Electropolishing influence on biocompatibility of additively manufactured Ti-Nb-Ta-Zr: in vivo and in vitro.

Balling defect of the additively manufactured titanium lattice implants easily leads to muscle tissue rejection, which might cause failure of implantation. Electropolishing is widely used in surface polishing of complex components and has potential to deal with the balling defect. However, a clad layer could be formed on the surface of titanium alloy after electropolishing, which may affect the biocompatibility of the metal implants. To manufacture lattice structured ß-type Ti-Ni-Ta-Zr (TNTZ) for bio-medical applications, it is necessary to investigate the impact of electropolishing on material biocompatibility. In this study, animal experiments were conducted to investigate the in vivo biocompatibility of the as-printed TNTZ alloy with or without electropolishing; and proteomics technology was used to elaborate the results. The following conclusions were drawn: (a) a 30% oxalic acid electropolishing treatment was effective in solving balling defects, and ~21 nm amorphous clad layer would be formed on the surface of the material after polishing; (b) the electropolished TNTZ suggested decreased cell cytotoxicity and improved blood biocompatibility as compared to as-printed TNTZ; (c) the amorphous clad layer could make a barrier to prevent Ta and Zr ions from penetrating into the muscle tissue, and could form a good tissue regeneration at the implantation site during 4 weeks, indicating that the electropolished TNTZ has the potential as implants; and (d) the cells attached to the electropolished TNTZ showed higher antioxidant capacity but less proliferation than attached to as-printed TNTZ.

[Changes to sleep patterns in young migrants at high altitude].

Objective: To explore the relationship between the level of acclimatization and the changes to sleep architecture in migrants at high altitude. Methods: Nocturnal sleep recordings of 50 subjects aged between 18 and 25 years [mean age (20.9±2.0) years] were analyzed. Those young volunteers were divided into 3 700 m-3 m group(n=10, migrated to an altitude of 3 700 metres for 3 months), 3 700 m-1 y group(n=10, for 1 year) , 5 380 m-3 m group(n=8), 5 380 m-1 y group(n=9), and compared with a control group(n=13, at 1 400 m altitude). Results: When the migrants stayed at 5 380 m for 3 months or 1 year, the wake time increased significantly during sleep[(81.81±59.80)min vs(47.19±24.98) min, P=0.026; (77.94±25.64)min vs(47.19±24.98)min, P=0.040]. Concerning the percentage of total sleep time(TST) in each stage, participants in the 5 380 m-3 m group had a shift in sleep stage distribution with near absence of slow wave sleep(SWS) and a significant increase of N1 , but N2 and rapid eye movement(REM) did not differ. Interestingly, there were entirely concordant changes among the other 3 groups of results, decreased N2 and increased REM. Conclusions: The migrants' abilities to acclimatize themselves to plateau were varied according to the arrived altitude and the length of stay. The sleep of short- time migrants was characterized by increased N1 and decreased SWS, whereas that of well acclimatized migrants was characterized by less N2 and more REM. The efficient recovery in SWS may be an objective reference in high altitude acclimatization.

Effect and mechanism of dihydroartemisinin on proliferation, metastasis and apoptosis of human osteosarcoma cells.

Osteosarcoma represents an aggressive type of bone malignancy that poses a significant health threat. The objective of the current study was to analyze the effect and mechanism of dihydroartemisinin (DHA) on the proliferation, metastasis and apoptosis of human osteosarcoma cells. A gradient concentration of DHA (15, 25 and 35 µmol.L-1) was used to stimulate the cells, along with control and Dimethyl sulfoxide (DMSO). The phenotypic outcomes were characterized using MTT assay, clone formation assay, Hoechst 33258 staining assay, luciferase reporter plasmid assay, Western blot and wound healing assay. In addition, IBM SPSS Statistics 18.0 software was applied for statistical analysis and all experimental data were expressed as mean ± s.d. Analysis of variance (ANOVA) was applied to compare the differences among multiple groups. Our results demonstrated that DHA inhibited the proliferation and metastasis of osteosarcoma cells and promoted the apoptosis in the cytomorphosis.

Additional diffusion-weighted imaging in the detection of new, very small hepatocellular carcinoma lesions after interventional therapy compared with conventional 3 T MRI alone.

