bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell biology of pulmonary neuroepithelial bodies—validation of an in vitro model. I. Effects of hypoxia and Ca2+ ionophore on serotonin content and exocytosis of dense core vesicles
Authors: Cutz Ernest , Speirs Valerie , Yeger Herman , Newman Charlotte , Wang Dashou , Perrin Donald G.
Published: February 2005

Pulmonary neuroendocrine (NE) cells including the innervated clusters of NE cells—neuroepithelial bodies (NEB)—are difficult to study because of their small numbers and diffuse distribution within the airway mucosa of the lung. We have previously reported a method for isolation and culture of NE cells from rabbit fetal lung using a combination of mechanical and enzymatic dissociation followed by gradient centrifugation. This method provides single cell suspension of mixed lung cells enriched in NE cells, particularly those originating from NEB.

This study further validates our in vitro model by detailed morphologic characterization of cultured NEB cells using high resolution light microscopy, transmission and scanning electron microscopy, HPLC for detection of serotonin (5‐HT), and molecular (Northern blot) analysis of mRNA encoding for 5‐HT synthesizing enzymes, tryptophane hydroxylase, and aromatic L‐amino acid decarboxylase. In addition to effects of hypoxia on NEB cells in vitro were investigated to define the role of these cells as possible airway chemoreceptors. Exposure of NEB cultures to hypoxia resulted in decreased intracellular content of 5‐HT accompanied by increased exocytosis of dense core vesicles (DCV). The amount of 5‐HT release correlated with the degree of hypoxia, suggesting modulation by ambient pO2 levels. The role of Ca2+ ions in exocytosis of DCV and 5‐HT release from NEB cells was tested in experiments with Ca2+ ionophore (A23187). Exposure of cultures to 5 μg/ml of ionophore resulted in up to 40% reduction in 5‐HT content of NEB cultures as well as increased exocytosis of DCV.

Our overall findings are consistent with a view that NEB cells are chemosensory in nature and that Ca2+ signaling pathway is involved in stimulus‐secretion coupling. Further refinements in cell separation and culture methodology are required before more detailed investigation of NEB cell membrane properties, signal transduction mechanisms, and intracellular signaling pathways can be carried out. © 1993 Wiley‐Liss, Inc.
Neuroendocrine cell populations in postnatal human lungs: Minimal variation from childhood to old age
Authors: Gosney John R.
Published: February 2005

Although changes in the human pulmonary neuroendocrine system have been described in association with a variety of pulmonary disease, little is known of how the system changes with age in healthy lungs. As delineated by their immunoreactivity for neuron‐specific enolase, protein gene product 9.5 and chromogranin A, the density of the system's component cells in terms of the rest of the pulmonary epithelium varied minimally between 10 groups of subjects divided according to age and ranging from children to nonagenarians, figures for the groups varying only between 2.91 and 4.19 neuoendocrine cells per 10,000 epithelial cells. In only three subjects were neuroendocrine cells found in the parenchyma; the vast majority were located in airways with about 65% in bronchi. Cells were more often arranged in the form of clusters in the younger subjects than in the elderly, in whom clusters were extremely rare, but the significance of this observation is unclear. © 1993 Wiley‐Liss, Inc.
Calcium and ionophore A23187 lower calcitonin gene‐related peptide‐like immunoreactivity in endocrine cells of organ cultured fetal rat lungs
Authors: Ebina Masahito , Hoyt Richard F. , Sorokin Sergei P. , McNelly Nancy A.
Published: February 2005

Small‐granule endocrine cells differentiate in airway epithelium of intact and cultured fetal rat lungs. We noted that the cells store calcitonin gene‐related peptide (CGRP) in vitro as well as in vivo and used the ionophore A23187 to test the effects of calcium on peptide secretion in this system. Lungs of 14‐day and 15‐day fetal rats, organ cultured for 6–9 days, were divided into groups of 5 explants each and incubated for 15 min at 37°C in the basic medium containing 0 mM, 1 mM, or 10 mM CaCl2, with or without 8 μM A23187, or 10 mM EGTA. Intracellular CGRP in these explants was quantified by supraoptimal dilution peroxidase immunocytochemistry (Springall et al.: J. Pathol. 155:259–267, 1988): counts were made of endocrine cells stained with a 1/60,000 dilution of anti‐CGRP and repeated on the same sections after restaining with antibody diluted at 1/1,000. Results, analyzed by Chi‐square test, were expressed as % cells stained with antibody at 1/60,000 vs. those stained at 1/1,000. Immunoreactivity for CGRP was significantly reduced by A23187 in the presence of high extracellular Ca2+ (10 mM), the inference being that these cells secrete peptide hormones in response to Ca2+ influx across the plasma membrane. The organ cultures evidently can be used to assess certain physiological responses of lung endocrine cells in an accessible, relatively organotypical setting. © 1993 Wiley‐Liss, Inc.
Dynamics of epithelial cells in the corpus of the mouse stomach. III. Inward migration of neck cells followed by progressive transformation into zymogenic cells
Authors: Karam Sherif M. , Leblond Charles Philippe
Published: February 2005

The neck cells (or mucous neck cells) present in the neck region and the zymogenic cells (or chief cells) present in the base region of the units in the mouse corpus were examined in the electron microscope (EM) and in radioautographs prepared after administration of 3H‐thymidine by single or multiple injections or by continuous infusion for 1–52 days. For these studies, the neck region of the units has been subdivided into three equal segments, respectively named high neck, mid neck, and low neck, while the base region has been similarly subdivided into high base, mid base, and low base.

