In vitro study of a multi-layer piezoelectric crystal attic hearing implant

2001 ◽  
Vol 115 (5) ◽  
pp. 359-362 ◽  
Author(s):  
R. P. Mills ◽  
Z. G. Wang ◽  
E. W. Abel
Keyword(s):  
High Frequency ◽  
In Vitro Study ◽  
Ossicular Chain ◽  
The Body ◽  
Laser Vibrometer ◽  
Optimal Method ◽  
Low Frequencies ◽  
Series Of Experiments ◽  
Multilayer Piezoelectric Actuator

We have developed a prototype middle-ear hearing implant which uses a multilayer piezoelectric actuator. In this series of experiments the actuator was attached to the medial wall of the attic so that it makes contact with the body of the incus. Initial in vitro evaluation has been carried out using a laser vibrometer (Polytec CLV) to measure stapes velocity. Stapes displacement is calculated by mathematical integration. The device used in this way is particularly effective at transmitting high frequency sound to the stapes. When switched off the actuator impairs the transmission of sound to the ossicular chain at low frequencies, but this effect is only 7 dB at most. The stapes displacements resulting from the action of the implant have a linear relationship with the voltages used to drive the system. The high capacitance of the present actuator means that its power requirements are higher than that of other comparable devices. An optimal method of coupling the device to the incus has yet to be identified.

In vitro evaluation of a malleus head to stapes head ‘incus replica’ prosthesis

2001 ◽  
Vol 115 (2) ◽  
pp. 97-100 ◽  
Author(s):  
Robert Mills ◽  
Eric Abel ◽  
Richard Lord
Keyword(s):  
Ossicular Chain ◽  
Acoustic Stimulation ◽  
Laser Vibrometer ◽  
Ossicular Replacement ◽  
Series Of Experiments ◽  
Incudostapedial Joint ◽  
Set Up ◽  
Temporal Bones ◽  
Replacement Prosthesis

An ossicular prosthesis produced by making a mould from a cadaveric incus and injecting ionomeric cement into it (incus replica prosthesis, IRP) has been cemented to the malleus head and stapes head and evaluated in fresh human temporal bones using a laser vibrometer. Stapes velocity was recorded under acoustic stimulation and foot plate displacements were derived. Fourteen frequencies between 125 Hz and 8000 Hz have been used. Measurements were made with the ossicular chain intact, following removal of the incus, with the prosthesis cemented to the malleus, but not the stapes, and with the incudo-stapedial joint cemented. In a second series of experiments the performance of the IRP was compared with that of a Causse partial ossicular replacement prosthesis, using the same experimental set-up. The results indicate that the prosthesis performs almost as well as the intact ossicular chain and that cementing the incudostapedial joint gives better sound transmission than leaving it uncemented. In addition the IRP outperforms the conventional partial ossicular replacement prosthesis.

scholarly journals Intravascular Ultrasound (IVUS): A Potential Arthroscopic Tool for Quantitative Assessment of Articular Cartilage

2009 ◽  
Vol 3 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Yan-Ping Huang ◽  
Yong-Ping Zheng
Keyword(s):  
Articular Cartilage ◽  
Intravascular Ultrasound ◽  
High Frequency ◽  
Quantitative Assessment ◽  
The Body ◽  
High Frequency Ultrasound ◽  
Surface Reflection ◽  
Before And After ◽  
Highly Correlated

Conventional ultrasound examination of the articular cartilage performed externally on the body surface around the joint has limited accuracy due to the inadequacy in frequency used. In contrast to this, minimally invasive arthroscopy-based ultrasound with adequately high frequency may be a better alternative to assess the cartilage. Up to date, no special ultrasound transducer for imaging the cartilage in arthroscopic use has been designed. In this study, we introduced the intravascular ultrasound (IVUS) for this purpose. An IVUS system with a catheter-based probe (Ø ≈ 1mm) was used to measure the thickness and surface acoustical reflection of the bovine patellar articular cartilage in vitro before and after degeneration induced by enzyme treatments. Similar measurement was performed using another high frequency ultrasound system (Vevo) with a probe of much larger size and the results were compared between the two systems. The thickness measured using IVUS was highly correlated (r = 0.985, p < 0.001) with that obtained by Vevo. Thickness and surface reflection amplitude measured using IVUS on the enzymatically digested articular cartilage showed changes similar to those obtained by Vevo, which were expectedly consistent with previous investigations. IVUS can be potentially used for the quantitative assessment of articular cartilage, with its ready-to-use arthroscopic feature.

