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172 results on '"NYENGAARD, J.R."'

5. Axonal swellings are related to type 2 diabetes, but not to distal diabetic sensorimotor polyneuropathy

Author

Karlsson, P., Gylfadottir, S.S., Kristensen, A.G., Ramirez, J.D., Cruz, P., Le, N., Shillo, P.R., Tesfaye, S., Rice, A.S.C., Tankisi, H., Finnerup, N.B., Nyengaard, J.R., Jensen, T.S., Bennett, D.L.H., and Themistocleous, A.C.

Subjects
stomatognathic system
Abstract

Aims/hypothesis\ud \ud Distal diabetic sensorimotor polyneuropathy (DSP) is a common complication of diabetes with many patients showing a reduction of intraepidermal nerve fibre density (IENFD) from skin biopsy, a validated and sensitive diagnostic tool for the assessment of DSP. Axonal swelling ratio is a morphological quantification altered in DSP. It is, however, unclear if axonal swellings are related to diabetes or DSP. The aim of this study was to investigate how axonal swellings in cutaneous nerve fibres are related to type 2 diabetes mellitus, DSP and neuropathic pain in a well-defined cohort of patients diagnosed with type 2 diabetes.\ud \ud \ud Methods\ud \ud A total of 249 participants, from the Pain in Neuropathy Study (UK) and the International Diabetic Neuropathy Consortium (Denmark), underwent a structured neurological examination, nerve conduction studies, quantitative sensory testing and skin biopsy. The study included four groups: healthy control study participants without diabetes (n = 45); participants with type 2 diabetes without DSP (DSP−; n = 31); and participants with evidence of DSP (DSP+; n = 173); the last were further separated into painless DSP+ (n = 74) and painful DSP+ (n = 99). Axonal swellings were defined as enlargements on epidermal-penetrating fibres exceeding 1.5 μm in diameter. Axonal swelling ratio is calculated by dividing the number of axonal swellings by the number of intraepidermal nerve fibres.\ud \ud \ud Results\ud \ud Median (IQR) IENFD (fibres/mm) was: 6.7 (5.2–9.2) for healthy control participants; 6.2 (4.4–7.3) for DSP−; 1.3 (0.5–2.2) for painless DSP+; and 0.84 (0.4–1.6) for painful DSP+. Swelling ratios were calculated for all participants and those with IENFD > 1.0 fibre/mm. When only those participants with IENFD > 1.0 fibre/mm were included, the axonal swelling ratio was higher in participants with type 2 diabetes when compared with healthy control participants (p 1.0 fibre/mm, axonal swelling ratio is related to type 2 diabetes but is not related to DSP or painful DSP. Axonal swellings may be an early marker of sensory nerve injury in type 2 diabetes.

Published
2021

7. Actinomyces naeslundii in initial dental biofilm formation

Author

Dige, I., Raarup, M.K., Nyengaard, J.R., Kilian, M., and Nyvad, B.

Subjects
Actinomycetes -- Health aspects, Actinomycetes -- Research, Microbial mats -- Research, Scanning microscopy -- Usage, Biological sciences
Abstract

The combined use of confocal laser scanning microscopy (CLSM) and fluorescent in situ hybridization (FISH) offers new opportunities for analysis of the spatial relationships and temporal changes of specific members of the microbiota of intact dental biofilms. The purpose of this study was to analyse the patterns of colonization and population dynamics of Actinomyces naeslundii compared to streptococci and other bacteria during the initial 48 h of biofilm formation in the oral cavity. Biofilms developed on standardized glass slabs mounted in intra-oral appliances worn by ten individuals for 6, 12, 24 and 48 h. The biofilms were subsequently labelled with probes against A. naeslundii (ACT476), streptococci (STR405) or all bacteria (EUB338), and were analysed by CLSM. Labelled bacteria were quantified by stereological tools. The results showed a notable increase in the number of streptococci and A. naeslundii over time, with a tendency towards a slower growth rate for A. naeslundii compared with streptococci. A. naeslundii was located mainly in the inner part of the multilayered biofilm, indicating that it is one of the species that attaches directly to the acquired pellicle. The participation of A. naeslundii in the initial stages of dental biofilm formation may have important ecological consequences.

Published
2009

13. Ketamine restores changes in glutamate release, dendrite morphology and BDNF trafficking in the hippocampus of rats vulnerable to chronic mild stress

Author

Tornese, P., primary, Musazzi, L., additional, Sala, N., additional, Seguini, M., additional, Bonini, D., additional, Milanese, M., additional, Bonifacino, T., additional, Treccani, G., additional, Racagni, G., additional, Nyengaard, J.R., additional, Wegener, G., additional, Bonanno, G., additional, Barbon, A., additional, and Popoli, M., additional

Published
2017
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14. Ketamine modulates glutamate release, BDNF trafficking and dendrite morphology in rats vulnerable to chronic mild stress

