal bone of young normal rats and mice. Giant cells on surfaces of bone particles 2, 3, and 4 weeks after implantation were multinucleated, had a homogeneous, nonvacuolated cytoplasm, and had a bone surface interface unremarkable by light microscopy. In a few cells randomly distributed, small cytoplasmic vacuoles were present and large vacuoles were noted next to the bone surface at high magnification. By transmission electron microscopy, folded membrane configurations forming extensive interdigitations with adjacent cells were prominent features on most surfaces of giant cells. In instances where these interdigitations abutted bone surfaces, configuration resembling a ruffled border were noted, but these regions were always part of two different cells when examined at lower magnification or in serial sections. Breakdown of bone particles appeared to be by phagocytosis of small pieces and subsequent intracellular digestion in electron‐dense cytoplasmic vacuoles. Osteoclasts from these same young animals were smaller with fewer nuclei, had cytoplasmic vacuoles concentrated next to bone surfaces, and had characteristic ruffled borders and clear zones. These results confirm those of others that native osteoclasts and multinucleated giant cells on dead bone particles are distinctly different with respect to both ultrastructure and mechanism of disruption of bone surfaces.