Drug-eluting biodegradable ureteral stent: New approach for urothelial tumors of upper urinary tract cancer

Upper urinary tract urothelial carcinoma (UTUC) accounts for 5-10% of urothelial carcinomas and is a disease that has not been widely studied as carcinoma of the bladder. To avoid the problems of conventional therapies, such as the need for frequent drug instillation due to poor drug retention, we developed a biodegradable ureteral stent (BUS) impregnated by supercritical fluid CO₂ (scCO₂) with the most commonly used anti-cancer drugs, namely paclitaxel, epirubicin, doxorubicin, and gemcitabine. The release kinetics of anti-cancer therapeutics from drug-eluting stents was measured in artificial urine solution (AUS). The in vitro release showed a faster release in the first 72h for the four anti-cancer drugs, after this time a plateau was achieved and finally the stent degraded after 9days. Regarding the amount of impregnated drugs by scCO₂, gemcitabine showed the highest amount of loading (19.57μg _drug/mg _polymer: 2% loaded), while the lowest amount was obtained for paclitaxel (0.067μg _drug/mg _polymer: 0.01% loaded). A cancer cell line (T24) was exposed to graded concentrations (0.01-2000ng/ml) of each drugs for 4 and 72h to determine the sensitivities of the cells to each drug (IC₅₀). The direct and indirect contact study of the anti-cancer biodegradable ureteral stents with the T24 and HUVEC cell lines confirmed the anti-tumoral effect of the BUS impregnated with the four anti-cancer drugs tested, reducing around 75% of the viability of the T24 cell line after 72h and demonstrating minimal cytotoxic effect on HUVECs.

Polymorphism of the CYP2D6 gene in women with breast cancer treated with tamoxifen

OBJECTIVE

To evaluate polymorphism frequency of the CYP2D6*4, *10, and * 17 alleles in women with breast cancer treated with tamoxifen.

MATERIALS AND METHODS

Ninety-five women with estrogen and progesterone receptor-positive breast carcinoma were investigated from September to December 2013. A three-ml sample of peripheral blood was collected from each patient to analyze the presence of CYP2D6 *4, *10, and *17 allele polymorphism by specific polymerase chain reaction technique (PCR) for analysis of haplotypes *1, *4, *10, and *17, determined by studies of different single-nucleotide polymorphism (SNP). The data obtained were compiled and analyzed with the aid of Excel software 2010.

RESULTS

The frequency of CYP2D6 alleles *4, *10, and *17 was 16%, 29%, and 2%, respectively, and haplotype * 1/*10 was shown in 22% of the women. The phenotype of intermediate metabolism occurred in 8% of women.

CONCLUSIONS

The present study showed a deficiency in tamoxifen metabolism, characterized by intermediate metabolism in 8% of Brazilian women.

Three-dimensional coherent diffractive imaging on non-periodic specimens at the ESRF beamline ID10

The progress of tomographic coherent diffractive imaging with hard X-rays at the ID10 beamline of the European Synchrotron Radiation Facility is presented. The performance of the instrument is demonstrated by imaging a cluster of Fe2P magnetic nanorods at 59 nm 3D resolution by phasing a diffraction volume measured at 8 keV photon energy. The result obtained shows progress in three-dimensional imaging of non-crystalline samples in air with hard X-rays.

In vitro and in vivo experiments with iron oxide nanoparticles functionalized with DEXTRAN or polyethylene glycol for medical applications: magnetic targeting

In this research work, DEXTRAN- and polyethylene glycol (PEG)-coated iron-oxide superparamagnetic nanoparticles were synthetized and their cytotoxicity and biodistribution assessed. Well-crystalline hydrophobic Fe3 O4 SPIONs were formed by a thermal decomposition process with d = 18 nm and σ = 2 nm; finally, the character of SPIONs was changed to hydrophilic by a post-synthesis procedure with the functionalization of the SPIONs with PEG or DEXTRAN. The nanoparticles present high saturation magnetization and superparamagnetic behavior at room temperature, and the hydrodynamic diameters of DEXTRAN- and PEG-coated SPIONs were measured as 170 and 120 nm, respectively. PEG- and DEXTRAN-coated SPIONs have a Specific Power Absorption SPA of 320 and 400 W/g, respectively, in an ac magnetic field with amplitude of 13 kA/m and frequency of 256 kHz. In vitro studies using VERO and MDCK cell lineages were performed to study the cytotoxicity and cell uptake of the SPIONs. For both cell lineages, PEG- and DEXTRAN-coated nanoparticles presented high cell viability for concentrations as high as 200 μg/mL. In vivo studies were conducted using BALB/c mice inoculating the SPIONs intravenously and exposing them to the presence of an external magnet located over the tumour. It was observed that the amount of PEG-coated SPIONs in the tumor increased by up to 160% when using the external permanent magnetic as opposed to those animals that were not exposed to the external magnetic field.

