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1.
Based on its proven anabolic effects on bone in osteoporosis patients, recombinant parathyroid hormone (PTH1-34) has been evaluated as a potential therapy for skeletal repair. In animals, the effect of PTH1-34 has been investigated in various skeletal repair models such as fractures, allografting, spinal arthrodesis and distraction osteogenesis. These studies have demonstrated that intermittent PTH1-34 treatment enhances and accelerates the skeletal repair process via a number of mechanisms, which include effects on mesenchymal stem cells, angiogenesis, chondrogenesis, bone formation and resorption. Furthermore, PTH1-34 has been shown to enhance bone repair in challenged animal models of aging, inflammatory arthritis and glucocorticoid-induced bone loss. This pre-clinical success has led to off-label clinical use and a number of case reports documenting PTH1-34 treatment of delayed-unions and non-unions have been published. Although a recently completed phase 2 clinical trial of PTH1-34 treatment of patients with radius fracture has failed to achieve its primary outcome, largely because of effective healing in the placebo group, several secondary outcomes are statistically significant, highlighting important issues concerning the appropriate patient population for PTH1-34 therapy in skeletal repair. Here, we review our current knowledge of the effects of PTH1-34 therapy for bone healing, enumerate several critical unresolved issues (e.g., appropriate dosing regimen and indications) and discuss the long-term potential of this drug as an adjuvant for endogenous tissue engineering.  相似文献   
2.
The chemotactic specificity of ia-positive and -negative macrophages was studied by using three macrophage chemotactic factors (MCF), -a, -b, and -c, isolated from delayed hypersensitivity reaction (DHR) skin sites in guinea pigs. Listeria-elicited macrophages migrated toward MCF-a, -b, and -c. The chemotactic responses suggested responsive subpopulations to MCF. The electronic programmable individual cell sorter (EPICS) was used to separate macrophages with anti-la monoclonal antibodies. Ia-positive subpopulations responded to MCF-c, although they did not migrate toward MCF-a and -b. In contrast, Ia-negative subpopulations migrated toward MCF-a and -b, but not toward MCF-c. Furthermore, MCF-c attracted Ia-positive macrophages, whereas MCF-a and -b were Ia-negative in vitro; MCF did not induce Ia-negative macrophages to express surface Ia-antigens in vitro. MCF-c was able to produce massive Ia-positive macrophage accumulations when injected i.p., whereas MCF-a accumulated Ia-negative macrophages. The data suggest that MCF-a and -b, which mediate initial macrophage reactions, attract Ia-negative macrophages, and that MCF-c, which mediates predominant macrophage reactions, attract Ia-positive macrophages in the DHR.  相似文献   
3.
Pulmonary macrophages in pre- and postnatal rats were examined histochemically with a battery of peroxidase labeled lectins. Among them, Griffonia simplicifolia agglutinin I-B4 (GSA I-B4) which binds specifically to terminal alpha-galactose showed selective affinity in lung for the monocyte-macrophage line. These cells were demonstrable with GSA I-B4 from the 14th day of gestation through the adult. Extension to the ultrastructural level showed strong selective binding of this lectin to the surface of the plasmalemma and inner face of membranes limiting phagosomes in macrophages. At day 14 of gestation, monocyte-like cells positive with GSA I-B4 were scattered in various organs including lung. The lectin reactive cells in lung increased in number and size with development, infiltrating the interstitium through day 20 of gestation and then also entering the alveolar space. These findings suggest that GSA I-B4 recognizes a surface glycoconjugate characteristic of the pulmonary monocyte-macrophage line. Such selective lectin affinity offers a marker for detecting the pulmonary macrophages and examining their kinetics by light and electron microscopy.  相似文献   
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5.
Prolonged loading repetitions can diminish the mechanosensitivity of bones, and increased intervals between loading might restore sensitivity. This study was designed to investigate the effects of intervals between loadings or bouts on osteogenic response. Forty female Fisher 344 rats aged 5 wk were divided into a control group and three exercise groups: 20 jumps in a single bout with a 3-s (S3) or 30-s (S30) jump interval, or 20 jumps in 2 bouts (10 x 2) separated by a 6-h interval with a 3-s jump interval (D3). After 8 wk of training, the bone masses per body weight of the femur and tibia were significantly greater in the three exercise groups than in the control group, and these values were also greater in S30 than in S3, although they were at the same level in D3 and S3. These data suggest that a longer interval (30 s) between individual loading had more effective anabolic effects on bone than a shorter interval (3 s).  相似文献   
6.
