Ageing in Amphibians

Kara, T.C.

doi:10.1159/000213585

Cited by 37 publications

(24 citation statements)

References 43 publications

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“…Short-lived species of amphibians appear to show gradual senescence, but the long-lived ones, may show very slow or negligible senescence (Kara, 1994).…”

Section: Aging In Amphibiansmentioning

confidence: 99%

Aging of the vertebrate immune system

Torroba

Zapata

2003

Microscopy Res & Technique

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We have summarized current knowledge on the aging of the immune system in three vertebrate groups: fish, amphibians and birds. Available data are few due to difficulties in studying ageing in natural populations and in accurately determining age. In all vertebrates, the most obvious evidence of the senescence of lymphoid tissue is the involution of thymus, which courses with decreased numbers of thymocytes, and loss of the histological organization of gland. On the other hand, there is little information on aged secondary lymphoid organs. Possible influence of the endocrine system in the changes observed in aged lymphoid organs is also discussed.

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“…Short-lived species of amphibians appear to show gradual senescence, but the long-lived ones, may show very slow or negligible senescence (Kara, 1994).…”

Section: Aging In Amphibiansmentioning

confidence: 99%

Aging of the vertebrate immune system

Torroba

Zapata

2003

Microscopy Res & Technique

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“…Treatment of the mouse myoblast cell line C2C12 (Katagiri et al, 1994; Akiyama et al, 1997) and muscle satellite cells isolated from adult mice (Asakura et al, 2001), with bone morphogenetic protein‐2 ( BMP‐2), inhibits myotube formation and induces the expression of osteocalcin and alkaline phosphatase (ALP) activity, changing the differentiation pathway of C2C12 and satellite cells into the osteoblastic lineage. Interestingly, ALP levels are increased in several muscular diseases (Kara, 1994; Amthor et al, 1996; Brunelli, 2001) and animal models for skeletal muscle dystrophy (Kirkeby and Moe, 1985). Our group and other authors have studied microenvironmental changes in the skeletal muscle of the mdx mouse, an animal model homologous to Duchenne muscular dystrophy (Allamand and Campbell, 2000), and observed important increases in the amount of extracellular matrix (ECM) proteoglycans present at the endomysium and perimysium (Caceres et al, 2000).…”

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confidence: 99%

Changes in secreted and cell associated proteoglycan synthesis during conversion of myoblasts to osteoblasts in response to bone morphogenetic protein‐2: Role of decorin in cell response to BMP‐2

Gutiérrez

Osses

Brandan

2005

Journal Cellular Physiology

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Proteoglycans have been identified within the extracellular matrices (ECM) of bone and are known to play a role in ECM assembly, mineralization, and bone formation. Bone morphogenetic protein-2 (BMP-2) specifically converts the differentiation pathway of C2C12 myoblasts into that of osteoblast lineage cells. Microarray analyses of the mouse myoblast cell line C2C12 and its differentiation into osteoblastic cells in response to BMP-2 have suggested the up-regulation of several proteoglycan species, although there is a lack of biochemical evidence for this response. In this study we have biochemically analyzed and characterized the proteoglycan populations that are induced in C2C12 cells upon osteoblastic differentiation produced by BMP-2. An important and specific increase in the synthesis of secreted decorin was observed in BMP-2-treated cells, as compared to untreated myoblasts and myoblasts induced to differentiate into myotubes. Decorin was seen to contain larger glycosaminoglycan (GAG) chains in induced than in non-induced cells. BMP-2 also produced an augment in the synthesis of different heparan sulfate proteoglycans such syndecan-2, - 3, glypican, and perlecan in detergent-soluble and non-soluble cellular fractions. We also examined whether the evident changes induced by BMP-2 in secreted decorin could have a functional role. BMP-2 signaling dependent as well as induction of alkaline phosphatase (ALP) activity was diminished in decorin null myoblasts compared to wild type myoblats although cell surface level of BPM-2 receptors was unchanged. These results are the first biochemical evidence and analysis for the effect of BMP-2 on the synthesis of proteoglycan during osteogenic conversion of myoblasts and suggest a role for decorin in cell response to BMP-2.

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“…Longevity data are available for many amphibian species (Bowler, 1977;Kara, 1994;Smirina, 1994). Amphibians from northern climates tend to have longer life spans than those from southern latitudes, and larger aquatic salamanders live longer than their smaller, terrestrial counterparts.…”

Section: Normal Valuesmentioning

confidence: 99%