Development and Test of an Extendable Endoprosthesis for Bone Reconstruction in the Leg

1994 ◽  
Vol 17 (3) ◽  
pp. 155-162 ◽  
Author(s):  
G.J. Verkerke ◽  
H. Schraffordt Koops ◽  
R.P.H. Veth ◽  
H.J. Grootenboer ◽  
L.J. De Boer ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Growth Plate ◽  
Animal Experiments ◽  
Bone Tumour ◽  
In Vitro Tests ◽  
Bone Reconstruction ◽  
Malignant Bone Tumour

A malignant bone tumour may develop in the femur of a child. In the majority of cases it will be necessary to resect the bone involved, growth plate and adjacent tissues. A modular endoprosthetic system has been developed which can be extended non-invasively to bridge the defect resulting from such a resection. Elongation is achieved by using an external magnetic field. In vitro tests with a prototype showed that the lengthening element met all requirements. Six animal experiments showed that the lengthening element also functioned in vivo.

Design of a Lengthening Element for a Modular Femur Endoprosthetic System

1989 ◽  
Vol 203 (2) ◽  
pp. 97-102 ◽  
Author(s):  
G J Verkerke ◽  
H Schraffordt Koops ◽  
R P H Veth ◽  
J Oldhoff ◽  
H K L Nielsen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Early Stage ◽  
Animal Experiments ◽  
Malignant Tumour ◽  
The Other ◽  
University Hospital ◽  
In Vitro Tests ◽  
Adjacent Tissue ◽  
Non Invasive

A malignant tumour may develop around the knee joint of a child. In the majority of cases it will then be necessary to resect the involved bone with adjacent tissue. A joint team of Groningen University Hospital and University of Twente is currently working on the project of developing a modular endoprosthetic system to bridge the defect resulting from the resection. Since the other, normal, leg continues to grow, the endoprosthetic system will have to include an element the length of which can be adjusted non-invasively. The main conditions to be met by the lengthening element are non-invasive continuous adjustability and a maximum total lengthening of 114 mm. This was achieved by using an external magnetic field. Animal experiments showed that the lengthening element worked well, although moisture infiltrated the telescopic tubes and the lengthening element was covered by proliferating bone at an early stage. Also, the necessary magnetic field proved to be larger than calculated. In a revised design, these problems are resolved. In vitro tests show that the new lengthening element meets all requirements.

Paraquat Poisoning by Skin Absorption: A Review

1988 ◽  
Vol 7 (1) ◽  
pp. 15-19 ◽  
Author(s):  
J.G. Smith
Keyword(s):  
Human Skin ◽  
Animal Experiments ◽  
Systemic Absorption ◽  
In Vitro Tests ◽  
Skin Damage ◽  
Fatal Poisoning ◽  
Head Restraint ◽  
Paraquat Poisoning

All reported cases of paraquat poisoning by absorption through the skin are briefly reviewed. It is concluded that, while paraquat cannot be absorbed significantly through intact human skin, damage to the skin, either by paraquat itself or by other means, will permit greater systemic absorption and possibly poisoning. The lowest known concentration of paraquat to result in fatal poisoning through the skin is 5 g/l. Animal experiments with paraquat are also reviewed. The fact that the reported lethal dermal dose of paraquat in rats is slightly less than the oral dose is probably due to the lack of head restraint on the rats in the dermal dosing experiments. In vivo and in vitro tests on human skin at concentrations of 9 g/l and 5 g/l did not result in significant absorption of paraquat through the skin but in these experiments the skin was intact.

Some aspects of metal oxide nanoparticles toxicity assessment on cell cultures as exemplified by NiO and Mn3O4

2017 ◽  
pp. 35-43 ◽  
Author(s):  
I. А. Minigalieva ◽  
T. V. Bushueva ◽  
V. G. Panov ◽  
A. N. Varaksin ◽  
V. Ya. Shur ◽  
...  
Keyword(s):  
Culture Media ◽  
Cell Damage ◽  
Metal Oxide Nanoparticles ◽  
Animal Experiments ◽  
Toxicity Assessment ◽  
In Vitro Tests ◽  
Fetal Bovine ◽  
Nio Nps

