The research of novel implantable medical devices is one of the most attractive, yet complex areas in the biomedical field. The design and development of sufficiently small devices working in an in vivo environment is challenging but successful encapsulation of such devices is even more so. Industry-standard methods using glass and titanium are too expensive and tedious, and epoxy or silicone encapsulation is prone to water ingress with cable feedthroughs being the most frequent point of failure. This paper describes a universal and straightforward method for reliable encapsulation of circuit boards that achieves ISO10993 compliance. A two-part PVDF mold was machined using a conventional 3-axis machining center. Then, the circuit board with a hermetic feedthrough was placed in the mold and epoxy resin was injected into the mold under pressure to fill the cavity. Finally, the biocompatibility was further enhanced with an inert P3HT polymer coating which can be easily formulated into an ink. The biocompatibility of the encapsulants was assessed according to ISO10993. The endurance of the presented solution compared to silicone potting and epoxy potting was assessed by submersion in phosphate-buffered saline solution at 37 °C. The proposed method showed superior results to PDMS and simple epoxy potting.
Thermal ablation is a well-known method used in interventional radiology to treat cancer. The treatment success is closely related to the exact catheter location in the treated area. Current navigation methods are based mostly on ultrasound or computed tomography. This work explores the possibility of tracking the catheter position during ablation treatment of hepatocellular carcinomas (HCC) using an ultra-wideband (UWB) antenna array and microwave radar imaging based on the "Delay and Sum" (DAS) algorithm. The feasibility was first numerically studied on a simple homogeneous liver model. A heterogeneous anthropomorphic 3D model of the treated region consisting of the main organs within the treated area was then used. Various standard radiofrequency ablation (RFA) catheters were placed virtually in the heterogeneous model. The location and orientation of the antenna elements of the developed imaging system and the applied frequency band were studied. Subsequently, an experimental setup consisting of a 3D printed homogeneous anthropomorphic model, eight UWB dipole antennas, and catheters was created and used in a series of measurements. The average accuracy determining the catheter position from simulated and experimental data was 3.88 ± 0.19 and 6.13 ± 0.66 mm, which are close to the accuracy of clinical navigation systems.
- Publikační typ
- časopisecké články MeSH
Radiofrequency ablation (RFA) is a routinely used, safe, and effective method for the tissue destruction. Often, in case of its application in malignant conditions, the extent of tissue destruction is insufficient due to the size of the target lesion, as well as due to the risk of heat-induced damage to the surrounding organs. Nevertheless, there are conditions requiring superficial precise-depth ablation with preservation of deeper layers. These are represented, for example, by mucosal resurfacing in case of Barrett's esophagus or treatment of recurrent mucosal bleeding in case of chronic radiation proctitis. Recently, new indications for intraluminal RFA use emerged, especially in the pancreatobiliary tract. In the case of intraductal use of RFA (e.g., biliary and pancreatic tract), there are currently available rigid and needle tip catheters. An expandable balloon-based RFA catheter suitable for use in such small-diameter tubular organs could be of benefit due to possible increase of contact between the probe and the target tissue; however, to prevent excessive tissue damage, a compatible generator suitable for low-impedance catheter/tissue is essential. This project aimed to develop a radiofrequency ablation generator and bipolar balloon-based catheter optimized for the application in the conditions of low-impedance tissue and (micro)endoluminal environment. Subsequent evaluation of biological effect in vivo was performed using duodenal mucosa in Wistar rat representing conditions of endoluminal radiofrequency ablation of low-impedance tissue. Experiments confirming the safety and feasibility of RFA with our prototype devices were conducted.
Gastric dysmotility can be a sign of common diseases such as longstanding diabetes mellitus. It is known that the application of high-frequency low-energetic stimulation can help to effectively moderate and alleviate the symptoms of gastric dysmotility. The goal of the research was the development of a miniature, endoscopically implantable device to a submucosal pocket. The implantable device is a fully customized electronic package which was specifically designed for the purpose of experiments in the submucosa. The device is equipped with a lithium-ion battery which can be recharged wirelessly by receiving an incident magnetic field from the charging/transmitting coil. The uplink communication is achieved in a MedRadio band at 432 MHz. The device was endoscopically inserted into the submucosal pocket of a live domestic pig used as an in vivo model, specifically in the stomach antrum. The experiment confirmed that the designed device can be implanted into the submucosa and is capable of bidirectional communication. The device can perform bipolar stimulation of muscle tissue.
- MeSH
- bezdrátová technologie MeSH
- design vybavení * MeSH
- elektrostimulační terapie přístrojové vybavení MeSH
- gastrointestinální endoskopie metody MeSH
- gastroparéza terapie MeSH
- implantabilní neurostimulátory * MeSH
- prasata MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- audiovizuální média MeSH
- časopisecké články MeSH
- práce podpořená grantem MeSH
The purpose of this study was to assess the convergent and discriminative validity of the Montreal Cognitive Assessment (MoCA) as a screening tool for cognitive dysfunction in Huntington's disease (HD). Twenty HD patients with cognitive deficit and 23 normal controls (NC) without cognitive deficit were matched for age, sex, and education. The mean MoCA score was 20.5 (SD = 5.5) in HD and 27.5 (SD = 2.2) in NC. The MoCA correlated in both samples with the brief cognitive battery composite score (r = .81, p < .001). With the screening and diagnostic cutoff scores determined at <26 points, the MoCA showed a sensitivity of 94% and a specificity of 84% in the detection of cognitive dysfunction in HD. The area under the receiver-operating characteristics curve (95% confidence interval) for the MoCA was 0.90 (0.809-0.997), p < .001. Our results show that the MoCA is a suitable tool for assessing cognitive dysfunction in patients with HD.
