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1.
Sci Rep ; 14(1): 9868, 2024 Apr 29.
Article in English | MEDLINE | ID: mdl-38684890

ABSTRACT

This comprehensive study delves into the intricate interplay between protons and organic polymers, offering insights into proton therapy in cancer treatment. Focusing on the influence of the spatial electron density distribution on stopping power estimates, we employed real-time time-dependent density functional theory coupled with the Penn method. Surprisingly, the assumption of electron density homogeneity in polymers is fundamentally flawed, resulting in an overestimation of stopping power values at energies below 2 MeV. Moreover, the Bragg rule application in specific compounds exhibited significant deviations from experimental data around the stopping maximum, challenging established norms.

2.
Rev. esp. anestesiol. reanim ; 70(8): 477-482, Octubre 2023. tab, ilus
Article in English | IBECS | ID: ibc-225931

ABSTRACT

We report retrospectively a series of four cases involving the successful use of the recently described parascapular sub-iliocostalis plane block (PSIP), for lateral-posterior rib fractures. The efficacy of the PSIP block may potentially depend on different mechanisms of action: (1) direct action in the fracture site by craniocaudal myofascial spread underneath the erector spinae muscle (ESM); (2) spread to deep layers through tissue disruption caused by trauma, to reach the proximal intercostal nerves; (3) medial spread below the ESM, to reach the posterior spinal nerves; and (4) lateral spread in the sub-serratus (SS) plane to reach the lateral cutaneous branches of the intercostal nerves; while avoiding significant negative hemodynamic effects and other possible complications associated to other techniques leading that the PSIP may be considered an alternative in some clinical scenarios to the erector spinae plane block or the paravertebral block. (AU)


Presentamos retrospectivamente una serie de 4 casos en los que se utilizó con éxito el bloqueo paraescapular del plano subiliocostal (PSIP), descrito recientemente, para fracturas costales laterales-posteriores. La eficacia del bloqueo PSIP puede depender potencialmente de diferentes mecanismos de acción: (1) acción directa en las fractura por la extensión miofascial craneocaudal por debajo del músculo erector de la columna, (2) diseminación a capas profundas a través de la disrupción tisular causada por el traumatismo, para alcanzar los nervios intercostales proximales, (3) extensión medial por debajo del músculo erector de la columna, para alcanzar los nervios espinales posteriores y (4) extensión lateral en el plano subserrato para alcanzar las ramas cutáneas laterales de los nervios intercostales, evitando al mismo tiempo efectos hemodinámicos negativos y otras posibles complicaciones asociados a otras técnicas, lo que hace que el bloqueo PSIP pueda considerarse en algunos escenarios clínicos una alternativa al bloqueo del plano erector de la columna vertebral o al bloqueo paravertebral. (AU)


Subject(s)
Humans , Ultrasonography , Nerve Block , Rib Fractures/therapy , Rib Fractures/complications , Retrospective Studies
3.
Rev Esp Anestesiol Reanim (Engl Ed) ; 70(8): 477-482, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37678457

ABSTRACT

We report retrospectively a series of four cases involving the successful use of the recently described parascapular sub-iliocostalis plane block (PSIP), for lateral-posterior rib fractures. The efficacy of the PSIP block may potentially depend on different mechanisms of action: (1) direct action in the fracture site by craniocaudal myofascial spread underneath the erector spinae muscle (ESM); (2) spread to deep layers through tissue disruption caused by trauma, to reach the proximal intercostal nerves; (3) medial spread below the ESM, to reach the posterior spinal nerves; and (4) lateral spread in the sub-serratus (SS) plane to reach the lateral cutaneous branches of the intercostal nerves; while avoiding significant negative hemodynamic effects and other possible complications associated to other techniques leading that the PSIP may be considered an alternative in some clinical scenarios to the Erector Spinae Plane block or the Paravertebral block.

