An iterative region-growing process for cell image segmentation based on local color similarity and global shape criteria

An image segmentation process was derived from an image model that assumed that cell images represent objects having characteristic relationships, limited shape properties and definite local color features. These assumptions allowed the design of a region-growing process in which the color features were used to iteratively aggregate image points in alternation with a test of the convexity of the aggregate obtained. The combination of both local and global criteria allowed the self-adaptation of the algorithm to segmentation difficulties and led to a self-assessment of the adequacy of the final segmentation result. The quality of the segmentation was evaluated by visual control of the match between cell images and the corresponding segmentation masks proposed by the algorithm. A comparison between this region-growing process and the conventional gray-level thresholding is illustrated. A field test involving 700 bone marrow cells, randomly selected from May-Grünwald-Giemsa-stained smears, allowed the evaluation of the efficiency, effectiveness and confidence of the algorithm: 96% of the cells were evaluated as correctly segmented by the algorithm's self-assessment of adequacy, with a 98% confidence. The principles of the other major segmentation algorithms are also reviewed.     

A quantitative analysis of the human bone marrow granulocytic cell lineage using the SAMBA 200 cell image processor. II. The blast cells in refractory anemia with an excess of blasts

A quantitative image analysis of bone marrow blast cells from eight patients with refractory anemia with an excess of blast cells was performed using the SAMBA 200 cell image analyzer. A total of 33 parameters was computed on 665 cells visually classified as B1 blasts (agranular cells), B2 blasts (cells containing a few azurophilic granules) and B3 blasts (cells with numerous granules). The continuum of variation of some cytoplasmic parameters (area, hue and standard deviation of the luminance, hue and saturation histograms) and some nuclear parameters (area and convexity degree) from the B1 cells to the B3 cells indicated a concomitant cytoplasmic and nuclear maturation, with the B1 cells being the most immature. An attempt to automatically classify these cells using a stepwise linear discriminant analysis resulted in an average of 68% correctly classified cells at the fifth step. Among the B1 and B2 blast cells considered together, an unsupervised classification method distinguished seven subgroups of blasts, which were principally different in cytoplasmic area, cytoplasmic color and nuclear texture. The percentages of cells belonging to two of these subgroups were highly discriminatory with respect to the prognosis. These two cell types had morphologic, textural and color features that put them very near the normal immature myeloidlike progenitor cells and normal myeloblasts, as demonstrated by means of canonical analysis. All patients having a very low percentage of these two cells among their blast cells died from overt leukemia less than one year after the first diagnosis of their disease.     

Correlation between silver-stained nucleolar organizer region area and cell cycle time

BACKGROUND: The relationship between the population doubling time and the quantity of silver-stained nucleolar organizer region (AgNOR) interphase proteins was studied in cell culture at three different temperatures used to modulate the cell cycle duration. METHODS: After MIB 1 and AgNOR combined staining, the quantity of AgNOR proteins was measured in cycling cells by image cytometry. RESULTS: Among the several parameters calculated, the AgNOR relative area showed a strong correlation with the changes of the population doubling time induced by different temperatures. CONCLUSIONS: The results support the hypothesis that the cell cycle time and the size of the ribogenesis machinery are coregulated and that measurements of AgNORs can thus be used as a static evaluation of the cell cycle duration in arbitrary units.     

First occurrence of early Homo in the Nachukui Formation (West Turkana, Kenya) at 2.3-2.4 Myr

Cognitive abilities and techno-economic behaviours of hominids in the time period between 2.6-2.3 Myr have become increasingly well-documented. This time period corresponds to the oldest evidence for stone tools at Gona (Kada Gona, West Gona, EG 10-12, OGS 6-7), Hadar (AL 666), lower Omo valley (Ftji1, 2 & 5, Omo 57, Omo 123) in Ethiopia, and West Turkana (Lokalalei sites -LA1 & LA2C-) in Kenya. In 2002 a new palaeoanthropological site (LA1alpha), 100 meters south of the LA1 archaeological site, produced a first right lower molar of a juvenile hominid (KNM-WT 42718). The relative small size of the crown, its marked MD elongation and BL reduction, the relative position of the cusps, the lack of a C6 and the mild expression of a protostylid, reinforced by metrical analyses, demonstrate the distinctiveness of this tooth compared with Australopithecus afarensis, A. anamensis, A. africanus and Paranthropus boisei, and its similarity to early Homo. The LA1alpha site lies 2.2 m above the Ekalalei Tuff which is slightly younger than Tuff F dated to 2.34+/-0.04 Myr. This juvenile specimen represents the oldest occurrence of the genus Homo in West Turkana.     

HOME: highly optimized microscope environment.

The Highly Optimized Microscope Environment (HOME) is a computerized microscope designed to assist pathologists and cytotechnicians in clinical routine tasks. The prototype system consists of a IBM-PC compatible computer and a light microscope in which a built-in high-resolution computer display image is superimposed on the optical image of the specimen. Also, a manually operated encoding stage and objective turret encoder are used to provide continuous monitoring of the stage coordinates and microscope magnification to the computer. This allows any position on a slide to be uniquely defined and makes it possible to measure interactively lengths and areas larger than the size of the microscope field. Software, written in the C language and operating under the MS-DOS/MS-Windows environment, is controlled by means of a mouse-driven cursor moving over menu light-buttons displayed on the microscope image. The HOME microscope workstation is potentially useful in a wide range of applications such as i) tagging information on particular cells and tissue structures that can thus be accurately located and relocated, ii) performing morphometric measurement, differential counting, and stereological assessment of biological specimens, and iii) training and educating laboratory personnel. Finally, HOME will offer in the near future a user-friendly interface for automatic image processing of cells and tissue entities in interactively selected specimen areas.     

Existence of two chalone-like substances in intestinal extract from the adult newt, inhibiting embryonic intestinal cell proliferation.

The inhibiting effect of tissue extract from fully differentiated intestinal mucosa of adult animals on proliferation kinetics of exponentially growing embryonic epithelial gut cell populations was studied in the newt Pleurodeles waltlii. Crude extract was fractionated by G-200 Sephadex chromatography and the effect of fractions on cell proliferation was studied using both mitotic index and 3-H-thymidine incorporation methods. The inhibitions we obtained were then displayed by means of cytophotometric study of age distribution of intestinal gut cells around the cell cycle, measuring the Feulgen-DNA content. The results revealed the presence of two chalone-like substances in the intestine of adults. One (factor 1) is characterized by a molecular weight of between 120,000 and 150,000 and inhibits the cell cycle at the end of the G1 phase, the other (factor 2) is characterized by a molecular weight lower than 2000 and inhibits the cell cycle in the course of the G2 phase. The cells delayed in the G2 phase escape from inhibition but the cells delayed in the G1 phase do not, although availability time of both factor 1 and factor 2 is about 12 hr. It is thus thought that cells prevented from dividing in G1 phase are indefinitely delayed in this phase and possibly differentiate.