A new quantitative method to determine the uptake of SPIONs in animal tissue and its application to determine the quantity of nanoparticles in the liver and lung of Balb-c mice exposed to the SPIONs

We propose a new method for determining the quantity of superparamagnetic iron oxide nanoparticles (Fe3O4, SPIONs) embedded in animal tissue using magnetization measurements. With this method, the smallest detectable quantity of magnetite nanoparticles in a tissue sample is -1 microg. We showed that this method has proved being efficient. In this study, we focused in determining the quantity of SPION confined in lung and liver tissue of mice injected with -13 nm magnetite superparamagnetic nanoparticles. Furthermore, the method allowed us to detect the magnetite nanoparticles present in animal tissues without letting the natural iron ions present in the tissue or blood interfere with the measurements.

Collecting system percutaneous access using real-time tracking sensors: first pig model in vivo experience

PURPOSE

Precise needle puncture of the renal collecting system is an essential but challenging step for successful percutaneous nephrolithotomy. We evaluated the efficiency of a new real-time electromagnetic tracking system for in vivo kidney puncture.

MATERIALS AND METHODS

Six anesthetized female pigs underwent ureterorenoscopy to place a catheter with an electromagnetic tracking sensor into the desired puncture site and ascertain puncture success. A tracked needle with a similar electromagnetic tracking sensor was subsequently navigated into the sensor in the catheter. Four punctures were performed by each of 2 surgeons in each pig, including 1 each in the kidney, middle ureter, and right and left sides. Outcome measurements were the number of attempts and the time needed to evaluate the virtual trajectory and perform percutaneous puncture.

RESULTS

A total of 24 punctures were easily performed without complication. Surgeons required more time to evaluate the trajectory during ureteral than kidney puncture (median 15 seconds, range 14 to 18 vs 13, range 11 to 16, p=0.1). Median renal and ureteral puncture time was 19 (range 14 to 45) and 51 seconds (range 45 to 67), respectively (p=0.003). Two attempts were needed to achieve a successful ureteral puncture. The technique requires the presence of a renal stone for testing.

CONCLUSIONS

The proposed electromagnetic tracking solution for renal collecting system puncture proved to be highly accurate, simple and quick. This method might represent a paradigm shift in percutaneous kidney access techniques.

Natural orifice transluminal endoscopic surgery (NOTES): where are we going? A bibliometric assessment

The aim of this study was to analyse natural orifice transluminal endoscopic surgery (NOTES)-related publications over the last 5 years. A systematic literature search was done to retrieve publications related to NOTES from 2006 to 2011. The following variables were recorded: year of publication; article type; study design; setting; Journal Citation Reports® journal category; authors area of surgical speciality; geographic area of origin; surgical procedure; NOTES technique; NOTES access route; number of clinical cases. A time-trend analysis was performed by comparing early (2006-2008) and late (2009-2011) study periods. Overall, 644 publications were included in the analysis and most papers were found in general surgery journals (50.9%). Studies were most frequently clinical series (43.9%) and animal experimental (48%), with the articles focusing primarily on cholecystectomy, access creation and closure, and peritoneoscopy. Pure NOTES techniques were performed in most of the published reports (85%) with the remaining cases being hybrid NOTES (7.4%) and NOTES-assisted procedures (6.1%). The access routes included transgastric (52.5%), transcolonic (12.3%), transvesical (12.5%), transvaginal (10.5%), and combined (12.3%). From the early to the late period, there was a significant increase in the number of randomised controlled trials (5.6% vs 7.2%) or non-randomised but comparative studies (5.6% vs 22.9%) (P < 0.001) and there was also a significant increase in the number of colorectal procedures and nephrectomies (P = 0.002). Pure NOTES remained the most studied approach over the years but with increased investigation in the field of NOTES-assisted techniques (P = 0.001). There was also a significant increase in the adoption of transvesical access (7% vs 15.6%) (P = 0.007). NOTES is in a developmental stage and much work is still needed to refine techniques, verify safety and document efficacy. Since the first description of the concept of NOTES, >2000 clinical cases, irrespective of specialty, have been reported. NOTES remains a field of intense clinical and experimental research in various surgical specialities.

