Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Image Cytometry”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,585 records · Page 88Linked to original sources
PubMed2005

Reduced infarct volume and differential effects on glial cell activation after hyperbaric oxygen treatment in rat permanent focal cerebral ischaemia.

Permanent middle cerebral artery occlusion (MCAO) causes neurodegeneration and a robust activation of glial cells primarily in sensorimotor brain regions of rats. It has been shown that hyperbaric oxygen (HBO) increases oxygen supply to ischaemic areas and reduces neuronal cell loss. The effects of HBO treatment on microgliosis and astrogliosis in permanent cerebral ischaemia have not been addressed so far, but might be critical for neurodegeneration and neuroprotection, respectively. Therefore, we used spontaneously hypertensive rats with permanent MCAO to investigate the time window to start HBO and to compare the effects of different HBO treatment frequencies on infarct volume and on differences with regard to microgliosis and astrogliosis. Seven days after MCAO the infarct volume was calculated from Nissl-stained brain sections by image analysis. HBO significantly decreased the infarct volume when used as early as 15, 90 or 180 min post-MCAO by 24%, 16% and 13%, respectively, in the single-treatment group. Repetitive HBO treatment (first HBO session 90 min after MCAO) was not effective. Microglial cells and astrocytes were detected by cytochemical fluorescent labelling and confocal laser scanning microscopy. In the single-treatment group we observed significantly higher astrocyte immunoreactivity but decreased microglial density in the peri-infarct region. These effects of HBO treatment on glial cells were not present in rats where HBO did not reduce the infarct volume (360 min after MCAO). Our data indicate that HBO-induced suppression of microgliosis and aggravated response of astrocytes might contribute to the reported beneficial effects of early HBO treatment in cerebral ischaemia.

Animals↗
PubMed2005

The white pulp in the setting of the septic spleen caused by different bacteria: a comparative morphometric study.

In the past little attention has been paid to histomorphologic changes accompanying the phenomenon of the septic spleen, thus indirectly reinforcing the old axiom that the spleen is an organ of mystery. It is especially noteworthy that the relationship between different causative bacteria and histopathologic abnormalities of the white pulp has not been investigated. In this study morphometric analysis was performed on the white pulp of 30 spleens obtained at autopsy from individuals with premortal sepsis. A strictly defined age- and sex-matched control group was analyzed for statistical comparison. Our findings demonstrate a significant depletion of B- and T-areas in the septic spleen, accompanied by a significant tendency towards reactive germinal center hyperplasia regardless of the type of bacteria responsible. However, depletion of splenic B-areas was shown to be significantly pronounced in the setting of premortal enterococcemia in comparison with a panel of gram-negative flagellated bacteria. It is felt that certain bacterial virulence factors (e.g. flagellation and/or structural components of the cell wall) might be pathogenetically involved in the observed changes, reflecting a partially different activation of splenic lymphocytes in the setting of the septic spleen.

Aged↗
PubMed2005

Sirolimus-induced thrombotic microangiopathy is associated with decreased expression of vascular endothelial growth factor in kidneys.

The aim of this study was to examine the clinical characteristics, the histological features and the renal expression of vascular endothelial growth factor (VEGF) of five patients with sirolimus-associated thrombotic microangiopathy (TMA). Sirolimus-induced TMA occurs preferentially in kidneys with concomitant endothelial injury: it was observed in three patients with acute cellular rejection on calcineurin inhibitor-free regimen, in one patient with chronic graft rejection on a calcineurin inhibitor-free protocol and in one patient with chronic calcineurin inhibitor nephrotoxicity. We found that renal VEGF expression during sirolimus-induced TMA was significantly lower than VEGF expression in normal transplanted kidneys (p < 0.01). Decreased expression of VEGF seems to be a consequence of sirolimus treatment since (i) analysis of two biopsies performed after the switch of sirolimus to calcineurin inhibitor showed reappearance of VEGF expression, (ii) no decreased expression of VEGF was found in five kidneys with classical TMA and, (iii) an increased expression of VEGF was observed in seven kidneys with acute cellular rejection on a sirolimus-free immunosuppressive regimen (p < 0.01). The potential role of sirolimus-induced downregulation of VEGF as a predisposing factor to the development of TMA is discussed.

