bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of intermediate filaments and actins in human dental pulp and embryonic dental papilla
Authors: Lombardi T. , Samson J. , Mühlhauser J. , Fiore‐Donno G. , Maggiano N. , Castellucci M.
Published: February 2005

The localization of different cytoskeletal proteins (keratin, vimentin, desmin, actin, and α‐smooth muscle actin) was examined by immunohistochemistry in normal human adult dental pulp and compared with dental papilla of tooth germs. Keratin and actin were localized in enamel organ. Vimentin and actin were observed in the dental papilla and in the adult dental pulp. Desmin and α‐smooth muscle actin were present only in the vessel walls. These data are discussed paying particular attention to the origin and the peculiar functional characters of the dental papilla and pulp.© Willey‐Liss, Inc.
Organization of the optic chiasm in the hatched chick
Authors: Drenhaus U. , Rager G.
Published: February 2005

In the hatched chick the fibers of the two optic nerves segregate into clearly defined bundles when they cross to the other side. These bundles run in horizontally oriented tiers. The tiers are demarcated by blood vessels and pial tissue. The organization of these tiers was investigated qualitatively and quantitatively using light and electron microscopy as well as tracer techniques. The fibers within the tiers cross to the contralateral optic tract without leaving their respective tier. The mean total number of tiers is 34 with a great individual variation. A preference in the superposition of one side over the other could not be observed. Comparing these data with our earlier study (Rager et al.: Anat. Embryol., 179:135–148, 1988) it can be concluded that neither the segregation of fibers into discrete bundles nor the variability in the number of alternating tiers seem to disturb the topography of fibers as it is achieved in the optic nerve. The pattern of vascularization correlates with the order of crossing axon bundles and contributes to the demarcation of the tiers. The chiasm is vascularized by the Aa. preopticae and the A. infundibularis.© Willey‐Liss, Inc.
Heterogenous distribution of glycoconjugates in the kidney of dogfish Scyliorhinus caniculus (l.) with reference to changes in the glycosylation pattern during ontogenetic development of the nephron
Authors: Hentschel Hartmut , Walther Paul
Published: February 2005

Eight fluorochrome‐coupled lectins with different sugar specificities were applied to cryosections of dogfish kidney. Despite profound differences in renal architecture between clasmobranch fish and other vertebrates, the sequence of nephron segments as revealed by the lectin‐binding pattern was rather similar to that of tetrapodes. Wheat germ agglutinin (WGA) bound to cell membranes of epithelial cells of glomeruli, proximal and distal tubules, their basement membranes, the collecting tubule, and epithelial cells. Among other broadly binding lectins were Ricinus communis agglutinin I (RCA‐I), soybean agglutinin (SBA), peanut agglutinin (PNA), Lycopersicon esculentum agglutinin (LEA), and Jacalin, all of which marked proximal as well as distal portions of the renal tubule. Dolichos biflorus agglutinin (DBA) did not react with any renal structure. Ulex europaeus agglutinin I (UEA‐I), which indicates the presence of α‐L‐fucose, very strongly and specifically marked single epithelial cells of the early distal nephron, all epithelial cells of the late distal tubule, the beginning of the collecting tubule in the mesial tissue zone, and single cells in the end portion of the collecting tubule in the lateral bundles. Binding of UEA‐I to receptors of distal nephron cells could be useful for the identification of these cells in functional studies employing teased tubule and/or isolated cell preparations. Binding of UEA‐I to dogfish kidney structures resembles staining with UEA‐I conjugates of late distal tubules and collecting tubules in the kidneys of frog and other, higher vertebrates. Epithelial cells of early developmental stages showed, very rarely, binding sites for most lectinfluorochrome conjugates. A large number of lectin binding sites was observed in the extracellular matrix of fibroblast layers surrounding the early anlage and the S‐shaped body. Lectin binding sites of the nephron epithelia appeared in a sequential manner in the next stages of development of the nephron. Ontogenetic and phylogenetic aspects of the merging region between nephron proper (late distal tubule) and collecting system (collecting tubule) are discussed. © 1993 Wiley‐Liss, Inc.
Localization of a biotinylated cathepsin B oligonucleotide probe in human prostate including invasive cells and invasive edges by in situ hybridization
Authors: Sinha Akhouri A. , Gleason Donald F. , Deleon Onofrea F. , Wilson Michael J. , Sloane Bonnie F.
Published: February 2005

