A basic study of electrical impedance spectroscopy for intravascular diagnosis and therapy monitoring of atherosclerosis

The thesis reports about the feasibility of electrical impedance spectroscopy with microsystems for the intravascular diagnosis of atherosclerosis. Based on a basic investigation on the cellular level, it describes how the impedance of vessel walls on the microscale is determined and how the cellular alteration related with atherosclerosis affects the measured impedance. For an intravascular impedance characterization of vessels, it shows the development of a balloon impedance catheter (BIC) equipped with a flexible microelectrode structure. BIC measurement proved to be sensitive enough to detect the thickness of vessel walls or plaque positions. From in situ animal experiments, it demonstrates the potential of BIC to characterize atheromatous vessels.Die vorliegende Arbeit beschäftigt sich mit Untersuchungen zum Einsatz von Mikrosystemen, basierend auf elektrischer Impedanzspektroskopie, für die intravaskuläre Diagnose von Atherosklerose. Auf zellulärer Ebene konnte zum einen die Impedanz von Gefäßwänden bestimmt sowie die Auswirkungen von zellulären Veränderungen auf diese gezeigt werden. Für die intravaskuläre Impedanzspektroskopie wurde ein Ballon-Katheter mit integrierten Mikroelektroden entwickelt. Durchgeführte Messungen zeigen eine ausreichend hohe Empfindlichkeit zur Detektion von Gefäßwandstärken oder zur Lokalisierung von Plaques. Abschließend konnte im Tierversuch die Charakterisierung von atherosklerotischen Gefäßen gezeigt werden

Dependence of impedance of embedded single cells on cellular behaviour

Non-invasive single cell analyses are increasingly required for the medicaldiagnostics of test substances or the development of drugs and therapies on the single celllevel. For the non-invasive characterisation of cells, impedance spectroscopy whichprovides the frequency dependent electrical properties has been used. Recently,microfludic systems have been investigated to manipulate the single cells and tocharacterise the electrical properties of embedded cells. In this article, the impedance ofpartially embedded single cells dependent on the cellular behaviour was investigated byusing the microcapillary. An analytical equation was derived to relate the impedance ofembedded cells with respect to the morphological and physiological change ofextracellular interface. The capillary system with impedance measurement showed afeasibility to monitor the impedance change of embedded single cells caused bymorphological and physiological change of cell during the addition of DMSO. By fittingthe derived equation to the measured impedance of cell embedded at different negativepressure levels, it was able to extrapolate the equivalent gap and gap conductivity betweenthe cell and capillary wall representing the cellular behaviour

Real-Time Monitoring of Neural Differentiation of Human Mesenchymal Stem Cells by Electric Cell-Substrate Impedance Sensing

Stem cells are useful for cell replacement therapy. Stem cell differentiation must be monitored thoroughly and precisely prior to transplantation. In this study we evaluated the usefulness of electric cell-substrate impedance sensing (ECIS) for in vitro real-time monitoring of neural differentiation of human mesenchymal stem cells (hMSCs). We cultured hMSCs in neural differentiation media (NDM) for 6 days and examined the time-course of impedance changes with an ECIS array. We also monitored the expression of markers for neural differentiation, total cell count, and cell cycle profiles. Cellular expression of neuron and oligodendrocyte markers increased. The resistance value of cells cultured in NDM was automatically measured in real-time and found to increase much more slowly over time compared to cells cultured in non-differentiation media. The relatively slow resistance changes observed in differentiating MSCs were determined to be due to their lower growth capacity achieved by induction of cell cycle arrest in G0/G1. Overall results suggest that the relatively slow change in resistance values measured by ECIS method can be used as a parameter for slowly growing neural-differentiating cells. However, to enhance the competence of ECIS for in vitro real-time monitoring of neural differentiation of MSCs, more elaborate studies are needed

Enhancement of protective vaccine-induced antibody titer to swine diseases and growth performance by Amino-Zn, yucca extract, and β-mannanase feed additive in wean-finishing pigs

