Bone Elastometric Measurements by Ultrasound Reflectometry: Observations on Physiology and Functional Organization of Bone

2000 ◽  
Author(s):  
Shreefal S. Mehta ◽  
Peter P. Antich ◽  
Billy Smith ◽  
Matthew A. Lewis ◽  
Edmond Richer
Keyword(s):  
Mechanical Properties ◽  
Functional Organization ◽  
Muscular Activity ◽  
Diagnostic Techniques ◽  
Rate Of Change ◽  
Activity Levels ◽  
Bone Material ◽  
Clinical Observations ◽  
First Time

Abstract Bone mechanical properties are strongly dependent on orientation and optimally adapted to the directional stresses induced by load bearing and muscular activity. Spatial and directional homogeneity and a slow rate of change of material mechanical properties are commonly assumed in the literature. The assumptions are based on limitations of widespread diagnostic techniques but are contradicted by results from several established techniques, including ultrasound reflectometry. A device based on the ultrasound reflectometry technique measures the mechanical elasticity of bone noninvasively at multiple sites and orientations, making it possible to carry out longitudinal studies at any chosen location in vivo. In vivo elastometric measurements over the length of a tibia were obtained with this device, demonstrating quantitatively for the first time the spatial and directional heterogeneity of bone material properties in vivo. Clinical observations made on two subjects also suggest that bone does exhibit rapid changes in response to altered activity levels.

1309 Mechanical Properties of Muscular Activity levels at the Heel Contact

2011 ◽  
Vol 2011.48 (0) ◽  
pp. 423-424
Author(s):  
Masanobu MANNO ◽  
Jyun MATSUI ◽  
Tomokazu ABE ◽  
Toshihide MURAOKA ◽  
Tomohiko FUJIKAWA
Keyword(s):  
Mechanical Properties ◽  
Muscular Activity ◽  
Activity Levels ◽  
Heel Contact

scholarly journals Understanding and Recognition of the Right Ventricular Function and Dysfunction: A Numerical Study

2020 ◽  
Author(s):  
Giulia Comunale ◽  
Paolo Peruzzo ◽  
Biagio Castaldi ◽  
Renato Razzolini ◽  
Giovanni Di Salvo ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Right Ventricular ◽  
Numerical Study ◽  
Hemodynamic Parameters ◽  
Right Heart ◽  
Clinical Observations ◽  
Lumped Parameter ◽  
The Right ◽  
First Time

Abstract The role played by the right ventricular (RV) dysfunction has long been underestimated in clinical practice. Recent findings are progressively confirming that when the RV efficiency deteriorates both the right and the left circulation is (significantly) affected, but studies dedicated to a detailed description of RV hemodynamic role still lack. In response to such a gap in knowledge, this work proposes a numerical model that for the first time evaluates the effect of isolated RV dysfunction on the whole circulation. Lumped parameter modelling was applied to represent the physio-pathological hemodynamics. Different grades of impairment were simulated for three dysfunctions i.e., systolic, diastolic, and combined systolic and diastolic. Hemodynamic alterations (i.e., of blood pressure, flow, global hemodynamic parameters), arising from the dysfunctions, are calculated and analysed. Results well accord with clinical observations, showing that RV dysfunction significantly affects both the pulmonary and systemic hemodynamics. Successful validation against in vivo data proved the clinical potentiality of the model i.e., the capability of identifying the degree of RV impairment for given hemodynamic conditions. This study aims at contributing to the improvement of RV dysfunction recognition and treatment, and to the development of tools for the clinical management of pathologies involving the right heart.