The cysteine endopeptidase cathepsin B (CB) can degrade basement membrane (BM) proteins (such as laminin, type IV collagen, and fibronectin) at both acid and neutral pHs suggesting that CB has a role in tumor invasion and distant metastasis. The distribution and intensity of CB protein localization vary in normal prostate, benign prostatic hyperplasia (BPH), and neoplastic prostate. These considerations have led us to examine whether the distribution of CB localization in malignant and normal cells is due to storage or active synthesis of CB. In the present study, we examined the localization patterns of CB at the mRNA level in normal prostate, BPH, and well to moderately differentiated neoplastic prostate, focusing on invasive groups of cells and invasive edges of malignant tumors. We used a 25‐base biotinylated oligonucleotide CB cDNA “sense” probe to localize CB message in prostate samples obtained from radical prostatectomies. We have determined that CB is actively synthesized by the epithelia of normal, hyperplastic, and neoplastic prostate including some invasive cells in the invasive edges. In both normal and BPH, CB mRNA was localized predominantly in acinar basal cells with some localization in cuboidal/columnar cells. In contrast, in neoplastic prostate, CB mRNA was localized predominantly in columnar cells and in groups of invasive cells and invasive edges. Thus, in malignant prostate the predominant cell types expressing CB differed from those of the normal prostate and BPH. Analysis of CB mRNA localizations indicated a heterogeneity in staining distribution in prostate cancer with some invasive groups of cells and invasive edges exhibiting CB mRNA and others exhibiting little or no reaction products. Using CB as a marker, we have been able to define invasive edges and invasive cells which may be actively involved in tumor progression. The potential ability to distinguish between malignant and nonmalignant foci and edges via localization of CB within the prostatic extracellular matrix may improve diagnosis and treatment of some higher grade tumor patients. This is especially important since histologic differentiation patterns of moderately to poorly differentiated human prostatic adenocarcinoma often do not differentiate between malignant and nonmalignant foci and edges in predicting aggressive behavior and course of the disease in patients. This is the first localization of cathepsin B mRNA in human prostate and its tumors. © 1993 Wiley‐Liss, Inc.
Proliferative and structural differences between male and female mouse submandibular glands
Authors: Chai Yang , Klauser Donna K. , Denny Patricia A. , Denny Paul C.
Published: February 2005

Sexual dimorphism has been observed in salivary glands of many species. In this study, evidence for sexual differences in adult mouse submandibular gland is extended beyond parenchymal cell composition, size, and volumes to include patterns of DNA synthesis and complexity of ductal branching. Computer‐assisted three‐dimensional reconstructions also revealed differences in overall organization of secretory complexes. Consistent with observations by others, granular intercalated duct cells were absent, while striated granular duct cells were low in proportion in the male glands relative to female glands. When the mean of average cell volumes were compared, acinar (AC) cells were smaller than granular duct (GD) cells in the male, but in the female the reverse was true. Furthermore, in addition to differences in average volumes of GD cells, the average volume of AC cells was significantly greater in females than males. The most dramatic evidence for sexual dimorphism was observed following a 90‐min labeling with 3H‐thymidine. Though all cell types showed DNA replication activity, the intercalated duct (ID) cells were substantially more active than AC and GD cells in the female, while in the maléeA the GD cells, ID cells, and AC cells all showed approximately equal activity. Three‐dimensional reconstructions indicated that the female possessed a more highly branched intercalated duct system and that the GD usually terminated within a secretory complex, whereas in males the GD typically passes through a secretory complex and forms a prominent cap‐like structure on the opposite side. © 1993 Wiley‐Liss, Inc.
Eosinophilic granulopoiesis in human fetal liver
Authors: Sohn Dong‐Suep , Kim Kyung‐Yong , Lee Won‐Bok , Kim Dong‐Chang
Published: February 2005

Eosinophilic granulopoiesis was investigated in human fetal liver during intrauterine life from 5 to 34 weeks of gestation. Eosinophilic granulocytes were observable for the first time at 5 weeks in the hepatic laminae and were frequently found in the late embryonic period around the large vessels and in the mesenchyme adjacent to the liver. Eosinophilic granulopoiesis increased gradually in the hepatic laminae (P < 0.01) after 20 weeks of gestation and in the portal areas (P < 0.05) after 16 weeks of gestation. The proportions of each cellular differentiation stage were relatively constant during fetal life, but a greater number of mature eosinophils were observed in the portal areas. Eosinophilic granulopoiesis was evident in all the hepatic tissue components, but developed more actively in portal areas than in hepatic laminae during intrauterine life. Eosinophilic granulopoiesis preceded both erythropoiesis and megakaryopoiesis in the human embryonic liver. Although the latter two occurred mainly in the hepatic laminae, eosinophilic granulopoiesis developed more actively in the portal areas, where it exhibited increasing activity along with the development of the component cells. © 1993 Wiley‐Liss, Inc.
Intercellular communication within the rat anterior pituitary gland: V. Changes in cell‐to‐cell communications as a function of the timing of castration in male rats
Authors: Nishizono Hisanori , Soji Tsuyoshi , Herbert Damon C.
Published: February 2005

Cell‐to‐cell communication by gap junctions was investigated in the male rat anterior pituitary gland following several experimental regimens involving castration. The regimens included the following animals: (1) Group 1, castrated at 10‐day intervals from day 10 to 50 and sacrificed at 60 days of age; (2) Group 2, castrated every 10 days from days 10 to 50 and sacrificed 50 days after castration; (3) Group 3, castrated at 5 days of age and sacrificed every 10 days from day 10 to 60; or (4) Group 4, remained intact and sacrificed every 10 days from days 10 to 60. In all of the castrated animals, numerous so‐called castration cells were scattered throughout the pars distalis of the pituitary gland, with occasional “signet ring cells” being observed. In Groups 1 and 2, the pattern of gap junction development and their number was no different from the intact control (Group 4). In contrast, the number of gap junctions in the animals castrated on day 5 remained very small even into adulthood. These data demonstrate that gonadal steroids are important in the intial development of gap junctions within the pituitary gland but are not necessary to sustain their presence once an animal becomes an adult. © 1993 Wiley‐Liss, Inc.
Ultrastructure of the human anogenital “sweat” gland
Authors: van der Putte S. C. J.
Published: February 2005