The primary purpose of this research is to determine the effect of Amino-Zn (AZn), Yucca schidigera extract (YE), and β-mannanase enzyme supplementation on growth performance, nutrient digestibility, fecal gas emission, and immune response in pigs. A total of 180 crossbred pigs (6.57 ± 1 kg) were randomly assigned to one of three dietary treatments: CON-corn soybean meal (basal diet); TRT1-CON +1,000 ppm AZn + 0.07% yucca extract (YE) + 0.05% β-mannanase; and TRT2-CON +2,000 ppm AZn + 0.07% YE+ 0.05% β-mannanase for 22 weeks. Each treatment had 12 replicates with 5 pigs per pen. Pigs fed a diet supplemented with AZn, YE, and β-mannanase linearly increased (p < 0.05) BW and average daily gain at weeks 6, 12, 17, and 18. In contrast, the gain-to-feed ratio showed a linear increase (p < 0.05) from weeks 6 to 17 and the overall trial period. Moreover, the inclusion of experimental diets linearly decreased (p > 0.05) noxious gas emissions such as ammonia, hydrogen sulfide, acetic acid, carbon dioxide, and methyl mercaptans. The dietary inclusion of AZn, YE, and β-mannanase significantly increased the serological immune responses to Mycoplasma hyopneumoniae (MH) and foot-and-mouth disease virus (FMDV-O type) at the end of week 6 and porcine circovirus-2 (PCV-2) at week 19. Based on this result, we infer that the combination of AZn, YE, and β-mannanase supplement would serve as a novel in-feed additive to enhance growth performance and act as a boosting agent and immune stimulatory to increase the efficacy of swine vaccinations

Cellular Imaging of Human Atherosclerotic Lesions by Intravascular Electric Impedance Spectroscopy

Background: Newer techniques are required to identify atherosclerotic lesions that are prone to rupture. Electric impedance spectroscopy (EIS) is able to provide information about the cellular composition of biological tissue. The present study was performed to determine the influence of inflammatory processes in type Va (lipid core, thick fibrous cap) and Vc (abundant fibrous connective tissue while lipid is minimal or even absent) human atherosclerotic lesions on the electrical impedance of these lesions measured by EIS. Methods and Results: EIS was performed on 1 aortic and 3 femoral human arteries at 25 spots with visually heavy plaque burden. Severely calcified lesions were excluded from analysis. A highly flexible micro-electrode mounted onto a balloon catheter was placed on marked regions to measure impedance values at 100 kHz. After paraffin embedding, visible marked cross sections (n = 21) were processed. Assessment of lesion types was performed by Movats staining. Immunostaining for CD31 (marker of neovascularisation), CD36 (scavenger cells) and MMP-3 (matrix metalloproteinase-3) was performed. The amount of positive cells was assessed semi-quantitatively. 15 type Va lesions and 6 type Vc lesions were identified. Lesions containing abundant CD36-, CD31- and MMP-3-positive staining revealed significantly higher impedance values compared to lesions with marginal or without positive staining (CD36+455650 V vs. CD36- 346653 V, p = 0.001; CD31+436643 V vs. CD31- 340655 V, p = 0.001; MMP-3+ 400668 V vs. MMP-3- 323633 V, p = 0.03)

Effects of herbal supplements on milk production quality and specific blood parameters in heat-stressed early lactating cows

The present study explored the influence of supplemental herbal mixtures on cow milk production, quality, and blood parameters in dairy cows under high ambient temperatures. Thirty Holstein cows were randomly assigned into three experimental groups of 10 each. The first control group was supplied with the commercial basal diet, whereas two treatment groups were provided with the commercial basal diet supplemented with 50 and 100 g/head/day of the herbal mixture, respectively. The results showed that the mixture of herbal supplementation did not influence weekly milk production. Milk total fat, triglyceride, and total protein values were not affected (p < 0.05) in cows fed on basal diets supplemented with herbal mixture; however, milk cholesterol was decreased significantly by 100 mg/head/day of the herbal mixture. On the other hand, lactose has increased significantly by adding 100 mg/head/day of herbal mixture. Furthermore, the total cholesterol level in serum was decreased by adding 100 mg/head/day of the herbal mixture, while plasma prolactin, cortisol, GOT, and GPT were unaffected. Regarding fatty acids (C18, C18:1 (c9), 18:1 (c11), 18:2 (c9, c12), 18:2 (t9, t12), and CLA (c9, t11)), there was no significant variation between the groups. Meanwhile, both C19:00 and 18:3 (c6, c9, and c12) were noticeably higher (p < 0.05) in the group that received 100gm, followed by 50 mg, compared to the control. In conclusion, the supplement with a herbal mixture positively affected milk quality by decreasing total cholesterol and increasing lactose, milk fatty acid profile by increasing unsaturated fatty acids content, and plasma cholesterol levels

Improving productive performance, immunity, and health status of growing rabbits by using honey bee venom (Apis mellifera)