Abstract P4-02-03: FDG PET/CT for early monitoring of response to neoadjuvant chemotherapy in breast cancer patients

Introduction: Neoadjuvant chemotherapy (NAC), initially used only for locally advanced breast cancer, is now commonly used in patients with operable but large breast cancer or unfavorable tumor/breast size index because increases the chances of performing breast conservative surgery (BCS) instead of mastectomy in this group of patients.

Patients and Methods: This is a prospective unicenter trial. FDG PET/CT were performed in 40 patients at baseline and after the second cycle of NAC. The level and relative changes in standardized uptake value (SUV) of FDG uptake were assessed regarding their ability to predict histopathologic response.

Pathologic complete response (pCR) was defined as no malignant cells (no invasive ductal carcinoma and no ductal carcinoma in situ) identifiable in sections from the site of the tumor in the breast and in the axillary lymph node.

Results: This prospectively study analyzed forty patients undergoing NAC, all female, age ranged 27–64 years (mean 41.0 years and median 38 years), all tumors were invasive ductal carcinoma, histological tumor grade 1, 2 and 3 were present respectively at 5%, 38.5% and 100% of the sample and nuclear grade 2 and 3 were present respectively at 12.5% and 87.5%. Estrogen receptor was positive in 60% of patients and the progesterone receptor was positive in 47.5% of patients. Her 2 was overexpressed in 12 patients (30%). Phenotype in this sample had the following distribution: 12.5% luminal A (5 patients), 50% Luminal B (20 patients: 14 patients with Ki-67&gt; 14% and 6 cases with HER 2 overexpression), 15 % HER 2 (6 patients) and cases triple negative 9 (22.5%). size of the primary tumor ranged from 4.10 cm to 12.0 cm (mean 7.10 cm). The size of the primary tumor ranged from had a mean of 6.7 cm and a median of 6.0 cm. This group showed great uniformity in relation to primary chemotherapy. NAC with cyclophosphamide and adriamycin were administered to 38 patients. In this study, pCR was obtained in 12 patients (30%). Baseline FDG SUV referring to pCR group was 11.26 and 7.26 in non-pCR group (p = 0.04). FDG SUV after second cycle was 2.73 in pCR group and 4.64 in non-pCR group (p = 0.048). When analyzing ΔSUV (difference between baseline SUV and SUV after second cycle), pCR group had a mean reduction of 81.58% and non-pCR group had a mean reduction of 81.58% (p = 0.001). Receiver operating curve analyses were performed to deter mine optimal differentiation cut-off values of ΔSUV for differentiation of pCR and non-pCR. After two courses of NAC the optimal cutoff value to early differentiation between pCR from non-pCR were 59,1% in decrease of SUV. The sensitivity and specificity were 64,3% and 100,0%, respectively.

Conclusion: The optimum role of FDG PET in predicting the response of breast cancers to neoadjuvant chemotherapy is still not clearly defined and the SUV cut-off needs to be validated. FDG-PET allows for prediction of treatment response by the level of FDG uptake in terms of SUV at baseline and after two cycles of chemotherapy and FDG-PET may be helpful for individual treatment stratification in breast cancer patients.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-02-03.