The Permeability of Dialytic Membranes to Endotoxins: Clinical and Experimental Findings

1989 ◽  
Vol 12 (8) ◽  
pp. 505-508 ◽  
Author(s):  
G. Passavanti ◽  
E. Buongiorno ◽  
G. De Fino ◽  
D. Fumarola ◽  
P. Coratelli
Keyword(s):  
Active Component ◽  
Lipid A ◽  
In Vitro Study ◽  
The Body ◽  
Biologically Active ◽  
Limulus Amebocyte Lysate ◽  
Membrane Interaction ◽  
Experimental Findings

This study of 20 endotoxemic patients submitted to 70 hemodialyses (HD) found a reduction of the pre-HD limulus amebocyte lysate (LAL) positivity in 50 HD (71%), without appreciable differences in terms of effectiveness between cuprophan and AN 69 membranes. To define the mechanisms responsible for the reduction in LAL positivity during HD, the membranes were used in two in vitro studies, the first of which showed that the LAL positivity of blood containing lipopolysaccharide (LPS), submitted to hemofiltration (HF) for 300 min, remained unchanged and the ultrafiltrate remained constantly LAL negative. These results suggest that the reduction in LAL positivity observed in HD in vivo, an expression of reduced endotoxemia, cannot be attributed either to the filtration of the LPS as such or to its fragmentation following blood-membrane interaction into theoretically less filtrable molecules or to mechanisms of LPS adsorption on the membrane. The in vivo reduction of LAL positivity is more likely due to removal of the filtrable endotoxin fragments already released in the body, like lipid A, the biologically active component of LPS, known to react to LAL. This hypothesis was borne out by the second in vitro study, where the LAL positivity of blood containing lipid A, treated by HF for 80 min, gradually decreased, and dialytic permeability to lipid A was confirmed by the appearance of LAL positivity in the ultrafiltrate.

scholarly journals Changes in pH as a result of galvanic currents used in percutaneous needle electrolysis

2020 ◽  
Vol 03 (01) ◽  
pp. 006-006 ◽  
Author(s):  
Ramón Margalef ◽  
Francisco Minaya-Muñoz ◽  
Fermín Valera-Garrido ◽  
Marc Bosque ◽  
Manel M. Santafé
Keyword(s):  
Saline Solution ◽  
In Vitro Study ◽  
The Body ◽  
Galvanic Current ◽  
Current Application ◽  
Ph Changes ◽  
Ringer’S Solution ◽  
Left Limb

Abstract Aim To determine whether sodium chloride electrolysis causes a change in the pH of tissues. Methods The effects of a 3 mA galvanic current has been evaluated, applied for 3 seconds and 3 repetitions (3:3:3). In vitro pH changes were evaluated in three experiments: 1) Eppendorf® tubes filled with Ringer's solution; 2) a very small volume of Ringer's solution (100µl); 3) Eppendorf® tubes filled with saline solution (NaCl 0.9%). The pH changes in the gastrocnemius of mice were evaluated, using the left limb as a control and the right limb for the intervention. The gastrocnemius muscles were ground up and the pH of each group was determined. Results In the in vitro experiments 1 and 2, no variation was observed in the pH of either the cathode in the Ringer's solution or the anode in the Ringer's solution (the variation did not exceed 16% in either of the cases, p> 0.05). In the third in vitro study, the pH after galvanic current application increased by 70% in the saline solution of the cathode and the anode pH decreased by 34% (p < 0.05 in both cases). In the in vivo experiments, no change in pH was obtained (% variation: 0.00 ± 0.00). Conclusions The galvanic current used in percutaneous needle electrolysis applying the 3:3:3 parameters generates very small changes in the pH, in the area near the needle, which the body is able to rapidly compensate for.

Modulation of bat wing venule contraction by transmural pressure changes

1992 ◽  
Vol 262 (3) ◽  
pp. H625-H634 ◽  
Author(s):  
M. J. Davis ◽  
X. Shi ◽  
P. J. Sikes
Keyword(s):  
Venous Pressure ◽  
Transmural Pressure ◽  
The Body ◽  
Intraluminal Pressure ◽  
Positive Pressure ◽  
Cross Sectional ◽  
Series Of Experiments ◽  
Pressure Changes ◽  
Bat Wing

We tested the hypothesis that the frequency and amplitude of spontaneous venular contractions in the bat wing could be modulated by changes in transmural pressure. In one series of experiments, venous pressure in the wing was elevated by pressurizing a box containing the body of the animal while the wing was exposed to atmospheric pressure. During this time, venular diameters were continuously recorded using intravital microscopic techniques while venular pressures were measured through servo-null micropipettes. In another series of experiments, single venular segments were dissected from the wing, cannulated, and pressurized in vitro. The results from both experimental protocols were qualitatively similar; alterations in venous pressure over a narrow range (+/- 5 cmH2O from control) produced substantial changes in contraction frequency and amplitude. The product of frequency and cross-sectional area was maximal over the venous pressure range between 10 and 15 cmH2O. Venules demonstrated a rate-sensitive component in their reaction to rapid pressure changes, because contraction bursts occurred immediately after positive pressure steps and quiescent periods often occurred after negative pressure steps. We conclude that venular vasomotion in the bat wing is modulated by intraluminal pressure and involves a bidirectional, rate-sensitive mechanism. In addition, comparisons with arteriolar vasomotion studies suggest that venules are more sensitive to luminal pressure changes than arterioles.