Comparative and combined damaging actions of NiO and Mn3O4 anoparticles were estimated on cultures of different established human cell lines. It was found out that the addition of the fetal bovine serum (FBS) to the culture media ,used in the investigation, renders NiO-NPs and, to even a greater extent, Mn3O4-NPs exponentially soluble while without FBS their dissolution was extremely low. Along with it, sedimentation of those MeO-NPs caused by their aggregation noticeably slowed down in the presence of the same FBS. The dependence of cell damage on the MeO-NPs concentration was found out, at a higher cytotoxicity of Mn3O4-NP as compared to NiO-NP. Thus, comparative assessment of NPs non-specific toxicity previously obtained in animal experiments was reproduced in the «in vitro» tests. However, with respect to manganese-specific brain damage «in vivo» discovered previously in sub-chronic intoxication with the same MeO-NPs, the present «in vitro» experiment on neurons only showed a certain enhancing effect of Mn3O4-NP on the action of NiO-NP, but the role of NiO-NP in the combination prevailed.

scholarly journals Genetic changes and growth promotion of glioblastoma by magnetic nanoparticles and a magnetic field

Nanomedicine ◽  
2021 ◽  
Author(s):  
Seung-Hyun Yang ◽  
Byeunghoon Kang ◽  
Yuna Choi ◽  
Hyun Wook Rho ◽  
Hye Young Son ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
External Magnetic Field ◽  
Tumor Growth ◽  
Growth Promotion ◽  
Biological Effects ◽  
Mrna Levels ◽  
Glioblastoma Cells

Aim: To confirm the biological effects of manganese ferrite magnetic nanoparticles (MFMNPs) and an external magnetic field on glioblastoma cells. Methods: U-87MG glioblastoma cells were prepared, into which the uptake of MFMNPs was high. The cells were then exposed to an external magnetic field using a neodymium magnet in vitro and in vivo. Results: LRP6 and TCF7 mRNA levels involved in the Wnt/β-catenin signaling pathway were elevated by the influence of MFMNPs and the external magnetic field. MFMNPs and the external magnetic field also accelerated tumor growth by approximately 7 days and decreased survival rates in animal experiments. Conclusion: When MFMNPs and an external magnetic field are applied for a long time on glioblastoma cells, mRNA expression related to Wnt/β-catenin signaling is increased and tumor growth is promoted.

Magnetic Microparticles for Endovascular Aneurysm Treatment: In Vitro and In Vivo Experimental Results

Neurosurgery ◽  
2011 ◽  
Vol 68 (5) ◽  
pp. 1388-1398 ◽  
Author(s):  
Johanna Oechtering ◽  
Peter J. Kirkpatrick ◽  
Alexander G. K. Ludolph ◽  
Franz J. Hans ◽  
Bernd Sellhaus ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Observational Period ◽  
Magnetic Microparticles ◽  
Term Stability ◽  
Long Term Stability ◽  
Aneurysm Model

AbstractOBJECTIVE:Endovascular treatment of intracranial aneurysms employing endosaccular coiling can be associated with aneurysm perforation, coil herniation or incomplete obliteration fueling the interest to investigate novel endovascular techniques. We aimed to test a novel embolization material in experimental aneurysms in vitro and in vivo whereby intra-arterially administered magnetic microparticles (MMPs) are navigated into the lumen of vascular aneurysms with assistance from an external magnetic field.METHODS:MMPs are core-shell particles suspended in saline that have a shell made of a polymeric material and a core made of magnetite (Fe3O4). They have a diameter of 1.4 μm. During MMP administration via a microcatheter, a magnetic field was applied externally to direct the particles with the use of a solid-state neodymium magnet. Experiments were performed in a perfused silicone vessel and aneurysm model to evaluate application techniques and fluid dynamics and in the elastase aneurysm model in rabbits to evaluate in vivo compatibility, including multiorgan histological examinations and long-term stability of aneurysm embolization.RESULTS:It was possible to steer and hold the MMPs within the aneurismal cavity where they occluded the lumen progressively. After removal of the external magnetic field, the results remained stable in vivo for the remainder of the observational period (30 minutes); after a 12-week observational period, recanalization of the aneurysm occurred.CONCLUSION:MMPs can be magnetically directed into aneurysms, allowing short-term obliteration. Although the method has yet to show reliable long-term stability, these experiments provide proof of concept, encouraging further investigation of intravascular magnetic compounds.

