Investigation on the properties of borate bonding agents: Ti6Al4V-porcelain bonding, chemical durability and preliminary cytotoxicity.

The purpose of this study was to investigate the properties of the borate bonding agents (BBAS) including chemical durability, biocompatibility and bonding characteristics of porcelain to Ti6Al4V. The bond strength was performed by the three-point bending test. And the chemical durability and ion release of BBAS were tested by chemical soaking and inductively coupled plasma optical emission spectrometry (ICP-OES), respectively. Moreover, cytotoxicity was evaluated by cell viability assay and cell adhesion using human osteosarcoma cells (MG-63) and cell counter kit-8 (CCK-8) assay. To investigate the influences of composition and microstructure changes on all the properties mentioned above, the 11B and 27Al spectra and infrared spectra of BBAS were measured by solid-state nuclear magnetic resonance (SSNMR) and Fourier transform infrared spectroscopy (FTIR), respectively. Combined with all these properties of BBAS, the optimal addition proportion of Al2O3 into BBAS is 20 mol%. The relative contents of [BO3], [BO4], [AlO4], [AlO5] and [AlO6] have great influences on these properties of BBAS. BBAS, possessing excellent chemical durability, good biocompatibility and low ion release and being an effective way to improve the Ti6Al4V-porcelain bond strength, have significant clinical potentials in porcelain fused to metal restorations.

[Study on handgrip strength of elderly ≥60 years old from longevity areas in China].

Objective: To assess the status of handgrip strength of elderly population from longevity areas in China, and to analyze the correlative factors of handgrip strength of elderly people. Methods: Data from Chinese Longitudinal Healthy Longevity Survey (CLHLS) in 2012 was used, from which1 967 participants aged ≥60 years old with valid data of grip strength value from 8 Chinese longevity areas were included. Information on demographics characteristic, life style and health status was collected using questionnaires. The handgrip strength of both left and right hands were measured by grip dynamometer. The different characteristics of group of participants with different grip strength were compared and then analyzed by adopting the Cumulative odds Logistic regression model to identify main factors associated with hand grip strength. Results: The P(50) (P(25)-P(50)) of hand grip strength of elderly people from the eight longevity areas was 20 (11-28) kg; The hand grip strength of males was 26 (18-34) kg, which was higher than that of females(14 (9-20) kg) (P<0.001). Cumulative odds Logistic regression model showed that the hand grip strength of females was lower than males, whose ß value (95%CI) was-1.22 (-1.43--1.00). The elderly who was at a higher age, smoking, drinking or with anemia, had a comparatively lower handgrip strength, whose ß (95%CI) value were separately-0.08(-0.09~-0.07),-0.29(-0.56~-0.02),-0.54(-0.80~-0.28), and-0.41(-0.62~-0.20). And the elderly who had a higher boby mass index, drinking tea and outdoor activities, had a comparatively higher handgrip strength, whose ß(95%CI) value were separately 0.28 (0.15-0.40), 0.25(0.03-0.47) and 0.51(0.30-0.71). Conclusion: Age and gender were the main correlative factors, lifestyles and physical conditions might also be correlative factors of hand grip strength of the elderly from longevity areas in China.

[Association between the hypersensitive C-reactive protein and activities of daily living among elderly adults in longevity areas of China].

