PubMed · 5022032
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M E Sands. 1972-04-29. Alginate casting method for recording dermatoglyphs.. https://doi.org/10.1136/bmj.2.5808.296-d
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A potentially cost-effective strategy for gene therapy of hemophilia B is to create universal factor IX-secreting cell lines suitable for implantation into different patients. To avoid graft rejection, the implanted cells are enclosed in alginate-polylysine-alginate microcapsules that are permeable to factor IX diffusion, but impermeable to the hosts' immune mediators. This nonautologous approach was assessed by implanting encapsulated mouse myoblasts secreting human factor IX into allogeneic mice. Human factor IX was detected in the mouse plasma for up to 14 days maximally at approximately 4 ng/mL. Antibodies to human factor IX were detected after 3 weeks at escalating levels, which were sustained throughout the entire experiment (213 days). The antibodies accelerated the clearance of human factor IX from the circulation of the implanted mice and inhibited the detection of human factor IX in the mice plasma in vitro. The encapsulated myoblasts retrieved periodically from the implanted mice up to 213 days postimplantation were viable and continued to secrete human factor IX ex vivo at undiminished rates, hence suggesting continued factor IX gene expression in vivo. Thus, this allogeneic gene therapy strategy represents a potentially feasible alternative to autologous approaches for the treatment of hemophilia B.
We have characterized immunohistochemically and biochemically the collagens accumulating in two compartments of the matrix formed by mature bovine articular chondrocytes in alginate beads. At all times of the 28-day culture period, more than 90% of the collagen molecules were recovered from the rim of cell-associated matrix (CM) which encapsulates individual chondrocytes and chondrocyte clusters. Both the total amount and concentration of collagens in this matrix compartment rose progressively with time. The ratio of collagen/proteoglycan remained relatively constant with time and was always five to seven times higher in the CM than in the interterritorial matrix compartment further removed from the cells. In the CM, collagen types II, IX and XI were present on Day 28 in relative proportions (95/l/3) similar to those in adult cartilage. A higher proportion of newly synthesized collagen type XI than types II or IX molecules did not become incorporated into the pericellular rim of matrix but accumulated in the further removed matrix. Although collagen type I was synthesized in small amounts by flattened cells at the surface of the beads, it did not become incorporated as heterotrimers or homotrimers in the matrix. Mature pyridinium crosslinks, principally pyridinoline, were detected as early as Day 7 of culture but became much more abundant between Days 15 and 28, especially in the CM which contained at all times more than 90% of the crosslinks formed. The codistribution of collagen types II, IX and XI and mature collagen-specific crosslinks support the contention that mature chondrocytes cultured in alginate matrix surround themselves with a protective shell whose composition is very similar to that which encapsulated the cells in vivo.
The metabolite flux of carbohydrates through primary catabolism and into hexose resynthesis has been investigated for alginic acid biosynthesis in Azotobacter vinelandii. To do these studies, we fed the microorganism a variety of 13C-labeled glucose precursors, including [U-13C6]glucose. The incorporations of the precursors were determined by 1D 13C-NMR, 2D 13C-DQF-COSY, and inverse triple-quantum correlation experiments. The results clearly show that the entire catabolism of hexose is through the Entner-Doudoroff (E-D) pathway and that the triose pools are in equilibrium. Reentry into gluconeogenesis prior to alginate synthesis occurs totally from the glyceraldehyde 3-phosphate generated by the E-D pathway. The obligatory intermediacy of triose intermediates in alginate biosynthesis was proved. The experiments and results presented in this paper constitute a new method for distinguishing the E-D pathway from glycolysis in bacteria.