Effects of continuous calcitonin treatment on osteoclasts derived from cocultures of mouse marrow stromal and spleen cells.

BACKGROUND: Continuous calcitonin (CT) treatment for bone diseases associated with increased bone resorption may be followed by prolonged depression of osteoclast response to CT. The mechanisms of this "escape" phenomenon remain unclear. METHODS: We examined the effects of continuous CT treatment on cell formation, calcitonin receptor (CTR) expression, response to CT, and bone resorption of osteoclasts in a coculture of mouse marrow stromal and spleen cells in the presence of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. Cells were cocultured and treated with salmon CT (sCT) for 7, 14, or 21 days. The effects of continuous CT treatment on osteoclast formation was determined by quantitation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells (MNCs). CTR expression in osteoclasts was determined by binding of [125I]sCT in autoradiography. Bone resorption and CT responsiveness were assessed by examining the formation of resorption pits and by enumerating osteoclast reattachment on dentine slices after sCT rechallenge. RESULTS: TRAP-positive MNCs appeared in cocultures treated with sCT and were similar in number and morphology to those in control cultures, regardless of the concentration and duration of sCT treatment. A decrease in CTR expression was identified as a loss of silver grains from the TRAP-positive cells in cocultures receiving sCT treatment for 14 or 21 days. Partial recovery of CTR expression in TRAP-positive cells was evident in cocultures treated with sCT for only the first 7 days of coculture. TRAP-positive MNCs in cocultures treated with sCT for 14 or 21 days were resistant to the rechallenge with sCT. They attached to dentine slices and caused numerous resorption pits compared with control cells and cells treated with sCT for the first 7 days of coculture (p < 0.01). CONCLUSION: These findings suggest that the escape phenomenon that develops after continuous CT treatment may be due, at least in part to: 1) loss of responsiveness to CT in existing osteoclasts; and 2) development of new osteoclasts that are CTR-deficient and, therefore, refractory to CT rechallenge.     

Kinetics of the biosynthesis of complement subcomponent C1q by murine macrophages: LPS, immune complexes, and zymosan alone and in combination with interferon-gamma.

We investigated the effects of bacterial lipopolysaccharide (LPS), immune complexes (IC), and C3b opsonized zymosan (AZ) alone and in combination with interferon-gamma (IFN-gamma) priming on macrophage synthesis and secretion of C1q. Our results indicated that LPS, IC, and AZ alone stimulated C1q mRNA and secretion in the absence of IFN-gamma. The increase in mRNA accumulation was detectable after 3 h, peaked at 6 h and was maintained at constitutive levels for 24 h. There was a corresponding early burst of increased secretion of functional C1q after 3 to 6 h which declined rapidly after 9 to 24 h culture of LPS-stimulated macrophages. Priming of macrophages with IFN-gamma and simultaneous triggering with LPS, IC, or AZ produced additive rather than synergistic increases in C1q mRNA accumulation. These same agents inhibited constitutive secretion of C1q in the absence of IFN-gamma priming as determined by autoradiographic analysis of metabolically radiolabeled secretory C1q. Triggering of IFN-gamma primed macrophages with LPS, IC, or AZ also markedly suppressed the increased rate of C1q secretion induced by IFN-gamma in a dose-related fashion. A corresponding dose-dependent increased accumulation of endogenous C1q in cell lysates was detected by Western blot analysis of macrophages which had been stimulated by LPS, IC, or AZ alone or in combination with IFN-gamma. Our findings indicate that LPS as well as FcR and C3bR triggering agents stimulate early and sustained C1q synthesis accompanied by an early and short-lived burst of C1q secretion which rapidly diminished and results in an increased intracellular accumulation of C1q due to ongoing synthesis. IFN-gamma appeared to further amplify the same kinetics of increased C1q mRNA accumulation and decreased extracellular accumulation mediated by LPS, IC, and ZM. Our results suggest that LPS, IC, and AZ alone or in combination with IFN-gamma stimulate early C1q production to modulate macrophage effector functions followed by an inhibition of C1q secretion when the activation process has been culminated.     

间硝苯地平对血管紧张素Ⅱ促进血管平滑肌细胞增殖和蛋白质合成的影响

以培养血管平滑肌细胞(vascularsmcothmusclecell,VSMC)为模型,观察了间硝苯地平(m-nifedipine,m-Nif)对血管紧张素Ⅱ(angiotensinⅡ,ANGⅡ)促进VSMC增殖和蛋白质合成的影响。结果表明,m-Nif抑制ANGⅡ(100nmol·L^-1)引起VSMC[³H]thymidine和[³H]leucine参入,并呈剂量依赖性。m-Nif(2×10^-6mol·L^-1)可抑制ANGⅡ对VSMC的刺激、DNA及蛋白质合成速率,分别降低了46%,58%,53%。提示m-Nif可抑制ANGⅡ对VSMC增殖和蛋白合成的促进作用。     

Properties of molten magnesium oxide

The Significant Structure Theory of Liquids has been used to calculate the thermodynamic properties, viscosity, self-diffusion coefficient, and specific conductance of molten magnesium oxide, taking account of the decomposition of MgO to Mg and O₂ species in the gas-like part of the partition function.     

