[Neuroprotective effect of ginsenoside Rb-1 on a rat model of Alzheimer's disease].

Objective: To investigate the protective mechanism of ginsenoside Rb-1 on the brain in a rat model of Alzheimer's disease. Methods: Fifty-six male Sprague-Dawley rats were randomly divided into control group, model group, low-dose Rb-1 group (Rb-1: 25 mg•kg(-1)•d(-1)) and high-dose Rb-1 group (Rb-1:50 mg•kg(-1)•d(-1)). Morris water maze was designed to observe the changes of learning and memory ability in rats. Flow cytometry was used to detect the apoptosis of hippocampal neurons. Immunohistochemistry and Western blot were employed to detect the expression levels of apoptosis-related genes (p53, Bax, cytochrome C (Cyto C), Caspase-3 and caspase-9) and anti-oxidative stress-associated genes (nuclear Factor-E2-related factor 2 (Nrf2), kelch-like ECH-associated protein 1 (keap-1), heme oxygenase 1(HO-1) and NADPH quinone dehydrogenase 1 (NQO1)).The activities of catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were detected by relevant kits. ANOVA and Tukey-Kramer test were used for statistical analysis. Results: The learning and memory ability of rats in the model group was lower than that of the control group (P<0.01).The learning and memory ability of rats in the high-dose Rb-1 treatment group was significantly higher than that of the model group [(80±8) s vs (100±11) s, t=5.390, P<0.01]. The expression levels of apoptosis-related genes (p53, Bax, Cyto C, caspase-3 and caspase-9) in the model group were significantly higher than those in the control group (P<0.01), while the expression levels of these genes in low-dose and high-dose Rb-1 groups were significantly lower than those of the model group (P<0.01). The expression levels of Nrf2, HO-1 and NQO1 genes in the model group were significantly lower than those in the control group (P<0.05), while the expression of these genes in low-dose and high-dose Rb-1 groupswere significantly higher than those of the model group (P<0.01). The activities of CAT, GSH-Px and SOD in the model group were lower than those in the control group (P<0.01), however the activities of CAT, GSH-Px and SOD in low-dose and high-dose Rb-1 groups were higher than those of model group (P<0.05). Conclusions: Both low-dose and high-dose Rb-1 have protective effect on memory and cognitive function of Alzheimer's disease rats by reducing the damage and apoptosis of hippocampal neurons, down-regulating the expression levels of p53, Bax, Cyto C, caspase-3 and caspase-9, up-regulating the expression of Nrf2, HO-1 and NQO1 genes, and increasing the activities of CAT, GSH-Px and SOD. Moreover, the protective effect of Rb-1 on rat brain may be dose-dependent.

[Classification of pregnancy complicating Guillain-Barré syndrome].

Objective: To explore the classification, clinical features, the short-term efficacy of intravenous immunoglobulin (IVIg) for Guillain-Barré syndrome(GBS) and look for predictors of acute motor axonal neuropathy (AMAN) during pregnancy. Methods: The clinical data of 45 hospitalized pregnant patients with GBS recruited from October 2008 to October 2017 at the Tianjin Medical University general hospital, Handan City First Hospital and Nankai University Affiliated Tianjin Fourth Central Hospital, were collected and analyzed retrospectively, and patients were divided into the acute inflammatory demyelinating polyneuropathies (AIDP) group and the AMAN group. The clinical features and efficacy of IVIg were compared between the two groups. Logistic regression analysis was used to analyze the predictors of AMAN. Results: There were 25 cases in the AIDP group and 20 cases in the AMAN group. AIDP usually started with distal limb weakness (P=0.001), and AMAN often started with limb weakness (P=0.001) and mostly accompanied by dyspnea (P=0.042). AIDP was often associated with paresthesia (P=0.001) and autonomic dysfunction (P=0.007). The response days of active treatment in the AIDP group and the AMAN group were (1.6±0.5)d and (2.3±0.8)d (P=0.022), the improvement days were (3.6±0.8)d and (5.9±1.0)d (P=0.000), the basic cure days were (7.7±1.3)d and (9.0±0.8)d (P=0.002), the cure days were (12.3±1.1)d and (12.8±0.9)d (P=0.148). Multivariate Logistic regression analysis revealed that preceding diarrhea (OR=13.750; 95% CI 1.386-136.387), limb weakness(OR=12.000;95% CI 2.359-61.048) and limb weakness with dyspnea (OR=10.000; 95% CI 1.048-95.457) were significantly associated with the AMAN-type GBS. Conclusions: AIDP and AMAN are the main types of pregnancy complicating GBS. Most patients present with a single and benign course of disease. IVIg is generally safe and effective. Preceding diarrhea, limb weakness and limb weakness with dyspnea are the predictors of AMAN-type pregnancy complicating GBS.