Adult↗
PubMedDate not supplied

Morphometric studies on treated and untreated heterotransplanted malignant tumours.

Short-term therapy effects on heterotransplanted tumours are important to know in order to study the action of anticancer treatment. They are, however, difficult to assess due to interference from such factors as edema, vascular swelling and necrosis. Non-invasive methods such as NMR can be of some use, but the applicability is limited since background noise from the host animal organism may confound measurements. We studied a series of Cisplatine-treated bladder carcinomas heterotransplanted to nude mice and their untreated controls in order to illustrate short-term chemotherapy effect. We applied simple unbiased morphometric methods on formalin-fixed and paraffin-embedded material in order to obtain an unbiased estimate of the volume of the whole tumour and the volume of vital tumour tissue on day 1 and day 3 after treatment, at which time no gross changes in tumour size were evident. Furthermore, we estimated the number of tumour cells in the tumours. The estimate was based on measurement of the mean nuclear volume and the nuclear volume fraction in combination with the measured volume of vital tissue in the tumour. The pronounced therapy effects seen in this experimental system may be of potential interest in monitoring effects at the clinic.

Animals↗
PubMed2002

Comparison of nuclear morphometric parameters in cytologic smears and histologic sections of spontaneous canine tumors.

BACKGROUND: Nuclear morphometry may provide useful diagnostic and prognostic information for neoplasms in animals. Most available data have been obtained from histologic sections. Nuclear morphometry of cytologic smears may provide important preoperative information. OBJECTIVE: The goal of this study was to compare nuclear morphometric parameters in cytologic smears and histologic sections from spontaneous canine tumors. METHODS: Mean nuclear area (MNA), mean nuclear perimeter (MNP), mean nuclear form factor (FF; nuclear perimeter(2)/4pi nuclear area) and their respective SDs were assessed by image analysis of both hematoxylin and eosin-stained histologic sections and May-Grünwald-Giemsa-stained cytologic smears from the same case in 20 spontaneous canine tumors of different histogenesis. The above parameters were selected as being the best morphometric tools for measuring variation in shape and size in cells after neoplastic transformation. Data were compared by ANOVA with P<.01 considered significant. RESULTS: There was a significant difference between histologic and cytologic specimens for MNA, MNP, and their SDs. Only the differences between FF and the SD of FF were not statistically significant. CONCLUSIONS: Only nuclear morphometric data related to nuclear shape and nuclear shape variability are comparable between histologic and cytologic specimens. Nuclear area and perimeter may be affected by the different fixation and smear preparation techniques used in histology and cytology.

Animals↗
PubMed2005

Rapid glucose sensing by protein kinase A for insulin exocytosis in mouse pancreatic islets.

The role of protein kinase A (PKA) in insulin exocytosis was investigated with the use of two-photon excitation imaging of mouse islets of Langerhans. Inhibitors of PKA selectively reduced the number of exocytic events during the initial period (< 250 s) of the first phase of glucose-induced exocytosis (GIE), without affecting the second phase, in intact islets or small clusters of islet cells. The PKA inhibitors did not reduce the extent of the glucose-induced increase in [Ca(2+)](i). The actions of glucose and PKA in Ca(2+)-induced insulin exocytosis (CIE) triggered by photolysis of a caged-Ca(2+) compound, which resulted in large increases in [Ca(2+)](i) and thereby bypassed the ATP-sensitive K(+) channel-dependent mechanism of glucose sensing, were therefore studied. A high concentration (20 mM) of glucose potentiated CIE within 1 min, and this effect was blocked by inhibitors of PKA. This PKA-dependent action of glucose required glucose metabolism, given that increasing the intracellular concentration of cAMP by treatment with forskolin potentiated CIE only at the high glucose concentration. Finally, PKA appeared to reduce the frequency of 'kiss-and-run' exocytic events and to promote full-fusion events during GIE. These data indicate that a PKA-dependent mechanism of glucose sensing, which is operative even at the basal level of PKA activity, plays an important role specifically in the first phase of GIE, and they suggest that the action of PKA is mediated at the level of the fusion reaction.

Animals↗
PubMedDate not supplied

Effect of cell migration on the maintenance of tension on a collagen matrix.