Effect of adenovirus-mediated transfer of the CTLA4IG gene in hamster-to-rat xenotransplantation

BACKGROUND: Costimulatory molecules such as CD28 and B7 are essential for T cell activation, as well as playing a role in the T cell receptor and major histocompatibility complex pathway. It is well known that rejection in allotransplantation is diminished by treatment with CTLA4Ig, but whether a similar effect occurs in xenotransplantation remains to be determined. METHODS: In this study, we investigated whether adenovirus-mediated gene transfer with CTLA4Ig cDNA by intravenous injection to the recipient is effective in suppression in hamster-to-rat cardiac xenotransplantation. RESULTS: With CTLA4Ig gene transfer, the duration of gene expression was clearly prolonged, based on reduced production of antiadenovirus antibody and shrinkage of the spleen. The survival of cardiac xenografts was significantly prolonged with CTLA4Ig gene transfer compared to the control graft, and survival with combination use of FK506 and CTLA4Ig gene transfer in xenotransplantation was also significantly prolonged compared to that with CTLA4Ig gene transfer alone. Cessation of the cardiac graft in the combination treatment occurred in parallel with the elevation of antihamster IgM antibodies in rat sera. CONCLUSIONS: These results suggest that adenovirus-mediated CTLA4Ig gene transfer is effective for immunosuppression in hamster-to-rat xenotransplantation.     

Effects on function and quality of life of postoperative home-based physical therapy for patients with hip fracture

OBJECTIVE: To evaluate the effects of a 3-month home-based physical therapy (PT) program for patients with hip fracture after surgery. DESIGN: Randomized controlled trial. SETTING: Home. PARTICIPANTS: Twenty-five patients recently discharged from an acute orthopedic department. INTERVENTIONS: Patients were randomized to the home-based PT group (n=13), where they received home-based PT 8 times from discharge to month 3 postdischarge, or to the control group (n=12). The home-based PT program included exercises for muscle strengthening, range of motion (ROM), balance, and functional training. Patients in the control group were instructed to practice the exercise program given at bedside before discharge. MAIN OUTCOME MEASURES: Patients were evaluated for hip ROM, strength, walking velocity, Harris hip score, and health-related quality of life (HRQOL) at the week of discharge and at 1, 3, and 6 months after discharge. RESULTS: The baseline characteristics showed no difference between the 2 groups. Harris score of the home-based PT group progressed from 58.6+/-8.5 to 90.1+/-5.4 at month 3, whereas Harris score of the control group progressed from 54.6+/-14.5 to 77.4+/-10.0 (P<.01). Scores of the psychologic domain of HRQOL for the home-based PT group were significantly better at month 1 (P<.05) and month 3 (P<.01) after discharge. Moreover, the physical domain score of the home-based PT group was also significantly better (P<.05) at 3 months after discharge. CONCLUSIONS: Home-based PT programs could help patients regain function and HRQOL earlier.     

Nonpeptide alphavbeta3 antagonists. Part 11: discovery and preclinical evaluation of potent alphavbeta3 antagonists for the prevention and treatment of osteoporosis

3-(S)-Pyrimidin-5-yl-9-(5,6,7,8-tetrahydro-[1,8]naphthyridin-2-yl)-nonanoic acid (5e) and 3-(S)-(methylpyrimidin-5-yl)-9-(5,6,7,8-tetrahydro-[1,8]naphthyridin-2-yl)-nonanoic acid (5f) were identified as potent and selective antagonists of the alpha(v)beta(3) receptor. These compounds have excellent in vitro profiles (IC(50) = 0.07 and 0.08 nM, respectively), significant unbound fractions in human plasma (6 and 4%), and good pharmacokinetics in rat, dog, and rhesus monkey. On the basis of the efficacy shown in an in vivo model of bone turnover following once-daily oral administration, these two compounds were selected for clinical development for the treatment of osteoporosis.     

Lipid nano/submicron emulsions as vehicles for topical flurbiprofen delivery

The application of lipid nano/submicron emulsions as topical drug carrier systems for the percutaneous absorption of flurbiprofen was investigated. The lipid emulsions were made up of isopropyl myristate (IPM), soybean oil, or coconut oil as the oil phase, egg lecithin as the predominant emulsifier, and double-distilled water as the external phase. Stearylamine (SA) and deoxycholic acid (DA) also were used to produce positively and negatively charged emulsions. To evaluate the physicochemical properties of the lipid emulsions, particle size by laser light scattering, the image of atomic force microscopy, and relaxation time values by Nuclear Magnetic Resonance (NMR) were determined. The in vitro permeation data showed that incorporation of SA significantly reduced the topical delivery of flurbiprofen. On the other hand, incorporation of DA exhibited no or a negligible effect on drug permeation. Enhancement of drug absorption was observed when adding oleic acid as part of the oil phase. The in vivo topical application of flurbiprofen from selected lipid emulsions showed a similar trend to the in vitro status. Furthermore, the intersubject variability was considerably reduced by lipid emulsions than by aqueous suspensions in both the in vitro and in vivo experiments. The irritant profiles of lipid emulsions showed that IPM elicited higher irritation than soybean oil. The incorporation of oleic acid also produced skin disruption. The results in the present study suggest the feasibility of lipid emulsions for the topical delivery of flurbiprofen.