[Zinc finger protein 521 suppresses osteogenic differentiation of rat mesenchymal stem cells by inhibiting the Wnt/beta-catenin signaling pathway].

Zinc finger protein 521 (Zfp521) is involved in a number of cellular processes in a variety of cells and tissues. In the present study, the effects of Zfp521 on osteogenic differentiation of rat mesenchymal stem cells (MSCs) were investigated. The results showed that, in rat MSCs, knocking down cellular Zfp521 by short hairpin RNA (shRNA) decreases cell proliferation while promoting ALP activity, calcium accumulation, and the expression of mRNA that encodes bone sialoprotein (BSP), osteocalcin (OCN) and Runx2. Furthermore, in Zfp521-depleted cells, the up-regulation of phospho-Wnt (p-Wnt) and beta-catenin expression levels was detected. However, over-expression of Zfp521 played the opposite role in proliferation and osteogenic differentiation of rat MSCs. To further demonstrate the functions of the Wnt/beta-catenin signaling in Zfp521 regulated-osteogenic differentiation, the activation of Wnt/beta-catenin was blocked with IWP-2 inhibitor. The suppression of the Wnt/beta-catenin pathway completely abrogated the effects of Zfp521 knockdown on osteogenic differentiation of rat MSCs. Therefore, we conclude that Zfp521 regulates osteogenic differentiation of rat MSCs through the suppression of the Wnt/beta-catenin signaling pathway.

Radiographic predictors for bone mineral loss: Cortical thickness and index of the distal femur.

OBJECTIVES: Researchers continue to seek easier ways to evaluate the quality of bone and screen for osteoporosis and osteopenia. Until recently, radiographic images of various parts of the body, except the distal femur, have been reappraised in the light of dual-energy X-ray absorptiometry (DXA) findings. The incidence of osteoporotic fractures around the knee joint in the elderly continues to increase. The aim of this study was to propose two new radiographic parameters of the distal femur for the assessment of bone quality. METHODS: Anteroposterior radiographs of the knee and bone mineral density (BMD) and T-scores from DXA scans of 361 healthy patients were prospectively analyzed. The mean cortical bone thickness (CBTavg) and the distal femoral cortex index (DFCI) were the two parameters that were proposed and measured. Intra- and interobserver reliabilities were assessed. Correlations between the BMD and T-score and these parameters were investigated and their value in the diagnosis of osteoporosis and osteopenia was evaluated. RESULTS: The DFCI, as a ratio, had higher reliability than the CBTavg. Both showed significant correlation with BMD and T-score. When compared with DFCI, CBTavg showed better correlation and was better for predicting osteoporosis and osteopenia. CONCLUSION: The CBTavg and DFCI are simple and reliable screening tools for the prediction of osteoporosis and osteopenia. The CBTavg is more accurate but the DFCI is easier to use in clinical practice.Cite this article: Q-F. He, H. Sun, L-Y. Shu, Y. Zhu, X-T. Xie, Y. Zhan, C-F. Luo. Radiographic predictors for bone mineral loss: Cortical thickness and index of the distal femur. Bone Joint Res 2018;7:468-475. DOI: 10.1302/2046-3758.77.BJR-2017-0332.R1.

Aberrant prostaglandin synthase 2 expression defines an antigen-presenting cell defect for insulin-dependent diabetes mellitus.

Prostaglandins (PGs) are lipid molecules that profoundly affect cellular processes including inflammation and immune response. Pathways contributing to PG output are highly regulated in antigen-presenting cells such as macrophages and monocytes, which produce large quantities of these molecules upon activation. In this report, we demonstrate aberrant constitutive expression of the normally inducible cyclooxygenase PG synthase 2 (PGS(2)/ COX-2) in nonactivated monocytes of humans with insulin-dependent diabetes mellitus (IDDM) and those with islet autoantibodies at increased risk of developing this disease. Constitutive PGS(2) appears to characterize a high risk for diabetes as it correlates with and predicts a low first-phase insulin response in autoantibody-positive subjects. Abnormal PGS(2) expression in at-risk subjects affected immune response in vitro, as the presence of a specific PGS(2) inhibitor, NS398, significantly increased IL-2 receptor alpha-chain (CD25) expression on phytohemagglutinin-stimulated T cells. The effect of PGS(2) on CD25 expression was most profound in subjects expressing both DR04 and DQbeta0302 high-risk alleles, suggesting that this cyclooxygenase interacts with diabetes-associated MHC class II antigens to limit T-cell activation. These results indicate that constitutive PGS(2) expression in monocytes defines an antigen-presenting cell defect affecting immune response, and that this expression is a novel cell-associated risk marker for IDDM.

[Comparison of two types of antithymocyte globulin in the treatment of children with aplastic anemia].

OBJECTIVE: This study was designed to compare the effects of the anti-human T lymphocyte globulin (Fresenius, ATG-F)and rabbit anti-human thymocyte immunoglobulin (Genzyme, R-ATG)in the treatment of childhood aplastic anemia (AA) and their effects. METHOD: A total of 59 children with aplastic anemia were analyzed in the present study, including 34 cases of severe aplastic anemia (SAA), 12 cases of very severe aplastic anemia (VSAA) and 13 cases of transfusion-dependent non-severe aplastic anemia (NSAA). While receiving immunosuppressive therapy (IST), 30 and 29 patients, with long-term oral supplement with cyclosporin A (CSA), androgen and Chinese traditional medicines, were treated with ATG-F and R-ATG, respectively. When it was necessary, some supportive cares such as component transfusion and infection control were also employed. Absolute counts of peripheral blood lymphocyte (ALC) at various time points were dynamically detected after ATG therapy. RESULT: According to the International Aplastic Anemia Treatment and Effect standards. There were no statistically significant differences in the overall response rate (67%(20/30)vs. 69%(20/29), χ(2)=0.036, P=0.676) and the survival rate (87%(26/30)vs. 83%(24/29), χ(2)=0.173, P=0.676) between the ATG-F and R-ATG groups. There were significant and long-term ALC decrease after ATG therapy, the rate of ALC decrease in ATG-F and R-ATG group, the ALC only recovered to 47.8% (ATG-F group) and 47.4% (R-ATG group) of the pre-treatment level respectively. CONCLUSION: ATG-F 5 mg/(kg·d) and R-ATG 3.75 mg/(kg·d)could achieve similar effects in the treatment of childhood AA, through similar significant clearance of T cells. Therefore, all of these suggest that ATG-F and R-ATG might serve as the drugs of front-line choice for IST in childhood AA patients who do not have an available human leukocyte antigen identical related donor.

