Comparison of a histology based multi layer artery model to its simplified axisymmetric model.

2021 ◽  
Vol 7 (2) ◽  
pp. 590-593
Author(s):  
Ashish Bhave ◽  
Knut Möller
Keyword(s):  
Arterial Wall ◽  
Circumferential Strain ◽  
Outer Wall ◽  
Biomechanical Properties ◽  
The Body ◽  
The Novel ◽  
Vital Function ◽  
Axisymmetric Model ◽  
Different Parts

Abstract Arteries are vessel structures that serve vital function of transportation of blood to different parts of the body. Researchers have experimented with some approaches to model the arterial behaviour and to analyse its biomechanical properties. To analyse the in-vivo arterial properties, at Furtwangen University an inflatable sensoractuator system is being developed, which provides the basis for a decision support system for vascular surgeons. The capabilities of this sensor shall be evaluated in simulations which requires appropriate modelling of the arteries. The inverse problem, i.e. how to efficiently identify arterial wall properties from sensor readings is targeted. A histology motivated 3D artery model was implemented in FEM using COMSOL (v5.5). The geometry of one model was based on a cross section of a real artery. The second model was axisymmetric and of equal dimensions with respect to volume, layer thickness etc. A biomechanical pressure-stretch analysis was performed applying an inflating pressure inside the walls of the vessels. Stretch in different areas of the first model was evaluated and the circumferential strain was compared to the axisymmetric model. The results show variation of strains within the segments of the first model of upto 10 percent. In addition, its outer wall circumferential stretch was found to be 10 percent lower compared to the axisymmetric setup. This comparison sheds light upon whether a simplification of arterial models is possible, without loss of accuracy in the context of the novel sensor evaluation. It provides useful information whether e.g. standardizing vessel structures to axisymmetric models will still provide results within allowable tolerance limits. Simulations proved useful to evaluate different vessel model formulations in the context of arterial diagnostics.

P2790Novel endomyocardial micro-biopsy device for higher precision and reduced complication risks

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
A Chireh ◽  
R Grankvist ◽  
M Sandell ◽  
A K Mukarram ◽  
N Jaff ◽  
...  
Keyword(s):  
Endomyocardial Biopsy ◽  
Diagnostic Yield ◽  
Molecular Data ◽  
Outer Diameter ◽  
The Novel ◽  
Rna Seq ◽  
Device Design ◽  
Biopsy Device ◽  
Different Parts

Abstract Introduction Endomyocardial biopsy (EMB) is the gold standard for diagnosis of several cardiac diseases, yet its use is limited by low diagnostic yield and significant complication risks. The size of the current devices allows only limited steering to different parts of the ventricle walls. In transplant monitoring, repeated biopsies with the current devices can cause scarring that makes it increasingly difficult to obtain adequate samples. We hypothesised that several of the shortcomings of EMB can be avoided with a smaller and more steerable device. Further, we hypothesised that the novel sampling procedure could be coupled to a low-input molecular analysis method, such as RNA-sequencing (RNA-seq), to provide molecular characterisation of the tissue without the need of large biopsy samples. Purpose To develop an EMB device with significantly smaller dimensions, for future use in diagnostics and research investigations. Specific aims were to test feasibility and safety of the procedure, as well as the quality of the generated molecular data. Methods 65 “micro biopsy” (micro-EMB) device prototypes were designed and evaluated in-house. The prototypes were evaluated either in an ex-vivo simulator or in acute non-survival pig experiments (n=23). Once the final device design was reached, an in vivo trial was set up using six naive Yorkshire farm pigs. Micro-EMB, conventional EMB, skeletal muscle and blood samples were collected for RNA-seq characterisation and comparison. In half of the animals (n=3), micro-EMB was the only intervention in order to prioritise safety evaluations. The animals were monitored for one week. Results The final device design has an outer diameter (OD) of 0.4 mm, compared to a conventional 11 mm device (in the opened position), Fig 1A. The device can be directed to different parts of the myocardium in both ventricles. In the in vivo evaluation in swine, 81% of the biopsy attempts (n=157) were successful. High quality RNA-seq data was generated from 91% of the sequenced heart micro-biopsy samples (n=32). The gene expression signatures of samples taken with the novel device were comparable with samples taken with a conventional device, Fig 1B. No major complications were detected either during periprocedural monitoring or during the follow-up. The tissue mark after micro-biopsy was markedly smaller than after conventional endomyocardial biopsy. A) Bioptome dimensions. B) RNA-seq data. Conclusions Our preliminary data suggest that the novel submillimeter biopsy device, coupled with RNA-seq, provides a feasible method to obtain molecular data from the myocardium. The method is less traumatic and has a higher flexibility compared to conventional methods, enabling safer and more specific sampling from different parts of the myocardium. In the long term, the procedure could open unprecedented diagnostic and research possibilities. Future studies should be directed to establish the capabilities of the novel method in a relevant disease model. Acknowledgement/Funding Family Erling Persson Foundation. The Söderberg foundations. KID (Karolinska Institutet). The 4D project. Stockholm county council. Astra Zeneca.