OBJECTIVE: To explore the association between the hypersensitive C-reactive protein (hs-CRP) and activities of daily living (ADL) in elderly adults in longevity areas of China. METHODS: This analysis included data on 2 352 adults aged ≥65 years from eight longevity areas from the Chinese Longitudinal Healthy Longevity Survey in 2012. We excluded information on adults who lacked ADL or blood test data; the final study population comprised 2 227 elderly adults. Using questionnaires, body measurement, and blood biochemical examination, information on demographic characteristics, lifestyle, ADL, blood pressure, blood lipids, and biomarkers was collected. Study participants who were able to independently carry out the six kinds of activities of daily living (bathing, dressing, indoor activities, toileting, eating, bowel and bladder control) comprised the normal ADL group, and those who could not were included in the impaired ADL group. A multivariate logistic regression model was used to analyze factors influencing ADL impairment. RESULTS: Among the 2 227 participants, 1 674 (75.2%) were included in the normal ADL group and 553 (24.8%) in the impaired ADL group. Among all participants. Adults in the normal ADL group had lower hs-CRP levels (P50 (P25-P75)=0.88; 0.38-2.29 mg/L) than those in the impaired ADL group (1.27; 0.47-4.28 mg/L); (Z=- 4.71, P<0.001). Participants in the normal ADL group also had lower hs-CRP elevation rates (214; 12.8%) than those in the impaired ADL group (125; 22.6%); (χ(2)= 31.06, P<0.001). Multivariate logistic regression analysis indicated that each age increase of one year increased the risk of ADL impairment by 1.08 times (OR 1.08 (95%CI: 1.07-1.10); P<0.001). Participants with increased hs-CRP levels, those of Han nationality, and participants with a previous history of stroke had a higher risk of ADL impairment (OR(95% CI) values were 1.42(1.04-1.94), 1.87(1.13-3.08), 2.81(1.87-4.23); P<0.05). Elderly adults who participated in recreational activities had a lower risk of impaired ADL (OR 0.29 (95%CI: 0.22-0.38); P<0.001). CONCLUSION: In this study among elderly adults living in longevity areas of China, hs-CRP levels were related to ADL and elevated hs-CRP was associated with a higher risk of ADL impairment.

[Management of subglottic stenosis in children with endoscopic balloon dilation].

OBJECTIVE: To evaluate the efficacy of endoscopic balloon dilation for subglottic stenosis. METHODS: The clinical outcomes of 9 pediatric patients treated with balloon dilation were retrospectively analyzed. There were 8 male and 1 female. Their age ranged from 7 months to 7 years (mean 2.5 years). The degree of stenosis was classified according to Myer-Cotton classification as follows: grade Ⅱ (n=7) and grade Ⅲ (n=2). The causes of the stenosis were postintubation lesions (n=8) and laryngeal penetrating trauma (n=1). RESULTS: The patients had undergone 1 to 3 dilations with an average of 1.8 procedures per patient. Six (66.7%) patients were decannulated. Among them, 4(44.4%) were decannulated after one dilation procedure. Pneumothoraces occurred in 2 children postoperatively. CONCLUSION: Endoscopic balloon dilation is an effective, relatively safe and minimally invasive surgical method for patients with low-grade subglottic stenosis.

[Segmental tracheal resection and anastomosis for the treatment of cicatricial stenosis in cervical tracheal].

OBJECTIVE: To evaluate the efficacy of segmental tracheal resection with end-to-end anastomosis for cicatricial cervical tracheal stenosis. METHODS: The clinical outcomes of 40 patients treated with tracheal resection were retrospectively reviewed. There were 28 male patients and 12 female patients with the age ranged from 6 to 64 years (mean 33.7 years). The degree of stenosis was classified according to Myer-Cotton classification as follows: grade Ⅱ (n=7), grade Ⅲ (n=22) and grade Ⅳ (n=11). The stenosis extension ranged from 1.0 to 4.3 cm (mean 2.5 cm). The causes of the stenosis were postintubation (n=33), cervical trauma (n=6) and resection of tracheal neoplasm (n=1). RESULTS: Thirty-four(85.0%) patients were decannulated and 6 failed. Of the 6 patients failed, 4 were decannulated after reoperation with the sternohyoid myocutaneous flap or thyroid alar cartilage graft. Complications occurred in 10 patients. In 8 patients granulation tissues formed at the site of the tracheal anastomosis, which needed endoscopic resction, and in 2 patients anastomosic dehiscence occurred. No injury to recurrent laryngeal nerve or trachoesophageal fistula occurred. CONCLUSION: Segmental tracheal resection with end-to-end anastomosis is an effective surgical method for tracheal stenosis, which has a higher successful rate for primary operation and shorter therapeutic period.

Structural determinants in the second intracellular loop of the human cannabinoid CB1 receptor mediate selective coupling to G(s) and G(i).