The neck region includes an average of 12.6 neck cells, characterized in the EM by dark, mucous secretory granules that frequently exhibit a light, pepsinogenic core. Continuous 3H‐thymidine infusion reveals that neck cells come from pre‐neck cells, which are believed to arise in the isthmus region from the undifferentiated granule‐free cells through a pre‐neck cell precursor stage. The pre‐neck cells, characterized by the presence of a few cored secretory granules, migrate inward (i.e., in the direction of the blind end of the units) and enter the neck region to become neck cells. It is estimated that 59% of the neck cells arise from differentiation of pre‐neck cells, whereas the other 41% are derived from their own mitoses. Neck cells migrate inward in 1–2 weeks from the high through the mid and low neck segments, while they keep on producing more and larger secretory granules and thus further differentiate as mucus‐producing cells.

When neck cells reach the high base segment, they become pre‐zymogenic cells that produce secretory granules in which appear light, irregular, pepsinogenic patches which encroach on the dark mucous content. With time, the pre‐zymogenic cells, of which there are 5.0 per unit on the average, keep on producing new granules with larger and larger light patches, so that in the end the cells produce granules which are entirely filled by light, pepsinogenic material. At this stage, the cells are zymogenic cells.

Zymogenic cells, which average 67.5 per unit, further migrate inward, while gradually enlarging and producing pepsinogenic granules of increasing size. In the low base segment, some zymogenic cells show signs of degeneration leading to death by either necrosis or apoptosis. While remnants of the necrotic cells appear to be released to the unit lumen, the apoptotic cells are phagocytosed by a neighboring zymogenic cell or by a connective tissue macrophage breaking through the basement membrane of the oxyntic unit.

Briefly, the zymogenic cell lineage, a cell sequence initiated from the stationary undifferentiated granule‐free cells, includes pre‐neck cell pre‐cursors, pre‐neck cells, neck cells, pre‐zymogenic cells, and finally zymogenic cells, which all migrate in the direction of the unit's blind end, near which zymogenic cells are lost. © 1993 Wiley‐Liss, Inc.
Dynamics of epithelial cells in the corpus of the mouse stomach. V. Behavior of entero‐endocrine and caveolated cells: General conclusions on cell kinetics in the oxyntic epithelium
Authors: Karam Sherif M. , Leblond Charles Philippe
Published: February 2005

Entero‐endocrine cells and the rare cells named caveolated or brush cells have been examined in light microscopic radioautographs of the mouse corpus after various periods of continuous 3H‐thymidine infusion. Moreover a search for immature forms and mitoses of these cells was undertaken in the electron microscope.

Entero‐endocrine cells are present in the four regions of the epithelial units, but their number is low in the pit, intermediate in the isthmus and neck, and high in the base. The labeling pattern after continuous 3H‐thymidine infusion indicates that these cells are produced in the isthmus from undifferentiated granule‐free cells presumed to be the stem cells of the epithelium, and may retain a limited ability to divide. A few of the newly formed entero‐endocrine cells migrate to the pit, but the majority goes to the neck and, from there, to the base where they are present in relatively high numbers.

Little information is available on the dynamics of caveolated cells. Since immature forms are present in the isthmus and mature ones in the other regions, it is concluded that they arise in the isthmus and migrate away in both directions.

Finally, concluding remarks are presented on the kinetics of each one of the cell lineages described in this and the four previous articles. © 1993 Wiley‐Liss, Inc.
Bronchoalveolar casting using formalin‐fixed canine lungs and a low viscosity silicone rubber
Authors: Nettum John A.
Published: February 2005

A method for creating tough, flexible, bronchoalveolar casts from formalin‐fixed canine lung is described. A lung was washed using simple methods and fixed in 10% neutral‐buffered formalin. While still wet with formalin, an intact lobe was injected with silicone sealant, Silsastic 734 RTV (Room Temperature Vulcanizing), using a caulk gun. Following digestion with protease and corrosion with potassium hydroxide, a bronchoalveolar cast was recovered giving detail as shown using scanning electron microscopy or conveniently seen by stereo light microscopy. This method should be useful for micro‐anatomy studies of normal and diseased lungs. © 1993 Wiley‐Liss, Inc.
Development of innervation of skeletal muscle fibers in man: Relation to acetylcholine receptors
Authors: Hesselmans L. F. G. M. , Jennekens F. G. I. , Van Den Oord C. J. M. , Veldman H. , Vincent A.
Published: February 2005

The aim of this study was to establish the time scale of developmental changes in innervation of skeletal muscle fibers in man. Specimens of thigh and intercostal muscle from 19 embryos and 18 infants were examined with histological methods which enabled the discrimination between fetal (gamma) and adult (epsilon) types of acetylcholine receptors (AChRs).