A preprogalanin cDNA from the turtle pituitary and regulation of its gene expression

2007 ◽  
Vol 292 (4) ◽  
pp. R1649-R1656 ◽  
Author(s):  
John Yuh-Lin Yu ◽  
Chin-Hon Pon ◽  
Hui-Chen Ku ◽  
Chih-Ting Wang ◽  
Yung-Hsi Kao
Keyword(s):  
Mrna Expression ◽  
Untranslated Region ◽  
Signal Sequence ◽  
Biological Effects ◽  
In Vitro Study ◽  
The Body ◽  
Mrna Levels ◽  
Coding Region ◽  
Reading Frame

Galanin is a hormone 29 or 30 amino acids (aa) long that is widely distributed within the body and exerts numerous biological effects in vertebrates. To fully understand its physiological roles in reptiles, we analyzed preprogalanin cDNA structure and expression in the turtle pituitary. Using the Chinese soft-shell turtle ( Pelodiscus sinensis order Testudines), we obtained a 672-base pair (bp) cDNA containing a 99-bp 5′-untranslated region, a 324-bp preprogalanin coding region, and a 249-bp 3′-untranslated region. The open-reading frame encoded a 108-aa preprogalanin protein with a putative 23-aa signal sequence at the NH2 terminus. Based on the location of putative Lys-Arg dibasic cleavage sites and an amidation signal of Gly-Lys-Arg, we propose that turtle preprogalanin is processed to yield a 29-aa galanin peptide with Gly1 and Thr29 substitutions and a COOH-terminal amidation. Sequence comparison revealed that turtle preprogalanin and galanin-29 had 48–81% and 76–96% aa identities with those of other vertebrates, respectively, suggesting their conservative nature. Expression of the turtle galanin gene was detected in the pituitary, brain, hypothalamus, stomach, liver, pancreas, testes, ovaries, and intestines, but not in the adipose or muscle tissues, suggesting tissue-dependent differences. An in vitro study that used pituitary tissue culture indicated that treatment with 17β-estradiol, testosterone, or gonadotropin-releasing hormone resulted in increased galanin mRNA expression with dose- or time-dependent differences, whereas leptin and neuropeptide Y reduced galanin mRNA levels. These results suggest a hormone-dependent effect on hypophyseal galanin mRNA expression.

scholarly journals Zinc and the Zinc Transporter SLC39A10/ZIP10 Are Required for Heme Synthesis in Developing Erythroid Progenitors

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 1320-1320
Author(s):  
Juyoung Kim ◽  
Jaekwon Lee ◽  
Moon-Suhn Ryu
Keyword(s):  
In Vitro Study ◽  
Fold Increase ◽  
Zinc Transporter ◽  
The Body ◽  
Zinc Homeostasis ◽  
Mean Corpuscular Hemoglobin ◽  
Erythroid Progenitors ◽  
Heme Synthesis ◽  
Cellular Zinc

Abstract Objectives Zinc is an essential nutrient for diverse biological processes in the body. Cellular zinc homeostasis is established through differential expressions of the transmembrane zinc transporter proteins, ZnTs and ZIPs. The aims of the current studies were to elucidate the roles of cellular zinc in erythrocyte maturation, and to determine the zinc transporters essential to erythroid zinc homeostasis. Methods G1E-ER4 mouse cells were employed as an in vitro study model of terminal erythroid differentiation. A cell-impermeable zinc chelator, diethylenetriamine pentaacetate (DTPA), was used to limit extracellular zinc availability. For gene silencing, gene-specific siRNAs were introduced to cells via Nucleofection. Functional impacts of zinc and gene deficiency were assessed via ICP-MS-based metal quantitation, heme assays, and gene expression assays using RNA-seq, qPCR, and western analyses. Results G1E-ER4 cells featured a 1.7-fold increase in total cellular zinc contents after 48 h of differentiation. Restriction of zinc import by 50 µM of DTPA led to less red coloration and lower increases in mean corpuscular hemoglobin contents by development. The heme deficiency by DTPA was fully restored by the addition of equimolar zinc, and was not due to changes in cellular iron contents. Zinc-deficient G1E-ER4 cells differentiated with normal Alas2 and Hbb-b1 transcript responses, but less Alad and alpha-globin expressions. Among the 24 zinc transporter genes, Zip10 produced the most prominent response to zinc restriction in differentiating erythroid cells. ZIP10-deficient G1E-ER4 cells were less efficient than control cells in hemoglobin production under zinc restriction. ZIP10 deficiency alone had no effects on the molecular indices of red cell hemoglobinization. Conclusions Our studies characterize zinc as a nutrient essential to normal erythroid maturation and heme synthesis. Moreover, we have identified a compensatory role of ZIP10 for erythroid zinc homeostasis during zinc restriction. Thus, poor zinc status and ZIP10 mutations might serve as potential risk factors and thus new therapeutic targets for anemia and other erythrocyte-related disorders. Funding Sources Supported by CFANS Graduate Fellowship to JK, and the Allen Foundation, Inc. and USDA NIFA Hatch Funds to M-SR.

