Laser-diode pumped glass-clad Ti:sapphire crystal fiber laser.

Efficient glass-clad crystal fiber (CF) lasers were demonstrated using a Ti:sapphire crystalline core as the gain medium. With a core diameter of 18 µm, the laser diode (LD) pump source can be effectively coupled and guided throughout the crystal fiber for a low threshold and high slope efficiency laser operation. The advantage of high heat dissipation efficiency of the fiber structure can be derived from the low core temperature rising measurement (i.e., 17 K/W) with passive cooling. At an output transmittance of 23%, the lowest absorbed threshold of 118.2 mW and highest slope efficiency of 29.6% were achieved, with linear laser polarization.

Broadband and high-brightness light source: glass-clad Ti:sapphire crystal fiber.

High-brightness near-infrared broadband amplified spontaneous emission (ASE) was generated by glass-clad Ti:sapphire crystal fibers, which were developed using the co-drawing laser-heated pedestal growth method. As much as 29.2 mW of ASE power was generated using 520 nm laser diodes as the excitation source on an a-cut, 18 µm core-diameter Ti:sapphire crystal fiber (CF). The 3 dB bandwidth was 163.8 nm, and the radiance was 53.94 W·mm(-2) sr(-1). The propagation loss of the glass-clad sapphire CF measured using the cutback method was 0.017 cm(-1) at 780 nm. For single-mode applications, more than 100 µW of power was coupled into a SM600 single-mode fiber.

Responsiveness of quantitative cartilage measures over one year in knee osteoarthritis: comparison of radiography and MRI assessments.

PURPOSE: To directly compare the responsiveness of quantitative imaging measures of disease progression in knee osteoarthritis (OA). In the medial compartment of the knee comparison was made between: 1) radiographic joint space narrowing (JSN); 2) global quantitative magnetic resonance imaging (qMRI) of cartilage volume; 3) regional qMRI of cartilage thickness; and 4) regional analysis using an ordered value (OV) methodology. MATERIALS AND METHODS: 3T MRI and weight-bearing radiography of the knees were performed at baseline and 1-year timepoints in 23 subjects (mean age 63 years) with symptomatic knee OA. Standardized response means (SRM) were calculated for each measure. Statistical analysis to determine significance of change between timepoints was performed with a two-tailed Student's t-test (JSN, global, regional analysis) and nonparametric Mann-Whitney test (ordered values). RESULTS: At 1 year, global cartilage volume losses of 2.3% (SRM -0.44) in the medial tibia and 6.9% in the medial femur (SRM -0.74) were recorded. SRM for JSN was -0.46. Regional analysis revealed largest reductions in cartilage thickness in the external (SRM -0.84) weight-bearing subregion of the medial femur and in the posterior subregion of the medial tibia (SRM -0.79). OV analysis in the medial compartment revealed areas of cartilage thinning (four ranked OV) and cartilage thickening (two ranked OV). CONCLUSION: The MRI OV approach proved to be a superior analysis tool for detecting changes in cartilage morphology over a 1-year period. Radiographically defined JSN was found to be the least responsive measurement method of knee OA disease progression.

Use of 3T MRI and an unspoiled 3D fast gradient echo sequence for porcine knee cartilage volumetry: preliminary findings.

PURPOSE: To assess the utility of knee cartilage volumetry using an unspoiled fat-suppressed 3D fast gradient echo (FGRE) sequence at 3T. MATERIALS AND METHODS: Sagittal magnetic resonance (MR) images were obtained with an unspoiled fat-suppressed 3D FGRE sequence in eight porcine knees. Manual segmentation was used to derive the cartilage volume. This volume was compared to a volume measurement of cartilage scraping specimens obtained by water displacement. Imaging was repeated five times in four of the knees to assess interscan volume measurement reproducibility and calculate precision error. A single 3D dataset was manually segmented five times at weekly intervals to assess intraobserver volume measurement reproducibility. RESULTS: Total cartilage volume obtained from MRI and water displacement correlated well (r = 0.75). The interscan reproducibility of total volume measurements, expressed as the coefficient of variation (CV), was 4.2%, and the precision error (root mean square [RMS] CV) was 4.1%. The CV of intraobserver estimates of total cartilage volume by MRI was 3.6%. CONCLUSION: Interscan reproducibility of quantification of total cartilage volume and reproducibility of the manual segmentation technique were both high (>95%). Accurate and reproducible cartilage volumetry can be obtained by using a clinical unspoiled fat-suppressed 3D FGRE acquired at 3T MRI.

