[Cephalic artery peak velocity variation during passive leg raising can predict fluid responsiveness in mechanically ventilated severe sepsis patients with spontaneous breathing].

Objective: To explore whether cephalic artery peak velocity variation during passive leg raising (ΔVpeak(CA)-PLR) could effectively predict fluid responsiveness in mechanically ventilated severe sepsis patients with spontaneous breathing. Methods: Total of 38 patients on mechanical ventilation with spontaneous breathing admitted to the Fourth Departments of Intensive Care Unit (ICU) of Fujian Provincial Hospital from January to December in 2017 were enrolled.The patients were diagnosed with severe sepsis or sepsis shock.The peak velocity in cephalic artery (Vpeak(CA)) during PLR was measured by bedside portable ultrasonic, and then ΔVpeak(CA)-PLR was calculated.All patients received volume expansion (VE) test and the changes of stroke volume during VE test (ΔSV-VE) were measured.Patients were classified as responsive group or non-responsive group according to the ΔSV-VE increased ≥15% or not after VE test.Furthermore, the sensitivity and specificity of ΔVpeak(CA)-PLR for predicting fluid responsiveness were evaluated by receiver operating characteristic (ROC) curve.The comparisons between groups were performed with Student's unpaired two-tailed t test, and Pearson's test was used for the correlation analysis. Results: Among the patients, 22 cases responded to VE test and the rest 16 cases did not.There were no significantly differences in age, gender, body mass index, infection site, sepsis-related organ failure assessment score, acute physiology and chronic health evaluation Ⅱ score, ventilator parameters and dose of vasoactive agent between the two groups.The ΔVpeak(CA)-PLR in responsive group was markedly higher than that in non-responsive group (15.7%±4.2% vs 6.9%±4.3%, t=6.240, P<0.05), and the ΔVpeak(CA)-PLR in the responsive group was positively related to the ΔSV-VE (r=0.723, P<0.05). Furthermore, the area of ΔVpeak(CA)-PLR under ROC curve was 0.912.The sensitivity and specificity of ΔVpeak(CA)-PLR≥12.2% to predict fluid responsiveness in the patients with sepsis were 81.8% and 87.5%, respectively. Conclusion: ΔVpeak(CA)-PLR measured by bedside portable ultrasonic can predict the fluid responsiveness in mechanically ventilated severe sepsis patients with spontaneous breathing, and it can be used to guide further fluid resuscitation.

[The effect of microRNA-21 on myocardial fibrosis in mice with chronic viral myocarditis].