Comparison of High Purity Factor IX Concentrates and a Prothrombin Complex Concentrate in a Canine Model of Thrombogenicity

1991 ◽  
Vol 66 (05) ◽  
pp. 609-613 ◽  
Author(s):  
I R MacGregor ◽  
J M Ferguson ◽  
L F McLaughlin ◽  
T Burnouf ◽  
C V Prowse
Keyword(s):  
High Purity ◽  
Time Course ◽  
Prothrombin Complex Concentrate ◽  
Degradation Products ◽  
Canine Model ◽  
Factor Ix ◽  
In Vitro Tests ◽  
Albumin Infusion

SummaryA non-stasis canine model of thrombogenicity has been used to evaluate batches of high purity factor IX concentrates from 4 manufacturers and a conventional prothrombin complex concentrate (PCC). Platelets, activated partial thromboplastin time (APTT), fibrinogen, fibrin(ogen) degradation products and fibrinopeptide A (FPA) were monitored before and after infusion of concentrate. Changes in FPA were found to be the most sensitive and reproducible indicator of thrombogenicity after infusion of batches of the PCC at doses of between 60 and 180 IU/kg, with a dose related delayed increase in FPA occurring. Total FPA generated after 100-120 IU/kg of 3 batches of PCC over the 3 h time course was 9-12 times that generated after albumin infusion. In contrast the amounts of FPA generated after 200 IU/kg of the 4 high purity factor IX products were in all cases similar to albumin infusion. It was noted that some batches of high purity concentrates had short NAPTTs indicating that current in vitro tests for potential thrombogenicity may be misleading in predicting the effects of these concentrates in vivo.

A Comparison of the in Vitro and in Vivo Thrombogenic Activity of Factor IX Concentrates Using Stasis (Wessler) and Non-Stasis Rabbit Models

1980 ◽  
Vol 44 (02) ◽  
pp. 081-086 ◽  
Author(s):  
C V Prowse ◽  
A E Williams
Keyword(s):  
Platelet Rich Plasma ◽  
Thrombus Formation ◽  
Factor Ix ◽  
Coagulation System ◽  
In Vitro Tests ◽  
Clinical Use ◽  
Low Activity

SummaryThe thrombogenic effects of selected factor IX concentrates were evaluated in two rabbit models; the Wessler stasis model and a novel non-stasis model. Concentrates active in either the NAPTT or TGt50 in vitro tests of potential thrombogenicity, or both, caused thrombus formation in the Wessler technique and activation of the coagulation system in the non-stasis model. A concentrate with low activity in both in vitro tests did not have thrombogenic effects in vivo, at the chosen dose. Results in the non-stasis model suggested that the thrombogenic effects of factor IX concentrates may occur by at least two mechanisms. A concentrate prepared from platelet-rich plasma and a pyrogenic concentrate were also tested and found to have no thrombogenic effect in vivo.These studies justify the use of the NAPTT and TGt50 in vitro tests for the screening of factor IX concentrates prior to clinical use.

Inhibition of Fibrinolysis and Fibrinogenolysis in Man: Comparison of ε-Aminocaproic Acid and Kallikrein Inhibitor

1963 ◽  
Vol 10 (01) ◽  
pp. 106-119 ◽  
Author(s):  
E Beck ◽  
R Schmutzler ◽  
F Duckert ◽  
Keyword(s):  
Aminocaproic Acid ◽  
Side Reactions ◽  
In Vitro Tests ◽  
Factor V ◽  
Clinical Use ◽  
Strong Inhibitor ◽  
Kallikrein Inhibitor ◽  
Therapeutic Possibilities

SummaryInhibitor of kallikrein and trypsin (KI) extracted from bovine parotis was compared with ε-aminocaproic acid (EACA): both substances inhibit fibrinolysis induced with streptokinase. EACA is a strong inhibitor of fibrinolysis in concentrations higher than 0, 1 mg per ml plasma. The same amount and higher concentrations are not able to inhibit completely the proteolytic-side reactions of fibrinolysis (fibrinogenolysis, diminution of factor V, rise of fibrin-polymerization-inhibitors). KI inhibits well proteolysis of plasma components in concentrations higher than 2,5 units per ml plasma. Much higher amounts of KI are needed to inhibit fibrinolysis as demonstrated by our in vivo and in vitro tests.Combination of the two substances for clinical use is suggested. Therapeutic possibilities are discussed.

