30,897 research outputs found

    New Descriptor for Glomerulus Detection in Kidney Microscopy Image

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    Glomerulus detection is a key step in histopathological evaluation of microscopy images of kidneys. However, the task of automatic detection of glomeruli poses challenges due to the disparity in sizes and shapes of glomeruli in renal sections. Moreover, extensive variations of their intensities due to heterogeneity in immunohistochemistry staining are also encountered. Despite being widely recognized as a powerful descriptor for general object detection, the rectangular histogram of oriented gradients (Rectangular HOG) suffers from many false positives due to the aforementioned difficulties in the context of glomerulus detection. A new descriptor referred to as Segmental HOG is developed to perform a comprehensive detection of hundreds of glomeruli in images of whole kidney sections. The new descriptor possesses flexible blocks that can be adaptively fitted to input images to acquire robustness to deformations of glomeruli. Moreover, the novel segmentation technique employed herewith generates high quality segmentation outputs and the algorithm is assured to converge to an optimal solution. Consequently, experiments using real world image data reveal that Segmental HOG achieves significant improvements in detection performance compared to Rectangular HOG. The proposed descriptor and method for glomeruli detection present promising results and is expected to be useful in pathological evaluation

    Computational exploration of molecular receptive fields in the olfactory bulb reveals a glomerulus-centric chemical map

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    © The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.Progress in olfactory research is currently hampered by incomplete knowledge about chemical receptive ranges of primary receptors. Moreover, the chemical logic underlying the arrangement of computational units in the olfactory bulb has still not been resolved. We undertook a large-scale approach at characterising molecular receptive ranges (MRRs) of glomeruli in the dorsal olfactory bulb (dOB) innervated by the MOR18-2 olfactory receptor, also known as Olfr78, with human ortholog OR51E2. Guided by an iterative approach that combined biological screening and machine learning, we selected 214 odorants to characterise the response of MOR18-2 and its neighbouring glomeruli. We found that a combination of conventional physico-chemical and vibrational molecular descriptors performed best in predicting glomerular responses using nonlinear Support-Vector Regression. We also discovered several previously unknown odorants activating MOR18-2 glomeruli, and obtained detailed MRRs of MOR18-2 glomeruli and their neighbours. Our results confirm earlier findings that demonstrated tunotopy, that is, glomeruli with similar tuning curves tend to be located in spatial proximity in the dOB. In addition, our results indicate chemotopy, that is, a preference for glomeruli with similar physico-chemical MRR descriptions being located in spatial proximity. Together, these findings suggest the existence of a partial chemical map underlying glomerular arrangement in the dOB. Our methodology that combines machine learning and physiological measurements lights the way towards future high-throughput studies to deorphanise and characterise structure-activity relationships in olfaction.Peer reviewe

    Sensory memory for odors is encoded in spontaneous correlated activity between olfactory glomeruli

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    Sensory memory is a short-lived persistence of a sensory stimulus in the nervous system, such as iconic memory in the visual system. However, little is known about the mechanisms underlying olfactory sensory memory. We have therefore analyzed the effect of odor stimuli on the first odor-processing network in the honeybee brain, the antennal lobe, which corresponds to the vertebrate olfactory bulb. We stained output neurons with a calcium-sensitive dye and measured across-glomerular patterns of spontaneous activity before and after a stimulus. Such a single-odor presentation changed the relative timing of spontaneous activity across glomeruli in accordance with Hebb's theory of learning. Moreover, during the first few minutes after odor presentation, correlations between the spontaneous activity fluctuations suffice to reconstruct the stimulus. As spontaneous activity is ubiquitous in the brain, modifiable fluctuations could provide an ideal substrate for Hebbian reverberations and sensory memory in other neural systems

    Inhalation of mercury vapor can cause the toxic effects on rat kidney

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    Dental amalgam has been used in dentistry as a filling material. The filler comprises mercury (Hg). It is considered one of the most important and widespread environmental pollutants, which poses a serious potential threat for the humans and animals. However, mercury deposition affects the nervous, cardiovascular, pulmonary, gastrointestinal, and especially renal systems. In most animals' species and humans, the kidney is one of the main sites of deposition of mercury and target organ for its toxicity. In this study, the effects of mercury intake on kidney in rats were searched. For the this purpose; we used 24 adult female Wistar albino rats (200g in weight) obtained from Experimental Research and Application Center of Ataturk University with ethical approval. Besides, they were placed into a specially designed glass cage. Along this experiment for 45 days, subjects were exposed to (1mg/m(3)/day) mercury vapor. However, no application was used for the control subjects. At the end of the experiment, kidney samples were obtained from all subjects and processed for routine light microscopic level and stereological aspect were assessed. Finally, according to our results, mercury affects the histological features of the kidney. That means, the severe effects of mercury has been shown using stereological approach, which is one of the ideal quantitative methods in the current literature. In this study, it was detected that chronic exposure to mercury vapor may lead to renal damage and diseases in an experimental rat model

    Blood pressure and indices of glomerular filtration area in hypertensive and normotensive Prague rats