Author

Tornese, P., primary, Musazzi, L., additional, Sala, N., additional, Seguini, M., additional, Bonini, D., additional, Milanese, M., additional, Bonifacino, T., additional, Treccani, G., additional, Racagni, G., additional, Nyengaard, J.R., additional, Wegener, G., additional, Bonanno, G., additional, Barbon, A., additional, and Popoli, M., additional

Published
2017
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15. 3D analysis of synaptic vesicle density and distribution after acute foot‐shock stress by using serial section transmission electron microscopy

Author

22353003 - Wegener, Gregers, Khanmohammadi, M., Wegener, G., Darkner, S., Nava, N., Nyengaard, J.R., 22353003 - Wegener, Gregers, Khanmohammadi, M., Wegener, G., Darkner, S., Nava, N., and Nyengaard, J.R.

Abstract

Behavioural stress has shown to strongly affect neurotransmission within the neocortex. In this study, we analysed the effect of an acute stress model on density and distribution of neurotransmitter‐containing vesicles within medial prefrontal cortex. Serial section transmission electron microscopy was employed to compare two groups of male rats: (1) rats subjected to foot‐shock stress and (2) rats with sham stress as control group. Two‐dimensional (2D) density measures are common in microscopic images and are estimated by following a 2D path in‐section. However, this method ignores the slant of the active zone and thickness of the section. In fact, the active zone is a surface in three‐dimension (3D) and the 2D measures do not accurately reflect the geometric configuration unless the active zone is perpendicular to the sectioning angle. We investigated synaptic vesicle density as a function of distance from the active zone in 3D. We reconstructed a 3D dataset by estimating the thickness of all sections and by registering all the image sections into a common coordinate system. Finally, we estimated the density as the average number of vesicles per area and volume and modelled the synaptic vesicle distribution by fitting a one‐dimensional parametrized distribution that took into account the location uncertainty due to section thickness. Our results showed a clear structural difference in synaptic vesicle density and distribution between stressed and control group with improved separation by 3D measures in comparison to the 2D measures. Our results showed that acute foot‐shock stress exposure significantly affected both the spatial distribution and density of the synaptic vesicles within the presynaptic terminal

Published
2017

16. Cover Image, Volume 29, Issue 12

Author

Kjølby, B.F., primary, Khan, A.R., additional, Chuhutin, A., additional, Pedersen, L., additional, Jensen, J.B., additional, Jakobsen, S., additional, Zeidler, D., additional, Sangill, R., additional, Nyengaard, J.R., additional, Jespersen, S.N., additional, and Hansen, B., additional

Published
2016
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17. Fast diffusion kurtosis imaging of fibrotic mouse kidneys

Author

Kjølby, B.F., primary, Khan, A.R., additional, Chuhutin, A., additional, Pedersen, L., additional, Jensen, J.B., additional, Jakobsen, S., additional, Zeidler, D., additional, Sangill, R., additional, Nyengaard, J.R., additional, Jespersen, S.N., additional, and Hansen, B., additional

Published
2016
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22. Practical implementation of the planar and spatial rotator in a complex tissue: the brain.

Author

HASSELHOLT, S., HAHN, U., VEDEL JENSEN, E.B., and NYENGAARD, J.R.

Subjects
NEUROSCIENCES, TISSUES, CYTOARCHITECTONICS, MOTOR cortex, HIPPOCAMPUS (Brain)
Abstract

Summary: In neuroscience, application of widely used stereological local volume estimators, including the planar rotator, is challenged by the combination of a complex tissue organisation and an estimator requirement of either isotropic or vertical sections, i.e. randomly oriented tissue. The spatial rotator is applicable with any tissue orientation but is sensitive to projection artefacts. The challenge is thus to select the most appropriate method for individual analyses. In this study, agreement between estimates of mean cell volume acquired with the vertical planar and the spatial rotator is assessed for two brain regions with different types of cytoarchitecture (motor cortex and hippocampal cornu ammonis 1). The possibility of using the planar rotator in tissues cut in an arbitrary direction is explored and requirements for a theoretically unbiased result as well as histological considerations are provided. Lay Description: Cells may change volume both during disease and with advancing age. Assessment of the volume of individual cells can therefore serve as a useful indicator of general tissue state. Most available methods to estimate cell volume in tissue sections, however, require that the tissue analysed has random orientation. Particularly for complex tissues such as the brain this is a challenge as identification, delineation and subdivision of many brain areas rely heavily on the use of anatomical atlases where illustrations depict the tissue in a few well‐known orientations. In this study, the practical application of two different methods for estimating mean cell volumes in tissues cut in a preferred orientation is evaluated. Requirements for the feasibility of cell volume estimation without random tissue orientation as well as histological considerations are provided. [ABSTRACT FROM AUTHOR]

Published
2019
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42. Aging in the human neocortex

Author

Pakkenberg, B., Pelvig, D., Marner, L., Bundgaard, M.J., Gundersen, H.J.G., Nyengaard, J.R., and Regeur, L.

Published
2003

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