At 8 weeks of development, AChRs were distributed diffusely in the myotube membranes. Following onset of innervation in approximately the ninth week the length of the AChR positive area diminished and reached its shortest size at the sixteenth developmental week. At the sixteenth and eighteenth week some nerve terminals opposed the muscle membrane outside the AChR positive area. Decrease in the number of nerve terminals, strongly suggesting elimination of polyneuronal innervation, started in the sixteenth week and was completed in the twenty‐fifth week. This fetal (gamma) type of AChR could no longer be demonstrated after the thirty‐first week. The length of the end‐plates as determined by the presence of AChRs increased again in the last week before birth and reached a plateau size by the end of the first year after birth.

It is concluded that in man the transition from poly‐ to mononeuronal innervation takes place between the sixteenth and twenty‐fifth weeks of development. The evidence available suggests that the retraction of nerve terminals is preceded by loss of AChRs from the muscle membrane facing the terminals. There is no relationship between retraction of nerve terminals and the switch from fetal to adult type of AChR. The size of the presynaptic apparatus changes little after the first year of life. © 1993 Wiley‐Liss, Inc.
A new model of vasculogenesis and angiogenesis in vitro as compared with vascular growth in the avian area vasculosa
Authors: Flamme Ingo , Baranowski Andreas , Risau Werner
Published: February 2005

In cultures of dissociated quail epiblast the basic constituents of the vascular system, blood cells and endothelial cells can be induced by basic fibroblast growth factor (Flamme and Risau, Development, 116:435–439, 1992). As we show here, in those cultures three types of vascular plexus differentiate spontaneously under different culture conditions: At the 3rd day a vascular plexus appears in situ closely resembling the vascular plexus of the quail area opaca vasculosa (vasculogenesis). Vascular sprouts are formed, extending long filopodia at their tips. Such filopodia are shown to build the first intervascular bridges in the growing vascular plexus of the area vasculosa at embryonic day 3. Connections of filopodia turn out to be precursors of new capillaries interconnecting pre‐existing blood vessels (angiogenesis). Two further types of in vitro capillary plexus differentiate in long term endothelial cell cultures derived from induced angioblasts. Whereas one closely resembles so‐called angiogenesis in vitro, the third type comprises mainly multinucleated giant endothelial cells lining loop like capillaries and represents a differentiation of aging endothelial cell culture. Thus, the present in vitro model is an approach to the sequence of angioblast induction, vasculogenesis, and angiogenesis. © 1993 Wiley‐Liss, Inc.
A scanning and transmission electron microscopic analysis of the cerebral aqueduct in the rabbit
Authors: Meller S. T. , Dennis B. J.
Published: February 2005

An examination of the surface of the cerebral aqueduct with the scanning electron microscope revealed that the walls of the cerebral aqueduct were so heavily ciliated that most of the ependymal surface was obscrued, yet certain specialized supreapendymal structures could be discerned lying on (or embedded within) this matt of cilia. These structures were determined by transmission electron microscopy and Golgi analysis to be either macrophages, supraependymal neurons, dendrites from medial periaqueductal gray neurons, or axons of unknown origin. Some axons, which were found to contain vesicles, appeared to make synaptic contacts with ependymal cells. Using the transmission electron microscope, the ependymal lining was found to consist of two different cell types: normal ependymal cells and tanycytes which have a long tapering basal process that was observed to contact blood vessels or, more rarely, seemed to terminate in relation to neuronal elements. While there have been previous reports on the structure of the third and lateral ventricles in other species, there are limited reports in the rabbit. The present report is not only the first description for the rabbit, but it is the first complete scanning and transmission electron microscopic analysis of the cerebral aqueduct in any species. © 1993 Wiley‐Liss, Inc.
Structure, innervation, and age‐associated changes of mouse forearm muscles
Authors: Carry Michael R. , Horan Steven E. , Reed Shelley M. , Farrell Robert V.
Published: February 2005

In spite of a decline in muscle strength with age, the cause of the overall decrease in motor performance in aged mammals, including rodents, is incompletely understood. To add clarity, the gross organization, innervation, histochemical fiber types, and age‐associated changes are described for mouse forearm muscles used in a variety of motor functions. The anterior (flexor) and posterior (extensor) forearm compartments have the same arrangement of muscles and gross pattern of innervation as the rat. Two primary histochemical fiber types, fast/oxidative/glycolytic (FOG) and fast/glycolytic (FG), with characteristic hitsochemical staining patterns were observed in all forearm muscles. Additionally, there was a small population of slow/oxidative (SO) fibers confined to the deep region of a single muscle, the flexor carpi ulnaris (FCU).

