DNA response to bleomycin in mammalian cells with variable degrees of chromatin condensation

BLM induces DNA degradation in living cells. We used CHO cells with maximal chromatin compactness (cells synchronized in metaphase), cells with chromatin decondensed by Na butyrate treatments, and control cells with normal chromatin condensation in order to analyze the correlation between chromatin compactness, DNA sensitivity to BLM, efficiency of repair of BLM-induced DNA lesions, and cell viability. We found that the DNA sensitivity to BLM and the efficiency of DNA repair is inversely correlated with the degree of chromatin coiling. Cells with decondensed chromatin are those showing higher DNA sensitivity to BLM but also those having the best efficiency to mend the damage. Accordingly, these cells show an amount of residual DNA lesions and a curve of growth similar to that of control cells. The situation is just the opposite for metaphase cells. The DNA of these cells is more resistant to BLM, but the damage is poorly repaired. The final result is that BLM induces a higher concentration of residual DNA lesions and a lower viability in metaphase than in control cells. Our results suggest that chromatin structure influences the quantity and repairability of the BLM-induced lesions, producing a higher incidence of double strand break in the DNA of cells with marked chromatin condensation. © 1993 Wiley-Liss, Inc.     

基于图像处理的菌落自动计数系统

目的针对现有菌落计数仪结构复杂、便携性差等缺点,本文设计了一种基于图像处理技术和Android平台来完成菌落自动计数的系统。方法该系统由硬件拍照设备采集菌落图像,以智能手机为主要操作载体,对图像进行光谱阈值分割、中值滤波、洪水填充、开值运算、八邻域边界跟踪等多种算法处理后实现自动计数。结果与菌落计数仪相比,该系统使用移动端手机APP实时获取菌落图像并得到计数结果,可直接在手机上对结果进行手动校正,具有成本低、操作简单、便携性好等优点。结论基于图像处理的菌落自动计数系统与人工计数结果的相对误差不超过5%,满足菌落计数的要求。     

Glutamate neurotoxicity in mouse cortical neurons: atypical necrosis with DNA ladders and chromatin condensation

The possibility that glutamate may induce neuronal apoptosis was examined in cultured cortical neurons. Neurons underwent widespread death 24 h following exposure to 50 μM glutamate. The glutamate neurotoxicity was blocked by inclusion of the glutamate antagonists, 10 μM MK-801 and 50 μM CNQX. The death was characterized by swelling cell body and bursting cytoplasmic membrane in the early phase of degeneration, suggesting that glutamate produces receptor-mediated excitotoxic necrosis. With blockade of excitotoxicity by addition of 10 μM MK-801 and 50 μM CNQX, cortical neurons exposed to 2 mM glutamate underwent necrosis morphologically identical to excitotoxicity but sensitive to 100 μM trolox, an antioxidant, suggesting that high doses of glutamate produce oxidative neuronal necrosis via non-receptor-mediated mechanisms. Interestingly, internucleosomal DNA fragmentation and chromatin condensation were observed in the course of glutamate-induced neuronal necrosis.     

Quantification of tumour-induced angiogenesis by image analysis

Quantitative techniques for in vivo and in vitro angiogenesis were developed using an image analyser. In the in vivo study, a Millipore chamber filled with mouse sarcoma 180 (S180) cells was transplanted subcutaneously to the dorsal side of a mouse, and the area of neovascularization induced by the tumour cells was quantified by image analysis. Images of vascular networks with poor contrast had their contrast improved by Laplacean transformation. The area of vascular network was 16.9 mm² in the control group without tumour cells and 44.2 mm² in the group with tumour cells, demonstrating a significant increase in neovascularized area by tumour cells. In the in vitro study, migration of vascular endothelial cells was induced with conditioned media of S180 cells. Image analysis was used to count automatically the nuclei of migrated endothelial cells, which were stained violet with Giemsa's solution. This automated measurement by image analyser is expected to save labour and time. Checkerboard analysis revealed that the endothelial cell migration induced by S180-conditioned medium was due to chemotaxis. The quantitation method using an automated image analyser is valuable in evaluating the induction of neovascularization by tumours and the effect of pharmacological agents on tumour angiogenesis in vivo and in vitro     

