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  • SAGE Publications  (3)
  • 1
    In: Cell Transplantation, SAGE Publications, Vol. 6, No. 5 ( 1997-09), p. 527-530
    Abstract: The permeation of components of complement and secreted peptides through polymer capsules (PM30, K6305, and K5708) were examined. To analyze permeability by complement, the degree of hemolysis of sensitized sheep erythrocytes (EA) (1 × 10 9 /ml) enclosed in each type of capsule was examined after 24-h incubation in culture medium containing 10% human serum. PM30 and K6305 prevented the permeation of complement well, while K5708 did not. EA suspended in alginate prevented hemolysis even in K5708. Peptide permeation through the capsules was assessed by measuring the concentration of ACTH secreted by proopiomelanocortin (POMC)-gene-transfected-Neuro2A in the culture medium on days 4, 7, 14, 21, and 28 after encapsulation. The ACTH levels in the culture medium remained high until day 28. Alginate appeared to prevent the secretion, because ACTH levels decreased in alginate-suspended cells after day 14. The PM30-K6305 double capsules containing cell lines, Neuro2A, BHK21 (hamster fibroblasts), L929 (mouse fibroblasts), and HF-SKFII (human fibroblasts) were transplanted into the cerebrospinal fluid (CSF) space of the monkeys in the lumber region. The morphological examination showed the partial survival of Neuro2A, and BHK21 and HF-SKFII, which were cells concordant with the monkeys. On the other hand, L929 cells, which were discordant with the monkeys, could not survive at all. Because these results suggest that the complement components penetrate the polymer capsules, concordant cells are preferable for xenografting with polymer capsules into the CSF space.
    Type of Medium: Online Resource
    ISSN: 0963-6897 , 1555-3892
    Language: English
    Publisher: SAGE Publications
    Publication Date: 1997
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  • 2
    Online Resource
    Online Resource
    SAGE Publications ; 1995
    In:  Cell Transplantation Vol. 4, No. 1_suppl ( 1995-01), p. 13-17
    In: Cell Transplantation, SAGE Publications, Vol. 4, No. 1_suppl ( 1995-01), p. 13-17
    Abstract: The purpose of this study was to assess whether xenogeneic tumor cells secreting β-endorphin and immunologically isolated in polymer capsules could survive and continue to reduce pain when transplanted into the spinal cerebro-spinal fluid (CSF) space of rats. Also, a silicone container for polymer capsules was designed for the clinical application of this method of cell therapy. The mouse tumor cell lines, proopiomelanocortin gene transfected Neuro2A which secrete β-endorphin, were enclosed in polymer capsules at a density of 5 x 10 6 /mL, and transplanted into the spinal CSF space from the occipito-atlantal junction of male Sprague-Dawley rats. Three analgesiometric tests —the tail pinch test, the hot plate test, and electrical stimulation test — showed that the rats with encapsulated Neuro2A (n = 6) were significantly less sensitive to pain after transplantation than control animals (n = 8). The analgesia induced by the encapsulated cells secreting β-endorphin was attenuated by the opiate antagonist naloxone. Morphological study revealed that the encapsulated cells survived for 1 mo after transplantation into the CSF space. An in vitro experiment on cultured capsules (3 cm long) with a silicone container (Kaneka Medics Co) showed that the encapsulated Neuro2A (5 x 10 6 mL) could secrete peptides for 1 mo. The results of this study indicate that immunologically isolated xenogeneic tumor cells can secrete opiate in the CSF space, and that a silicone container may help the application of this method to the treatment of cancer pain.
    Type of Medium: Online Resource
    ISSN: 0963-6897 , 1555-3892
    Language: English
    Publisher: SAGE Publications
    Publication Date: 1995
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  • 3
    In: Cell Transplantation, SAGE Publications, Vol. 8, No. 4 ( 1999-07), p. 431-434
    Abstract: In our previous study, xenogeneic mouse neuroblastoma cells bearing the POMC gene, the precursor of ACTH and β-endorphin, were implanted within polymer capsules into the CSF space of rats. Although ACTH and β-endorphin were secreted, we were not able to control the amounts or times of hormone release. A promoter that is inducible by administration of tetracycline derivatives (Tet) was linked to the POMC gene to control its gene expression (Neuro2A-Tet-On-POMC; NTP). The results showed that POMC gene expression in the implanted encapsulated NTP cells could be regulated in a dose-dependent manner by Tet administration to the hosts. However, no analysis of gene control with the Tet-On system over a long period has been performed. In this study, encapsulated NTP cells were treated in vitro with doxycycline (Dox) (1.0, 10, 100, 1000 ng/ml) continuously for a month. On day 4, the amount of ACTH secretion was dependent on the Dox dose. But in the course of the experiment, the difference of ACTH secretion among those treated with Dox 10, 100, and 1000 ng/ml was eliminated. On the other hand, NTP cells, which were treated with Dox (1000 ng/ml) just on days 7, 14, 21, and 28, secreted almost the same amount of ACTH in 24 h. From these results, for clinical use, an NTP cell line that secretes enough opiate to reduce pain sensitivity without Dox should be established, and Dox could then be administered if necessary.
    Type of Medium: Online Resource
    ISSN: 0963-6897 , 1555-3892
    Language: English
    Publisher: SAGE Publications
    Publication Date: 1999
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