4.
Data Brief ; 31: 106017, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32760765

ABSTRACT

This data article provides useful information often required for numerical modeling of the so-called microbond tests. It includes the experimental and simulation data of the microbond testing using Fibre Bragg Grating (FBG) fibres for optical strains. Microbond testing was performed on five different droplets of varying embedded length and diameter to collect the data. Finite element simulation was carried out and modelling was validated, by using two variables force and strain, to collect the data. The output data of the fitted models is given and is also visualized via graphs of force-strain derivative curves. The data of the simulations is provided for different finite element mesh densities. Here, to clarify the type and form of the data for the use by readers, the energy distribution curves describing various functionalities of the droplet, fibre and interface are presented. For further reading, the interpretation and analysis of this data can be found in a research article titled "3D interfacial debonding during microbond testing: Advantages of local strain recording" (R. Dsouza et al., 2020) [1].

5.
Opt Express ; 26(2): 2013-2022, 2018 Jan 22.
Article in English | MEDLINE | ID: mdl-29401922

ABSTRACT

This paper presents fiber Bragg grating (FBG) inscription with a pulsed 248 nm UV KrF laser in polymer optical fibers (POFs) made of different polymers, namely polymethyl methacrylate (PMMA), cyclic-olefin polymer and co-polymer, and Polycarbonate. The inscribed gratings and the corresponding inscription parameters are compared with grating inscribed in POFs made of the aforementioned materials but with the hitherto most used laser for inscription, which is a continuous wave 325 nm UV HeCd laser. Results show a reduction of the inscription time of at least 16 times. The maximum time reduction is more than 130 times. In addition, a reflectivity and a bandwidth close to or higher than the ones with the 325 nm laser were obtained. The polymer optical fiber Bragg gratings (POFBGs) inscribed with the 248 nm laser setup present high stability with small variations in their central wavelength, bandwidth, and reflectivity after 40 days.

6.
Cardiovasc Toxicol ; 17(4): 405-416, 2017 10.
Article in English | MEDLINE | ID: mdl-28084566

ABSTRACT

3,4-Methylenedioxymethamphetamine (MDMA or "ecstasy") is a recreational drug used worldwide for its distinctive psychotropic effects. Although important cardiovascular effects, such as increased blood pressure and heart rate, have also been described, the vascular effects of MDMA and metabolites and their correlation with hyperthermia (major side effect of MDMA) are not yet fully understood and have not been previously reported. This study aimed at evaluating the effects of MDMA and its main catechol metabolites, alpha-methyldopamine (α-MeDA), N-methyl-alpha-methyldopamine (N-Me-α-MeDA), 5-(glutathion-S-yl)-alpha-methyldopamine [5-(GSH)-α-MeDA] and 5-(glutathion-S-yl)-N-methyl-alpha-methyldopamine [5-(GSH)-N-Me-α-MeDA], on the 5-HT-dependent vasoactivity in normothermia (37 °C) and hyperthermia (40 °C) of the human internal mammary artery (IMA) in vitro. The results showed the ability of MDMA, α-MeDA and N-Me-α-MeDA to exert vasoconstriction of the IMA which was considerably higher in hyperthermic conditions (about fourfold for MDMA and α-MeDA and twofold for N-Me-α-MeDA). The results also showed that all the compounds may influence the 5-HT-mediated concentration-dependent response of IMA, as MDMA, α-MeDA and N-Me-α-MeDA behaved as partial agonists and 5-(GSH)-α-MeDA and 5-(GSH)-N-Me-α-MeDA as antagonists. In conclusion, MDMA abuse may imply a higher cardiovascular risk associated both to MDMA and its metabolites that might be relevant in patients with underlying cardiovascular diseases, particularly in hyperthermia.


Subject(s)
Fever/metabolism , Mammary Arteries/drug effects , Mammary Arteries/metabolism , N-Methyl-3,4-methylenedioxyamphetamine/metabolism , N-Methyl-3,4-methylenedioxyamphetamine/toxicity , Adult , Aged , Aged, 80 and over , Dose-Response Relationship, Drug , Female , Fever/pathology , Humans , Male , Mammary Arteries/pathology , Middle Aged , Organ Culture Techniques , Vasoconstriction/drug effects , Vasoconstriction/physiology
7.
Epidemiol Infect ; 145(5): 883-886, 2017 04.
Article in English | MEDLINE | ID: mdl-28004619

ABSTRACT

Non-typhoidal Salmonella is an important burden, particularly in developing countries of the African region. We report for the first time in Angola, a sub-Saharan African country with commercial/travel relationships with Europe, an unexpectedly high occurrence of Salmonella (n = 12/63, 19%) from a high diversity of sources, particularly farm and wild animals. The detection of diverse serotypes (n = 12), involving putative new S. enterica subsp. salamae serotypes, is also of note, reinforcing the need for a comprehensive surveillance in Angola critical to identify animal/food/environmental sources of salmonellosis with impact on animal health, local people, tourists and exported products.