Between 18 and 26 months the FCU muscle displayed fibers with morphological features distinct from earlier ages. Fibers displayed a greater variation in size, a loss of their uniform polygonal shape, and a dramatic increase in clumps of subsarcolemmal mitochondria, lysosomes, and lipofuscin granules. Many of the fibers had a distinctly atrophic, angular shape consistent with recent denervation. Morphometric analyses of the FCU's source of innervation, the ulnar nerve and one of its ventral roots (C8), were consistent with the denervation‐like changes in the muscle fibers. Although, there was no net loss of myelinated axons between 4 and 26 months of age, there was a significant increase in the density of degenerating cells in both the ulnar nerve and ventral root C8. © 1993 Wiley‐Liss, Inc.
Transport pathways for macromolecules in the aortic endothelium. II. The distribution analysis of plasmalemmal vesicles reconstructed by serial sections
Authors: Ogawa Kazushige , Taniguchi Kazuyuki
Published: February 2005

Three‐dimensional organization of vesicles was examined to elucidate the transendothelial transport properties for macromolecules in rat aortic endothelium using ultrathin serial sections and horseradish peroxidase (HRP) as a tracer molecule. A total number of reconstructing vesicles was 1,298 in nine series electron micrographs, if each vesicular entity was counted as one regardless of composite number of vesicles. The vesicles could be classified into the following six types: HRP‐positive luminal, abluminal and intercellular invaginations; HRP‐positive channels; HRP‐positive and ‐negative vesicles. The vesicular invaginations and the channels occupied 97.8% and 0.9% of the total vesicles, whereas HRP‐positive and ‐negative free vesicles were found in 0.8% and 0.5%, respectively. The average numerical density of the luminal invagination was 41.1/μm2 and approximately equal to that of the abluminal invagination (42.0/μm2), whereas the frequency of the latter was 1.4 times higher than that of the former since the abluminal surface of the endothelium was more irregular to increase a surface area. Each endothelial region varied in the vesicular density and the peripheral region generally showed the higher density, although the transendothelial channels composed of vesicles were not always found in every peripheral region. These results suggest that the shuttle hypothesis is unsuitable to explain “vesicular transport” in the arterial endothelium as well as in the capillary endothelium and that the channels in the peripheral region mainly control transendothelial transport for macromolecules via vesicles. © 1993 Wiley‐Liss, Inc.
Modulation of the Golgi apparatus in Saccharomyces cerevisiae sec7 mutants as seen by three‐dimensional electron microscopy
Authors: Rambourg A. , Clermont Y. , Képès F.
Published: February 2005

The three‐dimensional configuration of the Golgi apparatus has been examined with the electron microscope in thick Golgi sections of Saccharomyces cerevisiae prepared from a wild‐type strain and from sec7 mutants maintained for various periods of time at the nonpermissive temperature of 37°C and then returned to the permissive temperature of 24°C. Reduced osmium postfixation of glutaraldehyde fixed specimens stained intensely the content of Golgi elements and thus facilitated their three‐dimensional characterization. In wild‐type S. cerevisiae, the Golgi elements usually appeared as isolated networks of membranous tubules dispersed throughout the cytoplasm. Along such networks, distensions filled with stained material were similar in size to nearby secretory granules, suggesting that the latter formed by fragmentation of the Golgi elements. In sec7 mutants maintained at 37°C in low (0.1%) glucose medium, secretion granules progressively decreased in number and soon disappeared. Concomitantly the networks of Golgi tubules increased in size and complexity, lost their distensions, and then transformed into flattened sacules forming stacks of up to seven or eight saccules that were similar to the Golgi stacks seen in mammalian cells. However in contrast to the latter, connections between the saccules were evident and Golgi‐associated small vesicles were generally absent. Following return to the permissive temperature (24°C), secretion granules reappeared, the Golgi stacks progressively decreased in size, and resumed their initial state of separated small tubular networks. Thus in sec7 mutant, grown at 37°C in low glucose medium, segregation of secretory granules is blocked. As a result, Golgi membranes accumulate to form a continuous system of stacked and interconnected saccules. © 1993 Wiley‐Liss, Inc.
Ultrastructure of lipid‐containing cells of the anterior pituitary gland of the domestic chicken, Gallus domesticus
Authors: Liu Raymond C. M. , Lea Robert W. , Sharp Peter J. , Maxwell Martin H.
Published: February 2005

A combination of light and electron microscopy techniques was applied to characterize a luteinizing hormone (LH)‐gonadotroph‐like cell in the anterior pituitary gland of the adult domestic chicken. This cell type (mean ± sem, 91 ± 8 μm2) was larger than typical LH‐gonadotrophs (71 ± 5 μm2, P < 0.01) and seen in pituitary glands from adult males but not those from adult females of the same age. The ultrastructural features of these cells were similar to typical LH‐gnoadotrophs in the same section, except for the presence of large (1,126 ± 77 nm diameter), round, or polymorphic electron‐dense inclusions (14 ± 3 per cell) in the cisternae of the endoplasmic reticulum. When resin sections of anterior pituitary gland were stained with the vapours from the fixative osmium tetroxide and a solution of potassium ferricyanide, inclusions were found that appeared to be lipid in nature and were circumscribed by the cisternal membranes of the endoplasmic reticulum. These lipid inclusions were associated occasionally with acid phosphatase and lysosome‐like bodies. The cellular pigment, lipofuscin, considered to be a marker of aging, was absent from the anterior pituitary glands from these adult chickens. These observations suggest that the appearance of lipid in LH‐gonadotrophs is unlikely to be age‐related and an alternative explanation is discussed in relation to a sex difference in the LH response of adult chickens to gonadotrophin‐releasing hormone (GnRH). © 1993 Wiley‐Liss, Inc.
Spontaneous cortical granule release and alteration of zona pellucida properties during and after meiotic maturation of mouse oocytes
Authors: Okada Akiko , Inomata Kenichirou , Nagae Takeshi
Published: February 2005

Exocytosis of cortical granules (CGs) and the concomitant electron density changes of the zona pellucida (ZP) in the absence of sperm penetration were investigated in mouse oocytes processed with tannic acid containing fixation at various stages during and after maturation. After fusion of the CG membrane with the plasma membrane, the CG contents became very electron‐dense, due to tannic acid. CG material is seen to be made up of coarse granular structures which gradually change to fine amorphous structures, which accumulate within the developing perivitelline space (PVS).