scholarly journals Bioactivity of vitamin E

2006 ◽  
Vol 19 (2) ◽  
pp. 174-186 ◽  
Author(s):  
Regina Brigelius-Flohé
Keyword(s):  
Vitamin E ◽  
Molecular Basis ◽  
Antioxidant Properties ◽  
The Body ◽  
The Novel ◽  
Transfer Protein ◽  
Almost All ◽  
Selection Of

More than 80 years after the discovery of the essentiality of vitamin E for mammals, the molecular basis of its action is still an enigma. From the eight different forms of vitamin E, only α-tocopherol is retained in the body. This is in part due to the specific selection of RRR-α-tocopherol by the α-tocopherol transfer protein and in part by its low rate of degradation and elimination compared with the other vitamers. Since the tocopherols have comparable antioxidant properties and some tocotrienols are even more effective in scavenging radicals, the antioxidant capacity cannot be the explanation for its essentiality, at least not the only one. In the last decade, a high number of so-called novel functions of almost all forms of vitamin E have been described, including regulation of cellular signalling and gene expression. α-Tocopherol appears to be most involved in gene regulation, whereas γ-tocopherol appears to be highly effective in preventing cancer-related processes. Tocotrienols appear to be effective in amelioration of neurodegeneration. Most of the novel functions of individual forms of vitamin E have been demonstrated in vitro only and require in vivo confirmation. The distinct bioactivities of the various vitamers are discussed, considering their metabolism and the potential functions of metabolites.

Design and Performance Testing of a Novel In-Vivo Laparoscope Lens Cleaning Device

2021 ◽  
Author(s):  
Chris Idelson ◽  
John Uecker ◽  
James Garcia ◽  
Sunjna Kohli ◽  
Greta Handing ◽  
...  
Keyword(s):  
Mechanical Testing ◽  
Gold Standard ◽  
Performance Testing ◽  
The Body ◽  
The Novel ◽  
Surgical Safety ◽  
Bodily Fluids ◽  
Cleaning Device ◽  
And Performance

Abstract A common tool for diagnosis and treatment of gastrointestinal, gynecologic, and other anatomical pathologies is a form of minimally invasive surgery known as laparoscopy. Roughly 4 million laparoscopic surgeries are performed in the US every year, with an estimated 15 million globally. During surgeries, lens clarity often becomes impaired via (1) condensation or (2) smearing of bodily fluids and tissues. The current gold standard solution requires scope removal from the body for cleaning, offering opportunity for decreased surgical safety and efficiency, while simultaneously generating mounting frustration for the operating room team. A novel lens cleaning device was designed and developed to clean a laparoscope lens in-vivo during surgery. Benchtop experiments in a warm body simulated environment allowed quantification of lens cleaning efficacy for several lens contaminants. Image analysis techniques detected differences between original (clean), post-debris, and post-cleaning images. Mechanical testing was also executed to determine safety levels regarding potential misuse scenarios. Compared to gold standard device technologies, the novel lens cleaning device prototype showed strong performance and ability to clear a laparoscope lens of debris while mitigating the need for scope removal from the simulated surgical cavity. Mechanical testing results also suggests the design also holds inherently strong safety performance. Both objective metrics and subjective observation suggests the novel design holds promise to improve safety and efficiency during laparoscopic surgery.