基于CT图像的颅内血肿检测与分割

目的:为提高血肿分割精度,提出一种基于改进Canny算子的颅内类血肿噪声检测方法。方法:首先用区域生长算 法分割出颅脑组织,去掉颅骨等干扰信息。然后使用基于改进Canny边缘检测的方法检测颅脑边缘类血肿噪声,并与原 图像进行与运算消除该噪声。最后,通过使用OTSU适应度函数的遗传算法精准分割出颅内血肿。结果:该方法在随机 抽取的200例颅脑血肿图像中,血肿检测的准确率达到96.3%,Dice相似度达到93.5%。结论:该方法能准确、有效地检测 并分割出颅内血肿。     

基于图像处理技术分析细胞吸收光敏剂过程的研究

目的 探讨利用图像处理技术分析细胞吸收光敏剂过程的可行性.方法 将光敏剂血卟啉单甲醚(HMME)注入喉癌细胞的培养皿中一定时间后,利用倒置荧光显微镜在不同时刻拍摄细胞的荧光图片,应用Matlab软件等进行图像处理得到反映不同时刻的细胞荧光强度的参数值L,并对计算结果进行对比.结果 细胞的荧光强度随着时间在15、90、300 min逐渐提高,Sobel算法与Otsu算法都可以较好地反映图像的荧光强度.结论 应用图像处理方法分析光敏剂进入细胞过程的方法简便、实用,具有重要的参考价值.     

Integer filters for image processing

In the paper Lynn's fast integer filtering methods are extended to two-dimensional image processing applications. Examples are included which verify the speed and the quality of the filtering for various types of filters. Initial condition requirements for one-dimensional integer filters are also extended to the two-dimensional case.     

An image processing software applied to oral pathology

This study presents the development and evaluation of an image processing software for computer-assisted cellular structure counting. The proposed software consists of a set of processing and analytical tools which allows its use in several applications of cell and cellular structure counting. A particular application in AgNOR quantitative analysis is presented. The knowledge obtained from experienced pathologists has been codified in a sequence of processing steps in order to allow automatic estimation of the mean number of AgNORs per cell in ameloblastomas. The performance of the presented software in such application was verified by comparing the data provided by visual analysis, by two observers previously calibrated and under supervision of two experienced specialists (Group 1) and by the computer program (Group 2). No statistical difference was observed (p < 0.05) between the two groups. The use of the proposed method in AgNOR applications permitted attainment of accurate and precise data without the difficulties frequently found in the traditional visual analysis method (time, training and subjectivity). The developed software is an interesting tool as an aid in the study (estimation of the number of cells and cellular structures) of malignant and benign neoplasms.     

Study and performance evaluation of statistical methods in image processing

Two statistical image processing formalisms involving the entropy concept and Bayesian analysis are studied. Iterative imaging algorithms of the formalisms are formulated by employing, for the purpose of performance evaluation and easy implementation, the steepet descent method for the solution of entropy concept and the expectation maximization technique for the solution of Bayesian analysis. Quantitative evaluation and comparison of the convergence performance of the iterative algorithms on computer generated ideal and experimental radioisotope phantom imaging noisy data are given. The study concludes that the entropy algorithm can converge relatively fast, but it is very sensitive to noise in measured data due to the ill-posed nature of inverse problems and its lack of ability to consider the statistics of data and has the advantage of Bayesian algorithm converges monotonically even with noisy data and has the advantage of considering both the a priori source distribution information and the statistical fluctuation of measured data.     

Nuclear chromatin condensation of mouse lymphoma (L-1210) cells by methylnitrosourea. An electron microscopic and biochemical study

When the mouse lymphoma (L-1210) cells are treated with methylnitrosourea (MNU) at 37 degrees C for 30 min and then cultured for 4 h in a normal medium nuclear structure and functions of the cells are changed. We have investigated the mechanism as to how nuclear structure and functions are changed by MNU. In MNU-treated cells euchromatin area diminishes and chromatin condensation occurs. [3H]thymidine and [3H]uridine uptakes of the MNU-treated cells decrease. In contrast, when the MNU-treated cells are cultured in the presence of 3-aminobenzamide, a specific inhibitor of poly(ADP-ribose) synthetase changes of nuclear structure do not appear. [3H]Thymidine and [3H]uridine uptakes are partially and almost completely recovered, respectively. Autoradiographs of the cells labelled with [3H]NAD, a substrate of poly(ADP-ribose) synthetase show that silver grains due to [3H]ADP-ribose are densely located only in the cells where chromatin condensation occurs. Chromatin-bound proteins of molecular masses 20-25 X 10(3) daltons are specifically poly(ADP-ribosyl)ated in the MNU-treated cells. These results suggest that MNU-induced chromatin condensation is caused by poly(ADP-ribosyl)ation of chromatinbound proteins.     

