Determination of plasma-thiocyanate binding and the Donnan ratio under simulated physiological conditions

1966 ◽  
Vol 17 (2) ◽  
pp. 192-200 ◽  
Author(s):  
M. Pollay ◽  
A. Stevens ◽  
C. Davis
2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Frank Feyerabend ◽  
Martin Johannisson ◽  
Zhidan Liu ◽  
Regine Willumeit-Römer

AbstractSterilization is a necessary step for all implant materials. Different methods can influence the materials properties. Especially important for magnesium as degradable materials is the determination of the corrosion properties. In this study the influence of 70% ethanol, glutaraldehyde, autoclaving, dry heat, UV-, gamma- and electron beam-irradiation on mechanical and corrosion parameters were analyzed. As mechanical parameters hardness and grain size were determined. The corrosion rate under physiological conditions, weight of the corrosion layer and corrosion morphology was determined. It could be demonstrated that irradiation treatments and 70% ethanol are suitable methods, as they decrease the corrosion rate. Heat-introducing methods (autoclaving and dry heat) acted as incomplete ageing treatments on this alloy and therefore increased the corrosion rate. Furthermore, osmolality showed a better correlation to the actual corrosion rate than the pH. Therefore an optimum ratio between alloying system, implant and sterilization method has to be established, depending on the intended application.


Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2379 ◽  
Author(s):  
P. Yáñez-Sedeño ◽  
A. González-Cortés ◽  
S. Campuzano ◽  
J. M. Pingarrón

Proper functionalization of electrode surfaces and/or nanomaterials plays a crucial role in the preparation of electrochemical (bio)sensors and their resulting performance. In this context, copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) has been demonstrated to be a powerful strategy due to the high yields achieved, absence of by-products and moderate conditions required both in aqueous medium and under physiological conditions. This particular chemistry offers great potential to functionalize a wide variety of electrode surfaces, nanomaterials, metallophthalocyanines (MPcs) and polymers, thus providing electrochemical platforms with improved electrocatalytic ability and allowing the stable, reproducible and functional integration of a wide range of nanomaterials and/or different biomolecules (enzymes, antibodies, nucleic acids and peptides). Considering the rapid progress in the field, and the potential of this technology, this review paper outlines the unique features imparted by this particular reaction in the development of electrochemical sensors through the discussion of representative examples of the methods mainly reported over the last five years. Special attention has been paid to electrochemical (bio)sensors prepared using nanomaterials and applied to the determination of relevant analytes at different molecular levels. Current challenges and future directions in this field are also briefly pointed out.


Materials ◽  
2016 ◽  
Vol 9 (8) ◽  
pp. 627 ◽  
Author(s):  
Eshwara Nidadavolu ◽  
Frank Feyerabend ◽  
Thomas Ebel ◽  
Regine Willumeit-Römer ◽  
Michael Dahms

Antioxidants ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 373 ◽  
Author(s):  
Franco ◽  
Navarro ◽  
Martínez-Pinilla

Antioxidant action to afford a health benefit or increased well-being may not be directly exerted by quick reduction-oxidation (REDOX) reactions between the antioxidant and the pro-oxidant molecules in a living being. Furthermore, not all flavonoids or polyphenols derived from plants are beneficial. This paper aims at discussing the variety of mechanisms underlying the so-called “antioxidant” action. Apart from antioxidant direct mechanisms, indirect ones consisting of fueling and boosting innate detox routes should be considered. One of them, hormesis, involves upregulating enzymes that are needed in innate detox pathways and/or regulating the transcription of the so-called vitagenes. Moreover, there is evidence that some plant-derived compounds may have a direct role in events taking place in mitochondria, which is an organelle prone to oxidative stress if electron transport is faulty. Insights into the potential of molecules able to enter into the electron transport chain would require the determination of their reduction potential. Additionally, it is advisable to know both the oxidized and the reduced structures for each antioxidant candidate. These mechanisms and their related technical developments should help nutraceutical industry to select candidates that are efficacious in physiological conditions to prevent diseases or increase human health.


The Analyst ◽  
2015 ◽  
Vol 140 (8) ◽  
pp. 2823-2833 ◽  
Author(s):  
Xuheng Jiang ◽  
Kui Gao ◽  
Daopan Hu ◽  
Huanhuan Wang ◽  
Shujuan Bian ◽  
...  

Voltammetric studies on the simple ion transfer (IT) behaviors of an important water-soluble B-vitamin, folic acid (FA), at the liquid–liquid (L–L) interface were firstly performed and applied as a novel detection method for FA under physiological conditions. This work provides a new and attractive strategy for the detection of FA− and other biological anions.


