scholarly journals Is the bioactivity of induced membranes time dependent?

2021 ◽  
Author(s):  
Jan Gessmann ◽  
Thomas Rosteius ◽  
Hinnerk Baecker ◽  
Kavitha Sivalingam ◽  
Elvira Peter ◽  
...  
Keyword(s):  
Bone Grafting ◽  
Protein Microarray ◽  
Time Frame ◽  
Biologically Active ◽  
Time Dependent ◽  
Histological Structure ◽  
Cement Spacer ◽  
Time Points ◽  
Membrane Technique ◽  
Maturation Stages

Abstract Purpose The induced membrane technique (IMT) is a two-stage surgical procedure for reconstruction of bone defects. Bone grafting (second stage of IMT) is recommend after 4–8 weeks assuming the highest bioactivity of IMs. However, larger studies concerning the biology and maturation of IMs and a potential time dependency of the bioactivity are missing. Therefore, aim of this study was the time-dependent structural and cellular characterization of cement spacer IMs concomitantly to an analysis of membrane bioactivity. Methods IMs from 60 patients (35–82 years) were obtained at different maturation stages (1–16 weeks). IMs were studied by histology and co-culture with mesenchymal stem cells (MSC). IM lysates were analyzed by ELISA and protein microarray. Results Increasing vascularization and fibrosis were found in membranes older than 4 and 7 weeks, respectively. MSC grew out from all membranes and all membranes enhanced proliferation of cultured MSC. Osteocalcin and osteopontin (in membrane lysates or induced in MSC by membrane tissue) were found over all time points without significant differences. In contrast to alkaline phosphatase activity, increasing levels of osteoprotegerin were found in membranes. Conclusion The histological structure of IMs changes during growth and maturation, however, biologically active MSC and factors related to osteogenesis are found over all time points with minor changes. Thus, membranes older than 8 weeks exert regenerative capacities comparable to the younger ones. The postulated narrow time frame of 4–8 weeks until bone grafting can be questioned and surgeons may choose timing for the second operation more independently and based on other clinical factors.

scholarly journals Combined use of the Ilizarov non-free bone plasty and Masquelet technique in patients with acquired bone defects and pseudarthrosis

2020 ◽  
Vol 26 (4) ◽  
pp. 532-538
Author(s):  
D.Yu. Borzunov ◽  
◽  
D.S. Mokhovikov ◽  
S.N. Kolchin ◽  
E.N. Gorbach ◽  
...  
Keyword(s):  
Bone Grafting ◽  
Soft Tissues ◽  
Bone Defects ◽  
Bone Transport ◽  
Long Bone ◽  
Cement Spacer ◽  
Technical Problems ◽  
Induced Membrane ◽  
Masquelet Technique ◽  
Membrane Technique

Introduction The Masquelet induced membrane technique is effective in the management of acquired heterogeneous long bone defects and pseudarthrosis. The combination of the Masquelet technology and Ilizarov non-free bone grafting seems promising and reduces the risks of recurrence at long-term in patients with congenital pseudarthrosis. Purpose Presentation of new technological solutions that allow combining the advantages of the Ilizarov bone transport and Masquelet bone grafting in patients with acquired bone defects. Materials and methods Retrospective assessment of the results of bone reconstruction in 10 patients who were treated by a combination of Ilizarov and Masquelet bone grafting technologies to repair long bone defects after failures of previous treatment. Fragments of the biomembrane formed around the cement spacer temporarily replacing the tibial gap after resection bone defect or pseudarthrosis were examined in all patients. The studies were carried out using a Reichard sledge microtome, an AxioScope stereomicroscope and an AxioCam ICc 5 digital camera, a JSM- 840 scanning electron microscope and an INCA-200 Energy X-ray electron probe microanalyzer. Results and discussion The combined Masquelet technique and Ilizarov non-free bone plasty provide the conditions that are favorable for reparative processes of the transported fragments. After removal of the spacer, there is a tunnel formed in the interfragmental gap, the walls of which are made of the induced membrane. Bone transport is carried out without technical problems through the compromised tissues which are debrided at the time of distraction initiation, outside the scars. At the same time, there are low risks of inflammation around the transosseous elements; there is no danger of cutting and perforation of soft tissues by transported fragments. Conclusions Complete organotypic rearrangement of the distraction regenerate with the use of Ilizarov non-free bone plasty and the Masquelet technique excludes the possibility of deformities or fractures at the level of newly formed bone areas. Active distraction histogenesis ensures the closure of soft tissue defects without additional reconstructive plastic interventions. The revealed dependence of the induced membrane blood supply on the method of treatment previously used might be a criterion for predicting the treatment outcome in patients with acquired bone defects and pseudarthrosis.