Breast cancer detection of large size to DCIS by hypoxia and angiogenesis using NIRS.

This investigation aimed to test all tumor-bearing patients who undergo biopsy to see if angiogenesis and hypoxia can detect cancer. We used continuous-wave near-infrared spectroscopy (NIRS) to measure blood hemoglobin concentration to obtain blood volume or total hemoglobin [Hbtot] and oxygen saturation for the angiogenesis and hypoxic biomarkers. The contralateral breast was used as a reference to derive the difference from breast tumor as a difference in total hemoglobin Δ[HBtot] and a difference in deoxygenation Δ([Hb]-[HbO2]). A total of 91 invasive cancers, 26 DCIS, 45 fibroblastomas, 96 benign tumors excluding cysts, and 67 normal breasts were examined from four hospitals. In larger-size tumors, there is significantly higher deoxygenation in invasive and ductal carcinoma in situ (DCIS) than in that of benign tumors, but no significant difference was seen in smaller tumors of ≤ 1 cm. With the two parameters of high total hemoglobin and hypoxia score, the sensitivity and specificity of cancer detection were 60.3 % and 85.3 %, respectively. In summary, smaller-size tumors are difficult to detect with NIRS, whereas DCIS can be detected by the same total hemoglobin and hypoxic score in our study.

The new SRS/FSRT technique HyperArc for benign brain lesions: a dosimetric analysis.

To evaluate the potential benefit of HyperArc (HA) fractionated stereotactic radiotherapy (FSRT) for the benign brain lesion. Sixteen patients with a single deep-seated, centrally located benign brain lesion treated by CyberKnife (CK, G4 cone-based model) were enrolled. Treatment plans for HA with two different optimization algorithms (SRS NTO and ALDO) and coplanar RapidArc (RA) were generated for each patient to meet the corresponding treatment plan criteria. These four FSRT treatment plans were divided into two groups-the homogeneous delivery group (HA-SRS NTO and coplanar RA) and the inhomogeneous delivery group (HA-ALDO and cone-based CK)-to compare for dosimetric outcomes. For homogeneous delivery, the brain V5, V12, and V24 and the mean brainstem dose were significantly lower with the HA-SRS NTO plans than with the coplanar RA plans. The conformity index, high and intermediate dose spillage, and gradient radius were significantly better with the HA-SRS NTO plans than with the coplanar RA plans. For inhomogeneous delivery, the HA-ALDO exhibited superior PTV coverage levels to the cone-based CK plans. Almost all the doses delivered to organs at risk and dose distribution metrics were significantly better with the HA-ALDO plans than with the cone-based CK plans. Good dosimetric distribution makes HA an attractive FSRT technique for the treatment of benign brain lesions.

The feasibility and efficacy of new SBRT technique HyperArc for recurrent nasopharyngeal carcinoma: noncoplanar cone-based robotic system vs. noncoplanar high-definition MLC based Linac system.

The purpose of this study was to evaluate the feasibility and efficacy of HyperArc (HA) for recurrent nasopharyngeal cancer (NPC) by comparing it with the CyberKnife system (CK). Fifteen patients with recurrent nasopharyngeal cancer who were treated using the noncoplanar cone-based robotic CK system were enrolled. CK was delivered with a median dose of 37.5 Gy in 5 fractions. The delivered CK treatment plans were the sources for the corresponding homogeneous HA (HA-H) and inhomogeneous HA (HA-IH) plans. The HA-H plans were generated to meet the corresponding treatment plan criteria for the CK plans. The HA-IH plans were designed to emulate the corresponding inhomogeneous CK isodose distributions. These three SBRT treatment plans were compared with target coverage, sparing of organs at risk (OARs), and dose distribution metrics. The HA-H and HA-IH plans consistently exhibited CTV and PTV coverage levels similar or better to those of the CK plans but significantly reduced the dose to OARs. Using the HA techniques (both HA-H and HA-IH plans), the mean maximal doses to the spinal cord, brainstem, optic nerves, and optic chiasm were reduced by approximately 60%, compared to the CK plans. The high dose spillage, conformity, and homogeneity indices of the HA-H plans were significantly better than those of the CK plans. The HA-IH plans showed faster dose falloff and similar conformity of the HA-H plans and dose heterogeneity of the CK plans. Here we demonstrated the HA treatment plan system for recurrent NPC is feasible, either homogeneous or inhomogeneous delivery. Excellent sparing of OARs and dosimetric distribution and very efficient delivery make HA an attractive SBRT technique for recurrent NPC treatment.

