scholarly journals Audio waves and its loss of energy in puncture needles

2019 ◽  
Vol 5 (1) ◽  
pp. 21-24 ◽  
Author(s):  
Ivan Maldonado ◽  
Alfredo Illanes ◽  
Marco Kalmar ◽  
Thomas Sühn ◽  
Axel Boese ◽  
...  
Keyword(s):  
Structural Changes ◽  
Controlled Environment ◽  
Audio Signals ◽  
Tactile Information ◽  
Percutaneous Procedures ◽  
Tissue Resistance ◽  
Objective Feedback ◽  
Crucial Information ◽  
Needle Structure ◽  
Different Thickness

AbstractThe location of a puncture needle’s tip and the resistance of tissue against puncture are crucial information for clinicians during a percutaneous procedure. The tip location and needle alignment can be observed by image guidance. Tactile information caused by tissue resistance to rupture, allow clinicians the perception of structural changes during puncture. Nevertheless, this sense is individual and subjective. To improve percutaneous procedures, the implementation of transducers to enhance or complement the senses offer objective feedback to the user. Known approaches are e.g. based on integrated force sensors. However, this is connected to higher device costs, sterilization and certification issues. A recent publication shows the implementation of an audio transducer clipped at the proximal end of the needle. This sensor is capable of acquiring emitted sounds of the distal tiptissue interaction that are transmitted over the needle structure. The interpretation of the measured audio signals is highly depended on the transmission over the needle, the tissue and, the penetration depth. To evaluate the influence of these parameters, this work implements a simplified experimental setup in a controlled environment with a minimum of noise and without micro tremors induced by clinician’s hands. A steel rod simulating a needle is inserted into pork meat of different thickness. A controlled impact covering the needle’s tip mimics tissue contact. The resulting signals are recorded and analyzed for better understanding of the system.

Vascular and interstitial mechanics in canine pulmonary emphysema

1985 ◽  
Vol 59 (6) ◽  
pp. 1704-1715 ◽  
Author(s):  
S. N. Mink ◽  
H. W. Unruh ◽  
L. Oppenheimer
Keyword(s):  
Pulmonary Emphysema ◽  
Structural Changes ◽  
Lower Lobe ◽  
Fluid Exchange ◽  
Vascular Conductance ◽  
Edema Formation ◽  
Cross Sectional ◽  
Tissue Resistance ◽  
Wet Weight

We examined the changes in vascular and interstitial mechanics in pulmonary emphysema (PE) using a canine lobar model. PE was produced in the left lower lobe (LLL) of five dogs (group E) by six weekly intrabronchial instillations of the enzyme papain. In five control dogs (group C), a normal saline solution was used. In our in vivo preparation, vascular flow (Q) to the LLL was measured. Inflow (Ppa) and outlow (Pv) pressures to the LLL could be varied independently. The relationship of Ppa to Q was examined in zones 2 and 3 of West. The slope of the Ppa-Q relationship was used to determine vascular conductance, whereas the extrapolation to zero flow in zone 2 conditions represented the mean pressure required for vascular recruitment (Pi). Lobar weight gain was measured continuously. Following step increases in Ppa, the rapid increase in wet weight measured when Q to the LLL was zero was used to obtain vascular compliance (C). Subsequent slow increases in wet weight were used to determine the rate of fluid exchange with the interstitium (Qf). The slope of the Qf-Ppa relationship represented fluid conductance (Kf). The extrapolation to zero Qf gave the minimal pressure required for continuous edema formation (Pm). Compared with group C, vascular conductance (G) decreased and Pi increased in group E, whereas fluid conductance (Kf) and Pm increased. The decrease in G most likely resulted from the loss of vascular cross-sectional area in emphysematous lungs, whereas the increase in Pi was possibly due to mechanical changes in the lung interstitium which increased vessel closure. We propose that the increase in Kf in group E reflected an increase in interstitial conductance, such that due to structural changes in the interstitium in emphysematous lungs, tissue resistance to fluid flux decreased.

Structural Changes in Pericardium Tissue Modified with Tannic Acid

2005 ◽  
Vol 28 (6) ◽  
pp. 648-653 ◽  
Author(s):  
B. Cwalina ◽  
A. Turek ◽  
J. Nozynski ◽  
M. Jastrzebska ◽  
Z. Nawrat
Keyword(s):  
Structural Stability ◽  
Tannic Acid ◽  
Structural Changes ◽  
Enzymatic Digestion ◽  
Connective Tissues ◽  
Tissue Resistance ◽  
Sds Page ◽  
Microscopic Studies ◽  
Morphological Differences ◽  
Porcine Pericardium