Sensory and biomechanical responses to ramp-controlled distension of the human duodenum

2003 ◽  
Vol 284 (3) ◽  
pp. G461-G471 ◽  
Author(s):  
Chunwen Gao ◽  
Lars Arendt-Nielsen ◽  
Weiming Liu ◽  
Poul Petersen ◽  
Asbjørn Mohr Drewes ◽  
...  
Keyword(s):  
Circumferential Strain ◽  
Biomechanical Properties ◽  
Mechanical Stimulus ◽  
High Threshold ◽  
Visceral Perception ◽  
Stimulus Response ◽  
Balloon Distension ◽  
Biomechanical Responses ◽  
The Relationship

The aim of this study was to develop a new method for investigation of the relationship among the mechanical stimulus, the biomechanical properties, and the visceral perception evoked by volume/ramp-controlled distension in the human duodenum in vivo. An impedance planimetric probe for balloon distension was placed in the third part of the duodenum in seven healthy volunteers. Distension of the duodenum was done at infusion rates of 10, 25, and 50 ml/min. The pump was reversed when level 7 was reached on a visual analog scale ranging from 0 to 10. Distensions were done with and without the administration of the antimuscarinic drug butylscopolamine. The total circumferential tension (Ttotal) and the passive circumferential tension (Tpassive) were determined from the distension tests without and with the administration of butylscopolamine, respectively. Ttotal and Tpassive showed an exponential behavior as a function of strain (a measure of deformation). The active circumferential tension (Tactive) was computed as Ttotal−Tpassive and showed a bell-shaped behavior as a function of strain. At low distension intensities, the intensity of sensation at 10 ml/min was significantly higher than that obtained at 25 and 50 ml/min. The coefficient of variation at the pain threshold for circumferential strain (average 4.34) was closer to zero compared with those for volume (8.72), pressure (31.22), and circumferential tension (31.55). This suggests that the mechanoreceptors in the gastrointestinal wall depend primarily on circumferential strain. The stimulus-response functions provided evidence for the existence of low- and high-threshold mechanoreceptors in the human duodenum. Furthermore, the data suggest that high-threshold receptors are nonadapting.

Arterial wall oxygen consumption rate varies spatially

1982 ◽  
Vol 243 (6) ◽  
pp. H948-H958 ◽  
Author(s):  
D. G. Buerk ◽  
T. K. Goldstick
Keyword(s):  
Arterial Wall ◽  
Consumption Rate ◽  
Solubility Product ◽  
Transport Model ◽  
Outer Wall ◽  
Vasa Vasorum ◽  
Aortic Tissue ◽  
O2 Supply

The ratio of the O2 consumption rate (Q) to the O2 transmissibility (diffusivity-solubility product, Dk) was estimated by curve-fitting O2 tension profiles measured in vascular strips in vitro and in blood vessels in vivo. For rabbit aortic tissue in vitro, Q/Dk was 2.51 +/- 0.28 (SE) X 10(5) Torr/cm2 (n = 9). For various dog vessels in vivo, Q/Dk ranged from 0.15 to 47 X 10(5) Torr/cm2. In most cases, Q/Dk was higher near the endothelium than in the outer wall. This difference appears to be caused by a higher Q. Computer simulations using a two-layer O2 transport model with estimated Q/Dk indicate that the O2 supply from the vasa vasorum is essential to prevent medial wall hypoxia.