Subject(s)
Salmonella Infections, Animal/epidemiology , Salmonella Infections, Animal/microbiology , Salmonella Infections/epidemiology , Salmonella Infections/microbiology , Salmonella/classification , Salmonella/isolation & purification , Serogroup , Angola/epidemiology , Animals , Humans , Prevalence
9.
Clin Microbiol Infect ; 22(2): 110-121, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26708671

ABSTRACT

Salmonellosis remains one of the most frequent food-borne zoonoses, constituting a worldwide major public health concern. Currently, at a global level, the main sources of infection for humans include meat products, including the consumption of contaminated poultry meat, in spite of the success of Salmonella control measures implemented in food-animal production of industrialized countries. In recent years, a shift in Salmonella serotypes related to poultry and poultry production has been reported in diverse geographical regions, being particularly associated with the spread of certain well-adapted clones. Moreover, antimicrobial resistance in non-typhoidal Salmonella is considered one of the major public health threats related with food-animal production, including the poultry production chain and poultry meat, which is an additional concern in the management of salmonellosis. The circulation of the same multidrug-resistant Salmonella clones and/or identical mobile genetic elements encoding antibiotic resistance genes from poultry to humans highlights this scenario. The purpose of this review was to provide an overview of the role of poultry meat on salmonellosis at a global scale and the main problems that could hinder the success of Salmonella control measures at animal production level. With the increasing globalization of foodstuffs like poultry meat, new problems and challenges might arise regarding salmonellosis control, making new integrated intervention strategies necessary along the food chain.


Subject(s)
Meat/microbiology , Poultry/microbiology , Salmonella Food Poisoning/microbiology , Salmonella/classification , Animals , Drug Resistance, Multiple, Bacterial , Humans , Salmonella enterica/genetics , Zoonoses/microbiology
10.
Eur J Clin Microbiol Infect Dis ; 33(12): 2249-57, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25022446

ABSTRACT

To better understand the recent success/emergence of Salmonella enterica serotype 4,[5],12:i:- we characterized the population diversity, fljAB deletion patterns, antibiotic resistance features and associated genetic elements of a comprehensive collection obtained in the last decade from Portugal (2002-2010). One hundred thirty-one isolates from human clinical specimens, food, environment and piggeries, verified by PCR as S. 4,[5],12:i:-, were studied for clonality (Pulsed-Field Gel Electrophoresis and Multilocus Sequence Typing), antibiotic resistance by phenotypic (disk diffusion and/or agar dilution) and genotypic (PCR/Restriction Fragment Length Polymorphism and sequencing, genomic location) methods and fljAB-deletions (PCR). Plasmid analysis included determination of size, content and characterization of the incompatibility group (PCR-Based Replicon Typing and I-CeuI/S1-hybridization). Results showed three multidrug-resistant (MDR) clones circulating and causing infections, associated with particular phenotypic and genotypic features. Most of the isolates belonged to the widespread European (ASSuT phenotype, RR1-RR2 resistance regions, ST34) and Spanish (carrying a sul3-type III integron within IncA/C plasmids, ST19) clones circulating in Europe. A third clone, here designated Southern European clone (carrying a sul3-type I integron within IncR plasmids, ST19), presents a fljAB region different from the previous clones and similar to the US strains, despite differences in the MDR mobile genetic platforms. The success of S. 4,[5],12:i:- might be related to the selective advantage offered by MDR profiles associated with stable genetic elements, also carrying virulence features, along with well adapted clones to the animal food production and causing human infections.