A newly described type of cutaneous gland occurring in the human anogenital region was investigated in specimens from the vulva by electron microscopy. This gland, which is characterized by a long excretory duct opening at the skin surface, by a wide coiled secretory part with multiple lateral extensions in the form of diverticula and branches lined by a two‐layered pseudostratified of myoepithelium, and by a luminal layer of tall columnar cells with conspicuous “snouts”, could not be categorized as an eccrine, apocrine, or mammary gland. Electron microscopy confirmed its separate position by showing that the luminal layer of secretory cells with prominent cytoplasmic caps had elaborately folded lateral membranes, occasional canaliculi, and a large number of uniform electron‐lucent to moderately electron‐dense secretory granules as part of a probable merocrine secretion. The excetory duct showed a poorly developed cuticular border. This combination of ultra‐structural features is alien to the other tubular cutaneous glands. The function of this anogenital “sweat” gland remains obscure, but the presence of these granules suggests a secretion product that is different from that of other cutaneous glands. © 1993 Wiley‐Liss, Inc.
Isolation of chick primordial germ cells from stages 4–8 embryos
Authors: Matsumura George , England Marjorie A.
Published: February 2005

Chick embryo primordial germ cells (PGCs) stages 4–8 were manually isolated for the first time from the late hypoblast layer. They were confirmed to be PGCs by periodic acid‐Schiff (PAS) staining and examination by scanning electron microscopy (SEM). They were subsequently introduced onto a variety of artificial substrata. On two dimensional substrata, the cells change from a spherical shape covered with numerous microvilli to a rounded cell with a “skirt” of cytoplasm. Eventually a process projects from one side of the smooth cell.

On a three dimensional substrate the PGCs change from a spherical shape covered with numerous microvilli to a smooth surfaced cell with a long single process.

It is concluded that the PGCs which are originally spherical in situ in stage 4 alter their morphology both in vivo during their migration and in vitro studies. © 1993 Wiley‐Liss, Inc.
Long‐term selective culture of hamster pulmonary endocrine cells
Authors: Linnoila R. Ilona , Gazdar Adi F. , Funa Keiko , Becker Kenneth L.
Published: February 2005

We describe, for the first time, the development of a technique for a long‐term selective culture of endocrine (PE) cells from the lungs of normal animals. Epithelial cells were isolated from 1‐day‐old hamster lungs through mechanical and enzymatic dissociation with collagenase type II. Cells were then cultured in HITES medium which contained RPMI 1640, hydrocortisone, insulin, transferrin, estradiol, sodium selenite, and supplemented with 5% fetal bovine serum (FBS), or medium which contained HITES medium supplemented with bovine serum albumin, phosphoethanolamine, arginine vasopressin, bombesin, and 2% FBS (9N). HITES medium, originally developed for establishment and long‐term culture of human small cell lung cancer (SCLC) cell lines, allowed propagation of normal hamster PE cells up to 12 months as a mixed floating‐attached cell culture. No difference was noted in the results using HITES or 9N. By 3 months, 80% of the cultured cells contained characteristic dense‐core (endocrine type) granules. The cultured PE cells also expressed creatine kinase brain isoenzyme, and general NE markers including neuron specific enolase, and amine handling enzyme activity within the range of SCLC cell lines. Moreover, cultured PE cells contained and secreted immunoreactive calcitonin (iCT) which had a molecular profile similar to that of intact hamster lung. This long‐term culture technique should markedly assist in elucidating the role of PE cells in health and disease. © 1993 Wiley‐Liss, Inc.
Dynamics of epithelial cells in the corpus of the mouse stomach. IV. Bidirectional migration of parietal cells ending in their gradual degeneration and loss
Authors: Karam Sherif M.
Published: February 2005

The life story of parietal cells has been investigated in the corpus of the mouse stomach using electron microscopy and 3H‐thymidine radioautography. Parietal cells are scattered in the four regions of the unit. On the average 3.6 cells are in the pit, 6.2 in the isthmus, 5.6 in the neck, and 10.6 in the base. Parietal cells do not divide. They arise from partially differentiated pre‐parietal cells, which are believed to be derived in the isthmus from the three subtypes of granule‐free cells: undifferentiated cells, pre‐pit cell precursors, and pre‐neck cell precursors. Radioautography indicates that the transformation of granule‐free cells into pre‐parietal cells takes at least one day. The pre‐parietal cells, of which there are 0.6 per unit on the average, develop into parietal cells through three successive stages. Stage 1 is characterized by small immature cells that are identified by long apical microvilli. Stage 2 is characterized by larger cells, about one‐third the size of parietal cells, and by an incipient canaliculus and a few apical tubulovesicles. Stage 3 is characterized by the expansion of the canalicular and tubulovesicular systems as well as mitochondrial enlargement, which cause the pre‐parietal cell to gradually approach the size of, and eventually become, a parietal cell. This cell sequence mainly takes place in the isthmus, but may extend to the neck region.

Continuous infusion of 3H‐thymidine confirms that parietal cells originate in the isthmus and that they migrate in two directions: some go outward to the pit and the others migrate inward to the neck and eventually to the base. It has been estimated that for every six parietal cells produced per month in the isthmus, three migrate to the pit and three migrate to the neck to eventually reach the base.