BACKGROUND AND PURPOSE: The cannabinoid CB(1) receptor is primarily thought to be functionally coupled to the G(i) form of G proteins, through which it negatively regulates cAMP accumulation. Here, we investigated the dual coupling properties of CB(1) receptors and characterized the structural determinants that mediate selective coupling to G(s) and G(i). EXPERIMENTAL APPROACH: A cAMP-response element reporter gene system was employed to quantitatively analyze cAMP change. CB(1)/CB(2) receptor chimeras and site-directed mutagenesis combined with functional assays and computer modelling were used to determine the structural determinants mediating selective coupling to G(s) and G(i). KEY RESULTS: CB(1) receptors could couple to both G(s)-mediated cAMP accumulation and G(i)-induced activation of ERK1/2 and Ca(2+) mobilization, whereas CB(2) receptors selectively coupled to G(i) and inhibited cAMP production. Using CB(1)/CB(2) chimeric receptors, the second intracellular loop (ICL2) of the CB(1) receptor was identified as primarily responsible for mediating G(s) and G(i) coupling specificity. Furthermore, mutation of Leu-222 in ICL2 to either Ala or Pro switched G protein coupling from G(s) to G(i), while to Ile or Val led to balanced coupling of the mutant receptor with G(s) and G(i) . CONCLUSIONS AND IMPLICATIONS: The ICL2 of CB(1) receptors and in particular Leu-222, which resides within a highly conserved DRY(X)(5) PL motif, played a critical role in G(s) and G(i) protein coupling and specificity. Our studies provide new insight into the mechanisms governing the coupling of CB(1) receptors to G proteins and cannabinoid-induced tolerance.

[Formation of the allogeneic tissue engineered cartilage using injectable biomaterial].

OBJECTIVE: To study the feasibility of the formation of allogeneic tissue-engineered cartilage of certain shape in immunocompetent animal using the injectable biomaterial. METHODS: Fresh newborn rabbits' articular cartilages were obtained under sterile condition (< 6 hours after death) and incubated in the sterile 0.3% type II collagenase solution. After digestion of 8 to 12 hours, the solution was filtered through a 150 micron nylon mesh and centrifuged, then the chondrocytes were washed twice with phosphate buffered saline (PBS) and mixed with the biomaterial to create a final cell density of 5 x 10(7)/ml. The cell-biomaterial admixture was injected into rabbits subcutaneously 0.3 ml each point while we drew the needle back in order to form the neocartilage in the shape of cudgel, and the control groups were injected with only the biomaterial or the suspension of chondrocytes with the density of 5 x 10(7)/ml. After 4, 6, 8 and 12 weeks, the neocartilages were harvested to analyze. RESULTS: The new nodes could be touched subcutaneously after 2 weeks. In the sections of the samples harvested after 4 weeks, it was found that the matrix secreted and the collagen formed. After 6 weeks and later than that, the neocartilages were mature and the biomaterial was almost completely degraded. The cudgel-shaped samples of neocartilage could be formed by injection. In the experiment group, there was no obvious immune rejection response. On the contrary, there were no neocartilage formed in the control group. CONCLUSION: The injectable biomaterial is a relatively ideal biomaterial for tissue engineering, and it is feasible to form allogeneic tissue engineered cartilage of certain shape by injection in an immunocompetent animal.

Comparison of the effects of immunosuppressive factors from newly established colon carcinoma cell cultures on human lymphocyte proliferation and cytokine secretion.

Tumor cells may influence the host's immune reactivity by the production of immunosuppressive factors (ISFs). In this study, the effects of ISFs derived from nine polyclonal colorectal carcinoma (CRC) cell lines on PHA-induced lymphocyte proliferation and cytokine secretion was investigated. We found that most of the culture supernatants (8/9) from CRC cell lines contained ISFs, which inhibited T cell proliferation to a variable degree in a dose-dependent manner. Comparison of T cell proliferation in the presence or absence of monocytes showed that monocytes can modulate the effects of tumor-derived ISFs on lymphocyte function. In addition, exposure of activated PBMC to the tumor cell supernatants resulted in an altered secretion of cytokines by these cells, i.e. the secretion of IFN-gamma was generally reduced while the secretion of IL-1beta, IL-2 and TNF-alpha was little affected. We further investigated the supernatants' inhibitory effects on PBMC in respect to the production of prostaglandin E(2) (PGE(2)). It was found that PGE(2) was secreted by all tumor cell cultures. Therefore this substance is probably involved in the immunosuppression in vivo. However, the secreted PGE(2) was shown not to be solely responsible for the observed suppression of lymphocyte proliferation in vitro. Our results suggest that the secretion of ISF is a common property of CRCs as demonstrated with newly established CRC cell cultures, and therefore this may also be an important immune escape mechanism of colonic carcinomas in vivo.