Although it is known that cells promote structural reorganization of the collagen architecture, how individual cells exert mechanical tension on the matrix is not clearly understood. In the present study we have investigated the mechanical interaction of individual corneal fibroblasts with a collagen matrix using an improved version of our previously described in vitro force-measurement system (Roy, P. et al. Exp. Cell Res. 232:106-117, 1997). The elastic distortion of the collagen matrix exerted by cells was temporally recorded and analyzed using a two-dimensional finite-element model to quantify the forces exerted on the matrix. Time-lapse videomicroscopy of serum-cultured cells on the matrix for up to 6 h revealed that individual fibroblasts generated measurable tension on the matrix during pseudopodial extension and slow retraction. Fast retraction, an event observed during active cell migration, was associated with dramatic release of tension on the matrix. An apparent inverse correlation was observed between cell translocation and maintenance of matrix tension. Additional experiments with cells under serum-free conditions revealed that these cells fail to generate any detectable tension on the matrix despite undergoing filopodial extension and retraction. Since serum-free cells do not form focal adhesions or stress fibers, these experimental data suggest that contractility of nonmotile cells, coupled with strong cell-matrix adhesion, is the most favorable mechanism of generating and maintaining tension on the extracellular matrix.

Adhesiveness↗
PubMed2003

Light scattering from cervical cells throughout neoplastic progression: influence of nuclear morphology, DNA content, and chromatin texture.

A number of noninvasive fiber optic optical technologies are under development for real-time diagnosis of neoplasia. We investigate how the light scattering properties of cervical cells are affected by changes in nuclear morphology, DNA content, and chromatin texture, which occur during neoplastic progression. We used a Cyto-Savant computer-assisted image analysis system to acquire quantitative nuclear features measurements from 122 Feulgen-thionin-stained histopathologic sections of cervical tissue. A subset of the measured nuclear features was incorporated into a finite-difference time-domain (FDTD) model of cellular light scattering. The magnitude and angular distribution of scattered light was calculated for cervical cells as a function of pathologic grade. The nuclear atypia strongly affected light scattering properties. The increased size and elevated DNA content of nuclei in high-grade lesions caused the most significant changes in scattering intensity. The spatial dimensions of chromatin texture features and the amplitude of refractive index fluctuations within the nucleus impacted both the angular distribution of scattering angles and the total amount of scattered light. Cellular scattering is sensitive to changes in nuclear morphology that accompany neoplastic progression. Understanding the quantitative relationships between nuclear features and scattering properties will aid in the development of noninvasive optical technologies for detection of precancerous conditions.

Cell Nucleus↗
PubMed2002

Novel antiangiogenic effects of the bisphosphonate compound zoledronic acid.

Bisphosphonate drugs inhibit osteoclastic bone resorption and are widely used to treat skeletal complications in patients with tumor-induced osteolysis. We now show that zoledronic acid, a new generation bisphosphonate with a heterocyclic imidazole substituent, is also a potent inhibitor of angiogenesis. In vitro, zoledronic acid inhibits proliferation of human endothelial cells stimulated with fetal calf serum, basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (IC(50) values 4.1, 4.2, and 6.9 microM, respectively), and modulates endothelial cell adhesion and migration. In cultured aortic rings and in the chicken egg chorioallantoic membrane assay, zoledronic acid reduces vessel sprouting. When administered systemically to mice, zoledronic acid potently inhibits the angiogenesis induced by subcutaneous implants impregnated with bFGF [ED(50), 3 microg/kg (7.5 nmol/kg) s.c.]. These findings indicate that zoledronic acid has marked antiangiogenic properties that could augment its efficacy in the treatment of malignant bone disease and extend its potential clinical use to other diseases with an angiogenic component.

Angiogenesis Inhibitors↗
PubMed2004

A novel nonpeptide antagonist of the kinin B1 receptor: effects at the rabbit receptor.