Subject(s)
Communicable Diseases, Emerging/microbiology , Salmonella Infections/microbiology , Salmonella enterica/drug effects , Salmonella enterica/isolation & purification , Anti-Bacterial Agents/pharmacology , Drug Resistance, Multiple, Bacterial , Humans , Salmonella enterica/genetics
11.
Phys Med Biol ; 59(7): 1831-44, 2014 Apr 07.
Article in English | MEDLINE | ID: mdl-24625517

ABSTRACT

Brachytherapy treatment planning systems that use model-based dose calculation algorithms employ a more accurate approach that replaces the TG43-U1 water dose formalism and adopt the TG-186 recommendations regarding composition and geometry of patients and other relevant effects. However, no recommendations were provided on the transit dose due to the source traveling inside the patient. This study describes a methodology to calculate the transit dose using information from the treatment planning system (TPS) and considering the source's instantaneous and average speed for two prostate and two gynecological cases. The trajectory of the (192)Ir HDR source was defined by importing applicator contour points and dwell positions from the TPS. The transit dose distribution was calculated using the maximum speed, the average speed and uniform accelerations obtained from the literature to obtain an approximate continuous source distribution simulated with a Monte Carlo code. The transit component can be negligible or significant depending on the speed profile adopted, which is not clearly reported in the literature. The significance of the transit dose can also be due to the treatment modality; in our study interstitial treatments exhibited the largest effects. Considering the worst case scenario the transit dose can reach 3% of the prescribed dose in a gynecological case with four catheters and up to 11.1% when comparing the average prostate dose for a case with 16 catheters. The transit dose component increases by increasing the number of catheters used for HDR brachytherapy, reducing the total dwell time per catheter or increasing the number of dwell positions with low dwell times. This contribution may become significant (>5%) if it is not corrected appropriately. The transit dose cannot be completely compensated using simple dwell time corrections since it may have a non-uniform distribution. An accurate measurement of the source acceleration and maximum speed should be incorporated in clinical practice or provided by the manufacturer to determine the transit dose component with high accuracy.


Subject(s)
Brachytherapy/methods , Iridium Radioisotopes/therapeutic use , Radiation Dosage , Humans , Neoplasms/radiotherapy , Radiotherapy Dosage , Time Factors
12.
Med Phys ; 40(5): 051717, 2013 May.
Article in English | MEDLINE | ID: mdl-23635265

ABSTRACT

PURPOSE: Several studies have reported methodologies to calculate and correct the transit dose component of the moving radiation source for high dose rate (HDR) brachytherapy planning systems. However, most of these works employ the average source speed, which varies significantly with the measurement technique used, and does not represent a realistic speed profile, therefore, providing an inaccurate dose determination. In this work, the authors quantified the transit dose component of a HDR unit based on the measurement of the instantaneous source speed to produce more accurate dose values. METHODS: The Nucletron microSelectron-HDR Ir-192 source was characterized considering the Task Group 43 (TG-43U1) specifications. The transit dose component was considered through the calculation of the dose distribution using a Monte Carlo particle transport code, MCNP5, for each source position and correcting it by the source speed. The instantaneous source speed measurements were performed in a previous work using two optical fibers connected to a photomultiplier and an oscilloscope. Calculated doses were validated by comparing relative dose profiles with those obtained experimentally using radiochromic films. RESULTS: TG-43U1 source parameters were calculated to validate the Monte Carlo simulations. These agreed with the literature, with differences below 1% for the majority of the points. Calculated dose profiles without transit dose were also validated by comparison with ONCENTRA(®) Brachy v. 3.3 dose values, yielding differences within 1.5%. Dose profiles obtained with MCNP5 corrected using the instantaneous source speed profile showed differences near dwell positions of up to 800% in comparison to values corrected using the average source speed, but they are in good agreement with the experimental data, showing a maximum discrepancy of approximately 3% of the maximum dose. Near a dwell position the transit dose is about 22% of the dwell dose delivered by the source dwelling 1 s and reached 104.0 cGy per irradiation in a hypothetical clinical case studied in this work. CONCLUSIONS: The present work demonstrated that the transit dose correction based on average source speed fails to accurately correct the dose, indicating that the correct speed profile should be considered. The impact on total dose due to the transit dose correction near the dwell positions is significant and should be considered more carefully in treatments with high dose rate, several catheters, multiple dwell positions, small dwell times, and several fractions.


