Search results for "Biomedical"
showing 10 items of 2328 documents
Noise reduction in magnetic resonance images by Wavelet transforms: an application to the study of capillary water absorption in sedimentary rocks
2007
Magnetic resonance imaging (MRI) is a powerful technique to study capillary water absorption kinetics in sedimentary rocks. However, the noise in the images can limit the correct identification and the quantitative measurement of the average height reached by the wetting front inside the porous material where imbibition occurs. Therefore, denoising methods can be applied to improve the image quality for a more accurate analysis, without the disadvantages of longer acquisition times. This study attempts to improve the signal-to-noise ratio of the images acquired by MRI on a sedimentary rock (Pietra di Lecce) using a waveletbased thresholding technique. The idea is to average some slightly di…
The effect of adhesives on inflammatory immune-markers during renal injury healing
2017
Renal injury is common in abdominal trauma. Adhesives and sealants can be used to repair and preserve damaged organs. We describe the effect of three biomaterial treatments (TachoSil, GelitaSpon, and Adhflex) on injured renal tissue. Renal traumatic injuries were experimentally induced in male Wistar rats (n = 90) using a punch. Animals were divided into five groups: (1) sham noninjured (n = 3) and punch injury groups; (2) nontreated (n = 6); (3) TachoSil (n = 27); (4) GelitaSpon (n = 27); and (5) Adhflex (n = 27). Wound healing was evaluated 2, 6, and 18 days postinjury by inflammatory cytokines response, histopathological evolution of lesions, inflammatory reaction markers (CD68), and vas…
Implanted neonatal human dermal fibroblasts influence the recruitment of endothelial cells in mice
2012
The vascularization of new tissue within a reasonable time is a crucial prerequisite for the success of different cell- and material-based strategies. Considering that angiogenesis is a multi-step process involving humoral and cellular regulatory components, only in vivo assays provide the adequate information about vessel formation and the recruitment of endothelial cells. The present study aimed to investigate if neonatal human dermal fibroblasts could influence in vivo neovascularization. Results obtained showed that fibroblasts were able to recruit endothelial cells to vascularize the implanted matrix, which was further colonized by murine functional blood vessels after one week. The ve…
Paracrine Effects Influenced by Cell Culture Medium and Consequences on Microvessel-Like Structures in Cocultures of Mesenchymal Stem Cells and Outgr…
2011
Mesenchymal stem cells (MSC) from bone marrow and outgrowth endothelial cells (OEC) from peripheral blood are considered as attractive cell types for applications in regenerative medicine aiming to build up complex vascularized tissue-engineered constructs. MSC provide several advantages such as the potential to differentiate to osteoblasts and to support the neovascularization process by release of proangiogenic factors. On the other hand, the neovascularization process can be actively supported by OEC forming perfused vascular structures after co-implantation with other cell types. In this study the formation of angiogenic structures in vitro was investigated in cocultures of MSC and OEC,…
Nanoparticles and antigen-specific T-cell therapeutics: A comprehensive study on uptake and release
2015
Aim: T lymphocytes are used as cellular therapeutics in many disease entities including cancer. We investigated the uptake and retention of nanoparticles (NPs) by these nonphagocytic cells. Materials & methods: Uptake, release and toxicity of various polymeric NP preparations were analyzed by flow cytometry, confocal laser scanning microscopy and transmission electron microscopy. T-cell effector functions were measured using IFN-γ-ELISPOT and 51Chromium-release assays. Results: Amino-functionalized NPs were efficiently ingested by antigen-specific T cells without adversely influencing effector functions. NPs were stored in membrane-surrounded vesicles, with major proportions released e…
Multimodal device for assessment of skin malformations
2013
A variety of multi-spectral imaging devices is commercially available and used for skin diagnostics and monitoring; however, an alternative cost-efficient device can provide an advanced spectral analysis of skin. A compact multimodal device for diagnosis of pigmented skin lesions was developed and tested. A polarized LED light source illuminates the skin surface at four different wavelengths – blue (450 nm), green (545 nm), red (660 nm) and infrared (940 nm). Spectra of reflected light from the 25 mm wide skin spot are imaged by a CMOS sensor. Four spectral images are obtained for mapping of the main skin chromophores. The specific chromophore distribution differences between different skin…
LASCA and PPG imaging for non-contact assessment of skin blood supply
2013
Laser speckle contrast analysis (LASCA) offers a non-contact, full-field, and real-time mapping of capillary blood flow and can be considered as an alternative method to Laser Doppler perfusion imaging (LDPI). Photoplethysmography (PPG) is well known technique for assessment of skin blood pulsations that can be related to blood flow. In recent years several studies have been done on development of non-contact PPG imaging (PPGI). LASCA and PPGI techniques are simpler and cheaper compared with LDPI. LASCA technique has been implemented in several commercial instruments. However, these systems are still too expensive and bulky to be widely available. Several optical techniques have found new i…
The blood perfusion mapping in the human skin by photoplethysmography imaging
2010
A CMOS camera-based imaging photoplethysmographic (PPGI) system is described to detect the blood pulsations in tissue. Attention of PPGI is drawn to the potential applications in visualized blood perfusion. Intensity variations of three wavelengths (620 nm, 520 nm and 432 nm) were detected and analyzed in each pixel of image. To obtain a twodimensional mapping of the dermal perfusion measurement, custom image-processing software has been developed. The high-resolution PPGI images were derived from human fingers (transmission mode) and face (reflection mode), evaluated at three wavelengths. The newly developed system can be usable in skin blood perfusion monitoring for clinical applications.
The gait is less stable in children with cerebral palsy in normal and dual-task gait compared to typically developed peers
2021
There is limited evidence about gait stability and its alteration by concurrent motor and cognitive tasks in children with cerebral palsy (CP). We examined gait stability and how it is altered by constrained cognitive or motor task in CP and their typically developed (TD) controls. Gait kinematics were recorded using inertial-measurement units (IMU) from 18 patients with hemiplegia (13.5 +/- 2.4 years), 12 with diplegia (13.0 +/- 2.1 years), and 31 TD controls (13.5 +/- 2.2 years) during unconstrained gait, and motor (carrying a tray) and cognitive (word naming) task constrained gait at preferred speed (similar to 400 steps/task). Step duration, its standard deviation and refined-compound-m…
Revising the stretch reflex threshold method to measure stretch hyperreflexia in cerebral palsy
2022
Funding Information: This work was supported by the Olvi Foundation, Research Foundation of Cerebral Palsy Alliance (PHD00321), Finnish Cultural Foundation, University of Jyväskylä, Academy of Finland (grants #296240, #307250, #327288, #311877, #326988), including “Brain changes across the life-span” profiling funding to University of Jyväskylä, Jane and Aatos Erkko Foundation (#602.274), and the Netherlands Organization for Scientific Research (NWO-016.186.144). Ministry of Education and Culture (OKM/28/626/2022). Hyper-resistance is an increased resistance to passive muscle stretch, a common feature in neurological disorders. Stretch hyperreflexia, an exaggerated stretch reflex response, …