AIM: To evaluate the added value of diffusion-weighted imaging (DWI) combined with conventional magnetic resonance imaging (MRI) in the detection of new, very small hepatocellular carcinoma lesions (≤1 cm) in patients with hepatocellular carcinoma following interventional therapy compared to conventional MRI alone. MATERIALS AND METHODS: After interventional therapy, 45 patients with hepatocellular carcinoma underwent conventional MRI and DWI with a b-value of 0 and 700 s/mm(2). Twenty-one new, small hepatocellular carcinoma lesions were confirmed in 16 patients at follow-up MRI. Two observers independently retrospectively analysed the two imaging sets in random order. The diagnostic performance using each imaging set was evaluated by received operating characteristic curve analysis. RESULTS: Twenty-one new, very small hepatocellular carcinoma lesions found in 16 patients was confirmed as the final result. The area under the receiver operating characteristic curve of the DWI/conventional MRI combination (observer 1, 0.952; observer 2, 0.976) and conventional MRI images alone (observer 1, 0.905; observer 2, 0.905) were statistically significant. The kappa value of the DWI/conventional MRI combination was 0.884, and that of conventional MRI was 0.722. Among the 21 lesions, 100% (21/21) of the lesions were both recognized by two independent reviewers on DWI, while only 76% (16/21) and 71% (15/21) of the lesions were regarded as very small hepatocellular carcinomas on conventional MRI. CONCLUSION: Due to the higher detection rate of new subcentimetre lesions in hepatocellular carcinoma patients following interventional therapy, DWI could be considered complementary to conventional MRI in the diagnosis of hepatocellular carcinoma.

Additively manufactured biomedical Ti-Nb-Ta-Zr lattices with tunable Young's modulus: Mechanical property, biocompatibility, and proteomics analysis.

Some ß-Ti alloys, such as Ti-Nb-Ta-Zr (TNTZ) alloys, exhibit a low Young's modulus and excellent biocompatibility. These alloys are promising new generation biomedical implant materials. Selective laser melting (SLM) can further enable customer-specific manufacturing of ß-Ti alloys to satisfy the ever-increasing need for enhanced biomedical products. In this study, we quantitatively determined the relationships between porosity, yield strength, and Young's modulus of SLM-prepared TNTZ lattices. The study constitutes a critical step toward understanding the behavior of the lattice and eventually enables tuning the Young's modulus to match that of human bones. Fatigue properties were also investigated on as-printed lattices in terms of the stress limit. The biocompatibility study included a routine evaluation of the relative cell growth rate and a proteomics analysis using a common mouse fibroblast cell line, L929. The results indicated that the as-printed TNTZ samples exhibited evidence of protein proliferation of the L929 cells, particularly P06733, and that those proteins are responsible for biological processes and molecular functions. They in turn may have promoted cell regeneration, cell motility, and protein binding, which at least partially explains the good biocompatibility of the as-printed TNTZ at the protein level. The study highlights the promising applications of additively manufactured TNTZ as a bone-replacing material from mechanical and biocompatibility perspectives.

Low-modulus biomedical Ti-30Nb-5Ta-3Zr additively manufactured by Selective Laser Melting and its biocompatibility.

Low Young's modulus titanium alloys, such as Ti-30Nb-5Ta-3Zr (TNTZ) of this study, were promising biocompatible implant materials. In this work, TNTZ samples with relative density of 96.8%-99.2% were additively manufactured by powder-bed based Selective Laser Melting (SLM) through tuning processing parameters, i.e. varying the point distance between 50 and 75 µm, laser exposure time between 135 and 200 µs, and a fixed laser power of 200 W. The microstructure, elastic properties, fatigue properties and machining accuracy of the fabricated samples have been investigated. Lattice structure TNTZ samples with porosity of 77.23% were also fabricated to further reduce the Young's modulus of the TNTZ. According to the Relative Growth Rate (RGR) value, the as-printed TNTZ samples exhibited no cell cytotoxicity, where they showed even better biocompatibility than the comparative, as-printed Ti-6Al-4V samples. The as-printed TNTZ developed by the study demonstrates good biocompatibility, low stress shielding tendency and high mechanical properties.

Inflammatory pseudotumour associated with chronic persistent Eikenella corrodens infection: a case report and brief review.