In vitro 3D reconstruction of long bones using B-scan image processing

An echographic image processing method has been developed, and validated by in vitro experiments, for the 3D reconstruction of the long bones of the newborn. The reconstruction of successive parallel cross-sections is obtained by a 2D reconstruction technique using radial B-scan image processing. The automatic segmentation of all the calculated images allows the extraction of the external contours of the skeleton. After structuring the explored volume using a contour association method, a contour interpolation step is required to solve the anisotropy problem, to obtain a 3D representation with cubic voxel lists. The results are encouraging, and a new mechanical part prototype of the acquisition system is under test for in vivo experiments. The main originality of the paper lies in the combination of different steps to obtain a practical solution to a clinical problem.     

Andrology: Changes in chromatin condensation of human spermatozoa during epididymal transit as determined by flow cytometry

Inasmuch as caput epididymal and even testicular spermatozoaare now being used to generate pregnancies by direct injectioninto the oocyte, differences in the chromatin of spermatozoafrom proximal and distal locations in the epidldymis were studied.Acridine Orange staining was used to investigate chromatin structurein human spermatozoa which had left the testis and were undergoingmaturation in the epididymis. Measurement of green and red fluorescenceIntensities of human spermatozoa by flow cytometry demonstrateda decrease in binding of Acridine Orange to DNA as the spermatozoatraversed the epididymis. Using spermatozoa from the cauda epididymisas the standard, the percentages of spermatozoa from the efferentduct, proximal corpus epididymis, midcorpus epididymis, distalcorpus epididymis, proximal cauda epidldymis and distal caudaepididymis that had matured with regard to chromatin condensationwere 28 ± 5, 39 ± 3, 49 ± 5, 64 ±5, 69 ± 6 and 74 ± 4% respectively. It may beconcluded that eggs fertilized by ejaculated spermatozoa receivea more highly condensed form of chromatin than that receivedby eggs Inseminated with proximal epididymal or testicular spermatozoa.     

Melanomas non-invasive diagnosis application based on the ABCD rule and pattern recognition image processing algorithms

In this paper an automated dermatological tool for the parameterization of melanomas is presented. The system is based on the standard ABCD Rule and dermatological Pattern Recognition protocols. On the one hand, a complete stack of algorithms for the asymmetry, border, color, and diameter parameterization were developed. On the other hand, three automatic algorithms for digital image processing have been developed in order to detect the appropriate patterns. These allow one to calculate certain quantitative features based on the aspect and inner patterns of the melanoma using simple-operation algorithms, in order to minimize response time. The database used consists of 160 500×500-pixel RGB images (20 images per pattern) cataloged by dermatologists, and the results have turned out to be successful according to assessment by medical experts. While the ABCD algorithms are mathematically reliable, the proposed algorithms for pattern recognition produced a remarkable rate of globular, reticular, and blue veil Pattern recognition, with an average above 85% of accuracy. It thus proves to be a reliable system when performing a diagnosis.     

The teaching of computer programming and digital image processing in radiography

The increased use of digital processing techniques in Medical Radiations imaging modalities, along with the rapid advance in information technology has resulted in a significant change in the delivery of radiographic teaching programs. This paper details a methodology used to concurrently educate radiographers in both computer programming and image processing. The students learn to program in visual basic applications (VBA), and the programming skills are contextualised by requiring the students to write a digital subtraction angiography (DSA) package. Program code generation and image presentation interface is undertaken by the spreadsheet Microsoft Excel. The user-friendly nature of this common interface enables all students to readily begin program creation. The teaching of programming and image processing skills by this method may be readily generalised to other vocational fields where digital image manipulation is a professional requirement.     

An attempt to analyze locomotion of leukemia cells by computer image processing

Phase contrast photographs of locomotive leukemia cells from a time lapse film were analyzed by an image processing computer system. Various structural and directional parameters were chosen to characterize dislocation and shape changes of a moving cell. A correlation could be established between the cellular image seen in time lapse films and the numerical shape configuration based on automated image analysis. It seems, therefore, that the parameters chosen represent a basis for further evaluation of the quantitative model of cellular locomotion.