Automatic Counting Method Research Articles

画像処理法によるＣＮフィルムのエッチピット自動計数

The authors evaluated the performance of an automatic counting for CN film etch-pits in large area as 1cmcm2 by an image processing method. Since the gray-level of the etch-pit image made from a fixed α-particle energy (_??_ 4MeV) is almost constant after shading correction processing, it is expected to get the same counts as manual counts by determining suitable threshold at binarization. The decrease of counts due to pile-up of the etch-pit image could be corrected by calculating the pile-up probability geometrically. Using the image processing method and the pile-up correction, they could get the same counts by automatic counting and manual counting methods for the etch-pits ranging 0-4, 000tracks/cmcm2 made from 2MeV α-particles and 0-1, 000tracks/cmcm2 obtained with cup radon monitors in various living environments.

Enumeration of cells in bone marrow and peripheral blood stem cell collections: technical issues and prospects for standardization.

Enumeration of total nucleated cells and mononuclear cells is a fundamental part of the laboratory evaluation and quality control program for bone marrow and peripheral blood stem cell collections intended for transplantation. Measurement of the total nucleated cell content is especially useful for providing rapid feedback about the bone marrow product during or immediately after the harvest. However, the mononuclear cell content may be more informative because the nucleated cell population contains a variable number of mature granulocytes and nucleated red cells, which do not contribute to hematopoietic engraftment. The lack of comparative data among various laboratories and among different types of cell counting methods has hindered standardization of these assays among bone marrow processing laboratories. Specific issues needing attention in assay standardization include sample preparation and handling, identification and elimination of artifacts in automated counting, relative advantages and disadvantages of manual and automated counting methods, and criteria for differential counting of nucleated cells. The establishment of standards for bone marrow and other stem cell counting methods, as well as other evaluation procedures, should be preceded by collection and analysis of comparative data, and followed by a proficiency testing program for bone marrow processing laboratories.

A laser‐light pulse counting method for automatic and sensitive counting of bacteria stained with acridine orange

A laser‐light pulse counting method was developed and investigated for its ability automatically to count acridine orange‐stained bacteria and microcolonies of bacteria on the surface of polycarbonate membrane filters. The system consisted of an Argon laser which delivered a 5 μm diameter spot of coherent 488 nm wavelength light which was raster scanned across a 5×2 mm area of the membrane. Fluorescence pulses of orange light (ca 650 nm) were detected via a dichroic mirror and barrier filter with a photomultiplier tube. For microcolony preparations a good relationship between the number of light pulses and cell density down to below 102/ml was observed, but at lower cell densities counting was not reliable, probably because of fluorescent debris. The method was also able to count single cells, but background auto‐fluorescence and photo‐bleaching produced a high and variable background signal in some samples.

Accuracy of an automated counting method by television-computer equipment in the quantitative autoradiography

Commercially available television-computer equipment was used in the counting of silver grains in autoradiograms. The counting was made very rapidly and easily. The counts were compared with the counts made visually. With some limitations both counts showed excellent agreement. The accuracy of the method used is discussed.

The effect of advanced old age on the neurone content of the cerebral cortex: Observations with an automatic image analyser point counting method

The effect of advanced old age on the nerve cell content of the cerebral cortex was examined in 19 non-demented persons aged 69–95 years, using a Quantimet 720 image analysing computer to make area proportion measurements. Neurone loss around 1.0% per annum was found both in the neocortex and in the medial hippocampus. There was also significant shrinkage of neurones in the hippocampus. Macroscopic measurements of the cerebral hemispheres by means of point-counting morphometry showed a corresponding reduction in the volume of white matter amounting to about 0.8% per annum, but only a minor change in the cortex volume. This finding is consistent with the occurrence of dendritic growth of surviving neocortical neurones. By contrast, there appears to be no compensatory dendritic proliferation in the medial hippocampus since tissue atrophy was commen-surate with cell loss in this region.

The evaluation of airborne asbestos fibres using a scanning electron microscope.

Asbestos fibres sampled on Nuclepore filters can be directly examined by scanning electron microscope in much greater detail than is possible using the conventional optical microscope/membrane filter technique. Results obtained by the two methods for fibres > 5 μm in length were in good agreement. The new technique could facilitate the development of automatic counting methods for asbestos fibres.

Behavior of dog thrombocytes in the blood circulation system during infusions with colloidal blood substitutes

The behavior of platelets was investigated with an automatic platelet counting method. A pure dilution reaction was observed after infusion of Glucose and Dextran 75. Whereas Dextran 40 caused a considerable diminution of platelets, Haemaccel (Gelatine) decreased platelet concentration significantly, an effect which is reversed within 60 min at the latest. Is is thought that this is caused by platelet aggregation in combination with the filtration-mechanism of the capillary bed and subsequent disaggregation.