Dentin Sialoprotein (DSP) Has Limited Effects on In Vitro Apatite Formation and Growth

Sialoproteins such as bone sialoprotein (BSP) and dentin sialoprotein (DSP) accumulate at the mineralization fronts in bone and dentin, respectively, suggesting they have some function in the mineralization process. BSP, a highly phosphorylated protein rich in polyglutamate repeats, is an effective nucleator of hydroxyapatite (HA) formation in vitro. The present study examines the effect of DSP, a low phosphorylated but related sialoprotein, on the formation and growth of HA. In vitro, in a gelatin gel diffusion system, DSP at low concentrations (<25 μg/ml) slightly increased the yield of HA formed at 3.5 and 5 days, while at higher concentrations (50–100 μg/ml) it slightly inhibited accumulation. Fewer mineral crystals were formed in the presence of high concentrations of DSP but they tended to aggregate (making them appear larger by electron microscopic analysis) than those formed in DSP-free gels. X-ray diffraction line broadening analysis failed to show significant changes in c-axis crystal dimensions with increasing DSP concentration. When HA-seed crystals were coated with DSP before inclusion in the gelatin gel there was a reduction in mineral accumulation relative to HA-seeds which had not been coated with DSP, but the extent of inhibition was significantly less than that seen in this system with other mineralized tissue matrix sialoproteins, such as osteopontin or BSP. The low affinity of DSP for well-characterized seed crystals and the limited effect of this protein on HA formation and growth suggest that the role of DSP in dentin is not primarily that of a mineralization regulator. Received: 25 April 2000 / Accepted: 21 July 2000 / Online publication: 2 November 2000     

Cis-2-decenoic Acid Inhibits S. aureus Growth and Biofilm In Vitro: A Pilot Study

Background  

Cis-2 decenoic acid (C2DA) disperses biofilm in many strains of microorganisms. However, whether C2DA inhibits bacterial growth or has potential to boost the actions of antibiotics is unknown.     

Response of Human Osteoblasts to Polymethylmetacrylate In Vitro

The effects of a polymethylmetacrylate (PMMA) powder with a diameter between 0.5 and 25 μm have been studied in vitro on several human osteoblast populations obtained from different sources. Parameters of cell activity such as cell growth, collagen synthesis, osteocalcin, and interleukin-6 (IL-6) production have been evaluated. Cell proliferation and collagen synthesis were inhibited after exposure to bone cement, whereas osteocalcin and IL-6 production were stimulated. These results suggest that PMMA particles could affect osteoblast activity in a way that could contribute, together with other factors, to periprosthetic osteolysis through two different pathways: a reduced periprosthetic bone formation due to the reduced osteoblast proliferation and collagen synthesis, and an osteoblast-mediated activation of osteoclastic bone resorption as suggested by the increased osteocalcin and IL-6 synthesis. In fact, osteocalcin has been demonstrated to have a role in osteoclast recruitment to bone surfaces, and IL-6 is known to induce osteoclastogenesis and to directly stimulate bone resorption. Received: 20 December 1996 / Accepted: 2 July 1997     

Changes in Glucose and Fat Metabolism in Response to the Administration of a Hepato-Preferential Insulin Analog

Endogenous insulin secretion exposes the liver to three times higher insulin concentrations than the rest of the body. Because subcutaneous insulin delivery eliminates this gradient and is associated with metabolic abnormalities, functionally restoring the physiologic gradient may provide therapeutic benefits. The effects of recombinant human insulin (HI) delivered intraportally or peripherally were compared with an acylated insulin model compound (insulin-327) in dogs. During somatostatin and basal portal vein glucagon infusion, insulin was infused portally (PoHI; 1.8 pmol/kg/min; n = 7) or peripherally (PeHI; 1.8 pmol/kg/min; n = 8) and insulin-327 (Pe327; 7.2 pmol/kg/min; n = 5) was infused peripherally. Euglycemia was maintained by glucose infusion. While the effects on liver glucose metabolism were greatest in the PoHI and Pe327 groups, nonhepatic glucose uptake increased most in the PeHI group. Suppression of lipolysis was greater during PeHI than PoHI and was delayed in Pe327 infusion. Thus small increments in portal vein insulin have major consequences on the liver, with little effect on nonhepatic glucose metabolism, whereas insulin delivered peripherally cannot act on the liver without also affecting nonhepatic tissues. Pe327 functionally restored the physiologic portal–arterial gradient and thereby produced hepato-preferential effects.     