[A retrospective study on misdiagnosis and prognosis of acute pregnancy complicating Guillain-Barré syndrome].

Objective: To investigate the factors of first misdiagnosis, treatment and prognosis of acute pregnancy complicating with Guillain-Barré syndrome (GBS) in order to improve the first diagnosed rate. Methods: A total of 45 acute pregnancy complicating with GBS patients were retrospectively analyzed recruited from January 2009 to October 2017 at the Tianjin Fourth Central Hospital.Patients were divided into the first diagnosis group and the first misdiagnosis group, and GBS clinical types were classified into classic and variant types to analyze the misdiagnosis factors of the first diagnosis. All patients received intravenous immunoglobulin (IVIG) treatment, and the therapeutic effect and prognosis were compared and analyzed. Results: There were 20 cases in the first diagnosis group, 25 cases in the first misdiagnosis group, 35 cases in the typical GBS group, and 10 cases in the variant GBS group.There was no statistically significant difference in the baseline data of the patients(P>0.05).The misdiagnosis factors are divided into four categories: physician factors, patient factors, disease itself factors and laboratory factors. Variant GBS is more likely to lead to misdiagnosis in the first diagnosis than typical GBS. The therapeutic effect of the first diagnosis group was better than that of the first misdiagnosis group(P<0.05).Three patients died in the first misdiagnosis group, and the rest of the pregnant patients gave birth normally, and the babies were born without congenital malformation. Conclusions: Pregnancy is one of the inducing factors of GBS. Early diagnosis and correct treatment can improve maternal and infant clinical outcomes.

Microfluidics based on ZnO/nanocrystalline diamond surface acoustic wave devices.

Surface acoustic wave (SAW) devices with 64 µm wavelength were fabricated on a zinc oxide (ZnO) film deposited on top of an ultra-smooth nanocrystalline diamond (UNCD) layer. The smooth surface of the UNCD film allowed the growth of the ZnO film with excellent c-axis orientation and low surface roughness, suitable for SAW fabrication, and could restrain the wave from significantly dissipating into the substrate. The frequency response of the fabricated devices was characterized and a Rayleigh mode was observed at ∼65.4 MHz. This mode was utilised to demonstrate that the ZnO/UNCD SAW device can be successfully used for microfluidic applications. Streaming, pumping, and jetting using microdroplets of 0.5 and 20 µl were achieved and characterized under different powers applied to the SAW device, focusing more on the jetting behaviors induced by the ZnO SAW.

In vitro bioactivity and osteoblast response of porous NiTi synthesized by SHS using nanocrystalline Ni-Ti reaction agent.

Porous NiTi with an average porosity of 55 vol % and a general pore size of 100-600 microm was synthesized by self-propagating high temperature synthesis (SHS) with the addition of mechanically alloyed nanocrystalline Ni-Ti as the reaction agent. The SHS of porous NiTi using elemental powders was also performed for comparison. To enhance the bioactivity of the metal surface, porous NiTi synthesized by nanocrystalline Ni-Ti was subjected to chemical treatment to form a layer of TiO(2) coating. The porous NiTi with TiO(2) coating was subsequently immersed in a simulated body fluid (SBF) to investigate its apatite forming ability. The effects of the addition of nanocrystalline Ni-Ti as reaction agent and the application of apatite coating on osteoblastic behavior were studied in primary cultures of human osteoblast cells. Results showed that the main phases in porous NiTi synthesized by elemental powders were NiTi, Ti(2)Ni, and unreacted free Ni. By using nanocrystalline Ni-Ti as reaction agent, the secondary intermetallic phase of Ti(2)Ni was significantly reduced and the free Ni was eliminated. TiO(2) coating with anatase phase was formed on the surface of porous NiTi after the chemical treatment. A layer consisting of nanocrystalline carbonate-containing apatite was formed on the surface of TiO(2) coating after soaking in SBF. The preliminary cell culture studies showed that the porous NiTi synthesized with the addition of nanocrystalline Ni-Ti attracted marked attachment and proliferation of the osteoblast cells. This gives the evidence of the potential biomedical applications of the porous NiTi.