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    The involvement of the kidney in the pathogenesis of hypertension has long been recognised, although the specific renal mechanisms underlying this phenomenon are still unknown. A current hypothesis attributes hyper tension to a reduction in glomerular filtration area by glomerular loss, The present study analyses the relationship between glomerular number and volume and conscious systolic blood pressure (SBP) in 4- to 53-week-old hypertensive (PHR) and normotensive (PNR) rats of the Prague strain. Adult PHRs had higher SEP, were larger and had larger kidneys than PNRs, but 20% fewer glomeruli, A significant negative correlation between SEP and glomerular number was found in PHR males, but not in PHR females or PNRs. There was no correlation at all between glomerular volume and SEP and, in young animals, both SEP and glomerular number were higher in PHRs than in PNRs. In addition, in adult PHRs, glomerular volume and SEP were higher in males than in females. In summary, a generally valid, causal relation-ship linking raised blood pressure to decreased glomerular number or volume could not be demonstrated in the Prague rat model of genetically determined hypertension. The nature of the renal mechanism(s) determining the hypertension in this model remains unknown. Copyright (C) 2000 S. Karger AG, Basel

    An immunohistochemical study of the diagnostic value of TREM-1 as marker for fatal sepsis cases

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    Triggering receptor expressed on myeloid cells-1 (TREM-1) is produced and up-regulated by exposure of myeloid cells to lipopolysaccharides or other components of either bacterial or fungal origin, which causes it to be strongly expressed on phagocytes that accumulate in inflamed areas. Because TREM-1 participates in septic shock and in amplifying the inflammatory response to bacterial and fungal infections, we believe it could be an immunohistochemical marker for postmortem diagnosis of sepsis. We tested the anti-TREM-1 antibody in 28 cases of death by septic shock and divided them into two groups. The diagnosis was made according to the criteria of the Surviving Sepsis Campaign. In all cases, blood cultures were positive. The first group was comprised subjects that presented high ante-mortem serum procalcitonin and the soluble form of TREM-1 (s-TREM-1) values. The second group comprised subjects in which s-TREM-1 was not measured ante-mortem. We used samples of brain, heart, lung, liver and kidney for each case to test the anti-TREM-1 antibody. A semiquantitative evaluation of the immunohistochemical findings was made. In lung samples, we found immunostaining in the cells of the monocyte line in 24 of 28 cases, which suggests that TREM-1 is produced principally by cells of the monocyte line. In liver tissue, we found low TREM-staining in the hepatocyte cytoplasm, duct epithelium, the portal-biliary space and blood vessel. In kidney tissue samples, we found the TREM-1 antibody immunostaining in glomeruli and renal tubules. We also found TREM-1 staining in the lumen of blood vessels. Immunohistochemical staining using the anti-TREM-1 antibody can be useful for postmortem diagnosis of sepsis

    Discrimination and Quantification of Glomerular Receptor Subtypes for Atrial Natriuretic Factor (Anf)

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    Binding sites for atrial natriuretic factor (ANF) were determined on isolated rat glomeruli as well as on glomerular membranes. To define optimal conditions, binding of ANF was investigated varying incubation time, temperature and protein concentration. Binding conditions were found to be best at 4°C for 5 hours with 15 μg of glomerular protein. Saturation and affinity cross-linking experiments confirmed the presence of two distinct receptor subtypes - the B-receptor (130 kDa) and the C-receptor (65 kDa). Quantitative differentiation of both ANF binding sites was achieved by competitive displacement with two different unlabeled ANF ligands: a) rANF(99-126) (homologous displacement), b) des(18-22)rANF(4-23)NH2(heterologous displacement). Intact glomeruli and glomerular membranes did not differ significantly in receptor density for the B-receptor (71 ± 37 vs. 94 ± 53 fmol/mg protein) or the C-receptor (976 ± 282 vs. 966 ± 167 fmol/mg protein) or in affinity constants for the B-receptor (43 ± 36 vs. 52 ± 44 pM) or the C-receptor (876 ± 377 vs. 307 ± 36 pM). Glomerular membranes compared to glomeruli showed less nonspecific binding and less intra-assay variation of measuring points done in triplicates. This method of selective displacement should allow to study the influence of various physiological and pathophysiological conditions on the binding properties of B-and C-receptors for ANF

    In-vivo two-photon imaging of the honey bee antennal lobe

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    Due to the honey bee's importance as a simple neural model, there is a great need for new functional imaging modalities. Herein we report on the use of two-photon microscopy for in-vivo functional and morphological imaging of the honey bee's olfactory system focusing on its primary centers, the antennal lobes (ALs). Our imaging platform allows for simultaneously obtaining both morphological measurements of the AL and in-vivo calcium recording of neural activities. By applying external odor stimuli to the bee's antennas, we were able to record the characteristic odor response maps. Compared to previous works where conventional fluorescence microscopy is used, our approach offers all the typical advantages of multi-photon imaging, providing substantial enhancement in both spatial and temporal resolutions while minimizing photo-damages and autofluorescence contribution with a four-fold improvement in the functional signal. Moreover, the multi-photon associated extended penetration depth allows for functional imaging within profound glomeruli.Comment: 3 pages, 3 figure
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