| 1. |
- Abayazid, Fady, et al.
(författare)
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A New Assessment of Bicycle Helmets: The Brain Injury Mitigation Effects of New Technologies in Oblique Impacts
- 2021
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Ingår i: Annals of Biomedical Engineering. - : Springer Science and Business Media LLC. - 1573-9686 .- 0090-6964. ; 49:10, s. 2716-2733
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Tidskriftsartikel (refereegranskat)abstract
- New helmet technologies have been developed to improve the mitigation of traumatic brain injury (TBI) in bicycle accidents. However, their effectiveness under oblique impacts, which produce more strains in the brain in comparison with vertical impacts adopted by helmet standards, is still unclear. Here we used a new method to assess the brain injury prevention effects of 27 bicycle helmets in oblique impacts, including helmets fitted with a friction-reducing layer (MIPS), a shearing pad (SPIN), a wavy cellular liner (WaveCel), an airbag helmet (Hövding) and a number of conventional helmets. We tested whether helmets fitted with the new technologies can provide better brain protection than conventional helmets. Each helmeted headform was dropped onto a 45° inclined anvil at 6.3 m/s at three locations, with each impact location producing a dominant head rotation about one anatomical axes of the head. A detailed computational model of TBI was used to determine strain distribution across the brain and in key anatomical regions, the corpus callosum and sulci. Our results show that, in comparison with conventional helmets, the majority of helmets incorporating new technologies significantly reduced peak rotational acceleration and velocity and maximal strain in corpus callosum and sulci. Only one helmet with MIPS significantly increased strain in the corpus collosum. The helmets fitted with MIPS and WaveCel were more effective in reducing strain in impacts producing sagittal rotations and a helmet fitted with SPIN in coronal rotations. The airbag helmet was effective in reducing brain strain in all impacts, however, peak rotational velocity and brain strain heavily depended on the analysis time. These results suggest that incorporating different impact locations in future oblique impact test methods and designing helmet technologies for the mitigation of head rotation in different planes are key to reducing brain injuries in bicycle accidents.
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| 2. |
- Abel, Frida, 1974, et al.
(författare)
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A 6-gene signature identifies four molecular subgroups of neuroblastoma
- 2011
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Ingår i: Cancer Cell International. - : Springer Science and Business Media LLC. - 1475-2867. ; 11:9
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Background There are currently three postulated genomic subtypes of the childhood tumour neuroblastoma (NB); Type 1, Type 2A, and Type 2B. The most aggressive forms of NB are characterized by amplification of the oncogene MYCN (MNA) and low expression of the favourable marker NTRK1. Recently, mutations or high expression of the familial predisposition gene Anaplastic Lymphoma Kinase (ALK) was associated to unfavourable biology of sporadic NB. Also, various other genes have been linked to NB pathogenesis. Results The present study explores subgroup discrimination by gene expression profiling using three published microarray studies on NB (47 samples). Four distinct clusters were identified by Principal Components Analysis (PCA) in two separate data sets, which could be verified by an unsupervised hierarchical clustering in a third independent data set (101 NB samples) using a set of 74 discriminative genes. The expression signature of six NB-associated genes ALK, BIRC5, CCND1, MYCN, NTRK1, and PHOX2B, significantly discriminated the four clusters (p
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| 3. |
- Abel, Frida, 1974, et al.
(författare)
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Gain of chromosome arm 17q is associated with unfavourable prognosis in neuroblastoma, but does not involve mutations in the somatostatin receptor 2(SSTR2) gene at 17q24.
- 1999
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Ingår i: British journal of cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 81:8, s. 1402-9
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Tidskriftsartikel (refereegranskat)abstract
- Deletion of chromosome arm 1p and amplification of the MYCN oncogene are well-recognized genetic alterations in neuroblastoma cells. Recently, another alteration has been reported; gain of the distal part of chromosome arm 17q. In this study 48 neuroblastoma tumours were successfully analysed for 17q status in relation to known genetic alterations. Chromosome 17 status was detected by fluorescence in situ hybridization (FISH). Thirty-one of the 48 neuroblastomas (65%) showed 17q gain, and this was significantly associated with poor prognosis. As previously reported, 17q gain was significantly associated with metastatic stage 4 neuroblastoma and more frequently detected than both deletion of chromosome arm 1p and MYCN amplification in tumours of all stages. 17q gain also showed a strong correlation to survival probability (P = 0.0009). However, the most significant correlation between 17q gain and survival probability was observed in children with low-stage tumours (stage 1, 2, 3 and 4S), with a survival probability of 100% at 5 years from diagnosis for children with tumours showing no 17q gain compared to 52.5% for those showing 17q gain (P = 0.0021). This suggests that 17q gain as a prognostic factor plays a more crucial role in low-stage tumours. Expression of the somatostatin receptor 2 (SSTR2), localized in chromosome region 17q24, has in previous studies been shown to be positively related to survival in neuroblastoma. A point mutation in the SSTR2 gene has earlier been reported in a human small-cell lung cancer. In this study, mutation screening of the SSTR2 gene in 43 neuroblastoma tumours was carried out with polymerase chain reaction-based single-stranded conformation polymorphism/heteroduplex (SSCP/HD) and DNA sequencing, and none of the tumours showed any aberrations in the SSTR2 gene. These data suggest that mutations in the SSTR2 gene are uncommon in neuroblastoma tumours and do not correlate with either the 17q gain often seen or the reason some tumours do not express SSTR2 receptors. Overall, this study indicates that gain of chromosome arm 17q is the most frequently occurring genetic alteration, and that it is associated with established prognostic factors.