Subject(s)
Brachytherapy/methods , Iridium Radioisotopes/therapeutic use , Radiation Dosage , Radiotherapy Planning, Computer-Assisted/methods , Film Dosimetry , Monte Carlo Method , Radiotherapy Dosage , Reproducibility of Results
13.
Eur J Clin Microbiol Infect Dis ; 31(11): 3057-63, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22706513

ABSTRACT

We aim to characterise multiple ertapenem-resistant (ERT-R, n = 15) Enterobacteriaceae isolates identified as presumptive carbapenemase producers in a Portuguese hospital in a short period of time (March-July 2010). Antibiotic susceptibility patterns, ß-lactamases, genetic relatedness [pulsed-field gel electrophoresis (PFGE), multi-locus sequence typing (MLST)], plasmid content and major enterobacterial porins were investigated. Ertapenem resistance was associated with deficiencies in major porins and, in some cases, extended-spectrum ß-lactamase (ESBL) or AmpC ß-lactamase production among outbreak and non-outbreak clones. Most isolates (n = 8) corresponded to two ERT-R Klebsiella pneumoniae ST15 PFGE-types: (i) a sporadic variant (Kp-A-ERT, n = 1) presenting a premature stop codon in ompK36 and (ii) an epidemic variant (Kp-B-ERT, n = 7) exhibiting a new OmpK36 porin variant, which differed additionally in plasmid and antibiotic susceptibility profiles. ST14 (n = 1) and ST45 (n = 1) K. pneumoniae, ST131 (n = 1) and ST354 (n = 1) Escherichia coli, Enterobacter asburiae (n = 1), Enterobacter cloacae (n = 1) and Enterobacter aerogenes (n = 1) ERT-R clones were also sporadically detected. Porin changes in these isolates included non-sense mutations [ompK35, ompK36, ompF; minimum inhibitory concentration (MIC) = 4-32 mg/l], IS-mediated porin disruptions (ompK36, ompC; MIC = 12->32 mg/l) or alterations in the L3 loop (ompK36; MIC = 4-16 mg/l). We describe, for the first time in Portugal, the simultaneous emergence of multiple ERT-R Enterobacteriaceae species and clones in a short period of time. Moreover, our results support that a CTX-M-15-producing ST15 K. pneumoniae with an OmpK36-modified porin might successfully spread in the nosocomial setting.


Subject(s)
Bacterial Proteins/genetics , Carbapenems/pharmacology , Disease Outbreaks , Enterobacteriaceae Infections/epidemiology , Enterobacteriaceae/classification , Porins/genetics , beta-Lactam Resistance , DNA Fingerprinting , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Electrophoresis, Gel, Pulsed-Field , Enterobacteriaceae/genetics , Enterobacteriaceae/isolation & purification , Enterobacteriaceae Infections/microbiology , Hospitals , Humans , Microbial Sensitivity Tests , Molecular Sequence Data , Multilocus Sequence Typing , Plasmids/analysis , Portugal/epidemiology , Sequence Analysis, DNA , beta-Lactamases/analysis
14.
Transplant Proc ; 41(3): 932-4, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19376391

ABSTRACT

INTRODUCTION: For many patients suffering from end-stage heart failure, heart transplantation remains the only hope for survival, but the shortage of donor organ is increasing. The growing number of patients awaiting heart transplantation has led many centers to expand the donor pool by liberalizing donor criteria, including advances in surgical techniques on the donor heart, such as valve repair. PATIENTS AND RESULTS: We subjected 4 donor hearts to bench repair of the mitral valve. The first heart was from a 35-year-old woman whose echocardiogram showed mild to moderate sclerotic leaflets. We performed a posteromedial commissurotomy and posterior annuloplasty. Transthoracic echocardiography at 57 months after transplantation demonstrated mild mitral regurgitation and no enlargement of VE. The second organ was from a 17-year-old woman with no history of heart disease and an echocardiogram that showed evidence of slightly sclerotic leaflets and mild mitral regurgitation. We performed a posterior annuloplasty. Echocardiography at 12 months demonstrated minimal mitral regurgitation. The third heart was from a 28-year-old woman with a normal echocardiogram. After harvesting, we found a torn head of the posterior papillary muscle, which was reimplanted. Two weeks later, the echocardiogram showed no mitral regurgitation. The fourth was from a 47-year-old woman with no history of heart disease and a normal echocardiogram. Examination before implantation showed central insufficiency, for which we performed posterior annuloplasty. Echocardiography at 12 months showed no mitral regurgitation. CONCLUSION: An aggressive approach to use hearts from marginal donors expands the pool and decreases waiting time for patients who desire heart transplantation.