Critical mass of splenic autotransplant needed for the development of phagocytic activity in rats

When total splenectomy is inevitable, heterotopic splenic autotransplantation seems to be the only alternative to maintain the functions of the spleen. The present study was carried out to analyse the critical mass of splenic autotransplant (SAT) for the development of phagocytic activity in rats. Wistar rats were submitted to total splenectomy (TS) alone or in combination with slices of SAT ranging from an average rate of 21·9% (one slice) to 100% (five slices) of the total splenic mass implanted into the greater omentum. Sixteen weeks after the beginning of the experiment, the animals were inoculated intravenously with a suspension of Escherichia coli labelled with Tc-99m. After 20 min, the rats were killed and the liver, lung and spleen or SAT, as well as blood samples were removed to determine the percentage of labelled bacteria uptake in these tissues. As the percentage of the total splenic mass contained in the SAT increased, the bacteria remaining in the blood decreased. From the implant of 26% up to the implant of the total splenic mass (100%) there was no difference in the bacteria remaining in the blood between the healthy animals of the control group and those submitted to TS combined with SAT. This finding shows that the critical mass needed for the development of phagocytic activity of macrophages in splenic autotransplants in adult rats is 26% of the total splenic mass.

Mini-laparoscopy, laparoendoscopic single-site surgery and natural orifice transluminal endoscopic surgery-assisted laparoscopy: novice surgeons' performance and perception in a porcine nephrectomy model

Study Type--Therapy (case series) Level of Evidence 4. What's known on the subject? and What does the study add? Over the last few years, minimally invasive urological surgery has evolved towards less invasive, 'scarless' procedures. New surgical concepts, such as those of natural orifice transluminal endoscopic surgery (NOTES) and laparoendoscopic single-site surgery (LESS) have been introduced. Mini-laparoscopy has been rediscovered in an attempt to reduce the invasiveness of standard laparoscopy. This study is the first to compare the perception of surgeons when first facing three different scarless options for performing a porcine nephrectomy and when dealing with the constraints of each technique. The study findings suggest that: (i) when first approaching these techniques, surgeons tend to perform equally well under expert guidance in the porcine model; (ii) mini-laparoscopy is perceived as less difficult to perform; (iii) for all the techniques, surgeon's impressions are in line with their expectations.

OBJECTIVE

• To evaluate the perception and performance of urological surgeons when first applying scarless surgical techniques.

METHODS

• The study was conducted during the 2(nd) Minimally Invasive Urological Surgical Week annual course in Braga, Portugal. • Fourteen attendees performed three porcine nephrectomies by using each of the following techniques: mini-laparoscopy, laparoendoscopic single-site surgery (LESS) and natural orifice transluminal endoscopic surgery (NOTES)-assisted laparoscopy. • Peri-operative data were recorded, and operating performance was scored by one experienced surgeon for each working station, using a global rating scale. • The surgeons' subjective perceptions of degree of difficulty were graded and their expectations before the procedures were recorded.

RESULTS

• Forty-two porcine nephrectomies were performed. • There were no differences in overall operating time, or time to dissect and manage the renal vascular hilum, whereas time to gain access was faster for LESS than for mini-laparoscopy or NOTES-assisted laparoscopy (mean [sd] 8 [6] min vs 10.2 [5.3] min vs 9.9 [5.3] min, respectively; P = 0.59). • A better visualization of the surgical field was obtained with mini-laparoscopy and there was a higher degree of difficulty of bimanual dexterity for LESS, but no significant differences were found among the three techniques for any variable (operating field view: P = 0.52; bimanual dexterity: P = 0.49; efficiency: P = 0.77; tissue handling: P = 0.61; autonomy: P = 0.2). • Subjective perception of the degree of difficulty trended in favour of mini-laparoscopy (P= 0.17), but no significant difference was found in terms of surgeons' impression as compared with their expectations (P = 0.34).

CONCLUSIONS

• When first approaching new scarless techniques, surgeons tend to perform equally well under expert guidance in the porcine model. • Mini-laparoscopy is perceived as less difficult to perform and, for all the techniques, surgeons' impressions are in line with their expectations.

Natural orifice transluminal endoscopy surgery: A review

Minimally invasive surgery started spreading worldwide in 1987, when the first laparoscopic cholecystectomy was performed. Meanwhile, improvement of endoscopic equipment and instruments allowed gastroenterologists to attempt more aggressive endoluminal interventions, even beyond the wall barrier. The first transgastric peritoneoscopy, in 2004, brought to light the concept of natural orifice transluminal endoscopic surgery (NOTES). The idea of incisionless surgery is attractive and has become a new goal for both surgeons and other people interested in this field of investigation. The authors present a review of all developments concerning NOTES, including animal studies and human experience.