Objective: To explore the effect of microRNA-21 (miR-21) on myocardial fibrosis in mice with chronic viral myocarditis (CVMC) and related mechanisms. Methods: Forty 4-week-old Balb/c male mice were randomly divided into 4 groups (n=10 each): phosphate buffer saline (PBS) group, CVMC group, CVMC+miR-21 inhibitor group, CVMC+isotype control group. The first injection of Coxsackie virus B3 (CVB3) or PBS was performed on day 0, and the total study time was 42 days. Each mouse in CVMC group, CVMC+miR-21 inhibitor group and CVMC+isotype control group was intraperitoneally (i.p) injected with 100TCID50 CVB3 0.1, 0.15, and 0.2 ml on day 0, 14, and 28, respectively. The mice in PBS group were i.p injected with the same dose of PBS at the same time point. After the initial infection, each mouse in CVMC+miR-21 inhibitor group and CVMC+isotype control group was intravenously injected with 0.1 ml miR-21 inhibitor or 0.1 ml isotype control, on day 14 and 28. Cardiac function was measured on surviving mice of 4 groups by echocardiography on day 42. Then, the hearts were removed aseptically to observe the expressions of green fluorescence protein (GFP). The myocardial pathological changes were examined with HE, Masson staining and the myocardial pathological scores (PS), the collagen volume fraction (CVF) were calculated respectively. The levels of miR-21, collagen typeⅠ-A1 (COL1-A1) and collagen type Ⅲ-A1 (COL3-A1) mRNA in heart were detected by quantitative real-time polymerase chain reaction (RT-qPCR). Furthermore, the expressions of transforming growth factor-ß1 (TGF-ß1) and mothers against decapentaplegic homolog 7(Smad7) in heart were determined with Western blot assay. Results: (1) Cardiac function in 4 groups: Compared with PBS group, left ventricular end systolic diameter (LVESD) and left ventricular end diastolic diameter (LVEDD) were markedly increased in CVMC group and CVMC+isotype control group (all P<0.05), whereas the left ventricular ejection fraction (LVEF) was decreased (P<0.05). LVESD and LVEDD were significantly decreased, and LVEF was increased in CVMC+miR-21 inhibitor group compared with those in CVMC group and CVMC+isotype control group (all P<0.05). (2) Myocardial pathological changes: The expressions of GFP in CVMC+miR-21 inhibitor group and CVMC+isotype control group were visible in heart tissues frozen sections. The hearts in CVMC group and CVMC+isotype control group were enlarged and stiff, inflammatory cells were visible and significantly increased myocardial fibrosis was evidenced in mice of these two groups. Higher PS and CVF were evidenced in CVMC group (PS: 1.14±0.69 vs. 0, CVF: (17.86±2.61)% vs. (5.70±1.42)%, all P<0.05) and CVMC+isotype control group(PS: 1.00±0.63 vs. 0, CVF: (16.78±2.58)% vs. (5.70±1.42)%, all P<0.05) compared to PBS group. Compared with CVMC group and CVMC+isotype control group, degree of cardiac fibrosis was reduced in mice of CVMC+miR-21 inhibitor group (CVF: (11.01±2.55)% vs. (17.86±2.61)%, (11.01±2.55)% vs. (16.78±2.58)%, all P<0.05), whereas PS were similar between them (PS: 0.89±0.60 vs. 1.14±0.69, 0.89±0.60 vs. 1.00±0.63, all P>0.05). (3) Cardiac expressions of miR-21, COL1-A1 and COL3-A1 mRNA: The cardiac expressions of miR-21, COL1-A1 mRNA, COL3-A1mRNA in CVMC group and CVMC+isotype control group were markedly higher than those in PBS group (all P<0.05), which were significantly downregulated in CVMC+miR-21 inhibitor group (all P<0.05 vs. CVMC group and CVMC+isotype control group). (4) The cardiac expressions of TGF-ß1 and Smad7 protein: The cardiac expressions of TGF-ß1 protein in CVMC group and CVMC+isotype control group were markedly higher, whereas the cardiac Smad7 protein expressions were significantly lower (all P<0.05) than those in PBS group (all P<0.05), these changes could be reversed in CVMC+miR-21 inhibitor group (P<0.05 vs. CVMC group and CVMC+isotype control group). Conclusions: Our results suggest that miR-21 contributes to the myocardial fibrosis in CVMC mice through modulating TGF-ß1/Smad7 signaling pathway.

In situ forming oxidised hyaluronic acid/adipic acid dihydrazide hydrogel for prevention of epidural fibrosis after laminectomy.

Post-operative epidural fibrosis is a biological response after laminectomy that may lead to clinical symptoms, such as radicular pain. An ideal material for prevention of epidural fibrosis should be able to inhibit fibroblast adhesions and reduce formation of scar tissue. An injectable hydrogel would be the material of choice for this purpose, since it could fill an irregular surgical defect completely, gelate in situ and be delivered in a minimally-invasive manner. The objective of this study was to evaluate, in vitro and in vivo, the cytocompatibility and anti-adhesive effect of an oxidised hyaluronic acid/adipic acid dihydrazide (oxi-HA/ADH) hydrogel. Different cell types present in the spine were used to test the cytocompatibility of the hydrogel. The hydrogel extraction medium had no deleterious effects on neural cells (PC-12), but reduced fibroblasts viability (NIH/3T3). Although the hydrogel did not change the release of lactate dehydrogenase from myoblasts (C2C12) and Schwann cells (RSC96), the extraction medium concentration slightly affected the mitochondrial activity of these two cell types. qPCR showed that the hydrogel down-regulated S100a and P4hb expression in NIH/3T3 cells, supporting the hypothesis that the hydrogel might inhibit fibroblast activity. The animal study showed a reduction of scar tissue formation as well as severity of adhesion between scar tissue and the dura mater in a rat laminectomy model. Superficially, the peel-off test showed significantly decreased tenacity. In conclusion, the oxi-HA/ADH hydrogel is a promising injectable and thermosensitive material for prevention of post-operative epidural fibrosis.

Gonorrhea infection increases the risk of prostate cancer in Asian population: a nationwide population-based cohort study.