To investigate the effect of bee venom (BV) as a natural growth promotor on growing rabbits as an alternative to antibiotics, sixty 35-day-old Californian male rabbits with an average body weight of 584 ± 9 gm were randomly divided into five equal groups as follows: The 2nd group received drinking water supplied with 10 mg Oxytetracycline (OXT), while the 3rd, 4th, and 5th groups received 2, 4 and 8 mg bee venom (BV)/kg body weight/day in drinking water, and the first group was served as a control group. The growth performance features were positively impacted by adding BV (p ≤ 0.01) compared to the control, whereas LBW and BWG increased and FI reduced. Significantly improved carcass characteristics (p ≤ 0.01) as a result of the BV supplementation. Blood characteristics showed a significant reduction (p ≤ 0.01) in liver enzyme activities and Cholesterol, Triglycerides, and Low-density lipoproteins Cholesterol (LDL) as affected by BV treatment; inversely, total protein and globulin were significantly increased (p ≤ 0.01). Similarly, BV had a positive effect (p ≤ 0.01) on anti-oxidant status (Total anti-oxidant capacity (TAC), Glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT)). In contrast, the lipid peroxidation biomarker (Malondialdehyde (MDA)) was significantly decreased. The immunoglobulin (IgG and IgM) was significantly increased (p ≤ 0.01) by BV treatment. There was a positive effect of low BV levels on decreasing both cecum TBC and pathogenic bacterial count (Salmonella spp., E.coli spp., Proteus spp., and Clostridia spp.) that was significant (p ≤ 0.01). In conclusion, BV can be a natural growth promoter to enhance growth performance traits, immunological and anti-oxidative responses, and reduce pathogenic bacteria in the hindgut of growing rabbits

Grundlegende Untersuchungen zur elektrischen Impedanz-Spektroskopie für den Einsatz in der intravaskulären Diagnostik und in der Therapieüberwachung von Arteriosklerose

The thesis reports about the feasibility of electrical impedance spectroscopy with microsystems for the intravascular diagnosis of atherosclerosis. Based on a basic investigation on the cellular level, it describes how the impedance of vessel walls on the microscale is determined and how the cellular alteration related with atherosclerosis affects the measured impedance. For an intravascular impedance characterization of vessels, it shows the development of a balloon impedance catheter (BIC) equipped with a flexible microelectrode structure. BIC measurement proved to be sensitive enough to detect the thickness of vessel walls or plaque positions. From in situ animal experiments, it demonstrates the potential of BIC to characterize atheromatous vessels.Die vorliegende Arbeit beschäftigt sich mit Untersuchungen zum Einsatz von Mikrosystemen, basierend auf elektrischer Impedanzspektroskopie, für die intravaskuläre Diagnose von Atherosklerose. Auf zellulärer Ebene konnte zum einen die Impedanz von Gefäßwänden bestimmt sowie die Auswirkungen von zellulären Veränderungen auf diese gezeigt werden. Für die intravaskuläre Impedanzspektroskopie wurde ein Ballon-Katheter mit integrierten Mikroelektroden entwickelt. Durchgeführte Messungen zeigen eine ausreichend hohe Empfindlichkeit zur Detektion von Gefäßwandstärken oder zur Lokalisierung von Plaques. Abschließend konnte im Tierversuch die Charakterisierung von atherosklerotischen Gefäßen gezeigt werden

Electrochemical Immunosensor for the Early Detection of Rheumatoid Arthritis Biomarker: Anti-Cyclic Citrullinated Peptide Antibody in Human Serum Based on Avidin-Biotin System

Rheumatoid arthritis (RA) is a chronic autoimmune disease that produces a progressive inflammatory response that leads to severe pain, swelling, and stiffness in the joints of hands and feet, followed by irreversible damage of the joints. The authors developed a miniaturized, label-free electrochemical impedimetric immunosensor for the sensitive and direct detection of arthritis Anti-CCP-ab biomarker. An interdigitated-chain-shaped microelectrode array (ICE) was fabricated by taking the advantage of microelectromechanical systems. The fabricated ICE was modified with a self-assembled monolayer (SAM) of Mercaptohexanoic acid (MHA) for immobilization of the synthetic peptide bio-receptor (B-CCP). The B-CCP was attached onto the surface of SAM modified ICE through a strong avidin-biotin bio-recognition system. The modified ICE surface with the SAM and bio-molecules (Avidin, B-CCP, Anti-CCP-ab and BSA) was morphologically and electrochemically characterized. The change in the sensor signal upon analyte binding on the electrode surface was probed through the electrochemical impedance spectroscopy (EIS) property of charge-transfer resistance (Rct) of the modified electrodes. EIS measurements were target specific and the sensor response was linearly increased with step wise increase in target analyte (Anti-CCP-ab) concentrations. The developed sensor showed a linear range for the addition of Anti-CCP-ab between 1 IU mL−1 → 800 IU mL−1 in phosphate buffered saline (PBS) and Human serum (HS), respectively. The sensor showed a limit of detection of 0.60 IU mL−1 and 0.82 IU mL−1 in the PBS and HS, respectively. The develop bio-electrode showed a good reproducibility (relative standard deviation (RSD), 1.52%), selectivity and stability (1.5% lost at the end of 20th day) with an acceptable recovery rate (98.0% → 101.18%) and % RSD’s for the detection of Anti-CCP-ab in spiked HS samples