Influence of cation nature on stabilization of gold nanospecies in mordenites

Gold species deposited on NH4(+)- and H(+)-mordenites were studied by X-ray diffraction, xenon adsorption, NMR of 27Al and 129Xe, UV-Visible spectroscopy and TPR. Mordenite ion-exchange cations exert a significant effect on size distribution and electronic state of gold species supported on the zeolites. AuNH4M contains larger nanoparticles of gold on its external surface than AuHM because protonic form of zeolite has stronger sites for stabilization of gold nanospecies. In the case of NH4(+)-mordenite, Au clusters inside zeolite channels have bigger size and fill the side-pockets completely after gold deposition due to more complete reduction of gold entities, while in H(+)-mordenite only half the side-pockets are filled by gold species. H(+)-mordenite favors the stabilization of both small gold clusters and cations. Even after the reduction of gold by hydrogen flow at 100 degrees C, some gold species are not completely reduced and have certain effective charge (Au(n)delta+ clusters).

Low-cost reusable instrumentation for laparoendoscopic single-site nephrectomy: assessment in a porcine model

PURPOSE

To test different sets of prebent instruments and a new reusable access device for laparoendoscopic single-site (LESS) surgery.

MATERIALS AND METHODS

Three surgeons with previous experience in LESS performed 12 nephrectomies in six pigs. In all procedures, a multichannel access device (X-CONE) and a 5-mm extra-long telescope were used. Four sets of prebent instruments with different profiles (S-portal) were tested: Standard (one straight scissors and one curved grasper), Cuschieri, Carus, and Leroy set (each of them consisting of two curved instruments with different configurations). Assessment was performed based on both objective (procedure time; time to manage the pedicle; time to free kidney) and subjective parameters (entry/exit of instruments; triangulation; dissection up/down; dissection lateral; retraction; interdependence). The subjective assessment tool used was a Likert type scale (1 = easy to 5 = prohibitive). The access device was assessed by using objective (time to complete insertion of device after skin incision) and subjective (significant air leakage, movement constraint) parameters.

RESULTS

Time to insertion of the X-CONE was <1 minute in all the cases. Surgeons reported significant insufflant leakage in 58% of cases. The procedure was completed in 10/12 (83%) cases. Mean operative time was 8.3 ± 4.2 minutes, being lower for the Carus group (4.5 min) and higher for the standard group (13 min). Among the different sets, the standard one obtained the best mean scores for all subjective parameters.

CONCLUSIONS

X-CONE allows easy abdominal access, and its reusable properties represent cost savings for LESS compared with disposable devices. Prebent instruments might also represent attractive low-cost tools for LESS.

Laparoendoscopic single-site and natural orifice transluminal endoscopic surgery in urology: a critical analysis of the literature

CONTEXT

Natural orifice transluminal endoscopic surgery (NOTES) and laparoendoscopic single-site surgery (LESS) have been developed to benefit patients by enabling surgeons to perform scarless surgery.

OBJECTIVE

To summarize and critically analyze the available evidence on the current status and future perspectives of LESS and NOTES in urology.

EVIDENCE ACQUISITION

A comprehensive electronic literature search was conducted in June 2010 using the Medline database to identify all publications relating to NOTES and LESS in urology.

EVIDENCE SYNTHESIS

In urology, NOTES has been completed experimentally via transgastric, transvaginal, transcolonic, and transvesical routes. Initial clinical experience has shown that NOTES urologic surgery using currently available instruments is indeed possible. Nevertheless, because of the immaturity of the instrumentation, early cases have demanded high technical virtuosity. LESS can safely and effectively be performed in a variety of urologic settings. As clinical experience increases, expanding indications are expected to be documented and the efficacy of the procedure to improve. So far, the quality of evidence of all available studies remains low, mostly being small case series or case-control studies from selected centers. Thus, the only objective benefit of LESS remains the improved cosmetic outcome. Prospective, randomized studies are largely awaited to determine which LESS procedures will be established and which are unlikely to stand the test of time. Technology advances hold promise to minimize the challenging technical nature of scarless surgery. In this respect, robotics is likely to drive a major paradigm shift in the development of LESS and NOTES.