Introduction Structural modification of proteins, mainly collagen in connective tissues, is important in the manufacture of tissue-derived biomaterials. Natural compounds like genipin or tannic acid (TA) have been proposed instead of glutaraldehyde which shows cytotoxic effects on the processed tissue. Furthermore, calcification of glutaraldehyde-treated tissue limits the functional lifetime of bioprostheses. TA is known to form numerous hydrogen bonds with proteins. The purpose of our study was to investigate structural changes in porcine pericardium upon chemical modification with tannic acid. Methods Porcine pericardium tissue (PP) was soaked in 2% TA for 4, 24 or 48 hours. Changes in tissue structure were studied using electrophoresis (SDS-PAGE) and histological examination. Structural stability of PP tissue was evaluated by SDS/NaCl extraction method and enzymatic digestion with pancreatin. Results TA-modification of PP caused a time-dependent decrease in the number of peptides extracted from tissue. Microscopic studies revealed no significant morphological differences between native and TA-modified tissues, except for the native pancreatin-digested tissue where lack of both cells and low molecular peptides was observed. Conclusion Modification of PP with TA causes the structural changes leading to an increase in the tissue resistance to SDS/NaCl extraction and enzymatic digestion, providing experimental evidence for the higher structural stability of TA-treated tissue.

scholarly journals miR-21-KO Alleviates Alveolar Structural Remodeling and Inflammatory Signaling in Acute Lung Injury

2020 ◽  
Vol 21 (3) ◽  
pp. 822 ◽  
Author(s):  
Johanna Christine Jansing ◽  
Jan Fiedler ◽  
Andreas Pich ◽  
Janika Viereck ◽  
Thomas Thum ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Structural Damage ◽  
Structural Changes ◽  
Elastic Fibers ◽  
Inflammatory Signaling ◽  
Knock Out ◽  
Tissue Resistance ◽  
Pulmonary Remodeling ◽  
Lps Treatment

Acute lung injury (ALI) is characterized by enhanced permeability of the air–blood barrier, pulmonary edema, and hypoxemia. MicroRNA-21 (miR-21) was shown to be involved in pulmonary remodeling and the pathology of ALI, and we hypothesized that miR-21 knock-out (KO) reduces injury and remodeling in ALI. ALI was induced in miR-21 KO and C57BL/6N (wildtype, WT) mice by an intranasal administration of 75 µg lipopolysaccharide (LPS) in saline (n = 10 per group). The control mice received saline alone (n = 7 per group). After 24 h, lung function was measured. The lungs were then excised for proteomics, cytokine, and stereological analysis to address inflammatory signaling and structural damage. LPS exposure induced ALI in both strains, however, only WT mice showed increased tissue resistance and septal thickening upon LPS treatment. Septal alterations due to LPS exposure in WT mice consisted of an increase in extracellular matrix (ECM), including collagen fibrils, elastic fibers, and amorphous ECM. Proteomics analysis revealed that the inflammatory response was dampened in miR-21 KO mice with reduced platelet and neutrophil activation compared with WT mice. The WT mice showed more functional and structural changes and inflammatory signaling in ALI than miR-21 KO mice, confirming the hypothesis that miR-21 KO reduces the development of pathological changes in ALI.

scholarly journals Age related changes in the elastic fiber system of the interfoveolar ligament

2000 ◽  
Vol 55 (3) ◽  
pp. 83-86 ◽  
Author(s):  
Mario Luiz Quintas ◽  
Consuelo Junqueira Rodrigues ◽  
Hwan Yoo Jin ◽  
Aldo Junqueira Rodrigues Junior
Keyword(s):  
Structural Changes ◽  
Elastic Fiber ◽  
Elastic Fibers ◽  
Tissue Elasticity ◽  
Fiber System ◽  
Age Related ◽  
Tissue Resistance ◽  
Quantitative Changes ◽  
Oxytalan Fibers ◽  
Age Related Changes

In order to evaluate age related changes of the elastic fiber system in the interfoveolar ligament, we studied the deep inguinal ring from 33 male cadavers aged from stillborn to 76 years. Selective and alternated staining methods for elastic fibers were performed to differentiate oxytalan, elaunin, and mature elastic fibers. We confirmed quantitative changes of the elastic fiber system with aging. There was a significant and progressive reduction of the oxytalan fibers (responsible for tissue resistance) and a significant increment in the mature elastic and elaunin fibers (responsible for tissue elasticity). Furthermore, there were structural changes in the thickness, shortness and curling of these mature elastic fibers. These changes induced loss of the elastic fiber function and loss of the interfoveolar ligament compliance. These factors predispose individuals to the development of indirect inguinal hernias that frequently emerge in adults and aged individuals, especially above the fifth decade.

scholarly journals The Effect of Different Thawing Rates on Cryopreserved Human Iliac Arteries Allograft’s Structural Damage and Mechanical Properties