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| 4. |
- Abel, Frida, 1974, et al.
(författare)
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Imbalance of the mitochondrial pro- and anti-apoptotic mediators in neuroblastoma tumours with unfavourable biology.
- 2005
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Ingår i: European journal of cancer (Oxford, England : 1990). - : Elsevier BV. - 0959-8049. ; 41:4, s. 635-46
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Tidskriftsartikel (refereegranskat)abstract
- It has been proposed that a lack of apoptosis plays an important role in neuroblastoma (NB) progression. We therefore screened cDNA array filters, including 198 apoptotic genes, in order to identify mRNA transcripts that are differentially expressed in tumours with unfavourable versus favourable biology. Twenty-one genes were analysed further using real-time reverse-transcriptase-polymerase chain reaction (RT-PCR). Significantly lower levels of DNCL1 (PIN; P(c)(corrected) = 0.0054) and NTRK1 (TrkA; P(c) = 0.039) were found in NB tumours with unfavourable biology. In addition, BID, BCL2, APAF1, CASP2, CASP3 and CASP9 were found to be preferentially expressed in tumours with favourable biology, whereas CDKN1A (p21), IL2RA, and MCL1, were found to be preferentially expressed in NB tumours with unfavourable biology. In conclusion, mRNA levels of transcripts encoding pro-apoptotic mediators of the mitochondrial apoptotic pathway were found to be expressed to a lower extent in tumours with unfavourable biology. Our data also suggest that the mitochondrial pathway is suppressed in advanced stages of NB tumours, due to an imbalance between anti-apoptotic and pro-apoptotic mediators which is a finding that may have therapeutic significance.
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| 5. |
- Aberšek, Nina, et al.
(författare)
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Calprotectin levels in amniotic fluid in relation to intra-amniotic inflammation and infection in women with preterm labor with intact membranes: A retrospective cohort study
- 2022
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Ingår i: European Journal of Obstetrics & Gynecology and Reproductive Biology. - : Elsevier BV. - 1872-7654 .- 0301-2115. ; 272, s. 24-29
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate the concentrations of calprotectin in amniotic fluid with respect to intra-amniotic inflammation and infection and to assess the presence or absence of bacteria in the amnio-chorionic niche with respect to presence or absence of intra-amniotic inflammation. Study design: Seventy-nine women with singleton pregnancies and preterm labor with intact membranes (PTL) were included in the study. Amniotic fluid was collected at the time of admission by amniocentesis and calprotectin levels were analyzed from frozen/thawed samples using ELISA. Interleukin (IL)-6 concentration was measured by point-of-care test. Samples from amniotic fluid and the amnio-chorionic niche (space between amniotic and chorionic membranes) were microbiologically analyzed. Microbial invasion of the amniotic cavity (MIAC) was diagnosed based on a positive PCR result for Ureaplasma species, Mycoplasma hominis, 16S rRNA or positive culture. Intra-amniotic inflammation (IAI) was defined as amniotic fluid point-of-care IL-6 concentration ≥ 745 pg/mL. The cohort of included women was divided into 4 subgroups based on the presence or absence of IAI/MIAC; i) intra-amniotic infection, ii) sterile IAI, iii) intra-amniotic colonization and iv) neither MIAC nor IAI. Results: Women with intra-amniotic infection had a significantly higher intra-amniotic calprotectin concentration (median; 101.6 µg/mL) compared with women with sterile IAI (median; 9.2 µg/mL), women with intra-amniotic colonization (median; 2.6 µg/mL) and women with neither MIAC nor IAI (median 4.6 µg/mL) (p = 0.001). Moreover, significantly higher amniotic fluid calprotectin concentration was seen in women who delivered within 7 days (p = 0.003). A significant negative correlation was found between amniotic fluid calprotectin and gestational age at delivery (rho = 0.32, p = 0.003). Relatively more bacteria in the amnio-chorionic niche were found in the sterile IAI group compared with the other groups. Conclusions: Calprotectin concentrations in amniotic fluid were significantly higher in the intra-amniotic infection group compared with the other groups. Moreover, the bacterial presence in the amnio-chorionic niche was higher in IAI group.
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| 6. |
- Abtahi, Farhad, 1981-, et al.