Recent Advancements and Patents on Buccal Drug Delivery Systems: A Comprehensive Review

2021 ◽  
Vol 15 ◽  
Author(s):  
Nimisha Srivastava ◽  
Sahifa Aslam
Keyword(s):  
Drug Delivery ◽  
Dosage Form ◽  
Electrospun Nanofibers ◽  
Dosage Forms ◽  
The Body ◽  
The Novel ◽  
Drug Degradation ◽  
Methods Of Evaluation ◽  
Buccal Drug Delivery

: The major requirement for a dosage form to be successful is its ability to penetrate the site of application and the bioavailability of the drug released from the dosage form. The buccal drug delivery is an influential route to deliver the drug into the body. Here in this context, various novel approaches that include lipoidal carriers like ethosomes, transferosomes, niosomes, etc. and electrospun nanofibers are discussed with respect to buccal drug delivery. These carriers can be easily incorporated into buccal dosage forms like patches and gels which are responsible for increased permeation across the buccal epithelium. The in vivo methods of evaluation on animal models are conscribed here. The novel biocarriers of lipoidal and non-lipoidal nature can be utilised by loading the drug into them, which are helpful in preventing drug degradation and other drawbacks as compared to conventional formulations. The globally patented buccal formulations give us a wide context in literature about the patents filed and granted in recent years. When it comes to patient compliance, age is an issue, which is also solved by the buccal route. The paediatric buccal formulations are researched for the customisation to be delivered to children. Diseases like mouth ulcers, oral cancer, Parkinson’s disease, aphthous stomatitis, etc. have been successfully treated through the buccal route, which infers that the buccal drug delivery system is an effective and emerging area for formulation and development in the field of Pharmaceutics.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

Uptake, Internalization and Degradation of the Novel Plasminogen Activator Reteplase (BM 06.022) in the Rat

1995 ◽  
Vol 74 (06) ◽  
pp. 1501-1510 ◽  
Author(s):  
J Kuiper ◽  
H van de Bilt ◽  
U Martin ◽  
Th J C van Berkel
Keyword(s):  
Plasminogen Activator ◽  
Liver Cells ◽  
The Novel ◽  
Uptake Mechanism ◽  
Liver Uptake ◽  
Lysosomal Compartment ◽  
Β Phase ◽  
Α Phase ◽  
Parenchymal Liver

SummaryThe catabolism of the novel plasminogen activator reteplase (BM 06.022) was described. For this purpose BM 06.022 was radiolabelled with l25I or with the accumulating label l25I-tyramine cellobiose (l25I-TC).BM 06.022 was injected at a pharmacological dose of 380 μg/kg b.w. and it was cleared from the plasma in a biphasic manner with a half-life of about 1 min in the α-phase and t1/2of 20-28 min in the β-phase. 28% and 72% of the injected dose was cleared in the α-phase and β-phase, respectively. Initially liver, kidneys, skin, bones, lungs, spleen, and muscles contributed mainly to the plasma clearance. Only liver and the kidneys, however, were responsible for the uptake and subsequent degradation of BM 06.022 and contributed for 75% to the catabolism of BM 06.022. BM 06.022 was degraded in the lysosomal compartment of both organs. Parenchymal liver cells were responsible for 70% of the liver uptake of BM 06.022. BM 06.022 associated rapidly to isolated rat parenchymal liver cells and was subsequently degraded in the lysosomal compartment of these cells. BM 06.022 bound with low-affinity to the parenchymal liver cells (550 nM) and the binding of BM 06.022 could be displaced by t-PA (IC50 5.6 nM), indicating that the low-density lipoprotein receptor-related protein (LRP) could be involved in the binding of BM 06.022. GST-RAP, which is an inhibitor of LRP, could in vivo significantly inhibit the uptake of BM 06.022 in the liver.It is concluded that BM 06.022 is metabolized primarily in the liver and the kidneys. These organs take up and degrade BM 06.022 in the lysosomes. The uptake mechanism of BM 06.022 in the kidneys is unknown, while LRP is responsible for a low-affinity binding and uptake of BM 06.022 in parenchymal liver cells.