Effect of radiotherapy on survival in advanced hepatocellular carcinoma patients treated with sorafenib: a nationwide cancer-registry-based study.

Sorafenib is the standard treatment for advanced hepatocellular carcinoma (HCC) patients. This study aims to determine whether combining radiotherapy with sorafenib administration increases its efficacy. The study cohort included 4763 patients with diagnosed advanced HCC who received sorafenib between January 2012 and December 2015, as reported in medical records in the Taiwan Cancer Registry database. The effect of sorafenib with or without radiotherapy on survival was calculated using the Kaplan-Meier method and compared using the log-rank test. A Cox proportional hazards model was used for multivariate analysis. Patients receiving sorafenib plus radiotherapy had greater 1-year survival than did those receiving sorafenib alone (P < 0.001). Uni- and multivariate analyses also showed that radiotherapy increased survival after adjusting for confounders (adjusted HR 0.57; 95% CI 0.51-0.63). Further stratified analysis according to the timing of radiotherapy relative to sorafenib treatment revealed that patients who underwent radiotherapy after sorafenib had greater 1-year survival than did those undergoing radiotherapy within sorafenib use or sorafenib alone (adjusted HR 0.39; 95% CI 0.27-0.54). Combined treatment with sorafenib and radiotherapy results in greater HCC patient survival and should be considered an option for treating this challenging disease.

Microgel iron oxide nanoparticles for tracking human fetal mesenchymal stem cells through magnetic resonance imaging.

Stem cell transplantation for regenerative medicine has made significant progress in various injury models, with the development of modalities to track stem cell fate and migration post-transplantation being currently pursued rigorously. Magnetic resonance imaging (MRI) allows serial high-resolution in vivo detection of transplanted stem cells labeled with iron oxide particles, but has been hampered by low labeling efficiencies. Here, we describe the use of microgel iron oxide (MGIO) particles of diameters spanning 100-750 nm for labeling human fetal mesenchymal stem cells (hfMSCs) for MRI tracking. We found that MGIO particle uptake by hfMSCs was size dependent, with 600-nm MGIO (M600) particles demonstrating three- to sixfold higher iron loading than the clinical particle ferucarbotran (33-263 versus 9.6-42.0 pg iron/hfMSC; p < .001). Cell labeling with either M600 particles or ferucarbotran did not affect either cellular proliferation or tri-lineage differentiation into osteoblasts, adipocytes, and chondrocytes, despite differences in gene expression on a genome-wide microarray analysis. Cell tracking in a rat photothrombotic stroke model using a clinical 1.5-T MRI scanner demonstrated the migration of labeled hfMSCs from the contralateral cortex to the stroke injury, with M600 particles achieving a five- to sevenfold higher sensitivity for MRI detection than ferucarbotran (p < .05). However, model-related cellular necrosis and acute inflammation limited the survival of hfMSCs beyond 5-12 days. The use of M600 particles allowed high detection sensitivity with low cellular toxicity to be achieved through a simple incubation protocol, and may thus be useful for cellular tracking using standard clinical MRI scanners.

PCSK1 Overexpression in Rectal Cancer Correlates with Poor Response to Preoperative Chemoradiotherapy and Prognosis.