The kinin B1 receptor (B1R) has attracted interest as a potential therapeutic target because this inducible G protein-coupled receptor is involved in sustained inflammation and inflammatory pain production. Compound 11 (2-[(2R)-1-[(3,4-dichlorophenyl) sulfonyl]-3-oxo-1,2,3,4-tetrahydroquinoxalin-2-yl]-N-[2-[4-(4,5-dihydro-1H-imidazol-2-yl)phenyl]ethyl]acetamide) is a high-affinity nonpeptide antagonist for the human B1R, but it is potent at the rabbit B1R as well: its Ki value for the inhibition of [3H]Lys-des-Arg9-BK (bradykinin) binding to a novel myc-labeled rabbit B1R expressed in COS-1 is 22 pM. In contractility tests (organ bath pharmacology), we found that compound 11 is an apparently surmountable antagonist of des-Arg9-BK- or Lys-des-Arg9-BK-induced contraction of the rabbit isolated aorta (pA2 values of 10.6+/-0.14 and 10.4+/-0.12, respectively). It did not influence contractions induced by angiotensin II in the rabbit aorta or by BK or histamine in the jugular vein, but it suppressed the prostaglandin-mediated relaxant effect of des-Arg9-BK on the rabbit isolated mesenteric artery. Compound 11 (1 nM) inhibited both the phosphorylation of the extracellular signal-regulated kinase1/2 mitogen-activated protein kinases induced by Lys-des-Arg9-BK in serum-starved rabbit aortic smooth muscle cells and the agonist-induced translocation of the fusion protein B1R-yellow fluorescent protein expressed in human embryonic kidney (HEK) 293 cells. Compound 11 does not importantly modify the expression of myc-B1R over 24 h in HEK 293 cells (no detectable action as "pharmacological chaperone"). The present results support that compound 11 is a potent and highly selective antagonist suitable for further investigations of the role of the kinin B1R in models of inflammation, pain, and sepsis based on the rabbit.

Animals↗
PubMed2005

Resistance of human astrocytoma cells to apoptosis induced by mitochondria-damaging agents: possible implications for anticancer therapy.

The success of anticancer chemotherapy is often hampered by resistance to apoptosis, which may depend on defects in intracellular cell death pathways. Characterizing the alterations of these pathways is a prerequisite for developing alternative and effective antitumoral strategies. Here, we investigated the susceptibility of a human astrocytoma cell line, ADF, to apoptotic cell death induced by mitochondria-damaging agents. Neither the anticancer agent betulinic acid nor the "mitochondriotropic" poisons 2-deoxy-d-ribose and potassium cyanide induced apoptosis of these cells, despite induction of highly significant mitochondrial depolarization, eventually resulting in necrotic death. Resistance to apoptosis was not due to presence of the multidrug resistance pump or to impaired expression of caspase-8, caspase-9, or "executioner" caspase-3. Cloning of caspase-9 revealed the presence of full-length caspase-9alpha and a short variant (caspase-9beta), which, in other tumors, acts as a dominant negative of the long isoform. All analyzed clones showed a point mutation in the prodomain region that is known to interact with mitochondria-released factors. Thus, in these human astrocytoma cells, mitochondria-damaging agents induce a regulated form of mitochondrial-dependent necrotic cell death (oncosis). Resistance to apoptosis is due to an intrinsic defect of caspase-9, leading to inhibition of enzyme activation and/or impaired interaction with proteins released from depolarized mitochondria. These results may have implications for developing strategies aimed at overcoming tumor resistance to chemotherapy.

Amino Acid Sequence↗
PubMed2026

Spatiotemporal mapping of tertiary lymphoid structure heterogeneity shapes immune niches and clinical outcomes in intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (iCCA) is a highly lethal malignancy with limited therapeutic options. The spatial architecture and functional diversity of tertiary lymphoid structures (TLSs) in iCCA remain unclear. Here, we present a multimodal spatial atlas of TLSs and identified intratumoral TLSs (iTLSs) as independent prognostic markers. Bulk proteomic profiling of 214 discovery and 155 validation cases identified a four-tier TLS-based tumor microenvironment classification system and supported development of a TLS-predictive random forest classifier. Imaging mass cytometry revealed that iTLS+ tumors harbor structured immune architectures, where M1-like tissue-resident macrophages (RTMs), dendritic cells, and CXCL13+ CD4+ T cells colocalize to form antigen-presenting neighborhoods (apc-CNs) spatially coupled to TLS core regions (TLScore-CNs). Single-cell spatial transcriptomics further resolved 61 TLSs into 14 spatial niches and defined a pseudotemporal maturation continuum: aggregated, activated, and postactivated. Intraniche communication, primarily mediated by ifnCAFs, iCAFs, and CXCL12+ macrophages, evolved dynamically with maturation. Single-nucleus RNA sequencing combined with Tangram-based spatial mapping revealed CXCL12+ macrophages and iCAFs forming a peripheral band in aggregated TLSs, whereas ifnCAFs infiltrated TLS interiors during activation. These findings define TLS heterogeneity and provide insights for stroma-directed immunotherapy.