scholarly journals Mortality Risk and The Progression of The Electronic Frailty Index and Hospital Frailty Risk Score Over Time

2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Joe Hollinghurst ◽  
Alan Watkins
Keyword(s):  
Risk Score ◽  
Frailty Index ◽  
Time Frame ◽  
Time Dependent ◽  
Cox Models ◽  
Hazard Ratios ◽  
Increased Risk ◽  
The Matrix ◽  
Time Dependent Covariates ◽  
Over Time

IntroductionThe electronic Frailty Index (eFI) and the Hospital Frailty Risk Score (HFRS) have been developed in primary and secondary care respectively. Objectives and ApproachOur objective was to investigate how frailty progresses over time, and to include the progression of frailty in a survival analysis.To do this, we performed a retrospective cohort study using linked data from the Secure Anonymised Information Linkage Databank, comprising 445,771 people aged 65-95 living in Wales (United Kingdom) on 1st January 2010. We calculated frailty, using both the eFI and HFRS, for individuals at quarterly intervals for 8 years with a total of 11,702,242 observations. ResultsWe created a transition matrix for frailty states determined by the eFI (states: fit, mild, moderate, severe) and HFRS (states: no score, low, intermediate, high), with death as an absorbing state. The matrix revealed that frailty progressed over time, but that on a quarterly basis it was most likely that an individual remained in the same state. We calculated Hazard Ratios (HRs) using time dependent Cox models for mortality, with adjustments for age, gender and deprivation. Independent eFI and HFRS models showed increased risk of mortality as frailty severity increased. A combined eFI and HFRS revealed the highest risk was primarily determined by the HFRS and revealed further subgroups of individuals at increased risk of an adverse outcome. For example, the HRs (95% Confidence Interval) for individuals with an eFI as fit, mild, moderate and severe with a high HFRS were 18.11 [17.25,19.02], 20.58 [19.93,21.24], 21.45 [20.85,22.07] and 23.04 [22.34,23.76] respectively with eFI fit and no HFRS score as the reference category. ConclusionFrailty was found to vary over time, with progression likely in the 8-year time-frame analysed. We refined HR estimates of the eFI and HFRS for mortality by including time dependent covariates.

Regulation of HSP25 expression and phosphorylation in functionally overloaded rat plantaris and soleus muscles

2006 ◽  
Vol 100 (2) ◽  
pp. 451-456 ◽  
Author(s):  
Kimberly A. Huey
Keyword(s):  
Heat Shock ◽  
Muscle Hypertrophy ◽  
Soluble Fraction ◽  
Insoluble Fraction ◽  
Cytoskeletal Proteins ◽  
Time Dependent ◽  
Time Points ◽  
Hindlimb Muscle ◽  
Muscle Loading ◽  
Muscle Remodeling

Functional overload (FO) is a powerful inducer of muscle hypertrophy and both oxidative and mechanical stress in muscle fibers. Heat shock protein 25 (HSP25) may protect against both of these stressors, and its expression can be regulated by changes in muscle loading and activation. The primary purpose of the present study was to test the hypothesis that chronic FO increases HSP25 expression and phosphorylation (pHSP25) in hypertrophying rat hindlimb muscle. HSP25 and pHSP25 levels were quantified in soluble and insoluble fractions of the soleus and plantaris to determine whether 3 or 7 days of FO increase translocation of HSP25 and/or pHSP25 to the insoluble fraction. p38 protein and phosphorylation (p-p38) was measured to determine its association with changes in pHSP25. HSP25 mRNA showed time-dependent increases in both the soleus and plantaris with FO. Three or seven days of FO increased HSP25 and pHSP25 in the soluble fraction in both muscles, with a greater response in the plantaris. In the insoluble fraction, HSP25 was increased after 3 or 7 days in both muscles, whereas pHSP25 was only increased in the 7-day plantaris. p38 and p-p38 increased in the plantaris at both time points. In the soleus, p-p38 only increased after 7 days. These results show that FO is associated with changes in HSP25 expression and phosphorylation and suggest its role in the remodeling that occurs during muscle hypertrophy. Increases in HSP25 in the insoluble fraction suggest that it may help to stabilize actin and/or other cytoskeletal proteins during the stress of muscle remodeling.