While almost all parietal cells in the isthmus and neck appear normal, a large proportion of those reaching the pit (21%) and base (23%) undergo gradual alteration and degeneration. After the ensuing death, parietal cells are eliminated in one of two major ways: (1) extrusion into the gastric lumen, if they appear necrotic, or (2) phagocytosis by a neighboring cell or even by an invading connective tissue macrophage, if they are apoptotic. The overall turnover time of parietal cells averages 54 days.

Briefly, a sequence of cells—the parietal cell lineage—is initiated in the isthmus, where the three subtypes of granule‐free cells are presumed to give rise to pre‐parietal cells, which then differentiate into parietal cells. Half of the parietal cells migrate away in the direction of the gastric lumen and gradually degenerate as they approach the free surface, while the other half migrate in the other direction toward the unit's blind end, where they degenerate and are eliminated. © 1993 Wiley‐Liss, Inc.
Tapering of the intrafascicular endings of muscle fibers and its implications to relay of force
Authors: Eldred E. , Ounjian M. , Roy R. R. , Edgerton V. R.
Published: February 2005

The geometric shape of the filamentous, intrafascicular type of muscle fiber ending was reconstructed as a basis for understanding the pattern in relay of the fiber's force to the muscle tendon. Single motor units (MUs) identified physiologically as being fast and slow, respectively, were isolated in cat tibialis muscles and glycogen‐depleted for recognition in cross sections of the muscle frozen at its Lo. Serial measurements of cross‐sectional area (CSA) using an image processing system were made along 14 intrafascicular endings of MU fibers and an additional seve, nondepleted fibers identified histochemically as slow. Comparison of coefficients of variation for the linear relation of the CSAs and of the equivalent diameters with length along the taper indicated that in both fast and slow fibers the areas bore a closer relationship, that is, the taper had the equivalent of a parabolic, rather than a conical outline. The implications of these two conformations to relay of the fiber's contractile force to surrounding structures are displayed graphically. © 1993 Wiley‐Liss, Inc.
Long‐term osteopenic changes in cancellous bone structure in ovariectomized rats
Authors: Miller S. C. , Wronski T. J.
Published: February 2005

Cancellous bone mass decreases following ovariectomy in rodents, providing a useful model for post‐menopausal bone loss in humans. This study describes and quantifies the longer‐term changes in cancellous bone structure in the ovariectomized (OVX) rat. Rats were OVX or sham‐OVX at 100 days of age and bones were collected 540 days later. Lumbar vertebral bodies were prepared for microradiography and structural analyses (nodal analyses and star volume analyses) of cancellous bone. Proximal humerii were prepared for scanning electron microscopy (SEM). Microradiography confirmed the loss of cancellous bone from the central spongiosa regions of the vertebral bodies and the humerii in the OVX rats. Changes in trabecular structural elements included relative increases in the number of free to free, cortical to free, cortical to node struts and decreases in the node to node struts in the OVX animals compared with controls. There were increases in average lengths of the node to free, node to node, and free to free trabecular struts in the OVX animals. The marrow star volume was increased in the OVX animals indicating a greater trabecular separation in these animals compared with controls. Viewed by SEM, metaphyseal trabeculae in the controls consisted of rods and plates but in the OVX animals the remaining trabeculae were mostly longitudinal rods with smaller transverse connecting rods. The remaining bone in the OVX animals was found in the lateral metaphyseal areas and is consistent with maintenance of the structural capacity of the bone. These long‐term changes in cancellous bone structure are likely due to the continuation of functional skeletal loading but a decrease in gonadal hormones resulting in a decreased necessity to maintain a skeletal mineral store for reproduction (e.g., pregnancy and lactation). © 1993 Wiley‐Liss, Inc.
Cardiac conduction system in the chicken: Gross anatomy plus light and electron microscopy
Authors: Lu Ying , James Thomas N. , Yamamoto Shoji , Terasaki Fumio
Published: February 2005

Twenty‐three chicken hearts were used to study the cardiac conduction system by light and electron microscopy. In addition to a sinus node, atrioventricular node (AVN), His bundle, left and right bundle branches (LBB, RBB), the chicken also has an AV Purkinje ring and a special middle bundle branch (MBB). The sinus node lies near the base of the lower portion of the right sinoatrial valve. The AV node is just above the tricuspid valve and anterior to the coronary sinus. The His bundle descends from the anterior and inferior margin of the AV node into the interventricular septum, then dividing into right, left and middle branches some distance below the septal crest. The middle bundle branch turns posteriorly toward the root of the aorta. The AV Purkinje ring originates from the proximal AV node and then encircles the right AV orifice, joining the MBB to form a figure‐of‐eight loop. The chicken conduction system contains four types of myocytes: (1) The P cell is small and rounded, with a relatively large nucleus and sparse myofibrils. (2) The transitional cell is slender and full of myofibrils. (3) The Purkinje‐like cell resembles the typical Purkinje cell, but is smaller and darker. (4) The Purkinje cell is found in the His bundle, its branches, and the periarterial and subendocardial Purkinje network. © 1993 Wiley‐Liss, Inc.
Vascularization of the pineal complex in the lizard Tiliqua rugosa
Authors: Teo E. H. , Carati C. , Firth B. T. , Barbour R. A. , Gannon B.
Published: February 2005

