Clumping Of Nuclei Research Articles

Coupled segmentation of nuclear and membrane-bound macromolecules through voting and multiphase level set

Membrane-bound macromolecules play an important role in tissue architecture and cell–cell communication, and is regulated by almost one-third of the genome. At the optical scale, one group of membrane proteins expresses themselves as linear structures along the cell surface boundaries, while others are sequestered; and this paper targets the former group. Segmentation of these membrane proteins on a cell-by-cell basis enables the quantitative assessment of localization for comparative analysis. However, such membrane proteins typically lack continuity, and their intensity distributions are often very heterogeneous; moreover, nuclei can form large clump, which further impedes the quantification of membrane signals on a cell-by-cell basis. To tackle these problems, we introduce a three-step process to (i) regularize the membrane signal through iterative tangential voting, (ii) constrain the location of surface proteins by nuclear features, where clumps of nuclei are segmented through a delaunay triangulation approach, and (iii) assign membrane-bound macromolecules to individual cells through an application of multi-phase geodesic level-set. We have validated our method using both synthetic data and a dataset of 200 images, and are able to demonstrate the efficacy of our approach with superior performance.Supplementary Information: One online video example can be found with: http://vision.lbl.gov/People/hang/evolving_fronts.gif

Evaluation of gatifloxacin for its potential to induce antioxidant imbalance and retinopathy in rabbits

Gatifloxacin, a fluoroquinolone antibiotic, has been reported to produce several adverse reactions. In the present investigation, gatifloxacin administered at the dose rate of 10 and 20 mg kg(-1) body weight per day, respectively, for 21 consecutive days, was evaluated for its potential to induce antioxidant status alterations and retinal damage in rabbits. A significant alteration in the antioxidant status of rabbits particularly in the high-dose group was observed which is indicated by decreased activity of superoxide dismutase and levels of blood glutathione with a concomitant increase in the activity of catalase, glutathione peroxidase, and glutathione S-transferase enzymes. The activity of glutathione reductase differed nonsignificantly between groups throughout the study period. The levels of malondialdehyde were elevated in the high-dose group. The histopathological examination of eyeball tunics revealed clumping of nuclei of the retinal outer nuclear layer in the gatifloxacin-treated groups. The results from this study indicate that repeated gatifloxacin administration produces a dose-dependent oxidative stress and retinopathy.

Effect of cadmium, chromium and mercury on the liver histology of Clarias batrachus L.

Effect of cadmium (Cd), chromium (Cr) and mercury (Hg) on liver histology of Clarias batrachus L. was studied after 28 days of exposure to sub lethal concentrations in the said metals under laboratory condition. The common changes in the liver were disruption of hepatic cords, abnormal shape of hepatocytes, pyknotic nuclei, and congestion of blood vessels and sinusoids. Cadmium induced frequent vacuolation in hepatocytes, loss of cell boundary, clumping of nuclei. Atrophied hepatocytes with variegated cytoplasm and necrosed nuclei were specific to Cr stress, and prominent intercellular spaces around most of the hypertrophied hepatocytes appeared in the liver under Hg stress. DOI: http://dx.doi.org/10.3329/cujbs.v4i1.13387 The Chittagong Univ. J. B. Sci.,Vol. 4(1&2):63-72, 2009

Effects of Streptozotocin-Diabetes and Insulin Replacement on the Epididymis of Prepubertal Rats: Histological and Histomorphometric Studies

The present study evaluates the effects of streptozotocin (STZ)-induced diabetes and insulin replacementon the histoarchitecture of caput, corpus, and caudal epididymides during the critical period of sexualmaturation in rats. Prepubertal male Wistar rats (40 days old) were made diabetic by a single injection ofSTZ (120 mg/kg body weight, intraperitoneally). To one set of diabetic rats, insulin was replaced dailyat a dose of 3 U/100 g body weight, subcutaneously in two equally divided doses at 8:00 a.m and 6:00 p.m.All the rats were killed on the 61st day of postnatal life. STZ-diabetes reduced the body weight and alsocaused regression of epididymis, leading to a decrease in the absolute weight of caput, corpus, and caudalregions. Histological studies also revealed a considerable reduction in the size of the tubule and lumen ofthese segments with an increase in interstitial stroma. Because of shrinkage of tubules, principal cellswere packed tightly with clumping of nuclei. Stereological studies support atrophic changes in the caput,corpus, and caudal epididymides by reduction in tubular diameter, volume, and surface density. Theepididymal lumen of STZ-treated rats was totally devoid of spermatozoa. These findings emphasize thedetrimental effects of diabetes on the maintenance and establishment of fully differentiated epididymalepithelium during sexual maturation. Insulin replacement was only able to prevent the adverse effects ofdiabetes on certain parameters and this response was region-specific.