New techniques are proposed for differentiating each type of gastric epithelial cell in the same tissue section. The techniques combine the following stains: paradoxical concanavalin A staining (PCS) to identify mucous neck cells, periodic acid Schiff-concanavalin A staining to distinguish mucous neck cells from surface mucous cells, and a modified Bowie's stain to demonstrate zymogen granules of chief cells. Feulgen hydrolysis preceding the Bowie stain was found to remove most of the nonspecific coloration encountered with the original Bowie method. The results obtained by the new sequences were as follows: Feulgen hydrolysis-PCS-Bowie staining: mucous neck cells stained brown and chief cell zymogen granules deep blue. The other mucin-secreting cells remained unstained; Feulgen hydrolysis-PAS-concanavalin A-Bowie staining: mucous neck cells stained brown, zymogen granules stained deep blue to purplish blue and surface mucous cells stained purplish red.  相似文献   
7.
Comparison of growth properties of carrot hairy root in various bioreactors   总被引:1,自引:0,他引:1  
Summary Growth properties of carrot hairy root cells in various bioreactors were investigated. A turbine-blade reactor and an immobilized rotating drum reactor were found to be advantageous for the hairy root culture because of a high oxygen transfer coefficient (k in L a). After 30 days of culture, 10 g/l of dry hairy root cells were obtained in both bioreactors and maximum growth rates (V m ) were found to be 0.63 and 0.61 g/l per day for the turbine-blade reactor and immobilized rotating drum reactor, respectively. Specific growth rates () at various cultivation times were observed to be linearly proportional to X/k l a for both bioreactor configurations where X is the cell concentration. The estimated specific oxygen uptake rate of 0.34 mmol O2/g dry cells per hour compares fairly well with an experimental value of 0.3.  相似文献   
8.
Summary The apical surface coat of type II pneumocytes and Clara cells in pre- and post-natal rat lung was examined with lectin histochemical methods. Lectins fromHelix pomatia (HPA), peanut (PNA) andMaclura pomifera (MPA) were conjugated with horseradish peroxidase and used to stain paraffin sections of fixed lung with or without certain pre-treatments. HPA and MPA were observed to react with almost all type II pneumocytes at postnatal day 1. Type II pneumocytes that stained with a sialidase—PNA sequence increased from a few positive cells at postnatal day 5 to many in the adult. It has been reported that the surface coat of type II pneumocytes closely resembles that of Clara cells in its staining with histochemical methods employing cationic dyes or lectins including MPA and PNA. However, staining with HPA, especially after periodic acid oxidation, revealed many type II pneumocytes with strong reactivity but showed only a few Clara cells that were faintly positive. HPA also stained alveolar macrophages. The HPA affinity of macrophages, however, was labile to oxidation with periodic acid or galactose oxidase unlike that of type II pneumocytes. This difference suggests that HPA recognizes more than one type of sugar structure.To whom all correspondence and reprint requests should be addressed.  相似文献   
9.
Hairy roots were obtained following inoculation of the stems of Lobelia inflata L. with Agrobacterium rhizogenes strain ATCC 15834. These hairy roots contained agropine and mannopine. In addition, lobeline was detected by HPLC and confirmed by mass spectrometry. Various media were tested for the growth of hairy roots as well as for the content of lobeline in hairy roots. The growth rate of hairy roots cultured in Nitsch and Nitsch's medium was approximately one third of those cultured in other media. The lobeline content of hairy roots (18–54 g/g dry weight) cultured in these media was the same order of magnitude compared with that of roots of L. inflata (24 g/g dry weight) cultivated in pots. The hairy roots cultured in Nitsch and Nitsch's medium were morphologically different from those cultured in other media.Abbreviations MS medium Murashige and Skoog's medium - 1/2 MS medium one-half strength of the standard Murashige and Skoog's medium - B5 medium Gamborg's B5 medium - NN medium Nitsch and Nitsch's medium - FW fresh weight - DW dry weight  相似文献   
10.
The cytotoxin produced by Clostridium difficile was highly purified by using ammonium sulfate fractionation and successive column chromatographies of DEAE-Sephadex A-25, hydroxyapatite, Bio-Gel A-0.5m, Phenyl-Sepharose CL-4B, and Mono Q. The purified cytotoxin gave a single band on conventional and sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the presence of dithiothreitol. Its molecular weight was estimated to be 260,000 and 50,000 by gel filtration and sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis in the presence of dithiothreitol, respectively. Thus it was supposed that the toxin consists of 5 subunits having molecular weight of approximately 50,000. It had an isoelectric point of 6.6. The toxin was heat-labile (60 C for 10 min) and inactivated by treatment with trypsin and pronase, or at pH below 4 or over 10. The minimum cytotoxic dose of the cytotoxin against Chinese hamster ovary cells was 3 ng. It was also demonstrated that the toxin is antigenically different from enterotoxin of C. difficile.  相似文献   
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