Computer Reconstructions of Normal Human Alveoli From Serial Sections

1985 ◽  
Vol 43 ◽  
pp. 312-313
Author(s):  
Saundra C. Parra ◽  
Ricky Burnette ◽  
Timothy Takaro
Keyword(s):  
Cell Types ◽  
Type I ◽  
Type Ii ◽  
Serial Sections ◽  
Single Plane ◽  
Random Sections ◽  
Normal Human ◽  
Connective Tissue Matrix ◽  
Different Cell Types ◽  
Tissue Matrix

Portions of two adjacent normal human alveoli were reconstructed from serial sections in order to examine normal alveolar organization, including anatomical relationships among the different cell types, the connective tissue matrix and gaps in the alveolar septum. Computer reconstructions were prepared from montaged electron micrographs of serial sections. Rotation of these reconstructions in the x, y or z axes allowed examination of the alveoli from many different aspects other than the actual plane of sectioning. Anatomical relationships “between Type I and Type II epithelial cells, alveolar macrophages, and pores of Kohn that could not he deduced from a single plane of the section (random sections) were revealed.

scholarly journals How taste works: cells, receptors and gustatory perception

2015 ◽  
Vol 20 (5) ◽  
Author(s):  
Dariusz Kikut-Ligaj ◽  
Joanna Trzcielińska-Lorych
Keyword(s):  
Cell Types ◽  
Taste Buds ◽  
Taste Perception ◽  
Taste Bud ◽  
Type I ◽  
Type Ii ◽  
Different Cell Types ◽  
Gustatory Perception ◽  
I Cells ◽  
Chemosensory Organs

AbstractThe sensitivity of taste in mammals varies due to quantitative and qualitative differences in the structure of the taste perception organs. Gustatory perception is made possible by the peripheral chemosensory organs, i.e., the taste buds, which are distributed in the epithelium of the taste papillae of the palate, tongue, epiglottis, throat and larynx. Each taste bud consists of a community of ~100 cells that process and integrate taste information with metabolic needs. Mammalian taste buds are contained in circumvallate, fungiform and foliate papillae and react to sweet, salty, sour, bitter and umami stimuli. The sensitivity of the taste buds for individual taste stimuli varies extensively and depends on the type of papillae and the part of the oral cavity in which they are located. There are at least three different cell types found in mammalian taste buds: type I cells, receptor (type II) cells and presynaptic (type III) cells. This review focuses on the biophysiological mechanisms of action of the various taste stimuli in humans. Currently, the best-characterized proteins are the receptors (GPCR). In addition, the activation of bitter, sweet and umami tastes are relatively well known, but the activation of salty and sour tastes has yet to be clearly explained.

Mucopolysaccharidosis in Adults

2016 ◽  
Author(s):  
Christian J. Hendriksz ◽  
Francois Karstens
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Autosomal Recessive ◽  
Clinical Symptoms ◽  
Cell Types ◽  
Type Ii ◽  
System P ◽  
Different Types ◽  
The Central Nervous System ◽  
Different Cell Types

There are 8 different types of diseases of the mucopolysaccharides, each caused by a deficiency in one of 10 different enzymes involved in the degradation of glycosaminoglycans (GAGs). Partially degraded GAGs accumulate within the lysosomes of many different cell types and lead to clinical symptoms and excretion of large amounts of GAGs in the urine. Heritability is autosomal recessive except for MPS type II, which is X-linked. The disorders are chronic and progressive and, although the specific types all have their individual features, they share an abundance of clinical similarities. All involve the musculoskeletal, the cardiovascular, the pulmonary and the central nervous system.

scholarly journals Posttranslational regulation of keratins: degradation of mouse and human keratins 18 and 8.

1989 ◽  
Vol 9 (4) ◽  
pp. 1553-1565 ◽  
Author(s):  
D A Kulesh ◽  
G Ceceña ◽  
Y M Darmon ◽  
M Vasseur ◽  
R G Oshima
Keyword(s):  
Cell Types ◽  
Immunofluorescent Staining ◽  
Type I ◽  
Type Ii ◽  
Tail Domain ◽  
Proteolytic System ◽  
L Cells ◽  
Adult Mice ◽  
3T3 Fibroblasts ◽  
Keratin Filament