Novel PEGylated Basal Insulin LY2605541 Has a Preferential Hepatic Effect on Glucose Metabolism

The impact of the novel basal insulin LY2605541 (LY) on hepatic and nonhepatic glucose uptake (non-HGU) was evaluated. Conscious dogs underwent euglycemic clamps with tracer and hepatic balance measurements. Clamp period infusions were peripheral venous regular insulin (0.1 nmol ⋅ kg⁻¹ ⋅ h⁻¹ [control], n = 6) or LY (bolus [nmol/kg], continuous [nmol ⋅ kg⁻¹ ⋅ h⁻¹]: 0.5, 0.5 [n = 6]; 0.375, 0.375 [n = 5]; 0.25, 0.25 [n = 4]), somatostatin, and glucose, as well as intraportal glucagon (basal). During the clamp, the dogs switched from net hepatic glucose output to uptake (rates reached 2.1 ± 1.2, 0.9 ± 2.1, 8.6 ± 2.3, and 6.0 ± 1.1 µmol ⋅ kg⁻¹ ⋅ min⁻¹ within 5 h in control, LY_0.25, LY_0.375, and LY_0.5, respectively). Non-HGU in LY increased less than in control; the ratio of change from basal in non-HGU to change in net hepatic glucose balance, calculated when glucose infusion rates (GIRs) were ~20 µmol ⋅ kg^-1 ⋅ min⁻¹ in all groups, was higher in control (1.17 ± 0.38) versus LY_0.25 (0.39 ± 0.33), LY_0.375 (−0.01 ± 0.13), and LY_0.5 (−0.09 ± 0.07). Likewise, the change from baseline in glucose R_d-to-R_a ratio was greatest in control (1.4 ± 0.3 vs. 0.6 ± 0.4, 0.5 ± 0.2, and 0.6 ± 0.2 in LY_0.25, LY_0.375, and LY_0.5, respectively). In contrast to exogenously administered human insulin, LY demonstrated preferential hepatic effects, similar to endogenously secreted insulin. Therefore, the analog might reduce complications associated with current insulin therapy.     

WNT5A Has Anti‐Prostate Cancer Effects In Vitro and Reduces Tumor Growth in the Skeleton In Vivo

Prostate cancer is the most frequent malignancy in men, and a major cause of prostate cancer–related death is attributable to bone metastases. WNT5A is known to influence the clinical outcome of various cancer types, including prostate cancer, but the exact mechanisms remain unknown. The goal of this study was to assess the relevance of WNT5A for the development and progression of prostate cancer. WNT5A expression was determined in a cDNA and tissue microarray of primary tumor samples in well‐defined cohorts of patients with prostate cancer. Compared with benign prostate tissue, the expression of WNT5A and its receptor Frizzled‐5 was higher in prostate cancer, and patients with a WNT5A expression above the median had a higher probability of survival after 10 years. Using different osteotropic human prostate cancer cell lines, the influence of WNT5A overexpression and knock‐down on proliferation, migration, and apoptosis was assessed. In vitro, WNT5A overexpression induced prostate cancer cell apoptosis and reduced proliferation and migration, whereas WNT5A knock‐down showed opposite effects. In vivo, different xenograft models were used to determine the effects of WNT5A on tumor growth. Local tumor growth and tumor growth in the bone microenvironment was considerably diminished after WNT5A overexpression in PC3 cells. WNT5A exhibits antitumor effects in prostate cancer cells and may be suitable as a prognostic marker and therapeutic target for prostate cancer and associated skeletal metastases. © 2014 American Society for Bone and Mineral Research.     

Comparison of In Vitro Response to Growth Hormone by Chondrocytes from Mandibular Condyle Cartilage of Young and Old Mice

In several aspects the features of aging resemble those of the state of growth hormone (GH) deficiency. Alterations of bone density and increased incidence of osteoporosis are some of the characteristics of aging that are similar to the findings in GH-deficient adults. Osteoarthritis (OA), a nonfatal condition predominating in old age, is characterized by the slowly progressive destruction of articular cartilage of joints. OA lesions are observed in the temporomandibular joint of ICR mice aged 7 months and older. The aim of the present study was to compare the response of chondrocytes from mandibular condyle cartilage of young and old mice to GH and to ascertain whether chondrocytes of old animals could still be stimulated to proliferate and to synthesize matrix components under the direct effect of GH in vitro. Mandibular condyles from young (3-month-old) and old (20-month-old) female ICR mice were cultured up to 72 hours in the presence of recombinant rat GH (0.1–100 ng/ml). ³H-Thymidine and ³⁵S-sulfate were introduced during the last 24 hours of culture. Administration of GH appeared to increase only slightly the incorporation of ³H-thymidine in cartilage from young compared with the response in cartilage from old animals which was much more significant at 24 hours and 48 hours in culture. The same pattern was seen for the effect of GH on the incorporation of ³⁵S-sulfate. Cartilage from young animals responded only slightly to GH, whereas a significant response was observed in cartilage from old animals after 24 and 48 hours in vitro. DNA contents were significantly elevated at all time intervals in both old and young animals, yet more significantly in cultures from old animals. In contrast, the activities of both alkaline and acid phosphatases were elevated at all time intervals in cultures from young animals, whereas no induction was observed in cultures from old animals. Tissue sections from cultures of old animals treated with GH (10 ng/ml, 48 hours) revealed atypical hypertrophic cells along the articular surface and also dark staining along the cartilage-bone interface. Exposure to tetracycline (10 mg/ml, 24 hours) resulted in an induced fluorescence, indicating enhanced mineralization in this region. Results of this study indicate that mandibular condyle cartilage from OA old mice responds in vitro to the addition of GH via anabolic activities of cell proliferation, sulfated proteoglycan synthesis, and possibly enhanced mineralization. Received: 29 March 1996 / Accepted: 31 December 1996     