The vascularization of the pineal complex in the lizard Tiliqua rugosa was investigated by vascular corrosion and latex casting techniques. The fine structure of the pineal capillaries was also studied by transmission electron microscopy. The pineal complex in T. rugosa consists of an elongated pineal gland proper and a separate, distinct parietal eye. The pineal complex derives an abundant blood supply from branches of the middle and posterior cerebral arteries. Scanning electron microscopy of vascular corrosion casts revealed a dense and extensive pineal capillary bed which drains ultimately into a wide longitudinal sinus suggesting an efficient pathway for the rapid removal of substances secreted by the gland. The parietal eye, which receives a unilateral left‐sided blood supply from the unpaired anterior pineal artery, is shown to be a highly vascularized structure. The close morphological relationship between the pineal gland and dorsal sac, where the two structures apparently share the same blood vessels, suggests a functional relationship between them. The pineal capillaries are fenestrated with tight junctions between adjoining endothelial cells. Podia‐like abluminal extensions of the endothelial cells were observed in close relation to unmyelinated nerve bundles. The basal margin of the pineal parenchyma is highly invaginated with thin finger‐like cytoplasmic protrusions into the pericapillary space. Distinct bands of microfibrils form “struts” anchoring the pineal parenchyma to the endothelial wall. These features may have a role in the transfer of materials between the pineal gland and the blood stream. © 1993 Wiley‐Liss, Inc.
Effects of pretreatment with androgen or thyrold hormone on androgen‐induced proliferation of granular convoluted tubular cells in mouse submandibular glands
Authors: Fang Jun , Yamamoto Reiko , Takatsuka Daishiro , Tsuji Motomu , Terada Nobuyuki
Published: February 2005

The effects of pretreatment with androgen or thyroid hormone on androgen‐induced proliferation of granular convoluted tubular cells (GCT cells) in the submandibular glands of ovariectomized female BALB/c or C57BL/6 mice were investigated. The proliferation of GCT cells was estimated by their labeling index. Daily injections of 5α‐dihydrotestosterone (DHT) (100 μg/mouse/day) caused a transient increase in the labeling index of GCT cells of ovariectomized 60‐day‐old BALB/c mice during the first four injections, but injections of thyroxine (T4) (15 μg/mouse/day) did not. On the other hand, both DHT and T4 increased the esteroprotease activity, a marker of the differentiation of GCT cells, time dependently. Injections of DHT into ovariectomized 102‐day‐old BALB/c mice also caused a transient increase in the labeling index of GCT cells. However, pretreatment of ovariectomized 60‐day‐old BALB/c mice with DHT for 4 or 14 days completely abolished the DHT‐induced increase in the labeling index of 102‐day‐old mice, and pretreatment with T4 for 14 days reduced this increase. Pretreatment with DHT or T4 for 14 days did not affect the DHT‐induced increase in esteroprotease activity. Pretreatment of ovariectomized 60‐day‐old C57BL/6 mice with DHT for 14 days also completely abolished the DHT‐induced increase in the labeling index of GCT cells at the age of 102 days, but pretreatment with T4 for 14 days did not affect the increase. These results suggest that the proliferation of mouse GCT cells induced by androgen results in a complete abolition of their proliferative response to androgen, and that the effect of thyroid hormone on the proliferative response of GCT cells to androgen may differ in different strains of mice. © 1993 Wiley‐Liss, Inc.
Innervation distribution pattern, nerve ending structure, and fiber types in pigeon skeletal muscle
Authors: Torrella J. R. , Fouces V. , Palomeque J. , Viscor G.
Published: February 2005

Four fiber types have been characterized in different pigeon skeletal muscles according to their innervation pattern (nerve ending structure and innervation distribution) and histochemical properties (SDH and m‐ATPase activities). All fast fibers, types IIA and IIB, present aggregated distribution of their nerve endings with “en plaque” structures and very low innervation frequencies. The two kinds of slow fibers recognized are multiple innervated and present higher innervation frequencies. However, type I fibers have nerve terminals in small knobs with uniform localization, whereas type III fibers present “en grappe” nerve endings, which tend to be randomly distributed. Fiber type composition of skeletal muscles has been found closely related to their biomechanical function. Fast fibers are predominant in muscles with an active role in locomotive movements, whereas slow fibers are mainly or exclusively located in postural muscles. © 1993 Wiley‐Liss Inc.
Effects of chronic fluoride exposure on morphometric parameters defining the stages of amelogenesis and ameloblast modulation in rat incisors
Authors: Smith Charles E. , Nanci Antonio , Denbesten Pamela K.
Published: February 2005

