Epithelial supporting cells can differentiate into outer hair cells and Deiters' cells in the cultured organ of Corti

The organ of Corti is a complex structure containing a single row of inner hair cells (IHCs) and three rows of outer hair cells (OHCs), supported respectively by one row of inner phalangeal cells and three rows of Deiters' cells. When fetal rat organ of Corti explants are cultured, supernumerary OHCs and supernumerary Deiters' cells are produced, without any additional cell proliferation. Analysis of semi- and ultrathin sections revealed that supernumerary OHCs are produced at the distal edge of the organ of Corti. Quantitative analysis of cell types present in the organ of Corti demonstrates that when the number of OHCs increases: (i) the total number of cells remains constant; (ii) the number of Deiters' cells increases; (iii) the number of tectal cells decreases and of Hensen's cells decreases. Using specific HC markers, i.e. jagged2 (Jag2) and Math1, we showed that in addition to existing OHCs, supernumerary OHCs, tectal cells and Hensen's cells expressed these markers in embryonic day 19 organ of Corti explants after 5 days in vitro. The results of this study suggest that Hensen's cells retain the capacity to differentiate into either tectal cells, which differentiate into OHCs, or into undertectal cells which differentiate into Deiters' cells. Received 15 May 2002; received after revision 18 July 2002; accepted 7 August 2002 RID="*" ID="*"Corresponding author.     

Oncogenic properties of PPM1D located within a breast cancer amplification epicenter at 17q23

We found that PPM1D, encoding a serine/threonine protein phosphatase, lies within an epicenter of the region at 17q23 that is amplified in breast cancer. We show that overexpression of this gene confers two oncogenic phenotypes on cells in culture: attenuation of apoptosis induced by serum starvation and transformation of primary cells in cooperation with RAS.     

Spectrum of Aeromonas and Plesiomonas infections in patients with cancer and AIDS

The spectrum of infection with Aeromonas and Plesiomonas included gastroenteritis, bacteremia, biliary tract infection, perirectal infection, and disseminated disease. Most patients (86%) with bacteremia were neutropenic (less than 500 PMN/mm3). Colonization of stools and sputum also occurred. Therapy with aminoglycosides, beta-lactams, trimethoprim/sulfamethoxazole, and the newer quinolones was effective in patients with AIDS and cancer.     

Progesterone receptors in the foetal uterus of guinea-pig: its stimulation after oestradiol treatment.

This paper shows for the first time the presence of progesterone receptors in the foetal guinea-pig uterus, as well as the stimulation of progesterone receptors in foetal uterus in animals treated with oestradiol.     

A new species of Kurixalus (Anura: Rhacophoridae) from northern Vietnam with comments on the biogeography of the genus

ABSTRACT

We describe a new species of rhacophorid frogs from Nghe An Province in northern Vietnam based on morphological and molecular evidences. Morphologically, Kurixalus gracilloides sp. nov. is distinguished from its congeners by a combination of the following diagnostic characters: body size small (snout–vent length 27.9–31.2 mm in males); head width subequal to head length; snout rounded with no dermal projection; canthus rostralis distinct, curved; vomerine teeth present; single internal vocal sac; iris golden-brown; small nuptial pad in finger I; dorsal surfaces golden-brown with a saddle-shaped dark marking; large dark spots on ventral surfaces absent; dermal fringes along outer edge of limbs; conical dermal appendage at the heel; skin on dorsum rough; skin on throat and chest granular; finger webbing rudimentary and toe webbing moderately developed, webbing formula I 2–2½ II 1½–3 III 1¾–3½ IV 3–1½ V. The new species is separated from all other congeners by uncorrected genetic distances ranging from 5.4% to 12.7% based on mitochondrial 16S rRNA gene. Phylogenetic analyses of mtDNA suggest that the new species is nested within a clade of Taiwanese and Yunnan Kurixalus with strong support values. The new species is currently known only from secondary bamboo forest in Pu Mat National Park, northern Vietnam, at elevations of 150 m asl. We suggest the new species should be considered as Near Threatened (NT) following the IUCN’s Red List categories.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:C1BF843F-2F31-4CED-B1F9-13A9035C77C9     

A second species of the genus Vietnamorpha Golovatch, 1984 (Polydesmida: Paradoxosomatidae) and notes on the generic relationship