Inflammatory pseudotumour is an uncommon mass forming lesion, representing the histological expression of an infective or reactive/reparative process (pseudotumour) in most cases, and a bona fide neoplasm (for example, inflammatory myofibroblastic tumour) in a minority of cases. This report describes the case of an inflammatory pseudotumour with a pathology that unveiled proliferative CD68 positive and actin negative spindle shaped cells, with a mild mixed inflammatory infiltrate, and a culture that yielded an uncommon fastidious bacillus, Eikenella corrodens. The clinical course was indolent but protracted, with insidious progression to multifocal non-contiguous lesions, involving the lungs, liver, spleen, left kidney, and deep neck tissue, all of which responded to medical treatment with appropriate antibiotics. It is of paramount importance that clinicians search for an infective cause of an inflammatory pseudotumour, to ensure appropriate treatment.

Pharmacokinetics of fluphenazine, a highly lipophilic drug, estimated from a pulse dose of a stable isotopomer in dogs at steady state.

The potential utility of a pulse dose of a deuterium-labeled isotopomer (FLU-D(4)) in elucidating the pharmacokinetics of fluphenazine (FLU) at steady state was investigated in dogs. The single-dose oral pharmacokinetics of FLU in dogs were established. After resting the dogs for 3 weeks, the animals were dosed to steady state with oral FLU administered at 12-h intervals. Following 15 doses, one dose of FLU was replaced by a pulse dose of FLU-D(4), after which dosing with FLU was resumed. FLU and FLU-D(4) plasma concentrations were determined by tandem mass spectrometry. Comparable estimates of apparent oral clearance were calculated from (i) a single dose of FLU, (ii) a pulse dose of FLU-D(4), and (iii) over a dosing interval at steady state. Average steady-state plasma concentrations were reliably predictable from a pulse dose of FLU-D(4).

Plant regeneration from callus protoplasts of the forage legume Astragalus adsurgens Pall.

A reproducible release of viable protoplasts was obtained from friable calli of Astragalus adsurgens. Protoplasts underwent sustained divisions and formed cell colonies when cultured in either liquid or agarose-solidified Kao and Michayluk (1975) protoplast medium (KM8P) supplemented with 1.5 mg/l 2,4-D, 0.5 mg/l BA and 0.5 M glucose. Compared to liquid culture, agarose bead culture improved division frequency effectively, the two culture systems showing a plating efficiency of 0.8±0.5% and 6.5±0.7%, respectively. Upon transfer to Murashige and Skoog (1962) medium (MS) with 1-2 mg/l BA, alone or in combination with NAA or 2,4-D at 0.1 mg/l, the protoplast-derived calli produced complete plantlets through somatic embryogenesis. The maximum percentage of calli producing somatic embryos (52.5± 2.2%) occurred on MS medium containing 0.1 mg/l NAA and 1 mg/l BA, whereas the maximum number of calli regenerating plantlets (64.7±6.2) was obtained on MS medium with 0.1 mg/l NAA and 2 mg/l BA.

Callus induction and plant regeneration from hypocotyl explants of the forage legume Astragalus adsurgens.

An efficient procedure was developed for inducing callus and plant regeneration using hypocotyl segments of Astragalus adsurgens. The combinations and concentrations of different growth regulators were shown to be critical factors for both the frequency and the type of callus formation as well as for the potential of callus differentiation. Of the four morphologically distinct types of calli that were induced, a friable, yellow callus, i.e. type I, induced on MS medium supplemented with 9.0 µM 2,4-dichlorophenoxyacetic acid and 2.2 µM N6-benzylaminopurine (BA), and then transferred to MS medium containing 0.5 µM α-naphthaleneacetic acid and 8.9 µM BA, exhibited the maximum frequency of shoot regeneration (75%). After regenerated shoots were transferred onto half-strength MS medium without growth regulators, they rooted and complete plants were obtained. Plantlet regeneration from callus cultures required 7-8 weeks.

[Determination of cinnamaldehyde in Guizhi by HPLC].

OBJECTIVE: To establish a HPLC method for the determination of cinnamaldehyde in Guizhi. METHOD: Cinnamaldehyde was separated by a Kromasil C18 column (4.6 mm x 200 mm) with a mobile phase of acetonitrile-0.1% phosphoric acid solution(48:52) and an UV detection wavelength of 285 nm. RESULT: The calibration curve was linear in the range of 0.004-0.02 microliter.ml-1, with a correlation coefficient of 0.9996. The average recovery was 100.7%(n = 5), and RSD 0.3%(n = 6). CONCLUSION: The method is simple and accurate.