The response of ameloblasts to long‐term (6 weeks) exposure to 100 ppm fluoride was examined in continuously erupting mandibular incisors of female Sprague‐Dawley rats as compared to control rats receiving a similar diet (Teklad L‐356) but no sodium fluoride in their drinking water. After treatment, animals from both groups were perfused intravascularly with glutaraldehyde, and the incisors were removed and processed for light microscope morphometric analyses directly from 1 μm thick Epon sections. Other animals were injected intravenously with calcein (green fluorescence) followed 4 hours later by xylenol orange (red fluorescence) in order to reveal smooth‐ended ameloblast modulation bands and thereby allow quantification of parameters related to the creation and movement of modulation waves within the maturation zone of these teeth. The results indicated that rat incisors expressed four major changes in normal amelogenesis which could be attributed to the chronic fluoride treatment. First, ameloblasts produced a thinner than normal enamel layer by the time they completed the secretory stage and entered the maturation stage of amelogenesis. Second, enamel organ cells within the maturation zone, especially those from the papillary layer, were shorter in height than normal. Third, ameloblasts related to maturing enamel in areas where it was partially soluble and/or fully soluble in EDTA modulated at a rate that was much slower than normal. In some locations ameloblasts remained ruffle‐ended for as much as 30% longer than normal per cycle. This upset the usual pattern such that fewer total modulation cycles were completed per unit time by these ameloblasts. Fourth, enamel proteins were lost from the maturing enamel layer at a rate that was about 40% slower than normal. The data suggested that ameloblasts detected the delay in the extracellular breakdown and/or loss of enamel proteins and they responded by remaining ruffle‐ended for longer intervals than usual (positive feedback). © 1993 Wiley‐Liss Inc.
Presence and foveal enrichment of rod opsin in the “all cone” retina of the American chameleon
Authors: McDevitt David S. , Brahma Samir K. , Jeanny Jean‐Claude , Hicks David
Published: February 2005

The retinal photoreceptors of the eye of the American chameleon, Anolis carolinensis, have been considered to be exclusively cones. Its retina is unusual for possessing two foveas (areas associated with heightened visual acuity), with the major, central fovea deeply incised and very densely packed with photoreceptors. Immunoblotting and light‐ and electron microscopic‐immunocytochemistry, using several opsin monoclonal antibodies previously found specific for rods, demonstrated the presence and localization of this protein in the Anolis retina. This visual pigment appears sparsely in a subpopulation of photoreceptors in the periphery but overwhelmingly in the central fovea. Complementary results with cone‐specific antibody and lectin binding corroborated this spatial organization. These results, as well as those with geckos, suggest that photoreceptor morphology is not an accurate guide among the lacertilians to visual pigment content, and that this phylogenetic grouping may constitute a crossoads in vertebrate photoreceptor evolution. © 1993 Wiley‐Liss, Inc.
Immunohistochemical localisation of the 25 kDa heat shock protein in unstressed rats: Possible functional implications
Authors: Wilkinson Jenny M. , Pollard Irina
Published: February 2005

The distribution of the 25 kDa heat shock protein (hsp 25) in a number of tissue types from unstressed rats was investigated. Immunohistochemical analysis showed that hsp 25 was not found in the thymus, brain (cerebral cortex and cerebellum), testis, adrenal, liver, spleen, or kidney. A number of cells in the anterior pituitary showed strong staining. These cells were tentatively identified as being either gonadotropes or thyrotropes. Strong staining was also observed in the blood vessels within these tissues. Hsp 25 was found to be localised predominantly to intestinal smooth muscle of the duodenum and colon and to vascular smooth muscle. Smooth muscle from other sites, such as the trachea, was also intensely stained. Lower and more variable amounts of staining were observed in cardiac and skeletal muscle. These observations suggest that hsp 25 is associated with cytoskeletal elements in muscle, and that the high staining intensity in smooth muscle might be due to the lack of internal architecture present in this muscle type. © 1993 Wiley‐Liss, Inc.
Characterization of distal lymphoid nodules in the chicken caecum
Authors: del Cacho Emilio , Gallego Margarita , Sanz Albina , Zapata Agustin
Published: February 2005

In this report, we describe lymphoid nodules consistently found in the distal region of each chicken caecum at approximately 3 cm from the ileo‐cecal junction. These structures were studied by light microscopy both in normal and Eimeria tenella‐infected chickens. They were observed with the naked eye in infected birds but not in normal chickens. In these latter the region of the caecal lamina propria corresponding to that in which the lymphoid aggregates were visible revealed a light infiltration by diffuse lymphoid tissue as well as a few germinal centers. The distal lymphoid nodules were studied using a panel of monoclonal antibodies which are specific for chicken Ig‐containing cells, macophages, Ia‐like positive cells, and interdigitating cells, as well as a policlonal antiserum reactive with S‐100 protein to stain both interdigitating cells and follicular dendritic cells. The immunohistochemical study demonstrated the resemblance of these aggregates to the caecal tonsils, suggesting that they represent specialized mucosa‐associated lymphoid tissue that respond to antigens in the caecal lumen, their function being to enhance the mucosal defense provided by the caecal tonsils against antigens in the lumen of the caeca. © 1993 Wiley‐Liss, Inc.
Prolonged exposure of human chondrocytes to ascorbic acid modifies cellular behavior in an agarose gel
Authors: Aulthouse Amy Lynn
Published: February 2005