Subject(s)
Heart Transplantation/methods , Mitral Valve/surgery , Tissue Donors , Adolescent , Adult , Aged , Cardiomyopathy, Dilated/surgery , Echocardiography, Transesophageal , Female , Heart Valve Prosthesis Implantation , Humans , Male , Middle Aged , Mitral Valve Insufficiency/surgery , Papillary Muscles/surgery , Patient Selection , Retrospective Studies
15.
Sci Total Environ ; 407(1): 204-10, 2008 Dec 15.
Article in English | MEDLINE | ID: mdl-18845317

ABSTRACT

The present study quantifies and explains the differences between measured organ-specific polychlorinated biphenyls (PCBs) accumulation and elimination kinetics in seabass (Dicentrarchus labrax), comparing these results with calculations using the generic model OMEGA. Specimens of approximately 250 g were selected and fed with contaminated food with PCBs 18, 44, 49, 52, 101, 105, 118, 138, 180 and 187. The OMEGA model was applied using a measured biomass (re)production coefficient and the food ingestion coefficient. It produced estimations of total body concentrations within a factor between 1.5 and 7.0 times of the measured and it also reproduced the general trend of the PCB concentrations during the experiment. This study allows us to confirm that internal distribution of PCBs is slow, producing significant differences in the tissues elimination rate constants and consequently in tissues bioaccumulation factors (BAF). The distribution of PCBs within the organism was slower than reported before, due to the bigger body size and the high lipid content of these fish.


Subject(s)
Bass , Polychlorinated Biphenyls/pharmacokinetics , Water Pollutants, Chemical/pharmacokinetics , Animals , Bass/growth & development , Bass/metabolism , Inactivation, Metabolic , Models, Biological , Organ Specificity
16.
Eur J Surg Oncol ; 34(2): 222-6, 2008 Feb.
Article in English | MEDLINE | ID: mdl-17566692

ABSTRACT

INTRODUCTION AND AIMS: The Subclavian vein has been traditionally the vein of choice for central venous catheterization by general surgeons. Alternative settings for the introduction of totally implantable venous access devices (TIVAD) and the search for lower rates of morbidity led to the choice of other central veins. This study compares two different venous accesses, the subclavian (SC) versus the internal jugular (IJ), in terms of early and late morbidity. PATIENTS AND METHODS: This is a prospective, non-randomized, observational, uni-institutional (tertiary cancer centre) study. From March 2003 to March 2006, 1231 TIVADs were placed (1201 patients), in an ambulatory operating room, under vital signs and EKG monitoring, using local anaesthesia and without perioperative radiological control. RESULTS: Of the 1231 TIVAD, 617 were inserted via the SC and 614 via the IJ vein. The two groups (SC vs. IJ) were comparable as to general patient characteristics. Immediate complications were more frequent in the SC than in the IJ approach (respectively, 5.0% vs. 1.5%; p<0.001); Catheter malposition occurred in 2.3% when using the SC vein and in 0.2% for the IJ (p=0.001). Long term morbidity was also more frequent in the SC than in the IJ group (respectively, 15.8%, 87/551, vs. 7.6%, 39/512; p<0.001). Venous thrombosis developed in 2.0% of patients with an SC TIVAD as compared to 0.6% with an IJ TIVAD (p=0.044). Catheter malfunction was significantly dependent on the vein used: SC - 9.4% vs. IJ - 4.3% (p=0.001). CONCLUSIONS: Our results support the preferential use of the Internal Jugular vein for the insertion of TIVAD.