Effect of oxytocin on the pattern of electromyographic activity in the oviduct and uterus of the ewe around oestrus

1992 ◽  
Vol 4 (2) ◽  
pp. 193 ◽  
Author(s):  
CL Gilbert ◽  
PJ Cripps ◽  
DC Wathes
Keyword(s):  
Reproductive Tract ◽  
Muscular Activity ◽  
High Amplitude ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Free Standing ◽  
Late Luteal Phase ◽  
Before And After ◽  
First Time

This study tested the hypothesis that the administration of oxytocin in doses equivalent to endogenous concentrations at and around oestrus could affect uterine and oviductal muscular activity at the time of gamete transport. Four ewes were fitted with recording electrodes in the left ampulla, ampullary-isthmic junction, utero-tubal junction and uterine horn. After surgical recovery, recordings from conscious free-standing animals were made for up to 10 h per day from Day -3 to Day +3 relative to oestrus in each ewe. Daily blood samples were taken for progesterone radioimmunoassay, and a vasectomized ram used to assess oestrus. A range of physiological doses of oxytocin (10-100 mU), or control saline injections were given intravenously. Electromyographic (EMG) activity was measured before and after injections. Spontaneous activity throughout the reproductive tract was low on Day -3 but increased to peak at oestrus (P < 0.05), when the pattern of activity consisted of short (2-10 s) co-ordinated high amplitude bursts (2-5 min-1). After oestrus, as overall activity declined, longer episodes of activity appeared but these occurred with a much slower frequency (1-4 h-1). Responsiveness to oxytocin was greatest on the day of oestrus at all electrode sites. Elevated responsiveness (relative to Day -3, the late luteal phase) was seen from Day -1 to Day +2 at the ampullary-isthmic junction and uterus, but on the day of oestrus only at the ampulla and utero-tubal junction. Duration of increased EMG activity after oxytocin injection ranged from 5 to 20 min. These results show for the first time that the uterine and oviductal musculatures of the ewe in vivo reached a peak in sensitivity to physiological concentrations of oxytocin at oestrus. When combined with information on oxytocin receptor populations and endogenous circulating concentrations, this suggest that endogenous oxytocin could influence oviduct and myometrial activity at this time.

scholarly journals Understanding and recognition of the right ventricular function and dysfunction via a numerical study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Giulia Comunale ◽  
Paolo Peruzzo ◽  
Biagio Castaldi ◽  
Renato Razzolini ◽  
Giovanni Di Salvo ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Right Ventricular ◽  
Numerical Study ◽  
Hemodynamic Parameters ◽  
Right Heart ◽  
Clinical Observations ◽  
Lumped Parameter ◽  
The Right ◽  
First Time

AbstractThe role played by the right ventricular (RV) dysfunction has long been underestimated in clinical practice. Recent findings are progressively confirming that when the RV efficiency deteriorates both the right and the left circulation is (significantly) affected, but studies dedicated to a detailed description of RV hemodynamic role still lack. In response to such a gap in knowledge, this work proposes a numerical model that for the first time evaluates the effect of isolated RV dysfunction on the whole circulation. Lumped parameter modelling was applied to represent the physio-pathological hemodynamics. Different grades of impairment were simulated for three dysfunctions i.e., systolic, diastolic, and combined systolic and diastolic. Hemodynamic alterations (i.e., of blood pressure, flow, global hemodynamic parameters), arising from the dysfunctions, are calculated and analysed. Results well accord with clinical observations, showing that RV dysfunction significantly affects both the pulmonary and systemic hemodynamics. Successful verification against in vivo data proved the clinical potentiality of the model i.e., the capability of identifying the degree of RV impairment for given hemodynamic conditions. This study aims at contributing to the improvement of RV dysfunction recognition and treatment, and to the development of tools for the clinical management of pathologies involving the right heart.

Untersuchungen zur Quantifizierung der Änderung der Skelettmuskeldurchblutung nach Gefäßrevaskularisationen mit einem 99mTechnetiummarkierten Tracer

1990 ◽  
Vol 29 (05) ◽  
pp. 215-220 ◽  
Author(s):  
R. Benning ◽  
K. Nagel ◽  
M. Jugenheimer ◽  
S. Fischer ◽  
S. Worthmann ◽  
...  
Keyword(s):  
Transluminal Angioplasty ◽  
Lower Limbs ◽  
Surgical Patients ◽  
Treadmill Test ◽  
Negative Results ◽  
Clinical Observations ◽  
Before And After ◽  
Comparative Results ◽  
First Time ◽  
Percutaneous Transluminal