When the coarse CG material attaches to the ZP, small domains exhibiting higher electron density appeared, and the number of these domains gradually increased. Release of CG was observed from metaphase I through metaphase II. In metaphase I to immediately after ovulation, the higher electron density of ZP and CG release was restricted to the cortical area overlying the meiotic spindle. Finally, the CG‐free domain formed itself overlying the meiotic spindle as a result of CG release. However, in oviductal ova, CG release additionally occurred in the hemisphere opposite the spindle. At this stage the entire PVS was well developed and contained numerous fine electron‐dense materials. Moreover, the inner half of the ZP increased in electron density as well. This change in electron density of the ZP might be associated with released CG material.

These results suggest that the “partial cortical reaction” may play an important role in conditioning the ZP prior to ZP reaction. © 1993 Wiley‐Liss, Inc.
Intense vascular sprouting from rat femoral vein induced by prostaglandins E1 and E2
Authors: Diaz‐Flores Lucio , Gutierrez Ricardo , Valladares Francisco , Varela Hilda , Perez Miguel
Published: February 2005

The formation of new capillaries from the rat femoral vein was specifically explored to assess whether venous vessels of this caliber may participate in the process of angiogenesis. Prostaglandins of the E series (PGE1 and PGE2) were administered into the soft connective tissue surrounding the rat femoral vessels as angiogenic inducers. In these conditions, between 2 and 7 days, a great number of new capillaries were observed in the media of the femoral vein, arising from the endothelial cells (EC) in the intima. The events of the capillary growth from the femoral vein included EC activation, local degradation of the basal membrane followed by migration and proliferation of EC, solid sprout formation with posterior canalization, development of a new basal membrane, and appearance of pericytes around the new capillary. Although numerous vascular buds were also observed arising from the small venules and capillaries in the periadventitial tissues, they were separated at first from those in the media of the femoral vein by the venous adventitia. Later, connections were observed between both newly formed microcirculations. The present study shows the capacity of PGE1 and PGE2 in the extravascular position of inducing capillary sprouting from veins. Furthermore, the observations provide greater evidence that vessels with characteristics similar to those of the rat femoral vein may contribute to angiogenesis, on occasion with an intense neovascularization. This fact may be of interest for the establishment of a functional circulation after angiogenesis by anastomoses of the new capillaries with those arising from pre‐existing vessels of greater caliber than the venules. © 1994 Wiley‐Liss, Inc.
Microcirculation of gills and accessory respiratory organs from the air‐breathing snakehead fish, Channa punctata, C. gachua, and C. marulius
Authors: Olson K. R. , Roy P. K. , Ghosh T. K. , Munshi J. S. D.
Published: February 2005

Snakehead fish of the genus Channa have well‐developed air‐breathing organs (ABO) yet retain their gill arches for respiratory and non‐respiratory functions. Alterations in the macrocirculation accompany inclusion of the ABO and appear to enhance gas exchange efficiency (Munshi et al., 1994. Anat. Rec. 238:77–91). In the present study, the microcirculatory anatomy of gill and ABO from two facultative air‐breathing Channa, C. punctata and C. gachua, and one obligate air‐breather, C. marulius, were examined in detail using scanning electron microscopy (SEM) of vascular corrosion replicas and fixed whole‐sectioned tissue. The results show that the circulation in the filaments from the first, second, and third gill arches is similar to that found in water‐breathing teleosts. Fourth gill arch microcirculation of C. punctata is not different from the other three, whereas in C. marulius, it has been greatly modified into a network of low‐resistance vascular shunts, although remnants of an intralamellar filamental microcirculation remain. The vascular shunts are formed from extensions of afferent and efferent lamellar arterioles and the complete, or nearly complete, loss of a lamellar sinus. The vasculature of the ABO has been highly modified in all species into a coiled‐spiral capillary network with a constricted aperture guarding a dilated capillary dome at the epithelial surface. Microvilli are found congregated on the aperture endothelium of C. punctata but they are virtually absent from C. marulius endothelium. Less than 15% of the ABO capillary surface appears to face the epithelium and thereby contributes directly to gas exchange. These findings suggest that the microvascular modifications observed in Channa entail more than a simple increase in the contact surface between ABO vessels and air and they may serve other unknown physiological functions. © 1994 Wiley‐Liss, Inc.
Anatomical variations of the intrinsic muscles of the thumb
Authors: Jan Serge Van Sint , Rooze Marcel
Published: February 2005