Cholangiocarcinoma↗
PubMed1994

Survival and replication of Rhodococcus equi in macrophages.

Rhodococcus equi is a facultative intracellular bacterium of macrophages that can cause serious pneumonia in both young horses and immunocompromised people. Essential to understanding rhodococcus pathogenesis is a quantitative documentation of the intracellular events that follow macrophage phagocytosis of the organism. By using a bacterial immunofluorescence staining assay, we verified the intracellular survival and replicative potential of R. equi in both murine peritoneal macrophages and equine alveolar macrophages in vitro. Following an initial lag period of 6 to 12 h, the intracellular numbers of R. equi begin to rise, often reaching macrophage-compromising levels by 48 h. A quantitative determination of bacterial growth by a novel image analysis cytometry technique confirmed our fluorescence microscopic results. By 48 h postinfection, bacterial numbers had increased by more than fivefold, and the majority of infected macrophages in the monolayer contained 10 or more bacteria per cell. The intracellular organisms were viable, as evidenced by the ability to incorporate radiolabeled uracil. The use of these techniques has identified differences in the in vitro replicative capacities of a virulent strain and an avirulent strain of R. equi. A clinical isolate of R. equi expressing a 17-kDa virulence-associated plasmid-encoded antigen was able to survive and replicate within macrophages, whereas an avirulent, non-plasmid-containing strain replicated poorly. These results suggest that plasmid-encoded bacterial virulence factors may contribute to the ability of R. equi to replicate within its host cell, the macrophage.

Animals↗
PubMedDate not supplied

PathMaster: content-based cell image retrieval using automated feature extraction.

OBJECTIVE: Currently, when cytopathology images are archived, they are typically stored with a limited text-based description of their content. Such a description inherently fails to quantify the properties of an image and refers to an extremely small fraction of its information content. This paper describes a method for automatically indexing images of individual cells and their associated diagnoses by computationally derived cell descriptors. This methodology may serve to better index data contained in digital image databases, thereby enabling cytologists and pathologists to cross-reference cells of unknown etiology or nature. DESIGN: The indexing method, implemented in a program called PathMaster, uses a series of computer-based feature extraction routines. Descriptors of individual cell characteristics generated by these routines are employed as indexes of cell morphology, texture, color, and spatial orientation. MEASUREMENTS: The indexing fidelity of the program was tested after populating its database with images of 152 lymphocytes/lymphoma cells captured from lymph node touch preparations stained with hematoxylin and eosin. Images of "unknown" lymphoid cells, previously unprocessed, were then submitted for feature extraction and diagnostic cross-referencing analysis. RESULTS: PathMaster listed the correct diagnosis as its first differential in 94 percent of recognition trials. In the remaining 6 percent of trials, PathMaster listed the correct diagnosis within the first three "differentials." CONCLUSION: PathMaster is a pilot cell image indexing program/search engine that creates an indexed reference of images. Use of such a reference may provide assistance in the diagnostic/prognostic process by furnishing a prioritized list of possible identifications for a cell of uncertain etiology.

Abstracting and Indexing↗
PubMed2003

Appearance of an erythrocyte population with decreased deformability and hemoglobin content following sepsis.