Application of the Tornado-Like Flow Theory to the Study of Blood Flow in the Heart and Main Vessels: Study of the Potential Swirling Jets Structure in an Arbitrary Viscous Medium

2019 ◽  
Author(s):  
E. Talygin ◽  
G. Kiknadze ◽  
A. Agafonov ◽  
A. Gorodkov
Keyword(s):  
Blood Flow ◽  
Velocity Field ◽  
Analytical Solution ◽  
Coordinate System ◽  
Biologically Active ◽  
Time Dependent ◽  
Characteristic Functions ◽  
Swirling Jet ◽  
Cylindrical Coordinate ◽  
Definition Of

Abstract In previous works it has been proved that the dynamic geometry of the streamlined surface of the flow channel of the heart chambers and main arteries corresponds with a good agreement to the shape of the swirling flow streamlines. The vectorial velocity field of such a flow in a cylindrical coordinate system was described by means of specific analytical solution basing on the potentiality of the longitudinal and radial velocity components. The viscosity of the medium was taken into account only in the expression for the azimuthal velocity component and the significant effect of viscosity was manifested only in a narrow axial region of a swirling jet. The flow described by the above relations is quasipotential, axisymmetric, and convergent. The structural organization of this flow implies the elimination of rupture and stagnation zones, and minimizes the viscous losses. The proximity of the real blood flow under the normal conditions to the specified class of swirling flows allows us to determine the basic properties of the blood flow possessing the high pressure-flow characteristics without stability loss. The blood flow has an external border, and the interaction with the channel wall and between moving fluid elements is weak. These properties of the jet explain the possibility of a balanced blood flow in biologically active boundaries. Violation of the jet properties can lead to the excitation of biologically active components and trigger the corresponding cascade protective and compensatory processes. The evolution of the flow is determined by the time-dependent characteristic functions, which are the frequency characteristics of the rotating jet, as well as functions depending on the dimension of the swirling jet. Previous experimental studies revealed close connection between changes in the characteristic functions and dynamics of the cardiac cycle. Therefore, it is natural to express these functions in analytical form. For these purposes it was necessary to establish the link between these functions and the spatial characteristics of the swirling jet. To solve this problem the analytical solution for the velocity field of a swirling jet was substituted into the Navier-Stokes system and continuity differential equations in a cylindrical coordinate system. As a result, a new system of differential equations was obtained where the characteristic functions could be derived. The solution of these equations allows the identification of time-dependent characteristic functions, and the establishment of a link between the characteristic functions and the spatial coordinates of the swirling jet. This link gives the opportunity to substantiate a theoretical possibility for the modeling of quasipotential viscous flows with a given structure. The definition of characteristic functions makes it possible to obtain the exact solution which allows formalization of the boundary conditions for physical modeling and experimental study of this flow type. Such transformations allow the definition of the conditions supporting renewable swirling blood flow in the transport arterial segment of the circulatory system and provide the basis for new principles of modeling, diagnosis and surgical treatment of circulatory disorders associated with the changes in geometry of the heart and great vessels.

scholarly journals Evaluation of Door To Needle Time For Fibrinolytic Therapy of ST Elevation Myocardial Infarction (STEMI) Management In Emergency And Traumatology Department (ETD), Hospital Sultan Haji Ahmad Shah (HOSHAS), Temerloh, Pahang. Malaysia.

2017 ◽  
Vol 16 (3) ◽  
pp. 407-412
Author(s):  
Wadiah Mustafar ◽  
Sazwan Reezal Shamsuddin ◽  
Amelia Amir
Keyword(s):  
Myocardial Infarction ◽  
Medical Science ◽  
Time Frame ◽  
Cross Sectional Study ◽  
Fibrinolytic Therapy ◽  
Time Dependent ◽  
Sectional Study ◽  
Cross Sectional ◽  
Good Outcome ◽  
St Elevation

Introduction: Acute myocardial infarction is known with high mortality. The benefits of fibrinolytic administration in STEMI are time dependent. The purpose of this study is to evaluate the door-to-needle time for fibrinolytic therapy in STEMI patients.Methods: A cross sectional study of all patients who had STEMI was carried out to evaluate the management of STEMI. The duration from door-to-ECG time, door-to-needle time and the factors that contribute to the time frame in receiving treatment was reviewed. The outcomes and complications from fibrinolytic therapy were documented as well. The outcomes of the delayed in administering the treatment were also analyzed in the study.Result: Out of 19 patients received fibrinolytics within 30 minutes, 16 patients (84.2%) had good outcome. In 17 patients received fibrinolytics between 30 minutes to 1 hour, 6 patients (35.2%) had good outcome. In 15 patients received fibrinolytics more than 1 hour, 8 patients (53.3%) had good outcome.Conclusion: This study showed that a shorter door-to-needle time results in better outcome.Bangladesh Journal of Medical Science Vol.16(3) 2017 p.407-412

scholarly journals Assessment of the time-dependent dermatotoxicity of mechlorethamine using the mouse ear vesicant model

2018 ◽  
Vol 11 (4) ◽  
pp. 255-266
Author(s):  
Benedette J. Cuffari ◽  
Hemanta C Rao Tumu ◽  
Maria A. Pino ◽  
Blase Billack
Keyword(s):  
Inflammatory Cell ◽  
Sulfur Mustard ◽  
Skin Inflammation ◽  
Operational Definition ◽  
Inflammatory Cell Infiltration ◽  
Time Dependent ◽  
Cell Infiltration ◽  
Time Points ◽  
Holistic Understanding ◽  
Mouse Ear