Biomimetic deposition of apatite coating on surface-modified NiTi alloy.

TiO(2) coatings were prepared on NiTi alloy by heat treatment in air at 300, 400, 600 and 800 degrees C. The heat-treated NiTi alloy was subsequently immersed in a simulated body fluid for the biomimetic deposition of the apatite layer onto the surface of TiO(2) coating. The apatite coatings as well as the surface oxide layer on NiTi alloy were characterized using scanning electron microscopy equipped with energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy. Results showed the samples heat-treated at 600 degrees C produced a layer of anatase and rutile TiO(2) on the surface of NiTi. No TiO(2) was detected on the surface of NiTi after heat treatment at 300 and 400 degrees C by X-ray diffraction, while rutile was formed on the surface of the 800 degrees C heat-treated sample. It was found that the 600 degrees C heat-treated NiTi induced a layer consisted of microcrystalline carbonate containing hydroxyapatite on its surface most effectively, while 300 and 400 degrees C heat-treated NiTi did not form apatite. This was due to the presence of anatase and/or rutile in the 600 and 800 degrees C heat-treated NiTi which could provide atomic arrangements in their crystal structures suitable for the epitaxy of apatite crystals, and anatase had better apatite-forming ability than rutile. XPS and Raman results revealed that this apatite layer was a carbonated and non-stoichiometric apatite with Ca/P ratio of 1.53, which was similar to the human bone. The formation of apatite on 600 degrees C heat-treated NiTi following immersion in SBF for 3 days indicated that the surface modified NiTi possessed excellent bioactivity.

Effects of incorporation of HA/ZrO(2) into glass ionomer cement (GIC).

Glass ionomer cements (GICs) are a class of bioactive cements that bond directly to bone. In this paper, a new bioactive hydroxyapatite (HA)/zirconia (ZrO(2))-filled GIC composite was developed to improve the biocompatibility and bioactivity of the GICs with the surrounding bone and connective tissues. Nano-sized HA/30 wt% ZrO(2) powders were heat treated at 700 degrees Celsius and 800 degrees Celsius for 3 h to elucidate the influence of the crystallinity of composite powders on the performance of HA/ZrO(2)-GICs. The effects of different volume percentages of HA/ZrO(2) powders (4, 12, 28 and 40 vol%) substituted within GICs were investigated based on their microhardness, compressive strength and diametral tensile strength. The HA/ZrO(2)-GICs composite was soaked in distilled water for 1 day and 1 week before subjecting the samples to mechanical testing. Results showed that the glass and HA/ZrO(2) particles were distributed uniformly in the GIC matrix. The substitution of highly crystalline HA/ZrO(2) improved the mechanical properties of the HA/ZrO(2)-GICs due to the slow resorption rate for highly crystalline powders in distilled water. The mechanical properties of HA/ZrO(2)-GICs increased with increasing soak time due to the continuous formation of aluminium salt bridges, which improved the final strength of the cements. The compositions 4 and 12 vol% HA/ZrO(2)-GICs exhibited superior mechanical properties than the original GICs. The mechanical properties of HA/ZrO(2)-GICs were found to be much better than those of HA-GICs because ZrO(2) has the attributes of high strength, high modulus, and is significantly harder than glass and HA particles. Furthermore, ZrO(2) does not dissolve with increasing soaking time.

Radio frequency (rf) plasma spheroidized HA powders: powder characterization and spark plasma sintering behavior.