Role of in vivo and in vitro Tests in the Diagnosis of Severe Cutaneous Adverse Reactions (SCAR) to Drug

2019 ◽  
Vol 25 (36) ◽  
pp. 3872-3880 ◽  
Author(s):  
Marcel M. Bergmann ◽  
Jean-Christoph Caubet
Keyword(s):  
Adverse Reactions ◽  
Lymphocyte Transformation ◽  
Stevens Johnson Syndrome ◽  
In Vitro Tests ◽  
High Morbidity ◽  
Patch Tests ◽  
Severe Cutaneous Adverse Reactions ◽  
Cutaneous Adverse Reactions

Severe cutaneous adverse reactions (SCAR) are life-threatening conditions including acute generalized exanthematous pustulosis (AGEP), Stevens-Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN) and drug reaction with eosinophilia and systemic symptoms (DRESS). Diagnosis of causative underlying drug hypersensitivity (DH) is mandatory due to the high morbidity and mortality upon re-exposure with the incriminated drug. If an underlying DH is suspected, in vivo test, including patch tests (PTs), delayed-reading intradermal tests (IDTs) and in vitro tests can be performed in selected patients for which the suspected culprit drug is mandatory, or in order to find a safe alternative treatment. Positivity of in vivo and in vitro tests in SCAR to drug varies depending on the type of reaction and the incriminated drugs. Due to the severe nature of these reactions, drug provocation test (DPT) is highly contraindicated in patients who experienced SCAR. Thus, sensitivity is based on positive test results in patients with a suggestive clinical history. Patch tests still remain the first-line diagnostic tests in the majority of patients with SCAR, followed, in case of negative results, by delayed-reading IDTs, with the exception of patients with bullous diseases where IDTs are still contra-indicated. In vitro tests have shown promising results in the diagnosis of SCAR to drug. Positivity is particularly high when the lymphocyte transformation test (LTT) is combined with cytokines and cytotoxic markers measurement (cyto-LTT), but this still has to be confirmed with larger studies. Due to the rarity of SCAR, large multi-center collaborative studies are needed to better study the sensitivity and specificity of in vivo and in vitro tests.

Effects of Probiotics in the Management of Infected Chronic Wounds: From Cell Culture to Human Studies

2020 ◽  
Vol 15 (3) ◽  
pp. 193-206
Author(s):  
Brognara Lorenzo ◽  
Salmaso Luca ◽  
Mazzotti Antonio ◽  
Di M. Alberto ◽  
Faldini Cesare ◽  
...  
Keyword(s):  
Chronic Wounds ◽  
Animal Experiments ◽  
Multidrug Resistant ◽  
Preliminary Evidence ◽  
Human Studies ◽  
In Vivo Studies ◽  
Resistant Bacteria ◽  
Keywords Probiotics

Background: Chronic wounds are commonly associated with polymicrobial biofilm infections. In the last years, the extensive use of antibiotics has generated several antibiotic-resistant variants. To overcome this issue, alternative natural treatments have been proposed, including the use of microorganisms like probiotics. The aim of this manuscript was to review current literature concerning the application of probiotics for the treatment of infected chronic wounds. Methods: Relevant articles were searched in the Medline database using PubMed and Scholar, using the keywords “probiotics” and “wound” and “injuries”, “probiotics” and “wound” and “ulcer”, “biofilm” and “probiotics” and “wound”, “biofilm” and “ulcer” and “probiotics”, “biofilm” and “ulcer” and “probiotics”, “probiotics” and “wound”. Results: The research initially included 253 articles. After removal of duplicate studies, and selection according to specific inclusion and exclusion criteria, 19 research articles were included and reviewed, accounting for 12 in vitro, 8 in vivo studies and 2 human studies (three articles dealing with animal experiments included also in vitro testing). Most of the published studies about the effects of probiotics for the treatment of infected chronic wounds reported a partial inhibition of microbial growth, biofilm formation and quorum sensing. Discussion: The application of probiotics represents an intriguing option in the treatment of infected chronic wounds with multidrug-resistant bacteria; however, current results are difficult to compare due to the heterogeneity in methodology, laboratory techniques, and applied clinical protocols. Lactobacillus plantarum currently represents the most studied strain, showing a positive application in burns compared to guideline treatments, and an additional mean in chronic wound infections. Conclusions: Although preliminary evidence supports the use of specific strains of probiotics in certain clinical settings such as infected chronic wounds, large, long-term clinical trials are still lacking, and further research is needed.

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