Subject(s)
Antineoplastic Agents/administration & dosage , Catheterization, Central Venous/methods , Catheters, Indwelling , Jugular Veins , Subclavian Vein , Ambulatory Surgical Procedures , Catheterization, Central Venous/adverse effects , Cohort Studies , Device Removal , Equipment Failure , Equipment Safety , Female , Follow-Up Studies , Humans , In Vitro Techniques , Infusion Pumps, Implantable , Male , Neoplasms/drug therapy , Probability , Prospective Studies , Regression Analysis , Risk Assessment , Sensitivity and Specificity , Time Factors
17.
Langmuir ; 23(12): 6652-9, 2007 Jun 05.
Article in English | MEDLINE | ID: mdl-17489613

ABSTRACT

Four lignin samples were extracted from sugar cane bagasse using four different alcohols (methanol, ethanol, n-propanol, and 1-butanol) via the organosolv-CO2 supercritical pulping process. Langmuir films were characterized by surface pressure vs mean molecular area (Pi-A) isotherms to exploit information at the molecular level carrying out stability tests, cycles of compression/expansion (hysteresis), subphase temperature variations, and metallic ions dissolved into the water subphase at different concentrations. Briefly, it was observed that these lignins are relatively stable on the water surface when compared to those obtained via different extraction processes. Besides, the Pi-A isotherms are shifted to smaller molecular areas at higher subphase temperatures and to larger molecular areas when the metallic ions are dissolved into the subphase. The results are related to the formation of stable aggregates (domains) onto the water subphase by these lignins, as shown in the Pi-A isotherms. It was found as well that the most stable lignin monolayer onto the water subphase is that extracted with 1-butanol. Homogeneous Langmuir-Blodgett (LB) films of this lignin could be produced as confirmed by UV-vis absorption spectroscopy and the cumulative transfer parameter. In addition, FTIR analysis showed that this lignin LB film is structured in a way that the phenyl groups are organized preferentially parallel to the substrate surface. Further, these LB films were deposited onto gold interdigitated electrodes and ITO and applied in studies involving the detection of Cd+2 ions in aqueous solutions at low concentration levels through impedance spectroscopy and electrochemical measurements. FTIR spectroscopy was carried out before and after soaking the thin films into Cd+2 aqueous solutions, revealing a possible physical interaction between the lignin phenyl groups and the heavy metal ions. The importance of using nanostructured systems is demonstrated as well by comparing both LB and cast films.


Subject(s)
Cellulose/chemistry , Lignin/chemistry , Nanostructures/chemistry , Saccharum/chemistry , Spectrophotometry, Ultraviolet , Spectroscopy, Fourier Transform Infrared
18.
J Nanosci Nanotechnol ; 7(2): 510-4, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17450787

ABSTRACT

Nanostructured films of lignin (macromolecule extracted from sugar cane bagasse), polypyrrole (conducting polymer) and bis butylimido perylene (organic dye) were used in the detection of trace levels of fluorine (from H2SiF6), chlorine (from NaClO), Pb(+2), Cu(+2), and Cd(+2) in aqueous solutions. Langmuir monolayers on ultrapure water were characterised by surface pressure-mean molecular area (II-A) isotherms. Langmuir-Blodgett (LB) films were transferred onto gold interdigitated electrodes and used as individual sensing units of an electronic tongue system. Impedance spectroscopy measurements were taken with the sensor immersed into aqueous solutions containing the ions described above in different molar concentrations. Fourier transform infrared absorption (FTIR) was employed to identify possible interactions between the LB films and the analytes in solution, and no significant changes could be observed in the FTIR spectra of BuPTCD and Ppy. Therefore, the results for lignin point to an interaction involving the electronic cloud of the phenyl groups with the metallic ions.


Subject(s)
Biosensing Techniques , Electrochemistry/methods , Electronics , Membranes, Artificial , Nanostructures/chemistry , Cadmium/analysis , Chlorine/analysis , Copper/analysis , Electric Impedance , Electrodes , Fluorine/analysis , Gold/chemistry , Ions/analysis , Ions/chemistry , Lead/analysis , Lignin/analysis , Lignin/chemistry , Models, Chemical , Nanostructures/classification , Perylene/analogs & derivatives , Perylene/chemistry , Polymers/analysis , Polymers/chemistry , Pyrroles/analysis , Pyrroles/chemistry , Solutions/chemistry , Spectrophotometry, Ultraviolet , Spectroscopy, Fourier Transform Infrared , Water/chemistry
19.
Chemosphere ; 67(9): S58-64, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17207836