The present study describes the synthesis of spheroidized hydroxyapatite (HA) powders using a radio frequency (rf) inductively coupled plasma (ICP) torch. The spheroidized powders were consolidated through a spark plasma sintering (SPS) system. The microstructure and crystallographic phases in the synthesized powders were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD) and Raman spectrometry. Results showed that the HA feedstock decomposed after rf plasma processing. Crystalline HA, alpha-tri-calcium phosphate (alpha-TCP), tetra-calcium phosphate (TTCP) and calcium oxide (CaO) were detected in the plasma-spheroidized powders. Raman spectra results indicated strong presence of amorphous calcium phosphate (ACP) in the spheroidized powders. The particle size distribution and specific surface area were influenced through the rf plasma working plate power levels. The sintering behavior of the rf plasma synthesized powders was analyzed through the SPS process and the results indicated that the spheroidized powders commence sintering at approximately 900 degrees C and through to 1150 degrees C. After sintering above 1100 degrees C for 3min, the relative densities of the SPS compacts reached 96% of the theoretical value. The SPS compacts were immersed in simulated body fluids (SBF) for different durations and the results confirmed their bioactivities.

Microstructure and mechanical properties of plasma sprayed HA/YSZ/Ti-6Al-4V composite coatings.

Plasma sprayed hydroxyapatite (HA) coatings on titanium alloy substrate have been used extensively due to their excellent biocompatibility and osteoconductivity. However, the erratic bond strength between HA and Ti alloy has raised concern over the long-term reliability of the implant. In this paper, HA/yttria stabilized zirconia (YSZ)/Ti-6Al-4V composite coatings that possess superior mechanical properties to conventional plasma sprayed HA coatings were developed. Ti-6Al-4V powders coated with fine YSZ and HA particles were prepared through a unique ceramic slurry mixing method. The so-formed composite powder was employed as feedstock for plasma spraying of the HA/YSZ/Ti-6Al-4V coatings. The influence of net plasma energy, plasma spray standoff distance, and post-spray heat treatment on microstructure, phase composition and mechanical properties were investigated. Results showed that coatings prepared with the optimum plasma sprayed condition showed a well-defined splat structure. HA/YSZ/Ti-6Al-4V solid solution was formed during plasma spraying which was beneficial for the improvement of mechanical properties. There was no evidence of Ti oxidation from the successful processing of YSZ and HA coated Ti-6Al-4V composite powders. Small amount of CaO apart from HA, ZrO(2) and Ti was present in the composite coatings. The microhardness, Young's modulus, fracture toughness, and bond strength increased significantly with the addition of YSZ. Post-spray heat treatment at 600 degrees C and 700 degrees C for up to 12h was found to further improve the mechanical properties of coatings. After the post-spray heat treatment, 17.6% increment in Young's modulus (E) and 16.3% increment in Vicker's hardness were achieved. The strengthening mechanisms of HA/YSZ/Ti-6Al-4V composite coatings were related to the dispersion strengthening by homogeneous distribution of YSZ particles in the matrix, the good mechanical properties of Ti-6Al-4V and the formation of solid solution among HA, Ti alloy and YSZ components.

Spheroidization of glass powders for glass ionomer cements.

Commercial angular glass powders were spheroidized using both the flame spraying and inductively coupled radio frequency plasma spraying techniques. Spherical powders with different particle size distributions were obtained after spheroidization. The effects of spherical glass powders on the mechanical properties of glass ionomer cements (GICs) were investigated. Results showed that the particle size distribution of the glass powders had a significant influence on the mechanical properties of GICs. Powders with a bimodal particle size distribution ensured a high packing density of glass ionomer cements, giving relatively high mechanical properties of GICs. GICs prepared by flame-spheroidized powders showed low strength values due to the loss of fine particles during flame spraying, leading to a low packing density and few metal ions reacting with polyacrylic acid to form cross-linking. GICs prepared by the nano-sized powders showed low strength because of the low bulk density of the nano-sized powders and hence low powder/liquid ratio of GICs.

Bone-like apatite layer formation on hydroxyapatite prepared by spark plasma sintering (SPS).

