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Biomedical subjects

E Bengtsson

Publications and source records attributed to E Bengtsson.

At least 19 recordsLinked to original sources
PubMed1991

Image operations in quantification of atherosclerosis from digitized angiograms.

This report describes a method of quantifying the inner volume (lumen volume) of a contrast medium-filled femoral artery from a roentgenogram by computerized image analysis. The various factors influencing the accuracy of the volume determination are analyzed and an image-processing procedure for the elimination of artifacts due to crossing arteries is described and evaluated. The presented methods have been used in a large study of 281 patients and the short-term reproducibility has been found to be 1.00.

Arteriosclerosis↗
PubMed1979

Malaria and haemoglobin A2 levels in northern Liberia.

The influence of malaria on HbA2 levels was investigated in two groups of children aged two to nine years from the Mano tribe of northern Liberia. One group, 174 children living in a town where there is malaria control, had a parasite rate of 6.5%, only a few having palpable spleens, but 282 children living in an area of intense malaria transmission had a parasite rate of 92%. All but one child in this group had enlarged spleens. However, the difference in proportions of elevated HbA2 values within the limits for beta-thalassaemia, 8% and 10.3% respectively, was not statistically significant (0.5 greater than P greater than 0.1). It was concluded that the influence of malaria on HbA2 levels is not significant and that this parameter is valid for detecting beta-thalassaemia trait in this population. Further, iron deficiency may be a more important factor than malaria to consider when assessing the results of HbA2 estimations.

Child↗
PubMed1979

A pocket of controlled malaria in a holoendemic region of West Africa.

Yekepa, a mining town in northern Liberia, has been built entirely since 1960 and now has a population of 16 000 inhabitants including 1500 expatriates. Although situated in a holoendemic region with constant human movements in and out of the town, the mining company has succeeded in controlling malaria in Yekepa. Furthermore, there is a constant threat of the vector in the close surroundings to the town. Control is maintained by regular residual insecticide sprayings with DDT, regular larviciding with fuel oil and fortnightly issue of amodiaquine chemoprophylactic to all workers. A Malariometric survey showed that the spleen and parasite rates were 11% and 13% respectively in the controlled areas and 95% and 67% respectively in surrounding regions not subjected to control measures. The dominant malaria parasite in the area was Plasmodium falciparum. No adult vectors were found in the town. In the surrounding villages the average room density of adult vectors was 3.8 and the sporozoite rate in a village very close to the town was 9.2%. The dominant vector of the area was Anopheles gambiae with A. Funestusalso being present. The annual per capita cost, including all control activities, is about 4--5 US dollars.

Amodiaquine↗
PubMed1979

Habits of malaria chemoprophylaxis and an analysis of breakdowns in a West African mining town.

In a West African community approximately 80% of the non-African personnel were taking malaria prophylactics in the recommended manner. The non-takers stated that they were afraid of side-effects of the drugs and/or under-estimated the risks of the disease. During one year 123 patients with clinically suspected malaria were studied. All patients with positive slides were cured with regular dose of 1.5 g chloroquine base. No chloroquine resistance was therefore demonstrated, although 4-aminoquinoline prophylaxis had been given for almost 20 years to thousands of non-African non-immunes as well as in pregnant women and children in the town. Common reasons for 'breakdowns' were febrile disease other than malaria, false positive diagnosis and improper chemoprophylaxis.

Chloroquine↗
PubMed1979

The concentration of chloroquine in serum during short and long term malaria prophylaxis with standard and 'double' dosage in non-immunes: clinical implications.

The concentration of chloroquine in serum was analysed after one week, six weeks and one year on standard dose prophylaxis (300 mg chloroquine base once a week) and after six months on the double dose. After six weeks, the standard dose gave adequate protection against malaria. During the first weeks of prophylaxis insufficient protection might be achieved by the customary standard dose. In a double-dose group many values reached the point above which a higher incidence of side-reactions have been observed.

Adult↗
PubMed1979

Analysis of reproducibility of subjective grading systems for breast carcinoma.

The inter- and intra-observer reproducibility of three grading systems for breast cancer has been analysed: those of the World Health Organisation, of Black, and of Hartveit. In addition, the components forming the basis of these grading systems were analysed separately with regard to reproducibility and interrelationship. In this analysis, degree of differentiation was also included as a parameter. The grading systems of WHO and of Black gave a stratification of the material into three categories of tumours, but that of Hartveit did not. All three systems had a low inter- and intra-observer reproducibility. Truncated component analysis indicated that the grading systems of WHO and of Black are closely related to each other and to the 'nuclear lobulation' component of Hartveit's system. The components 'pleomorphism', 'mitotic frequency', and 'hyperchromasia' of the WHO system were closely interrelated. Descriptors such as 'differentiation' and 'tubule formation' were interrelated but acted in a different direction from the others.

Breast Neoplasms↗
PubMed1979

High resolution segmentation of cervical cells.

A major problem in the automation of cervical cytology screening is the segmentation of cell images. This paper presents the present status of the work on that problem at the University of Uppsala. A dual resolution system is used. Suspect malignant cells are located at 4 mu resolution. Each such cell is rescanned at 0.5 mu resolution at two different wavelengths, 530 and 570 nm. The nucleus and the cytoplasm are isolated each by two independent methods. For the nucleus adaptive thresholding in the histogram of the 570 nm image and a contouring in a radially transformed version of that image is used. For the cytoplasm a two dimensional thresholding in the 2D histogram and a contouring in a radially transformed version of the 530 nm image is used. If the two nuclear masks agree the surrounding area is checked for disturbing objects. If also the cytoplasm masks agree and are without disturbing objects the whole cell is accepted. The result of the cytoplasm masks agree and are without disturbing objects the whole cell is accepted. The result of the segmentation is thus three categories; free cells, free nuclei and rejected objects. The shape of the objects belonging to the former two categories is checked and irregularly shaped ones are rejected as probably consisting of several overlapping nuclei. Cells passing also this test are classified as normal or malignant. The experience from using this algorithm is discussed and areas for further research are pointed out.

Cell Nucleus↗
PubMed1979

Antibodies to Rift Valley fever virus in Swedish U.N. soldiers in Egypt and the Sinai.

Swedish United Nations Emergency Forces soldiers serving in Egypt and the Sinai peninsula were serologically tested for hemagglutination-inhibiting antibodies to Rift Valley fever (RVF) virus. Eight of 170 were positive. RVF has not been reported outside Africa, and a survey of 500 Swedish soldiers who had not served in the Middle East or Africa revealed no RVF virus antibodies. There were extensive RVF epidemics in Egypt in 1977 and 1978, and it is considered that these serologically positive soldiers contracted RVF disease while on duty in the Middle East.

Adult↗
PubMed1978

Computer analysis of cervical cells. Automatic feature extraction and classification.

A prescreening instrument for cervical smears using computerized image processing and pattern recognition techniques requires that single cells in the specimen can be automatically isolated and analyzed. This paper describes a dual wavelength method for automatic isolation of the cytoplasm and nuclei of cells. Density-oriented, shape-oriented and texture-oriented parameters were calculated and evaluated for more than 600 cells. It is shown that the computer can be taught to distinguish between normal and atypical cells with an accuracy of ca. 97%, while human classification reproducibility is ca. 95%. In addition, an attempt to assign a measure of atypia to individual cells is described.

Cell Nucleus↗