ABSTRACT

Contaminated mullet (Mugil cephalus) from Douro estuary was allowed to depurate in clean water and fed with uncontaminated food. Levels of PCBs and DDTs in muscle and liver, and ethoxyresorufin O-deethylase (EROD) activity were measured at day 0, 21, 120 and 270. In specimens captured in the estuary total PCB and total DDT concentrations were 311 and 65 ng g(-1) in muscle and 686 and 115 ng g(-1) in liver, respectively. At day 21, after an initial 10-15 days period of starvation, organochlorines levels increased in both analyzed tissues. Thereafter levels of all PCB congeners and DDT compounds decreased in muscle, and at the end of the 270 days were 49 ng g(-1) and 13 ng g(-1), respectively. These decreases were correlated to the lipids consumption. In liver no relationship between those variables was observed, suggesting different elimination processes and eventual exchange of contaminants between muscle and liver. EROD activities decreased in the first days of depuration experiment, but showed no relations with analysed organochlorines.


Subject(s)
Animal Husbandry/methods , DDT/metabolism , Gonads/drug effects , Liver/drug effects , Muscles/drug effects , Polychlorinated Biphenyls/metabolism , Smegmamorpha/physiology , Animal Feed , Animals , Cytochrome P-450 CYP1A1/metabolism , DDT/toxicity , Gonads/metabolism , Lipids/analysis , Liver/metabolism , Muscles/metabolism , Polychlorinated Biphenyls/toxicity , Time Factors , Water Pollutants, Chemical/administration & dosage , Water Pollutants, Chemical/metabolism , Water Pollutants, Chemical/toxicity
20.
Eur J Nucl Med Mol Imaging ; 34(7): 982-93, 2007 Jul.
Article in English | MEDLINE | ID: mdl-17225119

ABSTRACT

PURPOSE: Gallium-68 is a metallic positron emitter with a half-life of 68 min that is ideal for the in vivo use of small molecules, such as [68Ga-DOTA,Tyr3]octreotide, in the diagnostic imaging of somatostatin receptor-positive tumours. In preclinical studies it has shown a striking superiority over its 111In-labelled congener. The purpose of this study was to evaluate whether third-generation somatostatin-based, radiogallium-labelled peptides show the same superiority. METHODS: Peptides were synthesised on solid phase. The receptor affinity was determined by in vitro receptor autoradiography. The internalisation rate was studied in AR4-2J and hsst-HEK-transfected cell lines. The pharmacokinetics was studied in a rat xenograft tumour model, AR4-2J. RESULTS: All peptides showed high affinities on hsst2, with the highest affinity for the Ga(III)-complexed peptides. On hsst3 the situation was reversed, with a trend towards lower affinity of the Ga(III) peptides. A significantly increased internalisation rate was found in sst2-expressing cells for all 67Ga-labelled peptides. Internalisation into HEK-sst3 was usually faster for the 111In-labelled peptides. No internalisation was found into sst5. Biodistribution studies employing [67Ga-DOTA,1-Nal3]octreotide in comparison to [111In-DOTA,1-Nal3]octreotide and [67Ga-DOTA,Tyr3]octreotide showed a significantly higher and receptor-mediated uptake of the two 67Ga-labelled peptides in the tumour and somatostatin receptor-positive tissues. A patient study illustrated the potential advantage of a broad receptor subtype profile radiopeptide over a high-affinity sst2-selective radiopeptide. CONCLUSION: This study demonstrates that 67/68Ga-DOTA-octapeptides show distinctly better preclinical, pharmacological performances than the 111In-labelled peptides, especially on sst2-expressing cells and the corresponding animal models. They may be excellent candidates for further development for clinical studies.


Subject(s)
Gallium Radioisotopes/pharmacokinetics , Heterocyclic Compounds, 1-Ring/pharmacokinetics , Pancreatic Neoplasms/diagnostic imaging , Pancreatic Neoplasms/metabolism , Somatostatin/pharmacokinetics , Animals , Cell Line, Tumor , Gallium Radioisotopes/chemistry , Heterocyclic Compounds, 1-Ring/chemistry , Isotope Labeling/methods , Male , Metabolic Clearance Rate , Organ Specificity , Positron-Emission Tomography/methods , Radiopharmaceuticals/chemistry , Rats , Rats, Inbred Lew , Sensitivity and Specificity , Somatostatin/chemistry , Tissue Distribution
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