人工关节磨损微粒对体外培养外周血单核细胞的影响

目的：研究人工关节磨损微粒诱发骨溶解的机理，探讨不同微粒物质倡导骨溶解能力的差异。方法：通过体外培养人外周血单核细胞对超高分子聚乙烯微粒入钛合金（Ｔｉ６Ａ１４Ｖ）微粒反应，检测培养上清液中肿瘤坏死因子（ＴＮＦ－α）含量。结果：超高分子聚乙烯微粒和钛合金微粒均可刺激单核细胞，使之产生更多的ＴＮＦ－α，与对照组相比样差异有统计学意义（Ｐ〈０．０１）。但超高分子聚乙烯组与钛合金组的ＴＮＦ－α含量比较差异     

Downregulation of CPPED1 Expression Improves Glucose Metabolism In Vitro in Adipocytes

We have previously demonstrated that the expression of calcineurin-like phosphoesterase domain containing 1 (CPPED1) decreases in adipose tissue (AT) after weight reduction. However, the function of CPPED1 in AT is unknown. Therefore, we investigated whether the change in CPPED1 expression is connected to changes in adipocyte glucose metabolism. First, we confirmed that the expression of CPPED1 decreased after weight loss in subcutaneous AT. Second, the expression of CPPED1 did not change during adipocyte differentiation. Third, CPPED1 knockdown with small interfering RNA increased expression of genes involved in glucose metabolism (adiponectin, adiponectin receptor 1, and GLUT4) and improved insulin-stimulated glucose uptake. To conclude, CPPED1 is a novel molecule involved in AT biology, and CPPED1 is involved in glucose uptake in adipocytes.Lifestyle modification improves glucose metabolism and results in a substantial reduction in the risk of type 2 diabetes in the long-term (1). In searching new putative genes related to obesity and type 2 diabetes, we have previously demonstrated a multitude of changes in adipose tissue (AT) gene expression in response to weight reduction in individuals with metabolic syndrome (2,3). Among the downregulated genes was calcineurin-like phosphoesterase domain containing 1 (CPPED1) (2); its function in AT is completely unknown.Therefore, we continued to study the role of CPPED1 in AT in more detail. Interestingly, the experiment using a Simpson-Golabi-Behmel syndrome (SGBS) cell strain demonstrated an impact of CPPED1 small interfering RNA (siRNA) on insulin-stimulated glucose uptake in mature adipocytes. Overall, the results demonstrate that CPPED1 is a novel molecule expressed in AT and is related to adipocyte function.     

Caffeine Attenuates Acute Growth Hormone Response to a Single Bout of Resistance Exercise

The purpose of this study was to investigate the effects of caffeine consume on substrate metabolism and acute hormonal responses to a single bout of resistance exercise (RE). Ten resistance-trained men participated in this study. All subjects performed one repetition maximum (1RM) test and then performed two protocols: caffeine (CAF, 6 mg·kg^-1) and control (CON) in counter balanced order. Subjects performed RE (8 exercises, 3 sets of 10 repetitions at 75% of 1RM) after caffeine or placebo ingestion one hour prior to RE. Blood samples collected prior to treatment ingestion (pre-60), immediately prior to RE (pre-exe), and 0, 15, 30 min post to RE (P0, P15, P30) for analysis of insulin, testosterone, cortisol, growth hormone, glucose, free fatty acid and lactic acid. Each experiment was separated by seven days. In this study, statistical analysis of a two-way analysis of variance (treatment by time) with repeated measures was applied. After ingesting caffeine, the concentrations of free fatty acid (pre- exe, P0, P15, P30) in CAF were significantly higher than CON (p < 0.05). Additionally, the responses of GH (P0, P15, P30) in CAF were significantly lower than CON (p < 0.05), whereas the concentrations of insulin, testosterone and cortisol were not different between CAF and CON (p < 0.05) after RE. The results of this study indicated that caffeine ingestion prior to RE might attenuate the response of GH. This effect might be caused by the elevation in blood FFA concentration at the beginning of RE.