[A study on the relationship between the changes of salivary EGF and oromaxillofacial tumors].

OBJECTIVE: To investigate the relationship between the changes of salivary epidermal growth factor (sEGF) concentration and oromaxillofacial tumors so as to find out its potential clinical value. METHODS: The saliva of 123 patients with oromaxillofacial tumors,inflammations and precancerous lesions were measured for EGF concentration by radioimmunoassay (RIA) with the ligand(125)I-EGF and the saliva of 40 normal adults as the control. RESULTS: Compared with the control, sEGF level of malignant,benign salivary gland tumors increased obviously;the former is higher than the latter significantly. The sEGF levels of patients with squamous cell carcinoma (SCC) of mucosa,recurrence and precancerous lesion were significantly higher than that of the control. There was no significant difference among the groups,but there was a tendency to increase by degrees. Compared with the control,the increase of the sEGF level of SCC patients with lymph node metastasis was of no significance. The sEGF level of oromaxillofacial inflammation was significantly higher than that of control. CONCLUSION: The sEGF levels in patients with salivary gland tumor,SCC,inflammation increased in different degrees.

[Determination of three active ingredients in food additive sucrose fatty acid ester by TLC scanning].

A method of separation and quantitation of monoester, diester and triester in food additive sucrose fatty acid esters by TLC with dual-wavelength TLC scanner in the sawtooth scanning mode is described. The detective wavelength was 530 nm and the reference wavelength was 700 nm. A mixture of chloroform, methanol, acetic acid and water (80:10:8:1, V/V) was used as mobile phase. The calibration curve was linear over a range from 4 micrograms to 60 micrograms with correlation coefficients of 0.9949-0.9980. The average recoveries were 96.45%-98.73% (n = 3, RSD = 2.7%-3.2%). This method is accurate, simple and dependable, with a wide range of linearity. It has been applied to the analysis of various samples and can be used for the quality control of the food additive sucrose fatty acid ester.

Experimental study of radiation effect on the mandibular microvasculature of the guinea pig.

OBJECTIVE: This experimental study was performed to explore the intraosseous microvascular alterations in the irradiated mandible and to increase understanding of the pathogenesis of osteoradionecrosis. METHODS: One hundred twenty-eight guinea pigs were grouped according to different radiation sources and dosages. Fractioned radiation was delivered to the right mandibles. Dental extractions were conducted at 1, 3, and 5 months respectively, after radiation. One month later, the animals were examined by means of gross observation, histopathology, and microvascular corrosion castings. RESULTS: Histologic evaluation showed bone absorption within 2 months following radiation. Four months later, the number of osteocytes decreased and pyknosis and empty lacunae were commonly seen. The casting specimens revealed under scanning electron microscopy that capillary disconnection and obliteration with subsequent vein shrinkage aggravated over time. In the nonhealing dental extraction site, a large-scale vascular network defect presented with focal capillary proliferation around. CONCLUSIONS: The capillary is the part most vulnerable to the damage caused by radiation in the vascular system of the mandible. On the basis of "hypovascular, hypoxic, hypocellular" structure, local microcirculation failure induced by the trauma-repairing process leads to occurrence of osteoradionecrosis of jaws.

[A comparison of the effects of 180kv X-ray radiation and cobalt-60 radiation on the jaws of the guinea pigs]

OBJECTIVE: Study of the effects of 180kv x-ray and cobalt-60 radiation on jaws and enhance the understanding of pathology of osteroradionecrosis of jaws(ORNJ).METHODS: 128 guinea pigs were grouped according to different irradiation sources and doses.Fractioned radiation from both sources was delivered in right mandible.The teeth extractions were conducted one week prior to radiation and 1,3,5 months after radiation respectively.Following radiation,the guinea pigs were examined by gross observation, x-ray film and histopathological examination at regular interval. RESULTS: Bone resorption occured within 1 month after irradiation as result of osteoblast inhibition and osteoclast activation.From 2 to 4 month afterwards,the number of osteocytes reduced and pyknosis, empty lacunae as well as obliteration of small vessels in periodontal membrane were commonly seen.The teeth extractions conducted at 3 months,5 months after radiation lead to ORNJ in 7 amimals (14.6%).CONCLUSION: 180kv x-ray radiation was far more damaging to jaws than cobalt-60 radiation.The dental extraction is an important factor inducint the development of ORNJ.

[Observation on revascularization of free flaps with the technique of microvascular corrosion]

In order to study the process of revascularization of free flap bilateral dorsal-auricular free flaps of 18 Newzealand rabbits were completed and investigated with the technique of microvascular corrosion casting at 2,4,7,10 days and 2,4 weeks postoperatively.It was discovered that scarce neovascularity appeared around the margin of flap before 2 weeks following transplantation and extensive revascularization occured at 3 weeks postoperatively.The capillaries connected through their netword expansion while central artery and vein formed recirculation by means of multiple point anastomoses of the "vascular buds" sprouting up at both ends of vessels.