2020 ◽  
Vol 412 (29) ◽  
pp. 8145-8153
Author(s):  
Joanna Kruszewska ◽  
Jacek Sikorski ◽  
Jan Samsonowicz-Górski ◽  
Magdalena Matczuk

Abstract Over the past few years, superparamagnetic iron oxide nanoparticles (SPIONs) have attracted much attention due to their medicinally attractive properties and their possible application in cancer diagnosis and therapy. However, there is still a lack of appropriate methods to enable quantitative monitoring of the particle changes in a physiological environment, which could be beneficial for evaluating their in vitro and in vivo behavior. For this reason, the main goal of this study was the development of a novel capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS/MS) method for the determination of SPIONs suitable for the future examination of their changes upon incubation with proteins under simulated physiological conditions. The type and flow rate of the collision/reaction gas were chosen with the aim of simultaneous monitoring of Fe and S. The type and concentration of the background electrolyte, applied voltage, and sample loading were optimized to obtain SPION signals of the highest intensity and minimum half-width of the peak. Analytical parameters were at a satisfactory level: reproducibility (intra- and inter-day) of migration times and peak areas (presented as RSD) in the range of 0.23–4.98%, recovery: 96.7% and 93.3%, the limit of detection (for monitoring 56Fe16O+ by mass-shift approach) 54 ng mL−1 Fe (0.97 μM) and 101 ng mL−1 Fe (1.82 μM) for SPIONs with carboxyl and amino terminal groups, respectively. To the best of our knowledge, this is the first reported use of CE-ICP-MS/MS for the quantification of SPIONs and monitoring of interactions with proteins.


1977 ◽  
Vol 85 (1) ◽  
pp. 126-133 ◽  
Author(s):  
T. Fehér ◽  
L. Bodrogi ◽  
K. G. Fehér ◽  
E. Poteczin ◽  
I. S. Kölcsey

ABSTRACT A gas chromatographic method has been employed for the determination of dehydroepiandrosterone (D), androsterone (A), dehydroepiandrosterone sulphate (DS) and androsterone sulphate (AS) in the peripheral blood of human subjects and in various mammals under physiological conditions and after the administration of D or DS. Unconjugated D has been isolated and the resting level determined in the rat, rabbit, dog, sheep, pig and cow, while DS was detectable in the peripheral circulation of the rat, dog and pig. Unconjugated A was present in blood of the rodents and domestic ungulates studied, while the parent sulphate could be demonstrated only in rat, dog, pig and cow. The plasma of lower mammals contained D in higher (0.8–10.9 μg/100 ml), and DS, if any, in lower level (1.5–5.7 μg/100 ml) than the human plasma samples (0.1–2.7 and 86–308 μg/100 ml, respectively). There was a more pronounced increase in D and A than in the DS and AS level in the rat and dog following administration of D. On the contrary, exogenous D hardly affected unconjugated D and appreciably enhanced the DS level in human plasma. The conclusion drawn for human subjects, that D is the metabolically active and DS the reserve hormone, does not seem to be valid for all the animals here studied.


2015 ◽  
Vol 27 (10) ◽  
pp. 2272-2274 ◽  
Author(s):  
Katsuhiko Sato ◽  
Tetsuya Ono ◽  
Kentaro Yoshida ◽  
Toshinori Ito ◽  
Yoshitomo Kashiwagi