Human keratin 18 (K18) and keratin 8 (K8) and their mouse homologs, Endo B and Endo A, respectively, are expressed in adult mice primarily in a variety of simple epithelial cell types in which they are normally found in equal amounts within the intermediate filament cytoskeleton. Expression of K18 alone in mouse L cells or NIH 3T3 fibroblasts from either the gene or a cDNA expression vector results in K18 protein which is degraded relatively rapidly without the formation of filaments. A K8 cDNA containing all coding sequences was isolated and expressed in mouse fibroblasts either singly or in combination with K18. Immunoprecipitation of stably transfected L cells revealed that when K8 was expressed alone, it was degraded in a fashion similar to that seen previously for K18. However, expression of K8 in fibroblasts that also expressed K18 resulted in stabilization of both K18 and K8. Immunofluorescent staining revealed typical keratin filament organization in such cells. Thus, expression of a type I and a type II keratin was found to be both necessary and sufficient for formation of keratin filaments within fibroblasts. To determine whether a similar proteolytic system responsible for the degradation of K18 in fibroblasts also exists in simple epithelial cells which normally express a type I and a type II keratin, a mutant, truncated K18 protein missing the carboxy-terminal tail domain and a conserved region of the central, alpha-helical rod domain was expressed in mouse parietal endodermal cells. This resulted in destabilization of endogenous Endo A and Endo B and inhibition of the formation of typical keratin filament structures. Therefore, cells that normally express keratins contain a proteolytic system similar to that found in experimentally manipulated fibroblasts which degrades keratin proteins not found in their normal polymerized state.

scholarly journals Nodal signalling and apoptosis

Reproduction ◽  
2007 ◽  
Vol 133 (5) ◽  
pp. 847-853 ◽  
Author(s):  
Hongmei Wang ◽  
Benjamin K Tsang
Keyword(s):  
Transforming Growth Factor ◽  
Biological Effects ◽  
Transforming Growth Factor Β ◽  
Cell Types ◽  
Type I ◽  
Type Ii ◽  
Human Trophoblast ◽  
Adult Tissues ◽  
Ovarian Epithelial Cancer ◽  
Smad Proteins

Nodal, a member of the transforming growth factor β family, was first cloned from a 7.5 day post-coitum mouse embryo cDNA library. Nodal exerts its biological effects by signalling through its types I and II serine/threonine kinase receptor complex and intracellular Smad proteins. The type II receptors for Nodal are Activin type II receptors ActRIIA and ActRIIB, whereas the putative type I receptors are Activin receptor like kinase (ALK) 4 and ALK7. The main Smad proteins involved in Nodal signalling are Smad2 and Smad3. Studies of Nodal in adult tissues indicate that it is pro-apoptotic in rat ovarian granulosa cells, human trophoblast cells and human ovarian epithelial cancer cells and is growth inhibitory in the latter two cell types. This review summarises the progress made on the functions of Nodal in the apoptosis of adult tissues, especially in the ovary and placenta.

scholarly journals Separate cis-acting DNA elements of the mouse pro-alpha 1(I) collagen promoter direct expression of reporter genes to different type I collagen-producing cells in transgenic mice.

1995 ◽  
Vol 129 (5) ◽  
pp. 1421-1432 ◽  
Author(s):  
J Rossert ◽  
H Eberspaecher ◽  
B de Crombrugghe
Keyword(s):  
Transgenic Mice ◽  
Type I Collagen ◽  
Cell Types ◽  
Proximal Promoter ◽  
Type I ◽  
High Level Expression ◽  
Cis Acting ◽  
High Level ◽  
Different Cell Types ◽  
Beta Galactosidase

The genes coding for the two type I collagen chains, which are active selectively in osteoblasts, odontoblasts, fibroblasts, and some mesenchymal cells, constitute good models for studying the mechanisms responsible for the cell-specific activity of genes which are expressed in a small number of discrete cell types. To test whether separate genetic elements could direct the activity of the mouse pro-alpha 1(I) collagen gene to different cell types in which it is expressed, transgenic mice were generated harboring various fragments of the proximal promoter of this gene cloned upstream of the Escherichia coli beta-galactosidase gene. During embryonic development, X-gal staining allows for the precise identification of the different cell types in which the beta-galactosidase gene is active. Transgenic mice harboring 900 bp of the pro-alpha 1(I) proximal promoter expressed the transgene at relatively low levels almost exclusively in skin. In mice containing 2.3 kb of this proximal promoter, the transgene was also expressed at high levels in osteoblasts and odontoblasts, but not in other type I collagen-producing cells. Transgenic mice harboring 3.2 kb of the proximal promoter showed an additional high level expression of the transgene in tendon and fascia fibroblasts. The pattern of expression of the lacZ transgene directed by the 0.9- and 2.3-kb pro-alpha 1(I) proximal promoters was confirmed by using the firefly luciferase gene as a reporter gene. The pattern of expression of this transgene, which can be detected even when it is active at very low levels, paralleled that of the beta-galactosidase gene. These data strongly suggest a modular arrangement of separate cell-specific cis-acting elements that can activate the mouse pro-alpha(I) collagen gene in different type I collagen-producing cells. At least three different types of cell-specific elements would be located in the first 3.2 kb of the promoter: (a) an element that confers low level expression in dermal fibroblasts; (b) a second that mediates high level expression in osteoblasts and odontoblasts; and (c) one responsible for high level expression in tendon and fascia fibroblasts. Our data also imply that other cis-acting cell-specific elements which direct activity of the gene to still other type I collagen-producing cells remain to be identified.