scholarly journals Histological and microhardness evaluation of early artificial carious lesions in human and bovine enamel: in vitro study

2013 ◽  
Vol 16 (4) ◽  
pp. 49
Author(s):  
Allan Kenji Masuda ◽  
Mayra Fidelis Zamboni Quitero ◽  
Luciana Cardoso Espejo-Trung ◽  
Maria Aparecida Alves Cerqueira Luz
Keyword(s):  
Polarized Light ◽  
In Vitro Study ◽  
The Body ◽  
Polarization Microscopy ◽  
Cross Sectional ◽  
Enamel Caries ◽  
Carious Lesions ◽  
Ph Cycling ◽  
Bovine Enamel

<p><strong>Objective: </strong>Early carious lesions in bovine and humanenamel developed in vitro using a pH cycling regimenwere compared. <strong>Material and Methods: </strong>Fifteencentral bovine incisors and fifteen recently extractedhuman third molars were randomly divided into twogroups: ten for the cross-sectional microhardness test(MT) and five for polarized light microscopy (PLM)analysis. Enamel blocks measuring 5 x 5 mm weremade from the buccal face of the teeth. The blocksused for the MT were sliced into two halves: “A” and“B”. “A” slices were embedded in acrylic resin, withthe face of the dentin-enamel junction left exposedfor the MT prior to pH cycling. “B” slices and wholeblocks were coated with acid-resistant varnish,except a 3 x 3 mm central window, and submitted tothe pH cycling regimen (demineralizing solution for3 h and remineralizing solution for 21 h) over fiveconsecutive days. The “B” slices were then submittedto the MT and the whole blocks were processed forthe PLM study. <strong>Results: </strong>The PLM analysis revealedshallow, extensive lesions in the bovine enamel,hardly showing the superficial, dark and translucentzones, as well as deep cavity lesions in the humanenamel, with the body of the lesion and the darkzone evident. The MT revealed a significant decreasein microhardness in the superficial levels of thebovine enamel caries and at all depth levels of thehuman enamel caries. <strong>Conclusion: </strong>The pH cyclingregimen adopted led to the development of deeperand more demineralized carious lesions in humanenamel than bovine enamel</p><p>Keywords<br />Dental caries; Dental enamel; Microhardness tests; Polarization microscopy.</p>

The lung-eardrum pathway in three treefrog and four dendrobatid frog species: some properties of sound transmission.

1994 ◽  
Vol 195 (1) ◽  
pp. 329-343 ◽  
Author(s):  
G Ehret ◽  
E Keilwerth ◽  
T Kamada
Keyword(s):  
High Frequency ◽  
Body Wall ◽  
Low Frequency ◽  
Sound Intensity ◽  
The Body ◽  
Response Curves ◽  
Low Frequencies ◽  
Best Response ◽  
Lateral Body ◽  
Frequency Components

Frequency-response curves of the tympanum and lateral body wall (lung area) were measured by laser Doppler vibrometry in three treefrog (Smilisca baudini, Hyla cinerea, Osteopilus septentrionalis) and four dendrobatid frog (Dendrobates tinctorius, D. histrionicus, Epipedobates tricolor, E. azureiventris) species. The high-frequency cut-off of the body wall response was always lower than that of the tympanum. The best response frequencies of the lateral body wall were lower than those of the tympanum in some species (S. baudini, O. septentrionalis, D. tinctorius), while in the others they were rather similar. Best tympanic frequencies and best body wall response frequencies tended to differ more with increasing body size. Stimulation of the tympanum by sound transfer through 3.14 mm2 areas of the lateral body wall showed that the lung-eardrum pathway can be in two states, depending on breathing activity within the lungs: 44% (in Smilisca), 39% (in Hyla) and 31% (in Osteopilus) of the eardrum vibrations were 2.5-8 times (8-18 dB) larger when the frogs were breathing with the lungs compared with non-breathing conditions. The vibration amplitudes of the tympanum and lateral body wall of the treefrogs followed the same dependence on sound intensity, only absolute amplitudes differed between species. Our results suggest that the lung-eardrum pathway attenuates high-frequency components of species-specific calls and enhances low-frequency components. In addition, an amplitude modulation is imposed on the low frequencies during the rhythm of breathing.

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