This nationwide population-based retrospective cohort study evaluated the risk of developing prostate cancer among patients with gonorrhea. We identified cases of newly diagnosed gonorrhea in men between 2000 and 2010 from the Taiwan National Health Insurance Research Database. Each patient with gonorrhea was matched to four controls, based on age and index year. All subjects were followed up from the index date to December 31, 2010. The Cox proportional hazards regression model was used to assess the risk of prostate cancer. A total of 355 men were included in the study group, and 1,420 age-matched subjects without gonorrhea were included in the control group. After adjusting for age, comorbidities, urbanization level, hospital level, and monthly income, gonorrhea was significantly associated with an increased risk of prostate cancer (adjusted hazard ratio = 5.66, 95% confidence interval = 1.36-23.52). Men aged 45-70 years and those with lower monthly income were more strongly associated with prostate cancer in the study group than the control group. The higher risk for developing prostate cancer were also found in those without syphilis, without genital warts, without diabetes mellitus, without chronic obstructive pulmonary disease, without benign prostatic hypertrophy, without chronic prostatitis, and without alcoholism. The Kaplan-Meier analysis showed the risk of prostate cancer was significantly higher in the study group than in the control group. Gonorrhea may be involved in the development of prostate cancer. More intensive screening and prevention interventions for prostate cancer should be recommended in men with gonorrhea.

Cognitive impairment and hippocampal atrophy in chronic kidney disease.

BACKGROUND: Cognition impairment is well known in patients with chronic kidney disease (CKD). The relationship between brain structure and cognitive performance in CKD patients is still under investigation. The study aimed to quantitatively assess the relationship between brain structure and cognitive performance in patients with CKD. METHODS: We recruited 39 patients with CKD and 39 age- and sex-matched control participants from a tertiary medical center. All participants underwent 3-T MRI scan neuropsychological assessments, and renal function tests. FreeSurfer software was used for imaging processing and analysis, including measurement of cortical thickness and gray matter (GM) and white matter volumes. RESULTS: Compared with control subjects (73.1±7.5 years old), patients with CKD (76.4±8.4 years old) had significantly lower scores on the Mini-Mental State Examination, and forward digit span test (P<.01). Patients with CKD had smaller cerebral GM volume, hippocampus, and decreased cortical thickness (P<.01) relative to the control group. Estimated glomerular filtration rate (eGFR) was correlated with cognitive performance, cortical thickness, GM volume, and hippocampal volume (P<.001). Linear regression analysis revealed that eGFR and GM volume were independently negatively associated with cognitive performance (P<.001), while eGFR and age were negatively associated with cortical thinning and GM volume after controlling for confounding factors. CONCLUSIONS: This study demonstrated that impaired kidney function is associated not only with poor cognitive performance, but also with small cerebral GM volume and reduced cortical thickness.

The development of iron-free partially stabilized cement for use as dental root-end filling material.

AIM: To determine the effect of increasing the proportion of zinc on partially stabilized cement (PSC) produced using a one-step sol gel process. METHODOLOGY: A one-step sol-gel process of Portland cement-based PSC with Zn was synthesized by replacing iron nitrate. The crystalline phases of the PSC-Zn powder were analysed by using X-ray diffraction (XRD). The experimental groups [i.e., MTA, PSC-Fe (control), PSC with 1% Zn, PSC with 3% Zn, and PSC with 5% Zn] were immersed in simulated body fluid for 3 h, 1 and 3 days to evaluate the hydration product formation. The microstructure and surface morphology were analysed using scanning electron microscopy (SEM). Initial and final setting times of the materials were determined using an ASTM Vicat needle testing machine. To evaluate the cytotoxicity of PSC-Zn system, primary osteoblasts cell lines were used. RESULTS: The addition of increased weight percentages of Zn, resulted in a more unstable phase which favoured the formation of a monoclinic structure of C3 S with an increased hydration reaction of PSC and reduced setting time. The cytotoxicity testing of PSC with Zn revealed that the material was not toxic. CONCLUSIONS: The newly synthesized PSC-Zn material had short setting time and was biocompatible.

Combined effect of C-reactive protein gene SNP +2147 A/G and interleukin-6 receptor gene SNP rs2229238 C/T on anthropometric characteristics among school children in Taiwan.