CONCLUSIONS

NOTES is still an investigational approach in urology. LESS has proven to be immediately applicable in the clinical field, being safe and feasible in the hands of experienced laparoscopic surgeons. Development of instrumentation and application of robotic technology are expected to define the actual role of these techniques in minimally invasive urologic surgery.

In vivo assessment of gastrotomy closure with over-the-scope clips in an experimental model for varicocelectomy (with video)

BACKGROUND

Gastrotomy closure remains the major limiting factor for human translation of transgastric surgery; the over-the-scope clip (OTSC) system was proposed as a possibility for this purpose. Transgastric access is good for a pelvic approach, making varicocelectomy a possible indication for natural orifice transluminal endoscopic surgery (NOTES).

OBJECTIVE

To evaluate the reliability of the OTSC system in vivo after transgastric testicular vessel ligation (varicocelectomy model).

DESIGN

There were 3 experimental groups (5 animals in each): groups 1 and 3, gastrotomy dilation up to 18 mm, surgery was performed with a double-channel endoscope; group 2, gastrotomy dilation up to 13 mm, surgery was performed with a single-channel endoscope.

SETTING

Surgical Sciences Research Domain, Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.

INTERVENTIONS

Bilateral testicular vessel ligation by transgastric access. Gastrotomy closed with the largest version of OTSC system (12 mm): a single clip in groups 1 and 2, and 2 clips in group 3. Animals were monitored for 2 weeks, killed, and submitted for necropsy.

MAIN OUTCOME MEASUREMENTS

Adequacy of closure and healing after the use of the OTSC system. Statistical analysis.

RESULTS

Vessel ligation was easily achieved in all groups. Although differences in the complication rate did not reach statistical significance (P = .099), there was a clear tendency for a better prognosis in groups 2 and 3 than group 1. In fact, only 2 animals from group 1 had complications related to incomplete gastrotomy closure.

LIMITATIONS

Small number of animals per group; nonrandomized study.

CONCLUSIONS

The OTSC system was shown to be easy and efficient for gastrotomy closure in a survival experimental model of varicocelectomy, when correctly matching the gastrotomy size with the clip size and/or number.

An assessment of the resolution limitation due to radiation-damage in x-ray diffraction microscopy

X-ray diffraction microscopy (XDM) is a new form of x-ray imaging that is being practiced at several third-generation synchrotron-radiation x-ray facilities. Nine years have elapsed since the technique was first introduced and it has made rapid progress in demonstrating high-resolution three-dimensional imaging and promises few-nm resolution with much larger samples than can be imaged in the transmission electron microscope. Both life- and materials-science applications of XDM are intended, and it is expected that the principal limitation to resolution will be radiation damage for life science and the coherent power of available x-ray sources for material science. In this paper we address the question of the role of radiation damage. We use a statistical analysis based on the so-called "dose fractionation theorem" of Hegerl and Hoppe to calculate the dose needed to make an image of a single life-science sample by XDM with a given resolution. We find that for simply-shaped objects the needed dose scales with the inverse fourth power of the resolution and present experimental evidence to support this finding. To determine the maximum tolerable dose we have assembled a number of data taken from the literature plus some measurements of our own which cover ranges of resolution that are not well covered otherwise. The conclusion of this study is that, based on the natural contrast between protein and water and "Rose-criterion" image quality, one should be able to image a frozen-hydrated biological sample using XDM at a resolution of about 10 nm.

[Vaginal metastasis from renal cell carcinoma]

Vaginal metastases in renal cell carcinoma (RCC) have been reported in rare situations. We present a case of metastatic RCC in a 75-year-old woman, initially presenting with haematuria and vaginal pain. Workup further revealed a renal tumor and a vaginal mass. A nephrectomy and local vaginal excision were performed, leading to the diagnosis of metastatic RCC. This case illustrate the variability in RCC presentation. Also, because vaginal clear cell carcinoma is rare, all such lesions should be considered potentially renal in origin.