BACKGROUND: In a data mining search for potential therapeutic targets to improve the outcome of rectal cancer, we identified PCSK1 as the cell-cell signaling gene most significantly associated with poor response to concurrent chemoradiotherapy (CCRT). This study aims to investigate the prognostic value of PCSK1 expression in rectal cancer patients who underwent neoadjuvant CCRT. METHODS: Endoscopic biopsy specimens from 172 rectal cancer patients receiving neoadjuvant CCRT followed by curative surgery were assessed immunohistochemically for PCSK1 expression, and H-scores were determined. Expression levels of PCSK1 were further analyzed for correlations with clinicopathologic features, tumor regression grade, metastasis-free survival, disease-specific survival, and recurrence-free survival. RESULTS: PCKS1 overexpression was significantly associated with pretreatment tumor status (T3-4; p = 0.009), pretreatment nodal status (N1-2; p < 0.001), posttreatment tumor status (T3-4; p < 0.001), posttreatment nodal status (N1-2; p < 0.001), vascular invasion (p = 0.003), and perineurial invasion (p = 0.023). PCKS1 overexpression was also found to be significantly associated with a lower degree of tumor regression (p < 0.001). In the univariate analysis, PCSK1 overexpression was significantly associated with lower disease-specific survival, metastasis-free survival, and recurrence-free survival (p < 0.005). PCSK1 overexpression remained an independent prognostic factor of lower disease-specific survival (p = 0.003; hazard ratio, 5.478) in the multivariate analysis. CONCLUSION: Determination of PCSK1 overexpression may be useful for identifying rectal cancer patients at risk for a poor response and worse survival after CCRT.

Dosimetric comparison between RapidArc and HyperArc techniques in salvage stereotactic body radiation therapy for recurrent nasopharyngeal carcinoma.

BACKGROUND: To evaluate dosimetric differences of salvage irradiations using two commercially available volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) techniques: RapidArc (RA) and HyperArc (HA), for recurrent nasopharyngeal carcinoma (NPC) after initial radiation therapy. METHODS: Ten patients with recurrent NPC status previously treated with radiation therapy were considered suitable candidates for salvage SBRT using VMAT approach. Two separate treatment plans were created with HA and RA techniques for each case, with dosimetric outcomes compared with respect to tumor target coverage and organs-at-risk (OARs) sparing. Furthermore, the cumulative radiobiological effects to the relevant OARs from the original radiotherapy to the respective salvage SBRT plans were analyzed in terms of biologically effective dose (BED). RESULTS: Treatment with HA exhibited similar target dose coverage as with RA, while delivering a higher mean dose to the targets. Using RA technique, the mean maximal doses to optic apparatus and the mean brain dose were reduced by 1 to 1.5 Gy, comparing to HA technique. The conformity index, gradient radius, and intermediate dose spillage in HA plans were significantly better than those in RA. With HA technique, the volume of brain receiving 12 Gy or more was reduced by 44%, comparing to RA technique. The cumulative BEDs to spinal cord and optic apparatus with RA technique were 1 to 2 Gy3 less than those with HA. HA technique significantly reduced the volume within body that received more than 100 Gy. CONCLUSIONS: With better dose distribution than RA while maintaining sufficient target dose coverage, HA represents an attractive salvage SBRT technique for recurrent NPC.

Whole Pelvic Radiotherapy With Stereotactic Body Radiotherapy Boost vs. Conventionally Fractionated Radiotherapy for Patients With High or Very High-Risk Prostate Cancer.

Background: Whole pelvic radiotherapy (WPRT) with stereotactic body radiotherapy (SBRT) boost has been shown to be effective in patients with high-risk prostate cancer (PC). However, no study has directly compared the efficacy of WPRT with SBRT boost with that of conventionally fractionated radiotherapy (CFRT). We compared the clinical outcomes between CFRT and WPRT with SBRT boost in patients with high or very high-risk PC (National Comprehensive Cancer Network definition). Methods: In total, 132 patients treated with CFRT and 121 patients treated with WPRT followed by SBRT boost were retrospectively analyzed. For the CFRT group, the prescribed dose range was 74-79.2 Gray (Gy) administered at 1.8-2 Gy per fraction. For WPRT with SBRT boost, the prescribed doses were 45 Gy administered in 25 fractions to the whole pelvis followed by 21 Gy boost (3 fractions of 7 Gy each) to prostate and seminal vesicles. The overall survival (OS) and biochemical failure (Phoenix definition) free survival (bFFS) were assessed by using the Kaplan-Meier method or the Cox proportional hazards regression model. The gastrointestinal (GI) and genitourinary (GU) tract toxicity were assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) v3.0. Results: The estimated 4-years overall survival in the CFRT and WPRT with SBRT boost groups was 91.6 and 97.7%, respectively (P = 0.18). The estimated 4-years biochemical failure-free survival in the CFRT and WPRT with SBRT boost groups was 89.1 and 93.9%, respectively (P = 0.41). No acute grade 3 or higher GI and GU toxicity was observed in both groups. Late grade 3 GI and GU toxicity occurred in 2.3 and 2.3% in the CFRT group, and in 1.7 and 0.8% in the WPRT with SBRT boost group, respectively. There was no significant between-group difference with respect to acute or late toxicity. Conclusions: In patients with high or very high-risk localized PC, compared with CFRT, WPRT with SBRT boost resulted in similar biochemical-free and overall survival rate with minimal toxicity. WPRT with SBRT boost is a feasible option for patients with high or very high-risk PC.