OBJECTIVE: The purpose of this study was to explore the combined effect of the C-reactive protein (CRP) +2147 A/G (rs1205) and interleukin (IL)-6R rs2229238 C/T single-nucleotide polymorphisms (SNPs) on the anthropometric variables of school children in Taiwan. SUBJECTS AND DESIGN: Cross-sectional analyses were performed using the data from the Taipei Children Heart Study-II. After multi-stage sampling, we selected 430 boys and 463 girls with an average age of 13.1 years. We genotyped these individuals for the CRP +2147 A/G and IL-6R rs2229238 C/T SNPs using a TaqMan 5' nuclease assay. Anthropometric characteristics, which included body height, body weight (BW), body mass index (BMI), waist circumference (WC), hip circumference (HC), body fat percentage (BF), and waist circumference to height ratio (WHtR), were measured/calculated. RESULTS: When considering the CRP +2147 A/G polymorphism, GG genotype boys were heavier and had larger BMI, WC, HC, BF and WHtR than A allele carriers. The odds ratio (OR) of larger WHtR in GG genotype boys was 2.14 (95% CI: 1.09-4.21). For the IL-6R rs2229238 C/T polymorphism, T allele carrier girls had larger WC and WHtR than those carrying the CC genotype. The OR of a larger HC for T allele carrier boys was 2.33 (95% CI: 1.16-4.68). Boys with the GG genotype of CRP +2147 A/G and the CC genotype of IL-6R rs2229238 C/T had higher OR for BW, BMI, WC, HC, BF and WHtR than boys who were carriers of the A allele of CRP +2147 A/G and had the CC genotype of IL-6R rs2229238 C/T (OR range=3.86-8.04, all P<0.05). CONCLUSION: Boys who carry the GG genotype of CRP +2147 A/G and the CC genotype of IL-6R rs2229238 C/T have a greater risk of having abnormal BW, BMI, WC, HC, BF and WHtR and of developing obesity than individuals who do not have these genotypes.

The role of GABAB receptor activation in absence seizures of lethargic (lh/lh) mice.

Lethargic (lh/lh) mice, which function as an animal model of absence seizures, have spontaneous seizures that have behavioral and electrographic features and anticonvulsant sensitivity similar to those of human absence seizures. Antagonists of the gamma-aminobutyric acidB (GABAB) receptor suppressed these seizures in lethargic mice, whereas agonists of GABAB receptors exacerbated them. Furthermore, GABAB receptor binding and synaptically evoked GABAB receptor-mediated inhibition of N-methyl-D-aspartate responses were selectively increased in lh/lh mice. Therefore, enhanced GABAB receptor-mediated synaptic responses may underlie absence seizures in lh/lh mice, and GABAB receptor antagonists hold promise as anticonvulsants for absence seizures.

Chitosan/gelatin hydrogel prolonged the function of insulinoma/agarose microspheres in vivo during xenogenic transplantation.

PURPOSE: A chitosan/gelatin solution with glycerol 2-phosphate disodium salt hydrate in liquid phase at room temperature becomes a hydrogel at 37 degrees C. The material can be used as an injectable cell carrier into the human body for gelation in situ. We hoped that the chitosan/gelatin hydrogel provided extra protection for insulinoma/agarose microspheres during xenogenic transplantation. MATERIALS AND METHODS: Mouse insulinoma was microencapsulated in agarose as microspheres, which were macroencapsulated in chitosan/gelatin hydrogel. Insulin secreting profiles were first demonstrated in vitro. Diabetic rats were injected subcutaneously with insulinoma/agarose microspheres or insulinoma/agarose microspheres suspended in chitosan/gelatin solution. The nonfasting blood glucose concentrations (NFBG) of diabetic rats were measured perioperatively. Rats were humanely killed 1 month postoperatively and the hydrogel was retrieved for histological examination. RESULTS: The insulinoma/agarose microspheres continually secreted insulin for 1 month when macroencapsulated in chitosan/gelatin hydrogel in vitro. The NFBG of diabetic rats injected with insulinoma/agarose microspheres decreased to euglycemic status albeit hyperglycemia was restored within 10 days. The NFBG of diabetic rats injected with chitosan/gelatin hydrogel, which contained insulinoma/agarose microspheres, was maintained at less than 200 mg/dL for 25 days. The histological section revealed immune cell infiltration and accumulation within the hydrogel and around the iusulinoma/agarose microspheres that may have contributed to the slowly increasing NFBG after day 25. CONCLUSION: This study showed that chitosan/gelatin hydrogel can be used as a cell carrier for an injectable bioartificial pancreas; the hydrogel prolonged the function of cells encapsulated in agarose microspheres during xenogenic transplantation.