scholarly journals IMP-dehydrogenase inhibition in human lymphocytes and lymphoblasts by mycophenolic acid and mycophenolic acid glucuronide

1997 ◽  
Vol 43 (12) ◽  
pp. 2312-2317 ◽  
Author(s):  
Andrea Griesmacher ◽  
Günter Weigel ◽  
Gernot Seebacher ◽  
Mathias M Müller
Keyword(s):  
Human Plasma ◽  
Mycophenolic Acid ◽  
Human Lymphocytes ◽  
Cell Types ◽  
Type I ◽  
Type Ii ◽  
Inhibitory Effects ◽  
Mediated Effects ◽  
Transplant Patients ◽  
Mycophenolic Acid Glucuronide

Abstract Inosine 5′-monophosphate dehydrogenase (IMP-DH) activities were measured in human lymphocytes (exhibiting type I IMP-DH activity) and human lymphoblasts (exhibiting type II IMP-DH activity) in the presence of various amounts of mycophenolic acid (MPA) (0–20 μmol/L) and MPA glucuronide (MPAG) (0–200 μmol/L). Moreover, the influences of human serum albumin (HSA) and human plasma on the MPA- and MPAG-mediated effects were investigated. In the presence of water, 2.5 μmol/L MPA decreased the IMP-DH activity measured in lymphocytes by 60%, whereas in lymphoblasts a 80% inhibition was detectable. In the presence of ≥10 μmol/L MPA, lymphocytic as well as lymphoblastic IMP-DH activities were reduced in a similar manner. The concentration of MPAG required for 50% inhibition was for both cell types >25 μmol/L and <50 μmol/L, respectively. MPAG (200 μmol/L) reduced lymphocytic as well as lymphoblastic IMP-DH activity by ∼80%. With 100 g/L HSA or human plasma as diluent, the inhibitory effects of MPA and MPAG were significantly (P <0.05) diminished, whereas HSA concentrations ≤25 g/L only slightly influenced the inhibition of IMP-DH activity by MPA and MPAG. In summary, it can be clearly demonstrated that not only MPA but also MPAG contributes to the inhibition of both IMP-DH isoenzymes, which might be relevant for the immunosuppressive properties of mycophenolate mofetil in transplant patients.

Vestibular Type I and Type II Hair Cells. 1: Morphometric Identification in the Pigeon and Gerbil

1997 ◽  
Vol 7 (5) ◽  
pp. 393-406
Author(s):  
Anthony J. Ricci ◽  
Katherine J. Rennie ◽  
Stephen L. Cochran ◽  
Golda A. Kevetter ◽  
Manning J. Correia
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Cell Types ◽  
Type I ◽  
Type Ii ◽  
Body Width ◽  
Fixed Tissue ◽  
Neck Width ◽  
I Cells ◽  
Plate Width

Classically, type I and type II vestibular hair cells have been defined by their afferent innervation patterns. Little quantitative information exists on the intrinsic morphometric differences between hair cell types. Data presented here define a quantitative method for distinguishing hair cell types based on the morphometric properties of the hair cell’s neck region. The method is based initially on fixed histological sections, where hair cell types were identified by innervation pattern, type I cells having an afferent calyx. Cells were viewed using light microscopy, images were digitized, and measurements were made of the cell body width, the cuticular plate width, and the neck width. A plot of the ratio of the neck width to cuticular plate width (NPR) versus the ratio of the neck width to the body width (NBR) established four quadrants based on the best separation of type I and type II hair cells. The combination of the two variables made the accuracy of predicting either type I or type II hair cells greater than 90%. Statistical cluster analysis confirmed the quadrant separation. Similar analysis was performed on dissociated hair cells from semicircular canal, utricle, and lagena, giving results statistically similar to those of the fixed tissue. Additional comparisons were made between fixed tissue and isolated hair cells as well as across species (pigeon and gerbil) and between end organs (semicircular canal, utricle, and lagena). In each case, the same morphometric boundaries could be used to establish four quadrants, where quadrant 1 was predominantly type I cells and quadrant 3 was almost exclusively type II hair cells. The quadrant separations were confirmed statistically by cluster analysis. These data demonstrate that there are intrinsic morphometric differences between type I and type II hair cells and that these differences can be maintained when the hair cells are dissociated from their respective epithelia.

scholarly journals Detachment of cells from culture substrate by soluble fibronectin peptides.