Role of medial cortical, hippocampal and striatal interactions during cognitive set-shifting.

To date, few studies have examined the functional connectivity of brain regions involved in complex executive function tasks, such as cognitive set-shifting. In this study, eighteen healthy volunteers performed a cognitive set-shifting task modified from the Wisconsin card sort test while undergoing functional magnetic resonance imaging. These modifications allowed better disambiguation between cognitive processes and revealed several novel findings: 1) peak activation in the caudate nuclei in the first instance of negative feedback signaling a shift in rule, 2) lowest caudate activation once the rule had been identified, 3) peak hippocampal activation once the identity of the rule had been established, and 4) decreased hippocampal activation during the generation of new rule candidates. This pattern of activation across cognitive set-shifting events suggests that the caudate nuclei play a role in response generation when the identity of the new rule is unknown. In contrast, the reciprocal pattern of hippocampal activation suggests that the hippocampi help consolidate knowledge about the correct stimulus-stimulus associations, associations that become inappropriate once the rule has changed. Functional connectivity analysis using Granger Causality Mapping revealed that caudate and hippocampal regions interacted indirectly via a circuit involving the medial orbitofrontal and posterior cingulate regions, which are known to bias attention towards stimuli based on expectations built up from task-related feedback. Taken together, the evidence suggests that these medial regions may mediate striato-hippocampal interactions and hence affect goal-directed attentional transitions from a response strategy based on stimulus-reward heuristics (caudate-dependent) to one based on stimulus-stimulus associations (hippocampus-dependent).

The impact of marital status on survival in patients with surgically treated colon cancer.

The aim of this study was to investigate the relationship between marital status and disease outcome in patients with surgically treated colon cancer. Between June 2010 and December 2015, a total of 925 patients with newly diagnosed colon cancer receiving curative resection were enrolled. The effect of marital status on 5-year disease-specific survival (DSS) was calculated using Kaplan-Meier method, and was compared by log-rank tests. A Cox regression model was used to find significant independent variables and determine whether marriage had a survival benefit in patients with colon cancer, using stratified analysis. Among these patients, 749 (80.9%) were married, and 176 (19.1%) were unmarried, including 42 (4.5%) never-married, 42 (4.5%) divorced/separated, and 93 (10.1%) widowed. There was no significant difference between the married and unmarried groups in cancer stage or adjuvant treatment. Married patients had better 5-year DSS compared with unmarried patients (69.1% vs 55.9%, P < .001). Uni- and multivariate analyses also indicated that unmarried patients had worse 5-year DSS after adjusting for various confounders (adjusted HR [aHR], 1.66; 95% CI, 1.24-2.22). Further stratified analysis according to demographic variables revealed that unmarried status was a significant negative factor in patients with the following characteristics: age >65 years, female sex, well/moderately differentiated tumor, and advanced tumor-node-metastasis (TNM) stage disease (III-IV). Thus, marriage has a protective effect, and contributes to better survival in patients with surgically treated colon cancer. Additional social support for unmarried colon cancer patients may lead to improve outcomes.

Radiologic features of polyacrylamide gel mammoplasty.

OBJECTIVE: The objective of our study was to describe the imaging features of polyacrylamide gel breast implants in women with and those without complications from mammoplasty. CONCLUSION: Although polyacrylamide gel implants may mimic conventional implants on both sonography and MRI in women who do not have complications from mammoplasty, polyacrylamide gel implants have some distinguishing features. The imaging appearance of polyacrylamide gel implants is related to the technique of injection and whether there are any associated complications. The implants are usually in a retroglandular location. Mammography, sonography, and MRI can be used to evaluate short-term complications, although MRI appears to be the most sensitive. Common short-term complications include extravasation of polyacrylamide gel and secondary infection, which may be related to lactation. The long-term complications of polyacrylamide gel mammoplasty are unknown. Knowledge of the appearances of polyacrylamide gel implants in women with and those without complications from mammoplasty is useful in the radiologic evaluation of such patients.