Effects of EDTA on the hydration mechanism of mineral trioxide aggregate.

Ethylenediaminetetraacetic acid (EDTA) is commonly used during the preparation of obstructed root canals that face a high risk of root perforation. Such perforations may be repaired with mineral trioxide aggregate (MTA). Due to EDTA's ability to chelate calcium ions, we hypothesized that EDTA may disrupt the hydration of MTA. Using scanning electron microscopy and energy-dispersive x-ray spectroscopy, we found that MTA specimens stored in an EDTA solution had no crystalline structure and a Ca/Si molar ratio considerably lower than those obtained for specimens stored in distilled water and normal saline. Poor cell adhesion in EDTA-treated MTA was also noted. X-ray diffraction indicated that the peak corresponding to portlandite, which is normally present in hydrated MTA, was not shown in the EDTA group. The microhardness of EDTA-treated specimens was also significantly reduced (p < 0.0001). These findings suggest that EDTA interferes with the hydration of MTA, resulting in decreased hardness and poor biocompatibility.

Magnetoencephalographic mapping of interictal spike propagation: a technical and clinical report.

Distinguishing propagated epileptic activity from primary epileptic foci is of critical importance in presurgical evaluation of patients with medically intractable focal epilepsy. We studied an 11-year-old patient with complex partial epilepsy by using simultaneous magnetoencephalography (MEG) and electroencephalography (EEG). In EEG, bilateral interictal discharges appeared synchronous, whereas MEG source analysis suggested propagation of spikes from the right to the left frontal lobe.

Association between sleep disorders and hypertension in Taiwan: a nationwide population-based retrospective cohort study.

There is insufficient evidence to assess the risk for hypertension in patients with sleep disorders (SDs) in a large population-based cohort study. The aim of this study was to examine the risk of hypertension in groups both with and without SDs. Taiwan's National Health Insurance Research Database (NHIRD) data from 2005 to 2010 were used in a retrospective cohort study. A Cox proportional hazard regression analysis was used to evaluate the effects of SDs on hypertension risk. The overall incidence of hypertension was 120.7 per 1000 person-years for patients with SDs, which was significantly higher than that of the non-SD comparison cohort (76.4 per 1000 person-years). Overall, patients with SDs had a higher risk of hypertension compared with comparison cohort (adjusted hazard ratio (HR)=1.58, 95% confidence interval (CI)=1.26-1.79). Among patients aged <40 years, patients with SDs had a higher risk for hypertension than the comparison cohort (adjusted HR, 2.90 (95% CI, 2.46-3.14)). Compared with the cohort without insomnia, patients with insomnia had a 21% higher risk for hypertension (adjusted HR, 1.21 (95% CI, 1.01-1.76)). Compared with non-SD comparison cohort, patients with SDs had a higher risk for developing hypertension, particularly pronounced among those who were younger adults (age ⩽40 years) and who had insomnia. We suggest that possible persisting exposure to sleep problems was correlated with a greater risk of hypertension.

Hippocampal Atrophy Is Associated with Altered Hippocampus-Posterior Cingulate Cortex Connectivity in Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis.

