shape memory
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349 s. : il. ; 24 cm
- MeSH
- bludy MeSH
- mozek MeSH
- paměť fyziologie MeSH
- poruchy paměti patofyziologie MeSH
- sebepojetí MeSH
- znalosti MeSH
- Publikační typ
- kongresy MeSH
- Konspekt
- Anatomie člověka a srovnávací anatomie
- NLK Obory
- neurovědy
- psychologie, klinická psychologie
Memokath stenty představují jednu z možností zajištění derivace moči horních i dolních močových cest. Autoři uvádějí celkem čtyři kazuistiky, ve kterých popisují své první zkušenosti s Memokath stenty. Jejich inzerce byla indikována ve dvou případech pro benigní hyperplazii prostaty, v jednom případě pro strikturu uretry a v jednom případě pro stenózu distálního ureteru. Přes vysoké pořizovací náklady je skupina pacientů onkologických, eventuálně interně polymorbidních s vysokým rizikem celkové anestezie, u které je endoskopické zavedení Memokath stentu elegantním řešením obstrukce močových cest.
The objective of this article is to present our first experiences with insertion and follow up of nickel-titanium shape memory alloy stents Memokath (Engineers and Doctors, Denmark) in patients with long-term obstruction of urinary tract. We inserted 4 nickel-titanium shape memory Memokath stents from May to December 2006. All patients were men (mean age 69,5 years, range 47-87 years). The stents were inserted in urethral stricture in 3 cases (2 patients for BPH, 1 patient for stricture of bulbar urethra), last Memokath stent was inserted in a patient with ureteral stricture after radiotherapy for GIT tumour. The pacients were followed up for 8 months on the average (range 2-24 months). Decompression of urinary tract have achieved in all pacients. Memokath stent had to be removed in 2 cases: 1× for encrustation (from bulbar urethra, 5 months after insertion), 1× for spontaneous migration of stent (from ureter, 2 months after insertion). There was no problem in pacients with prostate Memokath stents. 1 pacient died due to cardial decompensation 9 months after insertion prostate Memokath stent. 1 patient has had no complication with prostate Memokath stent so far (24 months). Memokath stents has not been inserted in the Czech Republic before. Series of our patients is too small to draw reliable conclusions. We will indicate the insertion of Memokath stents in selected polymorbid or oncology patients in future too.
- MeSH
- financování organizované MeSH
- hyperplazie prostaty chirurgie terapie MeSH
- lidé MeSH
- stenty využití MeSH
- striktura uretry MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
Ve spolupráci ortopedického oddělení a Technické univerzity v Ostravě byl vyvinut a vyroben nový osteofixační prvek mající podobu svorky pro užití k osteosyntéze drobných a malých kostních fragmentů. Systematické studium umožnilo vyrobit paměťovou slitinu složenou z titanu a niklu, její ověření v pokusu na zvířeti a nakonec i úspěšné použití v klinické praxi u 64 pacientů. Na základě preklinických, klinických. radiologických a histologických závěrů dokládáme, že se podařilo vyrobit osteosyntetický prvek splňující teoretické předpoklady i praktické nároky.
A new internal fixative made form a titanium-nickel (TiNi) alloy having shape memory properties has been investigated and manufactured in cooperation betwe¬ en the Municipal Hospital Ostrava-Fifejdy, Department of Orthopaedic Surgery and the TU of Ostrava, Institute of Materials Engineering. The shape memory TiNi clamps with optimized parameters were designed after systematic study and development of required substructure. Experiments with animals supported the philosophy of the TiNi memory clamps application in small bone surgery. The conclusion drawn from preclinical, clinical, radiological and histological evidence from a total of 64 patients is that our new clamps pro¬ ved to meet both contemporary theoretical demands and practical needs.