Radiographic Number of Positive Pelvic Lymph Nodes as a Prognostic Factor in Cervical Cancer Treated With Definitive Concurrent Chemoradiotherapy or Intensity-Modulated Radiotherapy.

Background: This study aims to assess the prognostic significance of radiographic numbers of positive pelvic lymph nodes (PLNs) in patients with cervical cancer treated with definitive concurrent chemoradiotherapy (CCRT) or intensity-modulated radiotherapy (IMRT). Methods: We conducted a retrospective study that included 164 eligible adult patients with cervical cancer who were treated with definitive CCRT or IMRT at our institution from 2009 to 2016. After exclusion of 50 patients, a total of 114 patients whose clinicopathological data and follow-up were finally analyzed. The radiographic numbers of positive PLNs were assessed by pretreatment magnetic resonance imaging (MRI) or computed tomography (CT). The criterion for a positive lymph node was defined as a short-axis diameter >1 cm. Using the Kaplan-Meier method and the Cox proportional hazards regression model, we assessed the overall survival (OS), cancer-specific survival (CSS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival (LRFS). Results: The median follow-up duration was 40 (range: 2-100) months. For patients with 0, 1-2, and ≥3 positive PLNs, the estimated 3-year OS were 85.4% vs. 82.4% vs. 59.7% (p = 0.035), CSS were 90.1% vs. 86.1% vs. 62.9% (p = 0.010), DMFS were 89.4% vs. 91.3% vs. 49.6% (p < 0.001), and LRFS were 77.8% vs. 73.4% vs. 70% (p = 0.690). Per the multivariate Cox regression, positive PLNs ≥3 (HR, 2.51; 95% CI: 1.09-5.80; p = 0.031) and non-squamous cell carcinoma type (HR, 2.82; 95% CI: 1.19-6.69; p = 0.018) were unfavorable factors for the OS. Besides, positive PLNs ≥3 was the independent factor for the CSS (HR, 3.38; 95% CI: 1.32-8.67; p = 0.011) and DMFS (HR, 6.83; 95% CI: 2.62-17.83; p < 0.001). The patients that were treated without intracavitary brachytherapy exhibited inferior LRFS (HR, 13.15; 95% CI: 2.66-65.10; p = 0.002). Conclusions: The radiographic number of positive PLNs (≥ 3) is an independent prognostic factor for OS, CSS, and DMFS in patients treated with definitive CCRT or IMRT.

Solvent-free atom transfer radical polymerization for the preparation of poly(poly(ethyleneglycol) monomethacrylate)-grafted Fe3O4 nanoparticles: synthesis, characterization and cellular uptake.

Poly(poly(ethyleneglycol) monomethacrylate) (P(PEGMA))-grafted magnetic nanoparticles (MNPs) were successfully prepared via a solvent-free atom transfer radical polymerization (ATRP) method. The macroinitiators were immobilized on the surface of 6.4+/-0.8 nm Fe(3)O(4) nanoparticles via effective ligand exchange of oleic acid with 3-chloropropionic acid (CPA), which rendered the nanoparticles soluble in the PEGMA monomer. The so-obtained P(PEGMA)-grafted MNPs have a uniform hydrodynamic particle size of 36.0+/-1.2 nm. The successful grafting of P(PEGMA) on the MNP surface was ascertained from FTIR and XPS analyses. The uptake of the MNPs by macrophage cells is reduced by two-orders of magnitude to <2 pg Fe/cell after surface grafting with P(PEGMA). Furthermore, the morphology and viability of the macrophage cells cultured in a medium containing 0.2 mg/mL of P(PEGMA)-grafted MNPs were found similar to those of cells cultured without nanoparticles, indicating an absence of significant cytotoxicity effects. T(2)-weighted magnetic resonance imaging (MRI) of P(PEGMA)-grafted MNPs showed that the magnetic resonance signal is enhanced significantly with increasing nanoparticle concentration in water. The R(1) and R(2) values per millimole Fe, and R(2)/R(1) value of the P(PEGMA)-grafted MNPs were calculated to be 8.8 mm(-1)s(-1), 140 mm(-1)s(-1), and 16, respectively. These results indicate that the P(PEGMA)-grafted MNPs have great potential for application in MRI of specific biotargets.

