Effects of laminin-coated carbon nanotube/chitosan fibers on guided neurite growth

This study assesses the ability and potential of carbon nanotube (CNT)/chitosan to guide axon re-growth after nerve injuries. The CNT/chitosan fibers were produced via the coagulation and hydrodynamic focusing method. Fiber width and morphology were adjusted using such parameters as syringe pumping rate and the coagulant used. The CNT/chitosan fiber diameters were 50-300 μm for syringe pumping rates of 6-48 mL/h. Polyethylene glycol/NaOH (25%, w/w) solution was a suitable coagulant for forming fibers with small diameters. Physical property tests demonstrate that the CNT/chitosan composites had superior tensile strength and electrical conductivity compared with those of chitosan alone. The MTT and LDH tests reveal that CNT/chitosan composites were not cytotoxic. To improve the neural cell affinity of CNT/chitosan fibers, laminin was incorporated onto fiber surfaces via the oxygen plasma technique; cell adhesion ratio increased significantly from 3.5% to 72.2% with this surface modification. Immunofluorescence staining and SEM imaging indicate that PC12 cells adhered successfully and grew on the laminin (LN)-coated CNT/chitosan films and fibers. Experimental results show that PC12 grown on LN-coated CNT/chitosan fibers in vitro extend longitudinally oriented neurites in a manner similar to that of native peripheral nerves. With the inherent electrical properties of CNTs, oriented CNT/chitosan fibers have a potential for use as nerve conduits in nerve tissue engineering.     

Promoting regeneration of peripheral nerves in-vivo using new PCL-NGF/Tirofiban nerve conduits

Poly(ε-caprolactone) (PCL) scaffolds were modified by grafting nerve growth factor (NGF) and Tirofiban (TF), a clinical anti-thrombosis drug, as a new biomaterial for producing nerve conduits to promote the regeneration of sciatic nerves. The successful grafting of NGF and TF onto PCL scaffolds was confirmed by FTIR and ESCA spectra. In-vitro growths of the PC12 cells in PCL-NGF and PCL-NGF/TF scaffolds, determined by MTS, were significantly higher (P < 0.05, n = 4) than those in the PCL scaffolds following three days of cultivation. Interestingly, this study evaluation of the PCL, PCL-NGF, and PCL-NGF/TF nerve conduits in a 12 mm long gap of the rat sciatic nerve defect model that the gastrocnemius muscle mass of the tested rats in the PCL-NGF/TF groups significantly exceeded those in the PCL-NGF and PCL group. In the rats that had been implanted with PCL-NGF/TF conduits, the generated nerves passed through those conduits, expressing beta-III tubulin (TB), growth association protein-43 (GAP-43) and myelin basic protein (MBP) along their longitudinal axis, and the proximal and distal nerve ends of the rats were successfully connected. Those that had been implanted with PCL and PCL-NGF conduits did not exhibit these effects, as revealed by an immunochemical study of the expressions of the proteins in the conduits. Moreover, counting within the dorsal horn of the spinal cord (C(5)) demonstrated that the numbers of CTB-HRP-labeled neurons in the rats that had been implanted with PCL-NGF/TF conduits were significantly higher than those in the other groups. In this study, in-vivo examinations of the use of newly designed PCL-NGF/TF conduits to promote the generation of nerves in a defective rat model significantly increased the gastrocnemius muscle mass, and led to the successful regeneration of nerves that bridged a 12 mm long defected gap of nerves in rats. However, more rats must be tested to confirm the efficacy the newly designed nerve conduits.     