The observation of thirty dissections of intrinsic muscles of the thumb provides some information differing from earlier anatomical studies. The abductor pollicis brevis and the opponens pollicis have been divided into muscles having six or two fascicles (or bellies), respectively. The adductor pollicis muscle has been separated into nine fascicles. Many variations were observed: absence of fascicles, presence of atrophied or supplementary fascicles, or fascicles with varying insertions sites. Neither head of the flexor pollicis brevis muscle seemed to have any fascicles. The distal insertion of its superficial head observed in this work is not in accordance with the usual description found in the literature. A new classification of the thenar muscles is presented based on the present observations. Many variations were observed: some fascicles were absent, others were supplementary or atrophied, and some had variable insertions. The importance and the individual variations of the fascicles are discussed. © 1994 Wiley‐Liss, Inc.
Domains of differential cell proliferation and formation of amnion folds in chick embryo ectoderm
Authors: Miller Sue Ann , Bresee Kimberley L. , Michaelson Cheryl L. , Tyrell Dean A.
Published: February 2005

Patterns of cell proliferation in ectoderm epithelium that will form avian amnion correlate with morphogenesis, but not in an obvious pattern with respect to large‐scale folding. At sites where the pre‐axial amnion folds will first appear in 4‐ to 8‐somite embryos, patterns of proliferation do not separate into domains that presage location of the single pre‐axial fold that is commonly described in embryology texts. Instead, increased cell proliferation occurs in a significant, bilateral pattern. In stages with 13 to 27 somites, when lateral amnionic folds are prominent, five paraxial domains of cell proliferation correlate with morphology and show decreasing levels of cell proliferation with distance from the neural axis. Slowly growing areas surround rapidly growing areas and could assist buckling of epithelium by providing constraint on expansion of faster growing areas. Proliferation domains in ectoderm correlate with morphology and morphological events when localized changes in cell shape are lacking and suggest a role for differential cell proliferation in formation of large‐scale epithelial folds in early chick embryos. © 1994 Wiley‐Liss, Inc.
Initial vascularisation in the pig placenta: II. Demonstration of gland and areola‐gland subunits by histology and corrosion casts
Authors: Leiser Rudolf , Dantzer Vibeke
Published: February 2005

Tissues from 10 pregnant pigs between 9 1/2 and 43 days post coitum (p.c.) were prepared for histology and vascular corrosion casts to examine the vascularisation of the gland and areola‐gland subunits of the early pig placenta. The endometrial vascular networks shown by casts were equal in both glandular and interglandular fields from days 9 1/2 to 14–15 p.c. This represents a cyclic stage uninfluenced by the early implanting embryo on day 13 p.c. By day 15 p.c., the first areola formation was observed both histologically and on casts. The maternal areolar and glandular capillary network developed into a widely meshed loose type, in contrast to the interareolar type which had a dense and parallel architecture. In some cases extremely large, crooked, and highly anastomosed maternal capillaries developed between these two networks. This specialized transition is thought to form the base for the ring‐like seal formation (RSF) of the areolar periphery. A firm materno‐fetal anchor therefore “seals” the areola and its glandular secretory contents from its interareolar surroundings. Therefore, the glandular and maternal areolar vasculatures are clearly discernable from that of the fetal areolar vasculature. The former are associated with the known materno‐fetal substance transfer of the porcine areola‐gland subunit. This association, however, seems to remain unspecialized in early placentation, as only the regular roundish areola—not the irregular areola—can be distinctly detected. © 1994 Wiley‐Liss, Inc.
Basal cells in human bronchial epithelium
Authors: Baldwin Frank
Published: February 2005

The morphology and distribution of basal cells were investigated in adult human bronchial epithelium.

In both smokers and non‐smokers typical basal cells were more numerous than atypical basal cells, which were distinguished by their spindle‐shaped nucleus, polar cytoplasm, and processes that extended along the basal lamina. The nucleus of the atypical basal cell was consistently closer to the muco‐ciliary surface than was the nucleus of the typical basal cell.

In cross‐sections of bronchi the numbers of typical basal cells/mm epithelium were greatest in large airways; in smaller bronchi (i.e., generations 7–16) the frequency declined. The numbers of atypical basal cells/mm epithelium were similar throughout the bronchial tree.

Throughout the bronchial tree both types of basal cells contributed to the maintenance of epithelial cohesion by providing desmosomal attachment for columnar cells. The importance of typical basal cells in this role was indicated by their greater numbers, which collectively presented a large surface for epithelial cell attachment by desmosomes. The surface presented by the cell body and processes of each atypical basal cell for attachment of columnar cells by desmosomes was extensive.

If the basal cell is the most important progenitor of bronchial epithelium and the cell at risk in the development of lung cancer, the presence of more basal cells in upper airways, where many lung cancers originate, may be significant. The basal cell populations in larger bronchi are perhaps the greatest concentration of cells with proliferative capability and potential for neoplastic transformation in the human bronchial tree. © 1994 Wiley‐Liss, Inc.
Meckel's cartilage in the human embryo and fetus
Authors: Orliaguet T. , Darcha C. , Déchelotte P. , Vanneuville G.
Published: February 2005