Abstract Mechlorethamine (HN2) is an alkylating agent and sulfur mustard gas mimetic which is also used in anticancer therapy. HN2 is associated with skin inflammation and blistering which can lead to secondary infections. The purpose of the present study was to investigate the time-dependent dermatotoxicity of HN2 using the mouse ear vesicant model (MEVM). To this end, our operational definition of dermatotoxicity included tissue responses to HN2 consistent with an increase in the wet weights of mouse ear punch biopsies, an increase in the morphometric thickness of H&E stained ear sections and histopathologic observations including tissue edema, inflammatory cell infiltration and vesication. The ears of male Swiss Webster mice were topically exposed to a single dose of HN2 (0.5 µmol/ear) or DMSO vehicle (5 µl/ear) or left untreated (naive). Mice were then euthanized at 15 min, 1, 2, 4, 8 or 24 hr following HN2 exposure. Compared to control ears, mouse ears exposed to HN2 at all time points showed an increase in wet weights, morphometric thickness, edema, inflammatory cell infiltration and signs of vesication. The incidence in tissue vesication sharply increased between 4 and 8 hr after exposure, revealing that tissue vesication is well established by 8 hr and remains elevated at 24 hr after exposure. It is noteworthy that, compared to control ears, mouse ears treated with DMSO vehicle alone also exhibited an increase in wet weights and morphometric thickness at 15 min, 1, 2 and 4 hr following treatment; however, these vehicle effects begin to subside after 4 hr. The results obtained here using the MEVM provide a more holistic understanding of the kinetics of vesication, and indicate that time points earlier than 24 hr may prove useful not only for investigating the complex mechanisms involved in vesication but also for assessing the effects of vesicant countermeasures.

scholarly journals Presentation of Coupling Analysis Techniques of Maximum and Minimum Values Between N Sets of Data Using Matrix [µ][MKN]

2021 ◽  
Vol 6 (4) ◽  
pp. 1127-1136
Author(s):  
K. N. Makris ◽  
I. Vonta
Keyword(s):  
Time Series ◽  
Indirect Method ◽  
Direct Method ◽  
Time Dependent ◽  
Data Sets ◽  
Data Display ◽  
Coupling Analysis ◽  
Time Points ◽  
Analysis Techniques ◽  
Coupling Techniques

This paper deals with the presentation and study of alternative coupling techniques for maximum and minimum values between data sets, namely the problem which is examined in this work is the possible appearance of maximum or minimum values between data sets in the same or neighboring time points. The data can be time-dependent (time series) or non-time-dependent. In this work, the analysis is focused on time series and novel indices are defined in order to measure whether the values of N sets of data display in terms of time, the maximum or minimum values at the same instances or at very close instances. For this purpose, two methods will be compared, one direct method and one indirect method. The indirect method is based on Matrices of dimensionless indicators which are denoted by [μ][MKN], and the direct method is based on a variance-type measure which is denoted by [V][MKN].

scholarly journals Size- and Time-Dependent Aerosol Removal from a Protective Box during Simulated Intubation and Extubation Procedures

COVID ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 315-324
Author(s):  
Luka Pirker ◽  
Metod Čebašek ◽  
Matej Serdinšek ◽  
Maja Remškar
Keyword(s):  
Particle Size ◽  
Particle Concentration ◽  
Time Frame ◽  
Time Dependent ◽  
Medical Professionals ◽  
Particle Sizes ◽  
Background Levels ◽  
Aerosol Generator ◽  
Plastic Bag ◽  
Measured Particle

Because the SARS-CoV-2 virus primarily spreads through droplets and aerosols, a protective box could provide adequate protection by shielding medical professionals during the intubation and extubation procedures from generated droplets and aerosols. In this study, size- and time-dependent aerosol concentrations were measured inside and outside the protective box in the particle size ranging from 14 nm to 20 μm during simulated intubation and extubation procedures. An improved protective box with active ventilation was designed based on a plastic bag with armholes covered with latex sheets that utilizes a supportive frame. Coughing during the intubation and extubation procedure was simulated using an aerosol generator which dispersed the aerosol powder into the protective box. During the intubation and extubation procedure, the concentration of particles increased inside the protective box but, due to the high negative airflow, quickly dropped to background levels. The particle concentration of all measured particle sizes decreased within the same time frame. No leakage of particles was observed through the armhole openings. The presented protective box design provides excellent protection against generated droplets and aerosols. The decrease in concentration does not depend on the particle size. Outside the box, particle concentration did not change with time.

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