Imaging quality and diagnostic reliability of low-dose computed tomography lumbar spine for evaluating patients with spinal disorders

Background contextComputed tomography (CT) scans of the lumbar spine (CTLS) have demonstrated a higher level of accuracy than plain films and have been used to assess patients with spinal disorder when magnetic resonance imaging is not available. Nevertheless, radiation exposure remains a serious safety concern. Iterative reconstruction (IR) decreases the CT radiation dose for diagnostic imaging. However, the feasibility of using IR in CTLS is unclear.PurposeTo evaluate the imaging quality and diagnostic reliability of CTLS with IR.Study designA prospective study.Patient sampleAll patients from outpatient departments who suffered from spinal disorders and were referred for CTLS.Outcome measuresIn acquired CT images, the signal-to-noise ratio (SNR) of the dural sac (DS), intervertebral disc (IVD), psoas muscle (PM), and L5 vertebral body, the contrast-to-noise ratio between the DS and IVD (D-D CNR), and the subjective imaging qualities were compared across groups. Interobserver agreement was evaluated with kappa values.MethodsPatients receiving low radiation CTLS were divided into three groups. A 150 mAs tube current with 120 kVp tube voltage was used with Group A and a 230 mAs tube current with 100 kVp tube voltage with Group B. Intended end radiation exposure was 50% less than that of the control group. Tube modulation was active for all groups. The images of the two low-radiation groups were reconstructed by IR; those of the control group by filtered back-projection (FBP).ResultsThe SNRs of the DS, IVD, PM, BM, and D-D CNR of Group A were not inferior to those of the control group. All SNRs and D-D CNRs for Group B were inferior to those of the control group. Except for that of the facet joint, all subjective imaging ratings for anatomic regions were equivalent between Groups A and B. Interobserver agreement was highest for the control group (0.72–0.88), followed by Group A (0.69–0.83) and B (0.55–0.83).ConclusionsFifty percent tube current reduction combined with IR provides equivalent diagnostic accuracy and improved patient safety when compared with conventional CTLS. Our results support its use as a screening tool. With the tube modulation technique, further adjustments in weighting IR and FBP algorithms based on body mass index become unnecessary.     

Pulmonary delivery of insulin by liposomal carriers.

Growing attention has been given to the potential of a pulmonary route as a non-invasive administration for systemic delivery of therapeutic agents (mainly peptides and proteins). The lungs provide a large absorptive surface area, extremely thin absorptive mucosal membrane, and good blood supply. The non-invasive nature of this pathway makes it especially valuable for the delivery of large molecular protein. However, pulmonary delivery of peptides and proteins is complicated by the complexity of the anatomic structure of the human respiratory system and the effect of disposition exerted by the respiration process. In this study, novel nebulizer-compatible liposomal carrier for aerosol pulmonary drug delivery of insulin was developed and characterized. Experimental results showed that insulin could be efficiently encapsulated into liposomes by preformed vesicles and detergent dialyzing method. The optimal encapsulation efficiency was achieved when 40% ethanol was used. The particle size of liposomal aerosols from ultrasonic nebulizer approximated to 1 mum. Insulin was stable in the liposomal solution. Animal studies showed that plasma glucose level was effectively reduced when liposomal insulin was delivered by inhalation route of using aerosolized insulin-encapsulated liposomes. Including fluorescent probe (phosphatidylethanolamine-rhodamine) into liposome, we found that the liposomal carriers were effectively and homogeneously distributed in the lung aveolar. Liposome-mediated pulmonary drug delivery promotes an increase in drug retention-time in the lungs, and more importantly, a reduction in extrapulmonary side-effects which invariably results in enhanced therapeutic efficacies.     

Surgical Resection Is Better than Transarterial Chemoembolization for Hepatocellular Carcinoma Beyond Milan Criteria Independent of Performance Status

Background and Aims

Performance status is tightly linked with survival in patients with hepatocellular carcinoma (HCC). We investigated the impact of performance status on HCC patients beyond the Milan criteria receiving surgical resection (SR) or transarterial chemoembolization (TACE).

Methods

A total of 909 patients with HCC beyond the Milan criteria were retrospectively analyzed by using propensity score analysis.