This work studied the development of the ventral part of Meckel's cartilage in a series of human embryos (classified in stages) and fetuses. These stages appeared particularly important: stage 16, appearance of Meckel's cartilage; stage 20, beginning of membranous ossification of mandible; and stage 23, end of the embryonic period (8th week). The primitive bony nodule which develops from the embryonic mesenchyme appears as a double bony layer forming a groove containing the neurovascular bundle, into which the dental lamina is also invaginated. It was concluded that during the fetal period, the cartilage participates in the formation of the body of the mandible in an area close to the mental foramen via endochondral ossification. The cartilage disappears in parallel with the development of ossification by the sixth month. © 1994 Wiley‐Liss, Inc.
Ultrastructural, histochemical, and morphometric analysis of skeletal muscle in a murine model of type I diabetes
Authors: Klueber Kathleen M. , Feczko John D.
Published: February 2005

Background. Since peripheral nerves are damaged in diabetes mellitus, morphological changes occur within the diabetic muscle in response to the diabetic neuropathy. The aim of this study was to examine the extensor digitorum longus (EDL) from a 42‐day streptozotocin‐induced diabetic Swiss Webster mouse (STZ) and compare the muscle morphology and histochemistry to age‐matched, nondiabetic controls.

Methods. The EDL was evaluated using electron microscopy in order to investigate the morphological integrity of the myofibers and neuromuscular junctions. Histochemical analysis was completed using the myofibrillar CA + +‐ATPase reaction of Doriguzzi et al. (1983. Histochemistry, 79 :289–294) for use in computer‐assisted morphometric analysis of fiber size using Bioquant System 4 software.

Results. Ultrastructural analysis of the diabetic EDL (N = 5, 225 myofibers/animal) showed a significant number of abnormal myofibers, exhibiting various degrees of degeneration, signs of denervation, and necrosis. The STZ myofibers exhibited excessive lipid accumulations and abnormal mitochondrial arrangements. Histochemical analysis of the STZ EDL revealed a significant shift in fiber type profile (53.6% type 2A and 46.4% type 2B‐ STZ myofibers; 47.5% type 2A, 52.5% type 2B nondiabetic controls). Morphometric analysis of myofiber size by fiber type (200 myofibers/muscle/fiber type) indicated a significant decrease in myofiber size for both type 2A and type 2B fibers in the STZ diabetic mouse.

Conclusion. The degeneration and necrosis of myofibers concomitant with the sever atrophy of both the type 2A and 2B myofibers in the STZ muscle could account for the functional alterations seen in diabetic muscle. © 1994 Wiley‐Liss, Inc.
Comparative localization of carboxylesterase in F344 rat, Beagle dog, and human nasal tissue
Authors: Lewis J. L. , Nikula K. J. , Novak R. , Dahl A. R.
Published: February 2005

Background. Carboxylesterases (CE) exhibit high activity in the nasal mucosae and produce acid metabolites toxic to the olfactory epithelium following exposures to inhaled esters. The regional distribution and activity of CE have been studied in rodents, but no comparative studies have examined regional localization or activity in dog or human nasal tisses.

Methods. We determined the immunohistochemical distributions of CE in the nasal respiratory and olfactory mucosae of Beagle dogs, and the nasal respiratory mucosa of the human nose and compared these distributions to those in the F344 rat.

Results. In the dog respiratory mucosa, the greatest CE immunoreactivity was in the subepithelial glands and surface epithelial cells. In the olfactory mucosa, immunoreactivity was observed in the apical portion of the sustentacular cells, and in duct cells and acinar cells of Bowman's glands. This distribution is similar to that found in rat, except the subepithelial glands of the rat respiratory mucosa showed little to no immunoreactive CE. The human respiratory mucosa showed immunostaining in surface epithelial cells as well as glandular cells. Immunostaining in the human tissue samples was dramatically reduced in the presence of hyperplastic lesions and virtually eliminated in samples with squamous metaplasia.

Conclusions. The data indicate that the distribution of CE is very similar in healthy nasal mucosae across the three species studied. However, the loss of CE immunoreactivity correlated with nasal epithelial lesions in the human samples suggests enzymatic activity may be compromised by insults to nasal tissues. Further studies of CE activity in animals following nasal insult could improve the ability to predict human responses to inhaled esters. © 1994 Wiley‐Liss, Inc.
The pulmonary neuroepithelial endocrine system in the quail, Coturnix coturnix. Light‐ and electron‐microscopical immunocytochemistry and morphology
Authors: Adriaensen Dirk , Scheuermann Dietrich W. , Gomi Toshiaki , Kimura Akihiko , Timmermans Jean‐Pierre , De Groodt‐Lasseel Marie H. A.
Published: February 2005