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Robert Novotny ◽  
Pavel Mericka ◽  
Jaroslav Chlupac ◽  
Roman Matejka ◽  
Jakub Kristek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Structural Damage ◽  
Tensile Strain ◽  
Statistical Difference ◽  
Structural Changes ◽  
Testing Machine ◽  
Controlled Environment ◽  
Iliac Arteries ◽  
Relative Strain ◽  
Strain Testing

Introduction. The rate of thawing of cryopreserved human iliac arteries allografts (CHIAA) directly affects the severeness of structural changes that occur during this process. Method. The experiment was performed on ten CHIAA. The 10% dimethylsulphoxide in 6% hydroxyethyl starch solution was used as the cryoprotectant; all CHIAA were cooled at a controlled rate and stored in the vapor phase of liquid nitrogen (-194°C). Two thawing protocols were tested: (1) placing the CHIAA in a water bath at 37°C, and (2) the CHIAA were thawed in a controlled environment at 5°C. All samples underwent analysis under a scanning electron microscope. Testing of the mechanical properties of the CHIAA was evaluated on a custom-built single axis strain testing machine. Longitudinal and circumferential samples were prepared from each tested CHIAA. Results. Ultrastructural analysis revealed that all five CHIAA thawed during the thawing protocol 1 which showed significantly more damage to the subendothelial structures when compared to the samples thawed in protocol 2. Mechanical properties: Thawing protocol 1—longitudinal UTS 2,53±0,47 MPa at relative strain 1,27±0,12 and circumferential UTS 1,94±0,27 MPa at relative strain 1,33±0,09. Thawing protocol 2—longitudinal ultimate tensile strain (UTS) 2,42±0,34 MPa at relative strain 1,32±0,09 and circumferential UTS 1,98±0,26 MPa at relative strain 1,29±0,07. Comparing UTS showed no statistical difference between thawing methods. Conclusion. Despite the significant differences in structural changes of presented thawing protocols, the ultimate tensile strain showed no statistical difference between thawing methods.

Fine Structural Changes in the Microvasculature of the Mouse Pinna: Aging and Radiation Injury

1974 ◽  
Vol 32 ◽  
pp. 54-55
Author(s):  
S. Phyllis Steamer ◽  
Rosemarie L. Devine
Keyword(s):  
Structural Changes ◽  
Radiation Treatment ◽  
Arterial Stenosis ◽  
Ultrastructural Changes ◽  
Vascular Effects ◽  
Microvascular Changes ◽  
Surrounding Connective Tissue ◽  
Fission Neutrons ◽  
Total Body

The importance of radiation damage to the skin and its vasculature was recognized by the early radiologists. In more recent studies, vascular effects were shown to involve the endothelium as well as the surrounding connective tissue. Microvascular changes in the mouse pinna were studied in vivo and recorded photographically over a period of 12-18 months. Radiation treatment at 110 days of age was total body exposure to either 240 rad fission neutrons or 855 rad 60Co gamma rays. After in vivo observations in control and irradiated mice, animals were sacrificed for examination of changes in vascular fine structure. Vessels were selected from regions of specific interest that had been identified on photomicrographs. Prominent ultrastructural changes can be attributed to aging as well as to radiation treatment. Of principal concern were determinations of ultrastructural changes associated with venous dilatations, segmental arterial stenosis and tortuosities of both veins and arteries, effects that had been identified on the basis of light microscopic observations. Tortuosities and irregularly dilated vein segments were related to both aging and radiation changes but arterial stenosis was observed only in irradiated animals.

Evaluation of single-electron movies of glutamine synthetase molecules

1983 ◽  
Vol 41 ◽  
pp. 280-281
Author(s):  
W. Kunath ◽  
E. Zeitler ◽  
M. Kessel
Keyword(s):  
Electron Microscope ◽  
Glutamine Synthetase ◽  
Electron Irradiation ◽  
Structural Damage ◽  
Structural Changes ◽  
Single Electron ◽  
Continuous Series ◽  
Digital Recording ◽  
Recording Device ◽  
Low Exposure

The features of digital recording of a continuous series (movie) of singleelectron TV frames are reported. The technique is used to investigate structural changes in negatively stained glutamine synthetase molecules (GS) during electron irradiation and, as an ultimate goal, to look for the molecules' “undamaged” structure, say, after a 1 e/Å2 dose.The TV frame of fig. la shows an image of 5 glutamine synthetase molecules exposed to 1/150 e/Å2. Every single electron is recorded as a unit signal in a 256 ×256 field. The extremely low exposure of a single TV frame as dictated by the single-electron recording device including the electron microscope requires accumulation of 150 TV frames into one frame (fig. lb) thus achieving a reasonable compromise between the conflicting aspects of exposure time per frame of 3 sec. vs. object drift of less than 1 Å, and exposure per frame of 1 e/Å2 vs. rate of structural damage.