Using an agarose gel culture system, the response of adult human chondrocytes to prolonged exposure of ascorbic acid was evaluated using histochemical, immunocytochemical and morphological techniques. The response of these cells to ascorbic acid was different from those previously reported in the literature. Many chondrocytes branched within the agarose gel with continued exposure to ascorbic acid while other chondrocytes maintained a round configuration typical of chondrocytes in vivo. Fibronectin and type I collagen were closely associated with the cell processes of the branching cells. Type II collagen and an alcian blue‐staining matrix were associated with the rounded cells but not with the branched cells. These data suggest that the chondrocytes are able to express both dedifferentiated and redifferentiated phenotypes with ascorbic acid under these culture conditions. In addition, human chondrocytes were cultured in a collagen gel and began branching within 1 hour of culture. It is possible that an accumulation of type I collagen in the pericellular matrix of ascorbic acid treated cultures may enhance and explain the branching seen in these cultures. Studies by others have indicated that ascorbic acid may enhance, reduce, and/or modify the cartilage matrices produced by chondrocytes. These controversial reports in the literature are presumably due to variations between species and the culture methods employed. © 1994 Wiley‐Liss, Inc.
Cephalic circulation in the air‐breathing snakehead fish, Channa punctata, C. gachua, and C. marulius (ophiocephalidae, ophiocephaliformes)
Authors: Munshi J. S. D. , Roy P. K. , Ghosh T. K. , Olson K. R.
Published: February 2005

The macrocirculation in the head of three air‐breathing species of Channa was examined with the aid of vascular corrosion replicas and a scanning electron microscopic study was conducted on the pseudobranch, choroid gland and lentiform body. Two facultative air‐breathing murrles, C. punctata and C. gachua, and one obligate air‐breather, C. marulius were examined. In all three, the air‐breathing organs (ABO) and systemic circulations were in‐parallel, and both were in‐series with the branchial circulation. Efferent branchial arteries from the first and second gill arches formed the arterial supply to the ABO, whereas the third and fourth arch efferents perfused systemic tissues. Postbranchial blood from the second gill arch also entered the systemic circulation directly via a shunt from the efferent branchial artery to the lateral aorta and via hypobranchial arteries. Vascular specialization to prevent mixing of oxygenated ABO venous and deoxygenated systemic venous blood was evident in arterial, but not venous circuits. Pseudobranchs of C. gachua and C. punctata are tri‐lobed, in C. marulius they have numerous lobules. Pseudobranch lamellae are wider and shorter along the axis of blood flow than gill lamellae and folded perpendicular to this axis. Pseudobranch lamellae appear to be modified to minimize their epithelial surface while retaining an extensive vascular endothelial‐pillar cell surface area, counter‐current amplification is also possible. The choroid gland is an extensive planar counter‐current capillary rete. The lentiform body of the eye is a globular capillary rete but there is no evidence of a counter‐current circulation. The choroid and lentiform rete may have distinct physiological functions. © 1994 Wiley‐Liss, Inc.
Initial vascularisation in the pig placenta: I. Demonstration of nonglandular areas by histology and corrosion casts
Authors: Dantzer Vibeke , Leiser Rudolf
Published: February 2005

The vascular interrelationship of the well‐established porcine placenta has previously been described from vascular casts and histology, but not its developmental stages. This study was peformed using the same methods on 17 sows of well‐known stages of gestation ranging from 9 1/2 to 43 days post coitum (p.c.). At the precontact stage, days 9 1/2 to 12 1/2 p.c., the subepithelial capillaries formed a wide open meshwork of variable diameter, 3–14 μm, without any difference between meso‐ and antimesometrial side. At the early contact and adhesion stages (days 13 to 18 p.c.), the first increase in vasculature was seen at the mesometrial side close to the embryonic disc of the very long blastocyst at day 15 p.c., 2 days after the first contact between trophoblast and maternal epithelium was seen. At day 18 p.c., the areas with dense capillaries increased markedly at the mesometrial side with the same parallel organization as seen at day 15 p.c., whereas the antimesometrial side still had a relative loose appearance comparable to the previous stages. At the early placental stages (days 20 1/2 to 23 p.c.), the capillary bed formed smooth folds, which in some areas at day 20 1/2 days developed into smaller folds or prerugae. Here the capillaries changed to convoluted forms with slightly bulbous dilations measuring about 30–35 μm in diameter. This developmental progress became more elaborate at day 23: capillaries of the low ridges of prerugae formed irregular dilations up to 50 μm in some areas. At this stage the parallel arrangement of the capillary meshwork characteristic of the previous stage was not longer discernable. By days 32–43 p.c., an increase in microscopic folding was present, and the maternal arterioles could be traced to the top of the ridges, creating the characteristic vascular architecture needed for an efficient exchange of oxygen, carbon dioxide, and nutrients of the basically developed porcine placenta. © 1994 Wiley‐Liss, Inc.
Tongue structure and function in Oplurus cuvieri (reptilia: Iguanidae)
Authors: Delheusy Véronique , Toubeau Gérard , Bels Vincent L.
Published: February 2005