The influence of osteopathic correction on the rate of various rhythms of the body

2019 ◽  
pp. 64-71 ◽  
Author(s):  
A. E. Chernikova ◽  
Yu. P. Potekhina
Keyword(s):  
Heart Rate ◽  
Respiratory Rate ◽  
Age Groups ◽  
Biomechanical Properties ◽  
Dispersion Analysis ◽  
The Body ◽  
Body Tissues ◽  
Age Related ◽  
Significant Difference ◽  
Before And After

Introduction. An osteopathic examination determines the rate, the amplitude and the strength of the main rhythms (cardiac, respiratory and cranial). However, there are relatively few studies in the available literature dedicated to the influence of osteopathic correction (OC) on the characteristics of these rhythms.Goal of research — to study the influence of OC on the rate characteristics of various rhythms of the human body.Materials and methods. 88 adult osteopathic patients aged from 18 to 81 years were examined, among them 30 men and 58 women. All patients received general osteopathic examination. The rate of the cranial rhythm (RCR), respiratory rate (RR) heart rate (HR), the mobility of the nervous processes (MNP) and the connective tissue mobility (CTM) were assessed before and after the OC session.Results. Since age varied greatly in the examined group, a correlation analysis of age-related changes of the assessed rhythms was carried out. Only the CTM correlated with age (r=–0,28; p<0,05) in a statistically significant way. The rank dispersion analysis of Kruskal–Wallis also showed statistically significant difference in this indicator in different age groups (p=0,043). With the increase of years, the CTM decreases gradually. After the OC, the CTM, increased in a statistically significant way (p<0,0001). The RCR varied from 5 to 12 cycles/min in the examined group, which corresponded to the norm. After the OC, the RCR has increased in a statistically significant way (p<0,0001), the MNP has also increased (p<0,0001). The initial heart rate in the subjects varied from 56 to 94 beats/min, and in 15 % it exceeded the norm. After the OC the heart rate corresponded to the norm in all patients. The heart rate and the respiratory rate significantly decreased after the OC (р<0,0001).Conclusion. The described biorhythm changes after the OC session may be indicative of the improvement of the nervous regulation, of the normalization of the autonomic balance, of the improvement of the biomechanical properties of body tissues and of the increase of their mobility. The assessed parameters can be measured quickly without any additional equipment and can be used in order to study the results of the OC.

Diaghilev and British Writing

2009 ◽  
Vol 27 (1) ◽  
pp. 65-92
Author(s):  
Susan Jones
Keyword(s):  
Visual Arts ◽  
The Body ◽  
The Novel ◽  
Literary Responses ◽  
Literary Aesthetics ◽  
Ballets Russes ◽  
The Arts ◽  
The Subject ◽  
And Gender ◽  
Opening Up

This article explores the diversity of British literary responses to Diaghilev's project, emphasising the way in which the subject matter and methodologies of Diaghilev's modernism were sometimes unexpectedly echoed in expressions of contemporary British writing. These discussions emerge both in writing about Diaghilev's work, and, more discretely, when references to the Russian Ballet find their way into the creative writing of the period, serving to anchor the texts in a particular cultural milieu or to suggest contemporary aesthetic problems in the domain of literary aesthetics developing in the period. Figures from disparate fields, including literature, music and the visual arts, brought to their criticism of the Ballets Russes their individual perspectives on its aesthetics, helping to consolidate the sense of its importance in contributing to the inter-disciplinary flavour of modernism across the arts. In the field of literature, not only did British writers evaluate the Ballets Russes in terms of their own poetics, their relationship to experimentation in the novel and in drama, they developed an increasing sense of the company's place in dance history, its choreographic innovations offering material for wider discussions, opening up the potential for literary modernism's interest in impersonality and in the ‘unsayable’, discussions of the body, primitivism and gender.

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