Interparticle interactions effects on the magnetic order in surface of FeO4 nanoparticles

We report interparticle interactions effects on the magnetic structure of the surface region in Fe3O4 nanoparticles. For that, we have studied a desirable system composed by Fe3O4 nanoparticles with (d) = 9.3 nm and a narrow size distribution. These particles present an interesting morphology constituted by a crystalline core and a broad (approximately 50% vol.) disordered superficial shell. Two samples were prepared with distinct concentrations of the particles: weakly-interacting particles dispersed in a polymer and strongly-dipolar-interacting particles in a powder sample. M(H, T) measurements clearly show that strong dipolar interparticle interaction modifies the magnetic structure of the structurally disordered superficial shell. Consequently, we have observed drastically distinct thermal behaviours of magnetization and susceptibility comparing weakly- and strongly-interacting samples for the temperature range 2 K < T < 300 K. We have also observed a temperature-field dependence of the hysteresis loops of the dispersed sample that is not observed in the hysteresis loops of the powder one.

Annealing effects on 5 nm iron oxide nanoparticles

Morphological, structural and magnetic properties of 4.8 nm iron oxide nanoparticles have been investigated after annealing under inert atmosphere at different temperatures. The as-prepared iron oxide nanoparticles have been synthesized by chemical route from high temperature reaction of Fe(acac)3 solution in presence of oleic acid and oleylamine surfactant. Annealing the particles at low temperatures (Tann = 573 K) produces an increment of the mean size from 4.8 nm to 6.0 nm, preserving the same morphology. The coercive field of the annealed sample has a small increasing with respect to the as-prepared sample in agreement with the mean particle volume change. Annealing at higher temperature (Tann = 823 K) leads to a bimodal size distribution of the iron oxide nanoparticles with 6.0 nm and 17 nm mean sizes respectively, where the bigger particles dominate the observed magnetic properties.

129Xe NMR spectroscopy study of porous cyanometallates

Zinc and cadmium hexacyanocobaltates(III) were prepared, and their porous networks were explored using 129Xe spectroscopy. The crystal structures of these two compounds are representative of porous hexacyanometallates, cubic (Fm-3m) for cadmium and rhombohedral (R-3c) for zinc. In the cubic structure, the porosity is related to systematic vacancies created from the elemental building block (i.e., the hexacyanometallate anion), whereas the rhombohedral (R-3c) structure is free of vacant sites but has tetrahedral coordination for the zinc atom, which leads to relatively large ellipsoidal pores communicated by elliptical windows. According to the Xe adsorption isotherms, these porous frameworks were found to be accessible to the Xe atom. The structure of the higher electric field gradient at the pore surface (Fm-3m) appears and is accompanied by a stronger guest-host interaction for the Xe atoms and a higher capacity for Xe sorption. For cadmium, the 129Xe NMR signal is typical of isotropic movement for the Xe atom, indicating that it remains trapped within a spherical cavity. From spectra recorded for different amounts of adsorbed Xe, the cavity diameter was estimated. For the zinc complex, 129Xe NMR spectra are asymmetric because of the Xe atom movement within an elongated cavity. The line-shape asymmetry changes when the Xe loading within the porous framework increases, which was ascribed to Xe-Xe interactions through the cavity windows. The Xe adsorption revealed additional structural information for the studied materials.

Effects of strength and endurance training on antioxidant enzyme gene expression and activity in middle-aged men

This study was aimed at investigating the effects of a 21-week period of progressive strength or endurance training on peripheral blood mononuclear cells (PBMC) antioxidant enzyme gene expression and activity in healthy middle-aged untrained men. Strength (n=11) and endurance (n=12) training were performed twice a week, including resistance exercises to activate all the main muscle groups or cycle-ergometer pedaling, respectively. mRNA levels of catalase, glutathione peroxidase (GPx), mitochondrial superoxide dismutase (MnSOD) and cytosolic superoxide dismutase (CuZnSOD) were increased after 21 weeks of strength training, while endurance training induced significant changes only in MnSOD and GPx mRNA levels. CuZnSOD protein content was significantly increased only in strength-trained subjects. The program of strength or endurance exercise training had no significant effects on the activity of any of the antioxidant enzymes. In conclusion, in a middle-aged population, 21 weeks of strength or endurance training was a sufficient stimulus to up-regulate mRNA levels of PBMC antioxidant enzymes, the strength training being a more optimal stimulus. However, the discrepancies between enzyme protein and mRNA levels suggest that the present systematic strength or endurance training period had no beneficial effects on enzymatic antioxidant defense mechanisms in previously untrained middle-aged men.