Biliary glycoprotein (CD66a), a cell adhesion molecule of the immunoglobulin superfamily, on human lymphocytes: structure, expression and involvement in T cell activation.

The biliary glycoproteins (BGP or CD66a), a group of different splice variants of a single gene, are members of the carcinoembryonic antigen family and the immunoglobulin superfamily. Recently, we detected CD66a on IL-2 activated lymphocytes. In this study we characterized the structure and the expression pattern of BGP on human lymphocytes and investigated its role in T cell activation. Lymphocytes express 2 of the 13 known splice variants, i.e. BGPa and BGPb, which are glycosylated in a lymphocyte-specific manner. Both BGPa and BGPb have the long cytoplasmic tail, which contains two immunoreceptor tyrosine-based inhibitory motif (ITIM)-like motifs, but differ in their extracellular region containing 4 and 3 immunoglobulin-like domains, respectively. On PBL BGP is expressed in small amounts only on B cells and Th cells. Stimulation with IL-2 leads to a strong up-regulation of BGP by these cells, and induces de novo BGP expression on gammabeta T cells, CD8+ and CD56+ cells, but not on CD16+ lymphocytes. This up-regulation of BGP seems to be part of the physiological process of T cell activation, since stimulation with anti-CD3 mAb is sufficient to induce BGP up-regulation. Based on the presence of the two ITIM-like motifs, one may expect that BGP inhibits T cell activation, but surprisingly, engagement of BGP enhances the proliferation of anti-CD3-stimulated T cells.

Modulations of the effector function and cytokine production of human lymphocytes by secreted factors derived from colorectal-carcinoma cells.

We investigated the in vitro effects of factors secreted by 3 freshly explanted human colorectal-carcinoma (CRC) cell lines on lymphocyte proliferation, IL-2-receptor expression, LAK-cell generation and cytokine secretion. We found that the supernatants of all 3 CRC cell lines inhibited T-cell proliferation in a dose-dependent manner, due to the secretion of immunosuppressive factors (ISFs). In addition, the supernatants of 2 cell lines were able to inhibit LAK-cell generation and to depress IL-2R, but not HLA-DR expression, on PHA-activated T cells. Furthermore, the secretion of cytokines, i.e., IFN-gamma, IL-1beta, IL-2 and TNF-alpha, by peripheral-blood mononuclear cells (PBMC) was differently modulated by the tumor-cell supernatants, e.g., the production of IFN-gamma was reduced in normal PBMC stimulated with PHA. However, the effects induced by the supernatants were not identical: for example, factors from one CRC cell line (w25) influenced early and late events of T-cell activation and division, while 2 others (w19 and te6) contributed only to the inhibition of early events. Some biochemical properties of the ISFs were characterized. Our results suggest that colon-tumor cells can secrete ISFs, which may lead to the in vivo immunosuppression often observed in patients with these tumors.

Bilateral choroid plexus cysts in trisomy 21.

Whether karyotyping is indicated in a fetus with choroid plexus cysts who is otherwise structurally normal is still controversial. Many authors have suggested basing the decision on cyst size, bilaterality, persistence with advancing gestational age, and association with other anomalies. We report a case of large bilateral choroid plexus cysts in a fetus with trisomy 21 who had no evidence of congenital anomalies or ultrasonographic signs of Down syndrome. Cyst sizes diminished by half over a 3-week period of follow-up. It appears that diminishing size alone should not be considered sufficient reassurance about the normality of the fetal karyotype. A similar case has been previously reported, and it is conceivable that choroid plexus cysts are associated not only with trisomy 18 but also with trisomy 21.