The anatomy of the hyo‐lingual apparatus in the iguanid lizard Oplurus cuvieri has been studied by light microscopy and scanning electron microscopy. Four areas were observed on the dorsal lingual epithelium of the lizard. Tongue tips are covered with a smooth epithelium. Closely packed flattened and cylindriform papillae cover the foretongue. The surface of the midtongue bears an unpapillose epithelium. Short conical papillae are arranged on the two lateral posterior bundles of the tongue. At high magnification, microvilli and microridges are widely distributed over the surface of the papillae. The epithelium of the papillae is composed of cells filled with secretory granules. Each surface plays successive roles during food ingestion, intra‐buccal transport, and swallowing. The mucous interpapillary spaces would serve the adherence between the tongue and the food, the smooth epithelium of the midtongue should facilitate movements of the prey toward the pharynx, and conical papillae of the hindtongue present a rough surface which should act on the prey during the swallowing phase. The intrinsic morphology of the tongue is rather similar to that previously described for iguanids, but fibers of M. verticalis encircles ventrally the lingual process. These fibers could act in tongue protrusion as previously suggested for agamids. The morphology and function of the extrinsic tongue musculature and the hyoid musculature, analysed by electrical stimulations, are similar to the previous descriptions in iguanids and agamids either for feeding or displaying functions. © 1994 Wiley‐Liss, Inc.
Subdivision of the mitotic cycle into eleven stages, on the basis of the chromosomal changes observed in mouse duodenal crypt cells stained by the DNA‐specific feulgen reaction
Authors: El‐Alfy M. , Turner J. P. , Nadler N. J. , Liu D. F. , Leblond C. P.
Published: February 2005

The Feulgen reaction has been utilized to localize DNA in nuclei throughout the cycle of mouse duodenal crypt cells using Epon‐embedded 1 μm thick sections. The observed changes indicate that the 12.3 h long mitotic cycle of these cells can be subdivided into eleven stages, seven of which take place during the interphase. Computer measurements of Feulgen‐stained nuclei and previous radioautographic studies indicate that DNA synthesis begins during stage I and ends during stage IV. The staining pattern shows no distinctive feature in the nuclei of the 1.5 h long stage I. Thereafter, marked changes occur during the rest of the interphase—that is during the 6.3 h that precede karyokinesis and the 3.5 h that follow it. Thus, at stage II the background of the nuclei darkens; at stage III, there appear stained threads interpreted as densifying chromosomes and dots interpreted as chromomeres, both of which thicken from 0.2 to 0.4 μm; at stage IV they further thicken to about 0.5 μm and at stage V, to about 0.7 μm. At this stage, which approximately corresponds to prophase, the intensely stained, discrete dots are localized within the less intensely stained sausage‐shaped threads. As the breakup of the nuclear envelope introduces stage VI, whose early part corresponds to prometaphase, the intensely stained dots become close to one another within the threads and eventually fuse. The staining of the threads thus intensifies, and, by the late part of the stage that corresponds to metaphase, they have become the homogeneously dense metaphase chromosomes. At stage VII, the anaphase chromosomes reach each pole where they associate into a compact mass. This mass remains solid at stage VIII but gradually dissociates during stages IX, X, and XI as chromosomes are disassembled. © 1994 Wiley‐Liss, Inc.
Lymphatic capillaries of the pig lung: TEM and SEM observations
Authors: Marchetti C. , Poggi P. , Clement M. G. , Aguggini G. , Piacentini C. , Icaro‐Cornaglia A.
Published: February 2005

Pulmonary lymphatic vessels extend within the connective tissue sheets surrounding airways and blood vessels. Frequently in this location they also border the lobular parenchyma, but no lymphatic vessels have been found within intralobular compartments between blood capillaries and alveoli. The presence and distribution of lymphatic vessels in pulmonary tissue are consistent with an important role for the lymphatic system in the clearance of interstitial fluids in the lung. Pulmonary lymphatic channels have structural characteristics of initial lymphatics; their walls are formed only by an endothelial layer, and no muscular cells are present. A network of anchoring filaments and collagen and elastic fibers surrounds the vessel walls. Because the lung is a mobile organ the tissue undergoes compression and distension during respiratory phase. These modifications could have a role in the mechanisms for lymph formation and flow. © 1994 Wiley‐Liss, Inc.
Pulmonary hypoplasia associated with reduced thoracic space in mice with disproportionate micromelia (DMM)
Authors: Foster Meredith J. , Caldwell Angela P. , Staheli John , Smith David H. , Gardner John S. , Seegmiller Robert E.
Published: February 2005

Background: Fetal mice homozygous for the Disproportionate micromelia (Dmm) gene were studied as a model for pulmonary hypoplasia in chondrodystrophy.

Methods: Wet weight, dry weight, and biochemical content were determined in excised whole lungs, terminal sac morphology and presence of multilamellar bodies were determined by electron microscopy, and volume of the thoracic space was estimated from paraffin casts. Lung development of the mutant was further assessed in whole organ culture.

Results. Compared with normal littermates, the mutant showed a significant decrease (28%) in lung wet weight without showing altered lung dry weight or tissue content of DNA and protein. The terminal sacs of lungs fixed by intratracheal instillation were significantly smaller than normal. However, the lungs appeared to have undergone maturation on schedule since the surfactant precursors, multilamellar bodies, were observed and normal tissue‐levels of phospholipid were detected. The volume of the mutant's thorax was markedly reduced. Finally, the mutant's lungs when removed from the fetus prior to the onset of thoracic dystrophy (day 15) and cultured for three days demonstrated that, without the confining influence of a reduced thoracic space, they are capable of development comparable to normal.

Conclusions: These findings support the hypothesis that the Dmm mutant can be further studied as a model for human pulmonary hypoplasia associated with chondrodystrophy, and that the relationship between the reduced thorax and the lung disorder is cause‐and‐effect. © 1994 Wiley‐Liss, Inc.