(författare)
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Development and preliminary evaluation of an Android based heart rate variability biofeedback system
- 2014
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Ingår i: Engineering in Medicine and Biology Society (EMBC), 2014 36th Annual International Conference of the IEEE. - : IEEE. - 9781424479290 ; 2014, s. 3382-5
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Konferensbidrag (refereegranskat)abstract
- The reduced Heart Rate Variability (HRV) is believed to be associated with several diseases such as congestive heart failure, diabetes and chronic kidney diseases (CKD). In these cases, HRV biofeedback may be a potential intervention method to increase HRV which in turn is beneficial to these patients. In this work, a real-time Android biofeedback application based on a Bluetooth enabled ECG and thoracic electrical bioimpedance (respiration) measurement device has been developed. The system performance and usability have been evaluated in a brief study with eight healthy volunteers. The result demonstrates real-time performance of system and positive effects of biofeedback training session by increased HRV and reduced heart rate. Further development of the application and training protocol is ongoing to investigate duration of training session to find an optimum length and interval of biofeedback sessions to use in potential interventions.
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| 7. |
- Adamatzky, Andrew, et al.
(författare)
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East-West paths to unconventional computing
- 2017
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Ingår i: Progress in Biophysics and Molecular Biology. - : Elsevier BV. - 0079-6107 .- 1873-1732. ; 131, s. 469-493
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Forskningsöversikt (refereegranskat)abstract
- Unconventional computing is about breaking boundaries in thinking, acting and computing. Typical topics of this non-typical field include, but are not limited to physics of computation, non-classical logics, new complexity measures, novel hardware, mechanical, chemical and quantum computing. Unconventional computing encourages a new style of thinking while practical applications are obtained from uncovering and exploiting principles and mechanisms of information processing in and functional properties of, physical, chemical and living systems; in particular, efficient algorithms are developed, (almost) optimal architectures are designed and working prototypes of future computing devices are manufactured. This article includes idiosyncratic accounts of ‘unconventional computing’ scientists reflecting on their personal experiences, what attracted them to the field, their inspirations and discoveries.
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| 8. |
- Ahemaiti, Aikeremu, 1984, et al.
(författare)
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A multifunctional pipette for localized drug administration to brain slices
- 2013
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Ingår i: Journal of Neuroscience Methods. - : Elsevier BV. - 0165-0270 .- 1872-678X. ; 219:2, s. 292-296
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a superfusion method utilizing an open-volume microfluidic device for administration of pharmacologically active substances to selected areas in brain slices with high spatio-temporal resolution. The method consists of a hydrodynamically confined flow of the active chemical compound, which locally stimulates neurons in brain slices, applied in conjunction with electrophysiological recording techniques to analyze the response. The microfluidic device, which is a novel free-standing multifunctional pipette, allows diverse superfusion experiments, such as testing the effects of different concentrations of drugs or drug candidates on neurons in different cell layers with high positional accuracy, affecting only a small number of cells. We demonstrate herein the use of the method with electrophysiological recordings of pyramidal cells in hippocampal and prefrontal cortex brain slices from rats, determine the dependence of electric responses on the distance of the superfusion device from the recording site, document a multifold gain in solution exchange time as compared to whole slice perfusion, and show that the device is able to store and deliver up to four solutions in a series. Localized solution delivery by means of open-volume microfluidic technology also reduces reagent consumption and tissue culture expenses significantly, while allowing more data to be collected from a single tissue slice, thus reducing the number of laboratory animals to be sacrificed for a study. (C) 2013 Elsevier B.V. All rights reserved.
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| 9. |
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| 10. |
- Ahemaiti, Aikeremu, 1984, et al.
(författare)
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Spatial characterization of a multifunctional pipette for drug delivery in hippocampal brain slices
- 2015
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Ingår i: Journal of Neuroscience Methods. - : Elsevier BV. - 0165-0270 .- 1872-678X. ; 241, s. 132-136
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Tidskriftsartikel (refereegranskat)abstract
- Background: Among the various fluidic control technologies, microfluidic devices are becoming powerful tools for pharmacological studies using brain slices, since these devices overcome traditional limitations of conventional submerged slice chambers, leading to better spatiotemporal control over delivery of drugs to specific regions in the slices. However, microfluidic devices are not yet fully optimized for such studies. New method: We have recently developed a multifunctional pipette (MFP), a free standing hydrodynamically confined microfluidic device, which provides improved spatiotemporal control over drug delivery to biological tissues. Results: We demonstrate herein the ability of the MFP to selectively perfuse one dendritic layer in the CA1 region of hippocampus with CNQX, an AMPA receptor antagonist, while not affecting the other layers in this region. Our experiments also illustrate the essential role of hydrodynamic confinement in sharpening the spatial selectivity in brain slice experiments. Concentration-response measurements revealed that the ability of the MFP to control local drug concentration is comparable with that of whole slice perfusion, while in comparison the required amounts of active compounds can be reduced by several orders of magnitude. Comparison with existing method: The multifunctional pipette is applied with an angle, which, compared to other hydrodynamically confined microfluidic devices, provides more accessible space for other probing and imaging techniques. Conclusions: Using the MFP it will be possible to study selected regions of brain slices, integrated with various imaging and probing techniques, without affecting the other parts of the slices.
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