- MeSH
- chirurgické staplery MeSH
- kosti zápěstní MeSH
- kovy MeSH
- lidé MeSH
- metatarzální kosti MeSH
- ortopedie MeSH
- osteotomie metody MeSH
- Check Tag
- lidé MeSH
PURPOSE OF THE STUDY: Arthrodesis of the trapeziometacarpal joint is the method of choice in the treatment of degenerative arthritis of this joint. This procedure was indicated most frequently in middle-age patients doing hard manual labor. Methods for achieving a solid fusion of the trapeziometacarpal joint are known and often reported in the literature. Frequently, they are associated with some failure rate, particularly as concerns bone union. Our study presents a simple and effective method verified in cadaver specimens and then currently used at our department. MATERIAL AND METHODS: The procedure for arthrodesis of the trapeziometacarpal joint was verified fist in fixed wrist and hand specimens at the Institute of Anatomy, 1 st Faculty of Medicine, Charles University in Prague. If the original shape of the basal thumb joint between the trapezium and the metacarpal is maintained, it allows for correct reduction and subsequent arthrodesis in a required position. In patients, surgical treatment included the use of implants, two DePuy shape-memory staples, which facilitate sufficient fragment compression and provide stable fixation. The staples were inserted in pre-drilled and gauged tunnels in the body of the trapezium and in the proximal metaphysis of the fist metacarpal. RESULTS: Between 2011 and 2014, the procedure was used in 14 patients diagnosed with primary arthritis of the trapeziometacarpal joint. The group comprised nine women and five men, the average age was 52 years and the range was 44 to 69 years. Surgery was most frequently carried out on the dominant upper extremity (85%); there was no bilateral surgery. The average follow-up was 18.3 months (range, 5 to 39 months). Solid fusion was recorded at 7 weeks after surgery in all patients except for the one still treated at the time of this paper submission. All patients were free of pain, ten reported satisfaction with grip strength and hand function, the rest would have preferred improvement in fine motor skills of the thumb. All of them found the cosmetic appearance of the hand satisfactory.. DISCUSSION: The methods generally used for trapeziometacarpal joint arthrodesis are reported to carry some risk of pseudarthrosis development. A lot of modifications have been described, from conventional procedures using AO lag screws or Kirschner wires to up-to-date plate systems involving angle-stable fixation. Total fusion of the trapeziometacarpal joint is disputable in patients with rheumatoid arthritis from the technical point of view as well as the relevance of indication criteria. Some authors consider this procedure a contraindication for patients with rheumatoid arthritis. The use of joint replacement in treating trapeziometacarpal joint arthritis is another complex issue. CONCLUSIONS: An arthrodesis of the trapeziometacarpal joint based on careful assessment of indication criteria proved to be a simple, effective and low-cost method of stable osteosynthesis that provided good conditions for solid fusion of the trapezium with the base of the fist metacarpal. It allowed for sufficient abduction and opposition of the thumb, thus permitting satisfactory hand grip strength and full involvement in everyday life activities and occupations. It provided stability of the thumb, its painless movement and good cosmetic looks.
- MeSH
- artrodéza metody MeSH
- dospělí MeSH
- estetika MeSH
- karpometakarpální klouby chirurgie MeSH
- lidé středního věku MeSH
- lidé MeSH
- následné studie MeSH
- osteoartróza chirurgie MeSH
- senioři MeSH
- síla ruky MeSH
- spokojenost pacientů MeSH
- trapézová kost chirurgie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- anglický abstrakt MeSH
- časopisecké články MeSH
Shape memory alloys (SMA) are materials with specific electric, mechanic and thermal qualities originating in their microscopic structure and as such are used to design so-called Smart structures. In biomedicine, they are used mostly for their shape memory properties during intravasal surgery. The commonly used SMA material for biomedical purposes is Nitinol, a nickel-titanium alloy that exhibits, especially when annealed, among other properties also superelasticity and high resistivity with strain changes. This makes it suitable for usage in strain gauge sensors. In this work, NiTi annealed wires were used to create a strain gauge sensor, which exploits their unique properties. The properties of these sensors were then described using a climatic chamber, stretching device and a set of weights. Those properties were then compared to similar sensors, that are using different principles. The development, that followed, used these sensors in particular biomedical applications.