1985 ◽  
Vol 100 (6) ◽  
pp. 1948-1954 ◽  
Author(s):  
E G Hayman ◽  
M D Pierschbacher ◽  
E Ruoslahti
Keyword(s):  
Cultured Cells ◽  
Cell Attachment ◽  
Cell Types ◽  
Soluble Form ◽  
Detectable Effect ◽  
Type I ◽  
Recognition Mechanism ◽  
Synthetic Cell ◽  
Attachment Mechanism ◽  
Different Cell Types

The synthetic cell attachment-promoting peptides from fibronectin (Pierschbacher, M. D., and E. Ruoslahti, 1984, Nature (Lond.)., 309:30-33) were found to detach cultured cells from the substratum when added to the culture in a soluble form. Peptides ranging in length from tetrapeptide to heptapeptide and containing the active L-arginyl-glycyl-L-aspartic acid (Arg-Gly-Asp) sequence had the detaching activity, whereas a series of different peptides with chemically similar structures had no detectable effect on any of the test cells. The Arg-Gly-Asp-containing peptides caused detachment of various cell lines of different species and histogenetic origin. Studies with defined substrates showed that the active peptides could inhibit the attachment of cells to vitronectin in addition to fibronectin, indicating that vitronectin is recognized by cells through a similar mechanism as fibronectin. The peptides did not inhibit the attachment of cells to collagen. However, cells cultured on collagen-coated plastic for 24-36 h, as well as cells with demonstrable type I or type VI collagen in their matrix, were susceptible to the detaching effect of the peptides. These results indicate that the recognition mechanism(s) by which cells bind to fibronectinand vitronectin plays a major role in the substratum attachment of cells and that collagens may not be directly involved in cell-substratum adhesion. Since vitronectin is abundant in serum, it is probably an important component in mediating the attachment of cultured cells. The independence of the effects of the peptide on the presence of serum and the susceptibility of many different cell types to detachment by the peptide show that the peptides perturb an attachment mechanism that is intrinsic to the cells and fundamentally significant to their adhesion.

Mutations responsible for MYH9-related thrombocytopenia impair SDF-1-driven migration of megakaryoblastic cells

2011 ◽  
Vol 106 (10) ◽  
pp. 693-704 ◽  
Author(s):  
Valeria Bozzi ◽  
Emanuele Panza ◽  
Serena Barozzi ◽  
Cristian Gruppi ◽  
Marco Seri ◽  
...  
Keyword(s):  
Type I Collagen ◽  
Cell Types ◽  
Type I ◽  
Wild Type ◽  
Mutant Proteins ◽  
Wild Type Counterpart ◽  
Platelet Release ◽  
Myosin Iia ◽  
Different Cell Types

SummaryMYH9-related disease (MYH9-RD) is an autosomal-dominant thrombocytopenia caused by mutations in the gene for the heavy chain of nonmuscle myosin-IIA (NMMHC-IIA). Recent in vitro studies led to the hypothesis that thrombocytopenia of MYH9-RD derives from an ectopic platelet release by megakaryocytes in the osteoblastic areas of bone marrow (BM), which are enriched in type I collagen, rather than in vascular spaces. SDF-1-driven migration of megakaryocytes within BM to reach the vascular spaces is a key mechanism for platelet biogenesis. Since myosin-IIA is implicated in polarised migration of different cell types, we hypothesised that MYH9 mutations could interfere with this mechanism. We therefore investigated the SDF-1-driven migration of a megakaryoblastic cell line, Dami cells, on type I collagen or fibrinogen by a modified transwell assay. Inhibition of myosin-IIA ATPase activity suppressed the SDF-1-driven migration of Dami cells, while over-expression of NMMHC-IIA increased the efficiency of chemotaxis, indicat- ing a role for NMMHC-IIA in this mechanism. Transfection of cells with three MYH9 mutations frequently responsible for MYH9-RD (p.R702C, p.D1424H, or p.R1933X) resulted in a defective SDF-1-driven migration with respect to the wild-type counterpart and in increased cell spreading onto collagen. Analysis of differential localisation of wild-type and mutant proteins suggested that mutant NMMHC-IIAs had an impaired cytoplasmic re-organisation in functional cytoskeletal structures after cell adhesion to collagen. These findings support the hypothesis that a defect of SDF-1-driven migration of megakaryocytes induced by MYH9 mutations contributes to ectopic platelet release in the BM osteoblastic areas, resulting in ineffective platelet production.

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