Hydroxyapatite (HA) compacts with high density and superior mechanical properties were fabricated by spark plasma sintering (SPS) using spray-dried HA powders as feedstock. The formation of bone-like apatite layer on SPS consolidated HA compacts were investigated by soaking the HA compacts in simulated body fluid (SBF) for various periods (maximum of 28 days). The structural changes in HA post-SBF were analyzed with scanning electron microscopy, grazing incidence X-ray diffraction and X-ray photoelectron spectroscopy. It was found that a layer consisting microcrystalline carbonate-containing hydroxyapatite was formed on the surface of HA compacts after soaking for 24h. The formation mechanism of apatite on the surface of HA compacts after soaking in SBF was attributed to the ion exchange between HA compacts and the SBF solution. The increase in ionic concentration of calcium and phosphorus as well as the increase in pH after SBF immersion resulted in an increase in ionic activity product of apatite in the solution, and provided a specific surface with a low interface energy that is conducive to the nucleation of apatite on the surface of HA compacts.

Activity of plasma sprayed yttria stabilized zirconia reinforced hydroxyapatite/Ti-6Al-4V composite coatings in simulated body fluid.

Hydroxyapatite (HA)/yttria stabilized zirconia/Ti-6Al-4V bio-composite coatings deposited onto Ti-6Al-4V substrate through a plasma spray technique were immersed in simulated body fluid (SBF) to investigate their behavior in vitro. Surface morphologies and structural changes in the coatings were analyzed by scanning electron microscopy, thin-film X-ray diffractometer, and X-ray photoelectron spectroscopy. The tensile bond strength of the coatings after immersion was also conducted through the ASTM C-633 standard for thermal sprayed coatings. Results showed that carbonate-containing hydroxyapatite (CHA) layer formed on the surface of composite coatings after 4 weeks immersion in SBF solution, indicating the composite coating possessed excellent bioactivity. The mechanical properties were found to decrease with immersion duration of maximum 56 days. However, minimal variation in mechanical properties was found subsequent to achieving supersaturation of the calcium ions, which was attained with the precipitation of the calcium phosphate layers. The mechanical properties of the composite coating were found to be significantly higher than those of pure HA coatings even after immersion in the SBF solution, indicating the enhanced mechanical properties of the composite coatings.

In vitro studies of plasma-sprayed hydroxyapatite/Ti-6Al-4V composite coatings in simulated body fluid (SBF).

The bioactivity of plasma-sprayed hydroxyapatite (HA)/Ti-6Al-4V composite coatings was studied by soaking the coatings in simulated body fluid (SBF) for up to 8 weeks. This investigation was aimed at elucidating the biological behaviour of plasma-sprayed HA/Ti-6Al-4V composite coatings by analyzing the changes in chemistry, and crystallinity of the composite coating in a body-analogous solution. Phase composition, microstructure and calcium ion concentration were analyzed before, and after immersion. The mechanical properties, such as tensile bond strength, microhardness and Young's modulus were appropriately measured. Results demonstrated that the tensile bond strength of the composite coating was significantly higher than that of pure HA coatings even after soaking in the SBF solution over an 8-weeks period. Dissolution of Ca-P phases in SBF was evident after 24h of soaking, and, a layer of carbonate-apatite covered the coating surface after 2 weeks of immersion. The mechanical properties were found to diminish with soaking duration. However, slight variation in mechanical properties was found after supersaturation of the calcium ions was attained with the precipitation of the calcium phosphate layers.

Spark plasma sintering of hydroxyapatite powders.

Dense hydroxyapatite (HA) compacts have been successfully fabricated by a spark plasma sintering (SPS). The sintering behavior of HA powders at different temperatures ranging from 850 degrees C to 1100 degrees C was studied. Results showed that spark plasma sintering resulted in rapid densification to near theoretical density. The HA compact was homogeneously sintered at 950 degrees C in a short sintering duration of 5 min, while maintaining high quality and high relative density (>99.5%). The density, microhardness and Young's modulus of HA sintered compact initially increased with the sintering temperature, reached a maximum value at around 950-1000 degrees C, then decreased with further increase in the temperature due to the decomposition of HA into beta-tricalcium phosphates. Fracture toughness results showed no significant difference with increasing temperature due to the combined influences of density and grain size. Microstructure analysis showed no noticeable grain growth under different sintering temperatures due to the short time exposure at high temperatures.