The Ultrastructure of Monkey Gingival Epithelium

1967 ◽  
Vol 25 ◽  
pp. 16-17
Author(s):  
C.N. Sun
Keyword(s):  
Epithelial Cells ◽  
Macaca Nemestrina ◽  
Stratum Granulosum ◽  
Solution Ph ◽  
Gingival Epithelial Cells ◽  
Stratum Spinosum ◽  
Cell Layers ◽  
Gingival Epithelium ◽  
The Individual ◽  
Different Thickness

The present study demonstrates the ultrastructure of the gingival epithelium of the pig tail monkey (Macaca nemestrina). Specimens were taken from lingual and facial gingival surfaces and fixed in Dalton's chrome osmium solution (pH 7.6) for 1 hr, dehydrated, and then embedded in Epon 812.Tonofibrils are variable in number and structure according to the different region or location of the gingival epithelial cells, the main orientation of which is parallel to the long axis of the cells. The cytoplasm of the basal epithelial cells contains a great number of tonofilaments and numerous mitochondria. The basement membrane is 300 to 400 A thick. In the cells of stratum spinosum, the tonofibrils are densely packed and increased in number (fig. 1 and 3). They seem to take on a somewhat concentric arrangement around the nucleus. The filaments may occur scattered as thin fibrils in the cytoplasm or they may be arranged in bundles of different thickness. The filaments have a diameter about 50 A. In the stratum granulosum, the cells gradually become flatted, the tonofibrils are usually thin, and the individual tonofilaments are clearly distinguishable (fig. 2). The mitochondria and endoplasmic reticulum are seldom seen in these superficial cell layers.

Fine Structural Changes in the Adenohypophyses of Rats Following Destruction of the Pituitary Stalk

1977 ◽  
Vol 35 ◽  
pp. 496-497
Author(s):  
K. Kovacs ◽  
E. Horvath ◽  
J. M. Bilbao ◽  
F. A. Laszlo ◽  
I. Domokos
Keyword(s):  
Structural Changes ◽  
Tissue Injury ◽  
Anterior Lobe ◽  
Uranyl Acetate ◽  
Male Rats ◽  
Pituitary Stalk ◽  
Sequence Of Events ◽  
Pituitary Glands ◽  
Electrolytic Lesions ◽  
Ultrathin Sections

Electrolytic lesions of the pituitary stalk in rats interrupt adenohypophysial blood flow and result in massive infarction of the anterior lobe. In order to obtain a deeper insight into the morphogenesis of tissue injury and to reveal the sequence of events, a fine structural investigation was undertaken on adenohypophyses of rats at various intervals following destruction of the pituitary stalk.The pituitary stalk was destroyed electrolytically, with a Horsley-Clarke apparatus on 27 male rats of the R-Amsterdam strain, weighing 180-200 g. Thirty minutes, 1,2,4,6 and 24 hours after surgery the animals were perfused with a glutaraldehyde-formalin solution. The skulls were then opened and the pituitary glands removed. The anterior lobes were fixed in glutaraldehyde-formalin solution, postfixed in osmium tetroxide and embedded in Durcupan. Ultrathin sections were stained with uranyl acetate and lead citrate and investigated with a Philips 300 electron microscope.

Membrane Changes in Polymorphonuclear Leukocytes During Ionophore (A23187) - Induced Lysosomal Release

1977 ◽  
Vol 35 ◽  
pp. 482-483
Author(s):  
P.L. Moore ◽  
P.L. Sannes ◽  
H.L. Bank ◽  
S.S. Spicer
Keyword(s):  
Structural Changes ◽  
Calcium Release ◽  
Clear Understanding ◽  
Ionophore A23187 ◽  
Enzyme Release ◽  
Extracellular Medium ◽  
Pmn Leukocytes ◽  
Intracellular Ion Concentrations ◽  
Membrane Changes ◽  
Pmn Leukocyte

It is thought that calcium and/or magnesium may play important roles in polymorphonuclear (PMN) leukocyte functions such as chemotaxis, adhesion and phagocytosis. Yet, a clear understanding of the biological roles of these ions has awaited the development of techniques which permit a selective alteration of intracellular ion concentrations. Recently, treatment of cells with the ionophore A23187 has been used to alter intracellular divalent cation concentrations. This ionophore is a lipid soluble antibiotic produced by Streptomyces chartreusensis that complexes with both calcium and magnesium (3) and is believed to carry these ions across biological membranes (4). Biochemical investigations of human PMN leukocytes demonstrate that cells treated with A23187 and extracellular calcium release their lysosomal enzymes into the extracellular medium without rupturing and releasing their soluble cytoplasmic enzymes (5,6). The aim of the present study and and a companion report (7) was to investigate the structural changes that occur in leukocytes during ionophore-induced lysosomal enzyme release.

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