Despite extensive knowledge of the neuroepithelial endocrine (NEE) system in the lungs of species of various vertebrate classes, data on avians are limited. The present investigation deals with the light‐and electron‐microscopical immunocytochemistry and morphology of pulmonary NEE cells in the quail, Coturnix coturnix. Light‐microscopically, serotonin immunoreactivity was detected in numerous solitary and clustered NEE cells located in the cilio‐mucous epithelium of primary and secondary bronchi in adult as well as in newly hatched quails. Only in newly hatched quails could a small number of bombesin‐ and somatostatin‐like immunoreactive NEE cells be demonstrated. Electron‐microscopical morphology revealed that NEE cells contained dense‐cored vesicles of a wide range of diameters and electron densities. Nearly all of the NEE cells were seen to rest on the basement membrane of the cilio‐mucous epithelium, lacking direct contact with the luminal surface. Nerve varicostities or nerve endings, of both afferent and efferent morphological appearance, were found directly apposed to the basal portion of NEE cells, invaginating between NEE cells or between NEE cells and adjacent epithelial cells. Often, synaptic specializations could be recognized between NEE cells and nerve terminals. Electron‐microscopical immunocytochemistry confirmed that the intraepithelial serotonin‐containing cells correspond to the cells with NEE characteristics. Moreover, two types of NEE cells could be distinguished in newly hatched quail lungs. Both types showed serotonin immunoreactivity selectively distributed over the dense‐cored vesicles, but somatostatin‐ and bombesin‐like immunoreactivities were only noted in one of the NEE cell types and were never seen colocalized. Thus, the avian NEE system too, harbors at least three different bioactive substances and has a morphology comparable to that of mammals, reptiles and amphibians. © 1994 Wiley‐Liss, Inc.
Gross and microscopic anatomy of the canine intrinsic cardiac nervous system
Authors: Yuan Bing‐Xiang , Ardell Jeffrey L. , Hopkins David A. , Losier Andrea M. , Armour J. Andrew
Published: February 2005

Background: A three‐dimensional description of the distribution and organization of the canine intrinsic cardiac nervous system was developed in order to characterize its full extent physiologically.

Methods: The anatomy of the canine intrinsic cardiac nervous system was investigated in 67 mongrel dogs by means of visulization following methylene blue staining as well as by light and electron microscopic analyses.

Results: Collections of ganglia associated with nerves, i.e., ganglionated plexuses, were identified in specific locations in epicardial fat and cardiac tissue. Distinct epicardial ganglionated plexuses were consistently observed in four atrial and three ventricular regions, with occasional neurons being located throughout atrial and ventricular tissues. One ganglionated plexus extended from the ventral to dorsal surfaces of the right atrium. Another ganglionated plexus, with three components, was identified in fat on the left atrial ventral surface. A ganglionated plexus was located on the mid‐dorsal surface of the two atria, extending ventrally in the interatrial septum. A fourth atrial ganglionated plexus was located at the origin of the inferior vena cava extending to the dorsal caudal surface of the two atria. On the cranial surface of the ventricles a ganglionated plexus that surrounded the aortic root was identified. This plexus extended to the right and left main coronary arteries and origins of the ventral descending and circumflex coronary arteries. Two other ventricular ganglionated plexuses were identified adjacent to the origins of the right and left marginal coronary arteries. Intrinsic cardiac ganglia ranged in size from ones comprising one or a few neurons along the course of a nerve to ones as large as 1 × 3 mm estimated to contain a few hundred neurons. Intrinsic cardiac neuronal somata varied in size and shape, up to 36% containing multiple nucleoli. Electron microscopic examination demonstrated typical autonomic neurons and satellite cells in intrinsic cardiac ganglia. Many of their axon profiles contained large numbers of clear, round, and dense‐core vesicles. Asymmetrical axodendritic synapses were common.

Conclusions: The canine intrinsic cardiac nervous system contains a variety of neurons interconnected via plexuses of nerves, the distribution of which is wider than previously assumed. © 1994 Wiley‐Liss, Inc.
Immunoelectron microscopic study of the GH cell in the anterior pituitary gland of normal human fetus
Authors: Tachibana Toshiaki , Ito Takayasu , Kwon (Gotetsu Gon) Oh‐Chol
Published: February 2005

Background: Ultrastructural studies of growth hormoneproducing cells (GH cells) in the anterior pituitary gland have been reported using several experimental animals. However, no attempt has yet been made to identify the ultrastructural heterogeneity of the GH cells within the human anterior pituitary gland. To this end, we employed immunogold electron microscopy to investigate the ultrastructural characteristics of GH cells in relation to gestational age in normal human fetuses.

Materials: Based on ultrastructural characteristics, three distinct types of GH cells were identified by immunogold electron microscopy in the anterior pituitary glands of 34 normal human fetal pituitary glands. The age of the tissue samples ranged from 8 to 34 weeks.

Results: The Type‐I GH cell is a small, round cell with a narrow cytoplasm containing a few small secretory granules (268 nm in mean diameter). The GH cells designated Type‐II are polygonal and contain medium‐sized secretory granules (347 nm), profiles of rough endoplasmic reticulum (RER) arranged in parallel lamellae, and a Golgi complex which is frequently encountered but only in this cell type. The Type‐III GH cell is polygonal, large, and contains numerous large spherical‐shaped secretory granules (404 nm). The Type‐I was the predominant cell type until about 20 weeks of gestation; its incidence decreased thereafter. In contrast, the Type‐II and Type‐III cells increased in number starting at 20 weeks of gestational age.

Conclusion: From these results, we suggest that Type‐I is the most immature type of GH cell, Type‐III the most mature, and the Type‐II is intermediate in development. The marked difference in the incidence of each GH cell type between the first and second half of gestation appears to be a reflection of the development of the hypothalamic regulation of the anterior pituitary gland, which is reported to be established at around 20 weeks of gestation. © 1994 Wiley‐Liss, Inc.