A new 99mTc-labelled tracer (99mTc-Sestanriibi) was used for the first time to demonstrate the perfusion of the skeletal muscle. In 16 patients with obstructive atherosclerosis of the lower limbs the change of perfusion of thigh and lower leg was studied with SPECT before and after vascular surgery (n = 11) or percutaneous transluminal angioplasty (n = 5). Comparative results of scintigraphic measurements and clinical observations (ancle-arm pressure, treadmill test) in 10 surgical patients (14 operated legs) showed correct positive or negative results in 86% (12/14).

A Sensitive and Facile Assay for the Measurement of Activated Protein C Activity Levels in Vivo

1993 ◽  
Vol 69 (05) ◽  
pp. 441-447 ◽  
Author(s):  
Carolyn L Orthner ◽  
Billy Kolen ◽  
William N Drohan
Keyword(s):  
Protein C ◽  
Plasma Concentrations ◽  
Limited Proteolysis ◽  
Activated Protein C ◽  
Microtiter Plate ◽  
Reversible Inhibitor ◽  
Activity Levels ◽  
Standard Curve ◽  
Agarose Beads

SummaryActivated protein C (APC) is a serine protease which plays an important role as a naturally occurring antithrombotic enzyme. APC, which is formed by thrombin-catalyzed limited proteolysis of the zymogen protein C, functions as an anticoagulant by proteolytic inactivation of the coagulation cofactors VIIIa and Va. APC is inhibited by several members of the serpin family as well a by α2-macroglobulin. APC is being developed as a therapeutic for the prevention and treatment of thrombosis. We have developed an assay to quantify circulating levels of enzymatically active APC during its administration to patients, in healthy individuals, and in various disease states. This assay utilizes an EDTA-dependent anti-protein C monoclonal antibody (Mab) 7D7B10 to capture both APC and protein C from plasma, prepared from blood collected in an anticoagulant supplemented with the reversible inhibitor p-aminobenzamidine. Mab 7D7B10-derivatized agarose beads are added to the wells of a 96-well filtration plate, equilibrated with Tris-buffered saline, and incubated for 10 min with 200 μl of plasma. After washing, APC and protein C are eluted from the immunosorbent beads with a calcium-containing buffer into the wells of a 96-well microtiter plate containing antithrombin III (ATIII) and heparin. The amidolytic activity of APC is then measured on a kinetic plate reader following the addition of L-pyroglutamyl-L-prolyl-L-arginine-p-nitroanilide (S-2366) substrate.The rate of substrate hydrolysis was proportional to APC concentration over a 200-fold concentration range (5.0 to 1,000 ng/ml) when measured continuously over a 15 to 30 min time period. The coefficient of variation was 5.9% at 35 ng/ml and 8.8% at 350 ng/ml APC. The sensitivity of the assay could be increased by measuring the amount of color produced after longer incubation times in the endpoint mode. The measured APC activity levels were little affected by varying protein C or prothrombin over the extremes of 0 to 150% of normal plasma concentrations. By constructing the standard curve in protein C-deficient plasma, the concentration of APC activity in normal pooled plasma was determined to be 2.8 ng/ml (45 pM), which represents 0.08% of the protein C concentration. The assay was approximately 50-fold more sensitive than the identical assay, but using Mab-coated microtiter wells rather than immunosorbent beads as the capture step.

scholarly journals Hexapod Assassins’ Potion: Venom Composition and Bioactivity from the Eurasian Assassin Bug Rhynocoris iracundus

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 819
Author(s):  
Nicolai Rügen ◽  
Timothy P. Jenkins ◽  
Natalie Wielsch ◽  
Heiko Vogel ◽  
Benjamin-Florian Hempel ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Galleria Mellonella ◽  
Systemic Reactions ◽  
Venom Composition ◽  
Assassin Bug ◽  
Molecular Components ◽  
First Time ◽  
Tissue Digestion