BACKGROUND AND PURPOSE: Unilateral mesial temporal lobe epilepsy and hippocampal sclerosis have structural and functional abnormalities in the mesial temporal regions. To gain insight into the pathophysiology of the epileptic network in mesial temporal lobe epilepsy with hippocampal sclerosis, we aimed to clarify the relationships between hippocampal atrophy and the altered connection between the hippocampus and the posterior cingulate cortex in patients with mesial temporal lobe epilepsy with hippocampal sclerosis. MATERIALS AND METHODS: Fifteen patients with left mesial temporal lobe epilepsy with hippocampal sclerosis and 15 healthy controls were included in the study. Multicontrast MR imaging, including high-resolution T1WI, diffusion spectrum imaging, and resting-state fMRI, was performed to measure the hippocampal volume, structural connectivity of the inferior cingulum bundle, and intrinsic functional connectivity between the hippocampus and the posterior cingulate cortex, respectively. RESULTS: Compared with controls, patients had decreased left hippocampal volume (volume ratio of the hippocampus and controls, 0.366% ± 0.029%; patients, 0.277% ± 0.063%, corrected P = .002), structural connectivity of the bilateral inferior cingulum bundle (generalized fractional anisotropy, left: controls, 0.234 ± 0.020; patients, 0.193 ± 0.022, corrected P = .0001, right: controls, 0.226 ± 0.022; patients, 0.208 ± 0.017, corrected P = .047), and intrinsic functional connectivity between the left hippocampus and the left posterior cingulate cortex (averaged z-value: controls, 0.314 ± 0.152; patients, 0.166 ± 0.062). The left hippocampal volume correlated with structural connectivity positively (standardized ß = 0.864, P = .001), but it had little correlation with intrinsic functional connectivity (standardized ß = -0.329, P = .113). On the contralesional side, the hippocampal volume did not show any significant correlation with structural connectivity or intrinsic functional connectivity (F2,12 = 0.284, P = .757, R2 = 0.045). CONCLUSIONS: In left mesial temporal lobe epilepsy with hippocampal sclerosis, the left inferior cingulum bundle undergoes degeneration in tandem with the left hippocampal volume, whereas intrinsic functional connectivity seems to react by compensating the loss of connectivity. Such insight might be helpful in understanding the development of the epileptic network in left mesial temporal lobe epilepsy with hippocampal sclerosis.

Evidence for two forms of RNA-dependent DNA polymerase in Visna virus.

The visna viral RNA-dependent DNA polymerase has been resolved into two forms by affinity chromatography. Glycerine gradient centrifugation of the two forms showed that one form sedimented at 6.9 S corresponding to an apparent molecular weight of 135 000 and the other at 6.3 S corresponding to 118 000. Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of the two forms indicated that the 6.9 S enzyme is composed of 2 molecules of 68 000 mol. wt. chain and the 6.3 S is a single chain enzyme. The latter form has been identified as a glycoprotein. The 6.9 S form can be completely inactivated in 20 min at 45 degrees C, prefers poly(rC) over poly(rA) as template and has high efficiency in utilizing visna 70 S RNA as template. The 6.3 S form is stable at 45 degrees C, active with 70 S viral RNA as template, prefers poly(rA) over poly(rC), and requires higher concentration of Mn2+ (0.4 mM) for maximum activity than the 6.9 S form does (0.1 mM) with synthetic homopolymers as templates. However, both 6.9 S and 6.3 S forms prefer Mg2+ over Mn2+ regardless of the nature of the templates.

Glutamate decarboxylase isoforms in thalamic nuclei in lethargic mouse model of absence seizures.

To test the hypothesis that altered GABA synthesis within nucleus reticularis thalami (NRT) neurons regulates absence seizures, we analyzed and quantitated the distribution of GAD(67) and GAD(65), the rate-limiting enzymes of GABA synthesis, in thalamic nuclei from the Cacnb4lh model of absence seizures and non-epileptic (+/+) controls. In situ hybridization and Western blot results indicate a significant increase in GAD(67) expression (mRNA and protein) per cell but no change in GAD(65) in Cacnb4lh mice. These data suggest that GABA-synthesis is maintained or increased in NRT neurons in the Cacnb4lh mouse model.

Degradation behaviour of a new bioceramic: Ca2P2O7 with addition of Na4P2O7.10H2O.

A newly produced bioceramic, beta-Ca2P2O7 with addition of Na4P2O7.10H2O (SDCP), has been implanted into the femoral condyle of rabbits. Within 6 weeks after implantation, most of the bioceramic is replaced by new woven bone. On the contrary, block from hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP), which are osteoconductible, do not resorb within a short period of time. We believe that the biodegradable behaviour of SDCP may occur in two steps. The first and most important step is the digestion of particles and migration of the particles by phagocytosis. The object of this study is to examine the change in morphologies, chemical compositions and crystal structure of SDCP after soaking in distilled water for a certain period of time. The SDCP ceramic was also co-cultured with leucocytes to observe how the SDCP particles were digested by the leucocytes, so that the mechanism of biodegradable behaviour of SDCP ceramic in vivo might be clarified. Four types of sintered calcium phosphate ceramics were tested in the experiment: SDCP, pure beta-Ca2P2O7 (DCP), HA and beta-TCP. They wee soaked in distilled water at 37 degrees C for up to 30 days. The microstructure and morphology of crystals deposited on the surface were observed using scanning electron microscopy. Sodium, calcium and phosphorus ion contents in the supernatant solution were detected by atomic absorption analysis and ion coupled plasma. In summary, HA and DCP showed no significant evidence of dissolution in distilled water. In static distilled water, calcium ions may be released from beta-TCP into solution during the initial 7 days and then converted into HA by reprecipitation. The results showed that the SDCP was firstly dissolved into small grains or fragments by the solution. The small fragments should be so small as to be digested by the phagocytes in a physiological environment.