Comparison of amperometric biosensors fabricated by palladium sputtering, palladium electrodeposition and Nafion/carbon nanotube casting on screen-printed carbon electrodes.

Different strategies, including palladium electrodeposition (Pd(CV)), Pd sputtering (Pd(S)) and Nafion-solubilized carbon nanotube casting (Nafion/CNT), were used to modify screen-printed carbon electrodes (SPCEs) for the fabrication of amperometric enzyme biosensors. The electrochemical properties of the bare and modified SPCEs and the optimal conditions for surface modification were determined. The electrochemical response of the bare SPCE to H(2)O(2) under the potential of 0.3 V could be improved about 100-fold by Pd modification by electrodeposition or sputtering. By contrast, the electrochemical response of the bare SPCE was enhanced by only about 11-fold by Nafion/CNT casting. Moreover, the Pd(CV)-SPCEs exhibited better reproducibility of electrochemical response (a relative standard deviation (R.S.D.)<6.0%) than freshly prepared Pd(S)-SPCEs (R.S.D.>10%). The glucose biosensor fabricated from Pd-modified electrodes could be stored for up to 108 days without loosing significant activity. The Pd(CV)-SPCE also showed very reliable signal characteristics upon 50 consecutively repeated measurements of ascorbic acid. The electrocatalytic detection of the Pd-SPCE was combined with additional advantages of resistance to surface fouling and hence good stability. In conclusion, this study demonstrated that deposition of Pd thin film on SPCEs by electrodeposition or sputtering provided superior enhancement of electrochemical properties compared to Nafion/CNT-SPCEs. Despite their high electrochemical response, Pd(S)-SPCEs required an activation process to improve stability and Pd(CV)-SPCEs suffered from poor between electrode reproducibility.

Postoperative evaluation of the knee after autologous chondrocyte implantation: what radiologists need to know.

Articular cartilage lesions occur commonly. Cartilage is relatively avascular and is unable to self-repair. A chondral lesion may become symptomatic. It may lead to osteoarthritis and increased morbidity. The aim of cartilage repair is to restore hyaline cartilage. There are many types of cartilage repair surgery, most of which result in fibrocartilage repair tissue that is suboptimal. Autologous chondrocyte implantation has been shown to produce hyaline-type repair tissue. Magnetic resonance (MR) imaging is performed preoperatively to define the ulcer and postoperatively to evaluate the technical success of implantation and the state of cartilage healing and to identify potential complications. Features of the autologous chondrocyte implantation graft that are assessed include the degree of filling by repair tissue, its integration with native cartilage and subchondral bone, the character of the graft substance and surface, and the underlying bone. MR arthrography is superior to unenhanced MR imaging because intraarticular contrast material allows the recipient site to be physically separated from adjacent structures so that it can be characterized more accurately. MR imaging and arthroscopy are complementary investigations in the follow-up of an autologous chondrocyte implantation in the knee. The appearance of the knee after autologous chondrocyte implantation varies among individuals and according to the time-course of healing. Familiarity with the surgical procedure and imaging appearance is essential for an accurate postsurgical assessment.

Rhabdomyolysis following shoulder arthroscopy.

Fluid extravasation is not uncommon after shoulder arthroscopy. We report a case of massive fluid extravasation that resulted in rhabdomyolysis and renal shutdown following routine shoulder arthroscopic surgery. Compartment pressures in the deltoid, supraspinatus, and infraspinatus were normal. Magnetic resonance imaging of the shoulder revealed extensive subcutaneous edema and high-signal changes in the entire deltoid muscle. The patient made an uneventful recovery with adequate supportive treatment and renal dialysis. Repeat imaging studies 3 months later revealed complete restoration to normal of the deltoid muscle. In addition to extensive fluid extravasation in this patient, the use of nonsteroidal anti-inflammatory medication, the development of a transient allergic reaction to a prescribed antibiotic, and the inclusion of epinephrine in the infusion fluid may have collectively contributed to rhabdomyolysis. We recommend that the use of infusion pumps should be limited to the shortest time possible, and that gravity inflow should be used as much as possible. Inflow should preferably occur through the arthroscope itself, rather than through a separate portal cannula, which may dislodge, inadvertently causing infusion of high-pressure fluid into the surrounding tissue.