With the use of the cecal ligation and puncture model in mice, this study tested whether sepsis-induced decreased erythrocyte deformability is restricted to a subpopulation of cells. Erythrocyte subpopulations were isolated by centrifugal elutriation. Lineweaver-Burk conversion of deformability-response curves to shear stress was used to determine the shear stress at half-maximal cell elongation (K(EI)) and maximal cell elongation (EI(max)). Sepsis decreased erythrocyte deformability in whole blood. K(EI) values were elevated (2.7 vs. 2.1 Pa) and EI(max) values decreased (0.56 vs. 0.50) in sepsis compared with sham mice. K(EI) values for cells eluted at 7 ml/min (smallest and oldest cells) were similar; however, K(EI) values for cells eluted at 8 ml/min were greater in septic than sham animals (2.50 vs. 2.10). Younger and larger subpopulations of erythrocytes (eluted at 9, 10, and 11 ml/min) also showed a tendency of decreased deformability in sepsis. Mean corpuscular hemoglobin content was decreased in cells eluted at 7 and 8 ml/min in sepsis (4.5 and 10.2 pg) compared to sham (7.4 and 11.4 pg) mice. This study indicates that an erythrocyte subpopulation that represents 20% of circulating cells shows the most pronounced decrease in cell deformability during sepsis. Increased rigidity together with decreased corpuscular hemoglobin content in these cells may contribute to microcirculatory dysfunction and immune modulation during sepsis.

Animals↗
PubMed2006

Influence of electrotonic structure and synaptic mapping on the receptive field properties of a collision-detecting neuron.

The lobula giant movement detector (LGMD) is a visual interneuron of Orthopteran insects involved in collision avoidance and escape behavior. The LGMD possesses a large dendritic field thought to receive excitatory, retinotopic projections from the entire compound eye. We investigated whether the LGMD's receptive field for local motion stimuli can be explained by its electrotonic structure and the eye's anisotropic sampling of visual space. Five locust (Schistocerca americana) LGMD neurons were stained and reconstructed. We show that the excitatory dendritic field and eye can be fitted by ellipsoids having similar geometries. A passive compartmental model fit to electrophysiological data was used to demonstrate that the LGMD is not electrotonically compact. We derived a spike rate to membrane potential transform using intracellular recordings under visual stimulation, allowing direct comparison between experimental and simulated receptive field properties. By assuming a retinotopic mapping giving equal weight to each ommatidium and equally spaced synapses, the model reproduced the experimental data along the eye equator, though it failed to reproduce the receptive field along the ventral-dorsal axis. Our results illustrate how interactions between the distribution of synaptic inputs and the electrotonic properties of neurons contribute to shaping their receptive fields.

Action Potentials↗
PubMed1997

DNA measurement of overlapping cell nuclei in thick tissue sections.

The paper describes an improved image analysis procedure for measuring the DNA content of cell nuclei in thick sections of liver tissue by absorption densitometry. Whereas previous methods only permitted the analysis of isolated nuclei, the new technique enables both isolated and overlapping nuclei to be measured. A 3D segmentation procedure determines whether each object is an isolated nucleus or a pair of overlapping nuclei; in the latter case the combined optical density is redistributed to the individual nuclei. A selection procedure ensures that only complete nuclei are measured. The method has been tested on specially-prepared Feulgen-stained 20micro sections of normal liver tissue. The overall distribution of the nuclear DNA measurements shows well-defined diploid and tetraploid peaks, with coefficient of variations of less than 10%. Similar distributions were obtained from both the isolated nuclei and overlapped nuclei sub-populations.

Cell Nucleus↗
PubMed1997

Detection of malignancy associated changes in cervical cell nuclei using feed-forward neural networks.

Normal cells in the presence of a precancerous lesion undergo subtle changes of their DNA distribution when observed by visible microscopy. These changes have been termed Malignancy Associated Changes (MACs). Using statistical models such as neural networks and discriminant functions it is possible to design classifiers that can separate these objects from truly normal cells. The correct classification rate using feed-forward neural networks is compared to linear discriminant analysis when applied to detecting MACs. Classifiers were designed using 53 nuclear features calculated from images for each of 25,360 normal appearing cells taken from 344 slides diagnosed as normal or containing severe dysplasia. A linear discriminant function achieved a correct classification rate of 61.6% on the test data while neural networks scored as high as 72.5% on a cell-by-cell basis. The cell classifiers were applied to a library of 93,494 cells from 395 slides, and the results were jackknifed using a single slide feature. The discriminant function achieved a correct classification rate of 67.6% while the neural networks managed as high as 76.2%.

Female↗