Key points

• Caffeine ingestion may attenuate the response of GH to a single bout of resistance exercise.
• The depression of GH response may be caused by the elevation in serum FFA concentration at the beginning of resistance exercise.
• Caffeine ingestion before resistance exercise may not alert the concentration of cortisol and testosterone.

Key words: Nutritional supplementation, growth hormone, free fatty acid, ergogenic aids     

人工瓣膜材料细菌粘附与细菌生长的关系

目的通过体外实验,评价人工瓣膜材料细菌粘附与细菌生长的关系。方法采用平板菌落计数法、１２５Ⅰ标记细菌放射性测定法测定金黄色葡萄球菌、表皮葡萄球菌、大肠杆菌和绿脓杆菌的生长曲线,同时测定４种细菌对人工瓣膜材料涤纶、热解碳、聚四氟乙烯的粘附情况。结果４种细菌对３种人工瓣膜材料粘附能力与细菌生长曲线基本一致。细菌在体外生长不受人工瓣膜材料存在的影响,不同时间同一细菌对同一材料粘附不同。结论细菌对材料粘附与细菌生长曲线基本一致,细菌对人工瓣膜材料的粘附是一个动态变化过程     

PKA Enhances the Acute Insulin Response Leading to the Restoration of Glucose Control

Diabetes arises from insufficient insulin secretion and failure of the β-cell mass to persist and expand. These deficits can be treated with ligands to Gs-coupled G-protein-coupled receptors that raise β-cell cAMP. Here we studied the therapeutic potential of β-cell cAMP-dependent protein kinase (PKA) activity in restoring glucose control using β-caPKA mice. PKA activity enhanced the acute insulin response (AIR) to glucose, which is a primary determinant of the efficacy of glucose clearance. Enhanced AIR improved peripheral insulin action, leading to more rapid muscle glucose uptake. In the setting of pre-established glucose intolerance caused by diet-induced insulin resistance or streptozotocin-mediated β-cell mass depletion, PKA activation enhanced β-cell secretory function to restore glucose control, primarily through augmentation of the AIR. Enhanced AIR and improved glucose control were maintained through 16 weeks of a high-fat diet and aging to 1 year. Importantly, improved glucose tolerance did not increase the risk for hypoglycemia, nor did it rely upon hyperinsulinemia or β-cell hyperplasia, although PKA activity was protective for β-cell mass. These data highlight that improving β-cell function through the activation of PKA has a large and underappreciated capacity to restore glucose control with minimal risk for adverse side effects.     

Comparing Response to Cognitive Processing Therapy in Military Veterans With Subthreshold and Threshold Posttraumatic Stress Disorder

Research suggests that subthreshold posttraumatic stress disorder (PTSD) symptomatology is associated with increased risk for psychological and functional impairment, including increased risk for suicidal ideation. However, it does not appear that any studies to date have investigated whether subthreshold PTSD can effectively be treated with evidence‐based, trauma‐focused treatment. Accordingly, we tested response to cognitive processing therapy (CPT) in 2 groups of military veterans receiving care at a VA outpatient specialty clinic, 1 with subthreshold PTSD at pretreatment (n = 51) and the other with full, diagnostic PTSD (n = 483). Multilevel analysis revealed that both groups experienced a significant decrease in PTSD symptoms over the course of therapy (the full and subthreshold PTSD groups experienced an average decrease of 1.79 and 1.52 points, respectively, on the PTSD Checklist with each increment of time, which was coded from 0 at pretreatment to 13 at posttreatment). After controlling for pretreatment symptom severity, a between‐groups difference was not found. These results suggest that CPT is an effective form of treatment among military veterans, and that its effectiveness does not differ between subthreshold and threshold groups.     

产多元醇酵母的耐高渗生长特征

应用低水活度选择性增殖的方法从花卉、果园土壤、水果和蜂产品等样品中分离得到２６７株耐高渗酵母,其中２０６株生产阿拉伯醇、赤藓糖醇和甘油等各种多元醇．对随机挑选的６２株产多元醇的耐高渗酵母在不同质量浓度葡萄糖培养基中的生长特征进行了研究,结果显示酵母的耐高渗生长能力与其产多元醇的类别之间存在关联．在所调查的酵母中,产赤藓糖醇的酵母耐高渗生长能力最强、产阿拉伯醇的酵母耐高渗生长能力次之,产甘油的酵母耐高渗生长能力较弱．