Prevascularized bone graft cultured in sintered porous beta-Ca2P2O7 with 5 wt% Na4P2O7.10H2O addition ceramic chamber.

Autogenous bone transfer is an important part of reconstructive plastic surgery. Presently available techniques have the disadvantages of limitation of available donor site, loss of donor tissue and the possibility of donor defect or deformity. In the present study, a vascularized bone graft was created and cultured in the groin area of the New Zealand rabbit. The cylindrical ceramic chambers, 15 mm in length, 6 mm in outer diameter and 3 mm in inner diameter, were prepared by the addition of sintered porous beta-Ca2P2O7 with 5 wt% Na4P2O7.10H2O. In the first group, the chambers impregnated with autogenous bone fragments and allogenous demineralized bone matrix with volume ratio 1:1 were cultured in the rabbit's groin area with saphenous vessels passing through. In the second group, the chambers were treated by the same procedures as the first group but without saphenous vessels passing through. In the third group, the chambers were not impregnated, and were cultured in the groin area with saphenous vessels. After 2, 4, 6, 8 and 12 wk of operation, the animals were killed with an overdose of intravenous pentobarbital. The viability of the osseous tissue in the chamber was evaluated by histological examination, microangiograms and fluorochrome incorporation for the three groups. The autogenous bone chips could survive and retain their osteogenic properties while packed into the sintered porous beta-Ca2P2O7 (with 5 wt% Na4P2O7.10H2O addition) ceramic chamber and implanted in the rabbit groin area up to 12wk. However, even at the longest time periods, considerable amounts of dead bone were present in the chambers. In addition, we observed bone resorption in the three groups up to 12 wk, which might be attributed to lack of physiological stress. There were significant differences in new bone formation and osseous cell viability among the three groups. The prevascularized vessels and autogenous bone chips were both necessary for the formation of new bone and osteogenic property in the chamber under these heterotopic circumstances. The biodegradable ceramic used in this study was gradually absorbed and dissolved in the physiological environment. However, the degradation debris of the ceramic caused no injury to the new bone formation. These findings support the concept of creating a preformed vascularized bone graft to reconstruct segmental bone defects.

Preparation of high-temperature stabilized beta-tricalcium phosphate by heating deficient hydroxyapatite with Na4P2O7 x 10H2O addition.

In this paper, the high-temperature stabilized beta-tricalcium phosphate (betaTCP, beta-Ca3(PO4)2) were prepared by heating the deficient HAP (d-HAP, Ca10-x(HPO4)x(PO4)6-x(OH)2-x) with tetra-sodium diphosphate decahydrate (NP, Na4P2O7 x 10H2O) addition. The betaTCP, d-HAP and d-HAP doped with 2.5, 5, 7.5 and 10 wt % NP were heated to different temperatures and were investigated by X-ray diffraction analysis (XRD) and Fourier-transformed infrared spectroscopy (FTIR). The results demonstrated that the HPO4(2-) of d-HAP condensed into P2O7(4-) occurred before 650 degrees C. The P2O7(4-) ions could be traced in the FTIR spectrum when the d-HAP was heated up to 750 degrees C. The reaction of P2O7(4-) with OH- did not occur instantly but over a wide range of temperatures. The d-HAP doped with NP would decrease the decomposition temperature of d-HAP. NP doped into d-HAP not only induced the d-HAP decomposition at lower temperature but also stabilized the betaTCP crystal structure at higher-temperature. It could also increase the conversion temperature of betaTCP to alphaTCP from 1180 degrees C up to 1300 degrees C. We could successfully prepare high-temperature (up to 1300 C) stabilized ffTCP by heating NP doped d-HAP.