- MeSH
- afektivní symptomy diagnóza etiologie MeSH
- dospělí MeSH
- Huntingtonova nemoc komplikace MeSH
- kognitivní poruchy diagnóza etiologie psychologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- neparametrická statistika MeSH
- neuropsychologické testy * MeSH
- pohybová aktivita MeSH
- psychometrie MeSH
- reprodukovatelnost výsledků MeSH
- ROC křivka MeSH
- senioři MeSH
- záznam o duševním stavu MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
OBJECTIVES: Adiponectin was initially described as a regulator of metabolic homeostases. Further studies demonstrated its involvement in the regulation of inflammatory diseases, particularly rheumatic and vascular diseases and some fibrotic processes. The aim of this study was to evaluate adiponectin in the circulation of patients with systemic sclerosis (SSc) and characterise its potential association with skin changes and SSc-related features. METHODS: Serum levels of adiponectin, interleukin-6 and soluble receptor for interleukin-2 (by ELISA), lipid levels, CRP (by turbidimetry), ANA (by immunofluorescence), autoantibodies of the ENA complex (by immunoblot) and urine levels of pyridinoline and deoxypyridinoline (by HPLC) were measured in 39 patients with SSc, and adiponectin levels were determined in 30 healthy controls matched by age, sex, and body mass index (BMI). Organ manifestations were recorded and skin changes were assessed using the modified Rodnan skin score. RESULTS: Adiponectin serum levels were similar between patients with SSc and healthy controls (median (IQR), 6.9 (5.9-9.1) vs. 7.8 (6.2-9.5)μg/ml, p=0.670). Levels of serum (ln) adiponectin were negatively correlated with the skin score (r=-0.379, p=0.017). Regression analysis of the relationship between adiponectin and markers of interest provided two statistically significant models: A- with explanatory variables HDL-cholesterol, skin score, disease duration, age (R(2)=0.580); and B- with CRP, skin score, age (R(2)=0.550); in order of a decreasing influence. CONCLUSION: Based on the results of this study, it might be speculated that adiponectin plays a protective role in skin- and atherosclerosis-related changes during SSc.
- MeSH
- adiponektin krev MeSH
- dyslipidemie krev patologie MeSH
- fluorescenční protilátková technika MeSH
- kůže patologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- studie případů a kontrol MeSH
- systémová sklerodermie krev patologie MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
V letech 2008 - 2010 byla na oddělení BioStat ÚBI 1.LF UK a VFN v Praze provedena řada statistických analýz u osob vyšetřovaných s podezřením na získané sexuálně přenosné onemocnění (Sexually Transmitted Di-seases - STD), které byly anonymně dotazovány prostřednictvím sady standardizovaných anketních otázek na základní demografické charakteristiky a behaviorální (sexuální) zvyklosti. U většiny osob (přesněji 301/61 mužů/žen) ze souboru N=488 dotazovaných v letech 2007-8 byla diagnostikována některá STD z následujícího seznamu: syfilis primaria (21/0); syfilis secundaria recens (54/23), syfilis secundaria latens (12/8); gonorea(122/23); chlamydiální infekce (78/9); urogenitální infekce vyvolaná Mycoplasma hominis (2/4); Ureaplasma urealyticum (31/12); hepatitis C (4/1); HIV (7/0); infekce vyvolaná papilomaviry (24/0); u 28 pacientů se syfilis byla diagnostikována ještě jiná STD. Výběrový soubor je typický vysokým podílem osob s rizikovým sexuálním chováním (22% homosexuálů - mužů; více než 9% vyšetřovaných „nepoužívá nikdy kondom“; 21% uvedlo „první pohlavní styk ve věku do 15 let“; 10% dotazovaných přiznalo „více než 10 partnerů za posledních 12 měsíců“; 5% „poskytlo sexuální službu za úplatu“ atd). V rámci této studie jsme se pokusili formálními statistickými prostředky specifikovat, které z výše naznačených souvislostí mezi sledovanými proměnnými a STD nemocemi se indikují jako statisticky významné. Protože některé proměnné mohou být s nemocemi v kauzálním vztahu a některé s nimi pouze koexistovat, použili jsme pro analýzu několika zdánlivě různých statistických metod (matice párových korelačních koeficientů, testy chíkvadrát v kontingenčních tabulkách, ROC analýzy). Prezentované výsledky byly dosaženy a vznikly za podpory GP NS10292 (MZ0/NS, 2009-2011).
České vydání druhé 239 stran : barevné ilustrace ; 27 cm
Kniha popisuje velký zázrak vzniku nového života. Nakladatelská anotace. Kráceno
- MeSH
- fertilizace MeSH
- porod MeSH
- těhotenství MeSH
- Check Tag
- těhotenství MeSH
- Publikační typ
- monografie MeSH
- populární práce MeSH
- Konspekt
- Gynekologie. Porodnictví
- NLK Obory
- gynekologie a porodnictví