Laser-induced predissociative fluorescence: dynamics and polarization and the effect of lower-state rotational energy transfer on quantitative diagnostics.

Laser-induced predissociative fluorescence is often used for diagnostics because its short-lived upper states are minimally disturbed by collisions. We discuss the effects of lower-state collisions with parameters relevant to our atmospheric H(2)-O(2) flame. A pulse of tunable KrF excimer-laser light induces the A ? X, Q(1)(11), 3 ? 0 transition in OH. We measure the intensity and the polarization of the resulting A ? X, Q(1)(11), 3 ? 2 fluorescence as a function of laser brightness. A simple model that uses no adjustable parameters produces a reasonable fit to the data. It predicts that, even at very modest laser energies, the fluorescence intensity is almost directly proportional to the rate constant for rotational energy transfer (RET) within the lower vibrational state. That rate constant can be a strong function of local conditions. Furthermore, under typical operating conditions the excimer will pump an amount of OH out of the lower state that is many times as large as that originally present. This occurs because RET within the X-state continuously replenishes the lower state during the laser pulse. Even when this occurs, the signal may still vary linearly with laser intensity, and the polarization may be nearly that expected for weak pumping. At the higher laser intensities, a significant fraction of the measured OH arises from two-photon photodissociation of the water from the flame reaction.

An innovated treatment for intra-articular fracture of calcaneus.

An innovated composite treatment for intra-articular fracture of the calcaneus has been developed. A Steinmann's pin is introduced into the calcaneus percutaneously to release the impaction of the fragments and to lift the compressed subtalar joint facet, which forms a potential cavity in the calcaneal body facilitating restoration of Bohler's angle and correction of widening of the calcaneus by manual reduction. A new type external fixation device, the calcaneus fixation boot, is used to substitute for the traditional plaster immobilization. The boot can exert continuous centripetal pressure on both sides of the calcaneus to control transverse displacement and to maintain the normal height of the heel. The patient is allowed to do functional exercises 24 hours after reduction with the aid of the spring stepping roller, which not only helps dissipate swelling in the early stage but also remold the articular facet. Biomechanical determination showed that the power of triceps surae muscles returned to nearly normal in 4-5 weeks. The patients were allowed to bear weight with crutches in 6-7 weeks. In this series, 94 (87.8%) of 107 cases with an average follow-up period of 2 years and 9 months attained excellent and good results.

Treatment of forearm bone fractures by an integrated method of traditional Chinese and Western medicine.

Of 2221 forearm fractures (1300 left, 921 right) in adults (1167 men, 1043 women) treated from January, 1972, to December, 1982, 2117 were closed and 104 open fractures. The fractures are classified as follows: fracture of both radius and ulna, 1161 cases (52.3%); fracture of the ulna alone, 343 (15.4%); Monteggia fracture, 259 (11.7%); fracture of the radius alone, 222 (10%); and Galeazzi fracture, 236 (10.6%). For each type, the treatment consisted of closed reduction by manipulation, immobilization, and functional exercises. A total of 1054 cases of forearm fracture were followed for 0.5-6.5 years (average, 2.5 years). The results were excellent in 735 cases (69.7%); good, 153 (14.5%); fair, 79 (7.5%); and poor, 87 (8.3%). The time of bone union was from 21-258 days. Nonunion occurred in three cases. Anatomic observations were carried out in specimens of adult forearms, which showed that: the interosseous membrane is an important factor in maintaining the stability of the radius and ulna and is the anatomic basis for manipulative reduction by bone separation; the use of bone separator pads can maintain the normal tension of the interosseous membrane and the physiologic space between the radius and ulna. Stress analysis of the bone separator pads and splint immobilization suggests that treatment of forearm fracture by integrated traditional Chinese medicine and western medicine is simple, economical, relatively painless, and effective.(ABSTRACT TRUNCATED AT 250 WORDS)