A second Vietnamorpha species is described from Pu Mat National Park, north-central Vietnam. The new species is distinguished by the gonopod femorite being erect and cylindrically elongate; and the solenomere being completely sheathed by the solenophore, and being only exposed at the tip. The relationship between Vietnamorpha and several sulciferinine genera was analysed using a combination of a mitochondrial gene (16S rRNA) and two nuclear genes (18S and 28S rRNA). The genus Vietnamorpha is more closely related to the genus Anoplodesmus than to other sulciferinine genera.

www.zobank.org/urn:lsid:zoobank.org:pub:C8A19CFD-1329-427A-B380-08542BB25718     

Natural history of mesenchymal stem cells,from vessel walls to culture vessels

Mesenchymal stem/stromal cells (MSCs) can regenerate tissues by direct differentiation or indirectly by stimulating angiogenesis, limiting inflammation, and recruiting tissue-specific progenitor cells. MSCs emerge and multiply in long-term cultures of total cells from the bone marrow or multiple other organs. Such a derivation in vitro is simple and convenient, hence popular, but has long precluded understanding of the native identity, tissue distribution, frequency, and natural role of MSCs, which have been defined and validated exclusively in terms of surface marker expression and developmental potential in culture into bone, cartilage, and fat. Such simple, widely accepted criteria uniformly typify MSCs, even though some differences in potential exist, depending on tissue sources. Combined immunohistochemistry, flow cytometry, and cell culture have allowed tracking the artifactual cultured mesenchymal stem/stromal cells back to perivascular anatomical regions. Presently, both pericytes enveloping microvessels and adventitial cells surrounding larger arteries and veins have been described as possible MSC forerunners. While such a vascular association would explain why MSCs have been isolated from virtually all tissues tested, the origin of the MSCs grown from umbilical cord blood remains unknown. In fact, most aspects of the biology of perivascular MSCs are still obscure, from the emergence of these cells in the embryo to the molecular control of their activity in adult tissues. Such dark areas have not compromised intents to use these cells in clinical settings though, in which purified perivascular cells already exhibit decisive advantages over conventional MSCs, including purity, thorough characterization and, principally, total independence from in vitro culture. A growing body of experimental data is currently paving the way to the medical usage of autologous sorted perivascular cells for indications in which MSCs have been previously contemplated or actually used, such as bone regeneration and cardiovascular tissue repair.     

Domain structure and function of matrix metalloprotease 23 (MMP23): role in potassium channel trafficking

MMP23 is a member of the matrix metalloprotease family of zinc- and calcium-dependent endopeptidases, which are involved in a wide variety of cellular functions. Its catalytic domain displays a high degree of structural homology with those of other metalloproteases, but its atypical domain architecture suggests that it may possess unique functional properties. The N-terminal MMP23 pro-domain contains a type-II transmembrane domain that anchors the protein to the plasma membrane and lacks the cysteine-switch motif that is required to maintain other MMPs in a latent state during passage to the cell surface. Instead of the C-terminal hemopexin domain common to other MMPs, MMP23 contains a small toxin-like domain (TxD) and an immunoglobulin-like cell adhesion molecule (IgCAM) domain. The MMP23 pro-domain can trap Kv1.3 but not closely-related Kv1.2 channels in the endoplasmic reticulum, preventing their passage to the cell surface, while the TxD can bind to the channel pore and block the passage of potassium ions. The MMP23 C-terminal IgCAM domain displays some similarity to Ig-like C2-type domains found in IgCAMs of the immunoglobulin superfamily, which are known to mediate protein–protein and protein–lipid interactions. MMP23 and Kv1.3 are co-expressed in a variety of tissues and together are implicated in diseases including cancer and inflammatory disorders. Further studies are required to elucidate the mechanism of action of this unique member of the MMP family.     

TPX2: of spindle assembly,DNA damage response,and cancer

For more than 15 years, TPX2 has been studied as a factor critical for mitosis and spindle assembly. These functions of TPX2 are attributed to its Ran-regulated microtubule-associated protein properties and to its control of the Aurora A kinase. Overexpressed in cancers, TPX2 is being established as marker for the diagnosis and prognosis of malignancies. During interphase, TPX2 resides preferentially in the nucleus where its function had remained elusive until recently. The latest finding that TPX2 plays a role in amplification of the DNA damage response, combined with the characterization of TPX2 knockout mice, open new perspectives to understand the biology of this protein. This review provides an historic overview of the discovery of TPX2 and summarizes its cytoskeletal and signaling roles with relevance to cancer therapies. Finally, the review aims to reconcile discrepancies between the experimental and pathological effects of TPX2 overexpression and advances new roles for compartmentalized TPX2.