Results

The baseline characteristics were similar between the SR and TACE group for patients with performance status 0 in the propensity model. More patients in the TACE group with performance status ≥1 had Child-Turcotte-Pugh class A compared to the SR group (p?=?0.044) in the propensity model. SR provided significantly better long-term overall survival than TACE in patients selected in the propensity model regardless of performance status (both p?TACE was associated with 2.279-fold and 3.066-fold increased risk of mortality in performance status 0 and performance status ≥1 in the propensity model (95 % confidence interval, 1.476–3.591 and 1.570–5.989), respectively.

Conclusions

For either performance status 0 or ≥1 HCC patients beyond the Milan criteria, SR provides significantly better long-term survival than TACE. SR should be considered a priority treatment in these patients independent of performance status.     

High-efficiency cell seeding method by relatively hydrophobic culture strategy

Cell adhesion efficiency is one of the key factors affecting the results of manufacturing tissue engineering constructs. High efficiency is required for seeding low proliferation cells onto scaffolds. In this study, we designed a strategy to improve the efficiency of cell adhesion using hydrophobic cell culture environment to enhance cells adhering to a scaffold. Cells have lower affinity to the surface of polydimethylsiloxane (PDMS) than tissue culture polystyrene (TCPS) plates. When cells were cultured with gelatin microspheres or chitosan films in a PDMS-coated plate instead of a normal TCPS plate, there was a significant increase in cell attachment efficiency. Cells cultured in the PDMS-coated system tended to selectively attach onto the gelatin microspheres or chitosan films, which are relatively more hydrophilic than the PDMS surface. However, minimal cell attachment on gelatin microspheres or chitosan films was observed when gelatin microspheres or chitosan films were placed in normal TCPS plate. Cell counting experiments with gelatin microspheres in the PDMS-coated system resulted in a cell attachment efficiency of 89.8% after 1 day of cultivation, whereas the cell attachment efficiency was less than 1% in normal TCPS plate. The results demonstrate that the method is easy to use and could be useful for fast cultivation of cell-scaffold constructs.     

Acinar cell carcinoma of the pancreas: clinical and computed tomography manifestations

PURPOSE: Acinar cell carcinoma (ACC) is a subtype of pancreatic neoplasm sufficiently rare that its imaging has not been fully analyzed. The purpose of this article is to present the computed tomography (CT) appearance of ACC of the pancreas. METHODS: Clinical data and CT studies of 10 patients (7 male and 3 female) with pathologically proven ACC of the pancreas were reviewed. Among the CT features emphasized were the presence of a well-defined enhancing capsule, foci of internal calcification, intratumoral hemorrhage, presence of a central hypodense area, and degree of contrast enhancement. RESULTS: The presenting symptoms of ACC of the pancreas were nonspecific. An elevated serum level of alpha-fetoprotein, carcinoembryonic acid, and CA 19-9 was noted in 2 (20%), 1 (10%), and 3 (30%) patients, respectively. The tumor locations were in the uncinate process in 4 (40%), in the head and neck in 2 (20%), in the body in 1 (10%), and in the tail in 3 (30%) patients. The average tumor size was 7.2 cm (range: 3.3-18 cm). A well-defined enhancing capsule, internal foci of calcification, and intratumoral hemorrhage appeared in 6 (60%), 5 (50%), and 0 tumors, respectively. Eight (80%) tumors had a central hypodense area; of these, 4 (40%) tumors exhibited a hypodense area greater than 50% of the tumor. During dynamic CT in 8 patients, 6 tumors showed early arterial (EA) enhancement and persisted into the portal venous (PV) phase, whereas the other 2 tumors revealed enhancement in the EA phase and washout in PV phase. CONCLUSION: Acinar cell carcinoma typically presents as a sizable pancreatic mass with a well-defined enhancing capsule and internal calcifications. Significant central hypodensity is frequently present. Recognition of these features can provide clues to the CT diagnosis of ACC.