Assassin bug venoms are potent and exert diverse biological functions, making them potential biomedical goldmines. Besides feeding functions on arthropods, assassin bugs also use their venom for defense purposes causing localized and systemic reactions in vertebrates. However, assassin bug venoms remain poorly characterized. We collected the venom from the assassin bug Rhynocoris iracundus and investigated its composition and bioactivity in vitro and in vivo. It caused lysis of murine neuroblastoma, hepatoma cells, and healthy murine myoblasts. We demonstrated, for the first time, that assassin bug venom induces neurolysis and suggest that it counteracts paralysis locally via the destruction of neural networks, contributing to tissue digestion. Furthermore, the venom caused paralysis and melanization of Galleria mellonella larvae and pupae, whilst also possessing specific antibacterial activity against Escherichia coli, but not Listeria grayi and Pseudomonas aeruginosa. A combinatorial proteo-transcriptomic approach was performed to identify potential toxins responsible for the observed effects. We identified neurotoxic Ptu1, an inhibitory cystin knot (ICK) toxin homologous to ω-conotoxins from cone snails, cytolytic redulysins homologous to trialysins from hematophagous kissing bugs, and pore-forming hemolysins. Additionally, chitinases and kininogens were found and may be responsible for insecticidal and cytolytic activities. We demonstrate the multifunctionality and complexity of assassin bug venom, which renders its molecular components interesting for potential biomedical applications.

Carbon dots derived from Fusobacterium nucleatum for intracellular determination of Fe3+ and bioimaging both in vitro and in vivo

2021 ◽  
Author(s):  
Lijuan Liu ◽  
Shengting Zhang ◽  
Xiaodan Zheng ◽  
Hongmei Li ◽  
Qi Chen ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Fusobacterium Nucleatum ◽  
Living Cells ◽  
First Time ◽  
Fluorescent Carbon Dots ◽  
Fluorescent Carbon

Fusobacterium nucleatum has been employed for the first time to synthesize fluorescent carbon dots which could be applied for the determination of Fe3+ ions in living cells and bioimaging in vitro and in vivo with excellent biocompatibility.

scholarly journals Anti-Tumor and Anti-Inflammatory Activity In Vivo of Apodanthera congestiflora Cogn. (Cucurbitaceae)

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 743
Author(s):  
Geovana F. G. Silvestre ◽  
Renally P. Lucena ◽  
Genil D. Oliveira ◽  
Helimarcos N. Pereira ◽  
Jhonatta A. B. Dias ◽  
...  
Keyword(s):  
Inflammatory Activity ◽  
Phytochemical Investigation ◽  
Significant Toxicity ◽  
Biological Tests ◽  
Ehrlich's Carcinoma ◽  
Anti Inflammatory ◽  
Pharmacological Potential ◽  
First Time ◽  
Anti Tumor Activity

This work aimed to carry out a study of Apodanthera congestiflora by investigating its chemical composition and pharmacological potential. From the dichloromethane phase (Dic-Ac) of the A. congestiflora stems, three compounds were identified: cayaponoside C5b (Ac-1), cabenoside C (Ac-2) and fevicordin C2 glucoside (Ac-3), being last identified for the first time as a natural product. These compounds were obtained by chromatographic methods and their structures were elucidated by means of spectroscopic analysis of IR, MS and NMR. In the quantification of Dic-Ac, it was possible to observe the presence of 7% of cayaponoside C5b. Dic-Ac showed significant toxicity for in vivo tests, with macroscopic and biochemical changes. The anti-inflammatory activity of Dic-Ac was investigated using the paw edema model. A decrease in inflammatory signs was observed in the first 5 h and the most effective dose in reducing edema with was 7.5 mg kg−1 (66.6%). Anti-tumor activity of Dic-Ac was evaluated by Ehrlich’s carcinoma model, which showed inhibition rate of 78.46% at 15 mg kg−1 dosage. The phytochemical investigation, together with the biological tests carried out in this study, demonstrated that A. congestiflora is a promising species in the search for therapeutics, since it contains substances with high pharmacological potential in its composition.

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