The cell cycle in psoriasis

The cell cycle has been determined in eight in-patients with psoriasis. The cell cycle time for the germinative cell compartment has been found to be 91 h, and the turnover time for the epidermal compartment, beneath the keratin layer to be 120 h (5 days). The duration of the S phase (DNA synthesis) has been found to be 10 h, and that for mitosis 30 min. If it is accepted that the turnover time for the keratin layer is 2 days, then the turnover time for the epidermis in psoriasis is 7 days, and not 3–4 days as previously described.     

AUTOMATED LOCATION OF DYSPLASTIC FIELDS IN COLORECTAL HISTOLOGY USING IMAGE TEXTURE ANALYSIS

Automation in histopathology is an attractive concept and recent advances in the application of computerized expert systems and machine vision have made automated image analysis of histological images possible. Systems capable of complete automation not only require the ability to segment tissue features and grade histological abnormalities, but must also be capable of locating diagnostically useful areas from within complex histological scenes. This is the first stage of the diagnostic process. The object of this study was to develop criteria for the automatic identification of focal areas of colorectal dysplasia from a background of histologically normal tissue. Fields of view representing normal colorectal mucosa (n=120) and dysplastic mucosa (n=120) were digitally captured and subjected to image texture analysis. Two features were selected as being the most important in the discrimination of normal and adenomatous colorectal mucosa. The first was a feature of the co-occurrence matrix and the second was the number of low optical density pixels in the image. A linear classification rule defined using these two features was capable of correctly classifying 86 per cent of a series of training images into their correct groups. In addition, large histological scenes were digitally captured, split into their component images, analysed according to texture, and classified as normal or abnormal using the previously defined classification rule. Maps of the histological scenes were constructed and in most cases, dysplastic colorectal mucosa was correctly identified on the basis of image texture: 83 per cent of test images were correctly classified. This study demonstrates that abnormalities in low-power tissue morphology can be identified using quantitative image analysis. The identification of diagnostically useful fields advances the potential of automated systems in histopathology: these regions could than be scrutinized at high power using knowledge-guided image segmentation for disease grading. Systems of this kind have the potential to provide objectivity, unbiased sampling, and valuable diagnostic decision support. © 1997 John Wiley & Sons, Ltd.     

Blood Group Antibody Levels in Hiroshima

Blood group antibody levels were measured in 526 irradiated survivors ofthe 1945 atomic bombing of Hiroshima and in 516 nonirradiated subjects. Thestudy was undertaken in order to determine the age changes in antibody levelsin irradiated and nonirradiated subjects, as well as to investigate the patternof blood agglutinin levels in the Japanese population for comparison with thatof Caucasians. The following observations were made:

1. In 475 people of group A, 228 of group B, and 339 of group O, the meanserum levels of anti-A and anti-B antibodies were virtually identical irrespective of the blood group of the subjects.

2. In individual group O subjects, the titers of anti-A and anti-B antibodieswere very highly correlated (correlation coefficient of +.92).

3. Females exhibited higher antibody levels, although the magnitude of thedifference was small.

4. Peak antibody titers were reached at age 20-30, with progressive linearregression in levels with advancing age. Peak titers in early adulthood were5-10 times higher than those of the very elderly.

5. No correlation between blood group antibody levels and atomic irradiationwas detected, whether irradiation was represented by (a) presence or absenceof acute radiation symptoms in 1945, (b) distance from the hypocenter, or(c) numerical dosage estimate.

6. As one of a battery of tests of physiologic aging designed for detection ofirradiation induced nonspecific aging acceleration, blood group antibodylevels seem of modest value. After age 30, the linear correlation with chronologic age is -.72.

7. Differences in blood group antibody levels in Japanese and Caucasiansindicate that (a) Caucasians have higher anti-A antibody levels as comparedto anti-B levels than do Japanese, and (b) the peak antibody level occurs atan earlier age in Caucasians than in Japanese. It is not clear whether thesedifferences are related to race and heredity or to external antigenic stimulationwith A and B antigenic materials, but studies of blood group antibody levelsin different racial groups should help elucidate the nature of these differences.

Accepted on January 20, 1961     

Childhood Kaposi's sarcoma in Papua New Guinea

Abstract In the country of Papua New Guinea, with its diverse population of nearly 3 million people, some disease patterns have a strange similarity to those seen in tropical Africa. Kaposi's sarcoma is a condition which is commonly seen in adult males; childhood Kaposi's sarcoma is relatively uncommon. Six cases, all males, aged from 6 months to 12 years have been detected since 1978. The primary organ involvement included skin in four cases, oral cavity in one case and lymph node in one case. The varied clinico-pathological features are described. This is the first report of such cases from Papua New Guinea.