Zur Spontandegeneration im M. posticus

The intrinsic muscles of the larynx were prepared in 265 forensic postmortems (death by strangulation: 73; other violent deaths: 93, natural death: 79, others: 20) for a histological examination. Muscle-fiber alterations were found in the (macroscopically normal) PCA muscle in most cases where the persons were of middle age or older. There were abnormalities such as rows or clumps of nuclei (also inside muscle fibers), the accumulation of lipofuscin pigment, focal or total necrosis of muscle fibers with or without predominant histiocytic infiltration, atrophic muscle cells, and fibrosis. The changes were mostly mild (normal muscle cells predominated) but clearly visible. If there had been acute damage to the larynx (for instance, death some time after attempted strangulation), these preexistent alterations must be taken into consideration when interpreting the microscopical findings.

Thyrotoxic myopathy. Pathomorphological observations of human material and experimentally induced thyrotoxicosis in rats.

Proximal myopathy and different types of neuromuscular syndromes are frequently observed in hyperthyroid patients with complicated thyrotoxicosis. Conflicting reports on the changes seen in muscle biopsies range from no abnormalities to muscle necrosis with the fibers being replaced by connective tissue and fat. On the basis of 21 skeletal muscle biopsies from chronic thyrotoxic myopathic patients, coupled with studies in experimentally induced triiodothyronine myopathy in rats, the histological, histochemical, immunofluorescent, and electron-microscopic findings diagnostic for thyrotoxic myopathy are defined. These criteria include: clumping of nuclei, loss of cross-striation, vacuolar degeneration, and fatty infiltration of endo- and perimysium, presence of giant mitochondria, increased number of mitochondria, disorganization of contractile elements, swelling of transverse tubules, presence of microtubular aggregations, and a significant increase of lipofuscin granules. Both muscle fiber types or in some cases selective type II fibers display atrophy with signs of reinnervation. These alterations are polyfocal and polyphasic and, therefore, polychronous and stereotyped rather than pathognomonic. However, they are related to the severity of thyrotoxic myopathy and the duration of disease. The results of muscle biopsies have a predictive value in determining the reversibility of irreversibility of pathologic changes with therapeutic consequences.

Flow cytometry of DNA in mouse sperm and testis nuclei

Mutations that occur in spermatogenic cells may be expressed as changes in DNA content, but developmentally-dependent alteration of its staining properties complicates the quantitation fo DNA in individual germ cells. These alterations have been studied with flow cytometric techniques. Nuclei from mouse testis cells and sperm were stained by the acriflavine-Feulgen method. The fluorescence intensity frequency distribution of nuclei of testis cells was characterized by 2 major and 5 minor peaks. Nuclei sorted from the various peaks with a fluorescence-activated cell sorter were identified microscopically. These data were confirmed by generation of peaks with nuclei prepared from cell suspensions enriched in specific cell types. One of the major peaks corresponded to round spermatid nuclei. The other major peak, located at 0.6 of the fluorescence intensity of the round nuclei, corresponded to elongated spermatid nuclei. Purified nuclei of epididymal and vas deferens spermatozoa displayed asymmetric fluorescence distributions. A minor peak at 0.8 the intensity of the round spermatid nuclei was tentatively assigned to elongating spermatids. 2 of the minor peaks, located at 1.7 and 2.0 times the fluorescence intensity of the round nuclei, corresponded to clumps of 2 haploid and diploid nuclei. The additional peaks, located at 3.0 and 3.7 times the fluorescence intensity of round spermatid nuclei correspond to leptotene and zygotene spermatocytes and to late pachytene spermatocytes, respectively. These peaks contained clumps of nuclei. The homogeneity of the nuclei sorted from the peaks, as well as the relative sizes of the peaks, was enhanced when the nuclei were prepared from cells enriched in specific stages of development. The relative fluorescence intensities of the various testis nuclei were characteristic and repeatedly found but were not stoichiometric with the DNA content of the nuclei.