- MeSH
- automatizované zpracování dat metody přístrojové vybavení MeSH
- biomedicínské technologie MeSH
- biomedicínský výzkum MeSH
- chytré materiály analýza škodlivé účinky terapeutické užití MeSH
- elektrická impedance MeSH
- kvantitativní vztahy mezi strukturou a aktivitou MeSH
- manometrie metody přístrojové vybavení MeSH
- nikl škodlivé účinky terapeutické užití MeSH
- slitiny s tvarovou pamětí * chemie klasifikace škodlivé účinky MeSH
- titan škodlivé účinky terapeutické užití MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
Účel: Simulace vlivu úbytku neuronů a jejich propojení v různých typech neuronových sítí na jejich výkon. Metody: Na dopředně neuronové síti se zpětnou propagací byl modelován vliv úbytku synapsí na její výkon. Tato síť s lineární a nelinární přenosovou funkcí byla trénována v rozeznávání 36 reprezentací různých písmen a čísel. Odebíráním propojení mezi neurony byla neuronová síť poškozována. Byla sledována závislost počtu rozeznaných vzorů na počtu odebraných propojení. Dále byl sledován vztah mezi počtem odebraných neuronů a celkovým počtem propojení u vrstevnaté neuronové sítě s a bez horizontálních a zpětných propojení. Výsledky: Vztah mezi počtem neuronů a jejich propojení u vrstevnatých sítí s horizontálními propojeními a zpětnými vazbami je nelineární. Neuronové sítě jsou částečně odolné vůči poškození v důsledku redundantního kódování informace. Křivka zapomínání se liší také v závislosti na přítomnosti lineární a nelineární přenosové funkce. Závěr: Tato práce ukazuje, že nelineární průběh úbytku kognitivních schnopností u demence může mít několik příčin: nehnární závislost mezi počtem neuronů a jejich propojení (synapsí) u určitých síťových architektur (přítomných v lidském mozku), částečná odolnost proti destrukci díky redundantnímu kódování informace a nelineární přenosová funkce (přítomnou také v biologických neuronových sítích).
Objective: To examine how the destruction of individual neurons or interconnections of the different neural networks models reduce their performance. Methods: The feed-forward backpropagation neural network served as a model for synaptic lost and its influence on the network performance. This network with linear and non-linear transfer function has been trained to recognize 36 differen t re- presentations of the different characters and numbers. The network has been then damaged by the elimination of connections betw een selected artificial neurons. The number of recognized patterns has been then compared to the number of lost connections. Relati onship between number of neurons and connections has been studied in layered neural networks with and without back loop and horizontal connections. Results: Relationship between number of neurons and connections in layered networks with horizontal connections and feedback connections is non-linear. Neural networks have partial destruction tolerance via redundant information coding. Shape of the curve of forgetting differs depending on presence of linear or non-linear transfer function. Conclusion: This work indicates that the non-linear dependency of the deterioration of the cognitive abilities may have several reasons: non-linear relationship between number of neurons and number of connections (synapses) in certain network architectures (present in the human brain), partial destruct ion tolerance via redundant information coding and non-linear transfer function (present also in biological neural networks).
The aim of this study was to assess 17-β-estradiol (E2) influence on sciatic nerve regeneration after injury followed by a repair with chitosan conduit in ovariectomized female rats. The study was performed in 2 groups (n = 16) of rats: OVChit - after excision of a fragment of the sciatic nerve, a chitosan conduit was implanted; OVChitE10 group - additionally to chitosan conduit, shape-memory terpolymer rods based on poly(L-lactide-co-glycolide- co-trimethylene carbonate) releasing 17-β-estradiol for 20 weeks were implanted. The mean number of regenerating axons and mean fiber area were significantly greater in 17-β-estradiol-treated animals. In this group, the infiltrate of leukocytes was diminished. The presence of 17-β-estradiol receptors alpha and beta in motoneurons in the spinal cord were discovered. This may indicate the location where 17-β-estradiol affects the regeneration of the injured nerve. Estradiol released from the terpolymer rods for 20 weeks could enhance, to some extent, sciatic nerve regeneration after injury, and diminish the inflammatory reaction. In the future, 17-β-estradiol entrapped in terpolymer rods could be used in the repair of injured peripheral nerves, but there is a need for further studies.
- MeSH
- chitosan * farmakologie MeSH
- estradiol farmakologie MeSH
- krysa rodu rattus MeSH
- nervus ischiadicus chirurgie MeSH
- potkani Wistar MeSH
- receptory estradiolu MeSH
- regenerace nervu MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