2020 ◽  
Vol 7 (2) ◽  
pp. 76-80
Author(s):  
V. Alekseeva ◽  
V. Gargin

DETERMINATION OF THE STRUCTURE OF THE WALLS OF THE FRONTAL SINUS ACCORDING TO SPIRAL COMPUTED TOMOGRAPHY Alekseeva V., Gargin V. The anatomical structure of the frontal sinus is of key importance for the development of its inflammation and the development of complications with spread to neighboring organs and tissues (orbital phlegmon, brain abscesses, meningitis). The aim of our study was to compare the density and thickness of the bone tissue of the unchanged frontal sinus and in various forms of chronic inflammation. Materials and methods. We observed 121 patients with various forms of chronic frontal sinusitis: 56 with chronic hyperplastic (mucosal hyperplasia (up to 6 mm) and 33 patients with chronic purulent-polypous frontal sinusitis, manifested by a total and subtotal decrease in sinus pneumatization according to spiral computed tomography (SCT). 32 SCT samples were selected to form a comparison group without any abnormalities of the paranasal sinuses. Results. The maximum density typical for the lower wall of the frontal sinus under physiological conditions and was found to be 107.96 ± 201.64Hu, the minimum for the posterior wall in purulent-polypous frontal sinusitis was -103.74 ± 195.37Hu. The bone thickness both in the posterior region and in the region practically does not depend on the degree of the severity of pathological changes in it and is 1.0006 ± 0.538 mm, 0.91 ± 0.26 mm, 0.82 ± 0.169 mm under physiological conditions , with mucosal hyperplasia and with purulent-polypous frontal sinusitis in the posterior wall, respectively. In the region of the lower wall, 4.05 ± 2.04 mm, 2.32 ± 1.16 mm, and 4.002 ± 1.16 mm, respectively, according to the above order. Conclusion. It can be assumed that the larger the change in PNSs, the lower the bone density. This in turn affects the prediction of possible complications during surgical treatment of chronic frontal sinusitis. Key words: frontal sinus, computed tomography, bone thickness, bone density   Резюме. ВИЗНАЧЕННЯ МОРФОЛОГІЧНОЇ СТРУКТУРИ СТІНОК ЛОБНОЇ ПАЗУХИ ЗА ДОПОМОГОЮ СПІРАЛЬНОЇ КОМП'ЮТЕРНОЇ ТОМОГРАФІЇ Алєксєєва B.B., Гаргін B.B. Анатомічна будова лобної пазухи має ключове значення для виникнення запальних процесів та розвитку ускладнень із поширенням на сусідні органи та тканини (формування флегмони орбіти, абсцесів мозку, менінгіту). Метою нашого дослідження було порівняння щільності та товщини кісткової тканини лобної пазухи в фізіологічних умовах та при різних формах хронічного запального процесу. Матеріали та методи. Під спостереженням було 89 пацієнтів з різними формами хронічного фронтального синуситу: 56 - з хронічним гіперпластичним фронтальним синуситом (гіперплазією слизової оболонки до 6 мм) та 33 пацієнти з хронічним гнійно-поліпозним фронтальним синуситом, що при проведенні спіральної комп’ютерної томографії (СКТ) проявлявся тотальним і субтотальним зниженням пневматизації. Контрольна група - 32 СКТ людей з фізіологічним станом навколоносових пазух. Результати. Максимальна щільність кісткової тканини була визначена в області нижньої стінки лобної пазухи та становила - 107.96 ± 201.64 Hu, мінімальна - в області задньої стінки при гнійно-поліпозному лобному синуситі - -103.74 ± 195.37 Hu. Товщина кісток практично не залежала від ступеня виразності патологічних змін у ній і становить в області задньої стінки - 1.0006 ± 0.538 мм, 0.91 ± 0.26 мм, 0.82 ± 0.169 мм у фізіологічних умовах, при гіперплазії слизової оболонки і при гнійно-поліпозному фронтальному синуситі. В області нижньої стінки 4.05 ± 2.04 мм, 2.32 ± 1,16 мм та 4.002 ± 1.16 мм відповідно. Висновки. Можна припустити, що щільність кісткової тканини залежить від ступеня виразності патологічних змін в лобній пазусі. Це в свою чергу впливає на прогнозування розвитку ускладнень. Ключові слова: лобна пазуха, спіральна комп'ютерна томографія, товщина кісток, щільність кісток.   Резюме. ОПРЕДЕЛЕНИЕ МОРФОЛОГИЧЕСКОЙ СТРУКТУРЫ СТЕНОК ЛОБНОЙ ПАЗУХИ С ПОМОЩЬЮ СПИРАЛЬНОЙ КОМПЬЮТЕРНОЙ ТОМОГРАФИИ Алексеева B.B., Гаргин B.B. Анатомическое строение лобной пазухи имеет ключевое значение для возникновения воспалительных процессов и развития осложнений с распространением на соседние органы и ткани (формирование флегмоны орбиты, абсцессов мозга, менингита). Целью нашего исследования было сравнение плотности и толщины костной ткани лобной пазухи в физиологических условиях и при различных формах хронического воспалительного процесса.Материалы и методы. Под наблюдением находилось 89 пациентов с различными формами хронического фронтального синусита: 56 - с хроническим гиперпластическим фронтальным синуситом (гиперплазией слизистой оболочки до 6 мм) и 33 пациента с хроническим гнойно-полипозным фронтальным синуситом, что при проведении спиральной компьютерной томографии (СКТ) проявлялся тотальным и субтотальным снижением пневматизации. Контрольная группа - 32 СКТ людей с физиологическим состоянием околоносовых пазух.Результаты. Максимальная плотность костной ткани была определена в области нижней стенки лобной пазухи в физиологических условиях и составила - 107.96 ± 201.64 Hu, минимальная - в области задней стенки при гнойно-полипозном лобном синусите - -103.74 ± 195.37 Hu. Толщина костей практически не зависила от степени выраженности патологических изменений в ней и составляла в области задней стенки - 1.0006 ± 0.538 мм, 0.91 ± 0.26 мм, 0.82 ± 0.169 мм в физиологических условиях, при гиперплазии слизистой оболочки и при гнойно-полипозном фронтальном синусите. В области нижней стенки 4.05 ± 2.04 мм, 2.32 ± 1.16 мм и 4.002 ± 1.16 мм, соответственно. Выводы. Можно предположить, что плотность костной ткани зависит от степени выраженности патологических изменений в лобной пазухе. Это в свою очередь влияет на прогнозирование возможности развития осложнений. Ключевые слова: лобная пазуха, спиральная компьютерная томография, толщина костей, плотность костей.


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