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Biomedical subjects

H Samuelsen

Publications and source records attributed to H Samuelsen.

4 recordsLinked to original sources
PubMed2001

A study of risk factors for intestinal helminth infections using epidemiological and anthropological approaches.

This study. conducted in Kisumu District, Kenya, identified important risk factors for infection with intestinal helminths using traditional epidemiological methods. This was combined with a rapid assessment study using qualitative methods, which focused on sanitation practices and local illness perceptions. The multiple logistic regression analysis revealed that the absence of latrines was a significant predictor for hookworm infection with an odds ratio (OR) of 1.9. The analysis also revealed that households without soap had a 2.6 times higher risk of being infected with Ascaris lumbricoides compared with households where soap was available, and that the number of inhabitants living in a household was a significant predictor for infections with hookworms (OR=3.2). Furthermore, the presence of children of 5 years and under in the household was a predictor for infection with A. lumbricoides (OR=2.7), while the absence of this age group was a predictor for hookworm infection (OR=3.8). The qualitative part of the study revealed that people did not consider worms as a serious health threat, but as a nuisance. Among the population. latrines were seen as beneficial because they were believed to prevent disease, to provide privacy and to keep the environment free of faeces. Handwashing was done many times a day but usually not with soap, which was mainly used when bathing or washing the whole body. Many inhabitants in a household or the presence of children of 5 years and under were never mentioned as being a disadvantage, and these elements would therefore be difficult to include in a control strategy. Since the lack of latrines and of soap were identified as risk factors for infection, while latrines, soap and medicine were seen as assets by the population, it is suggested that helminth control interventions should be concentrated within these areas in this particular society.

Age Distribution↗
PubMed1996

The combined effects of environmental conditions on lipolysis of pork fat by lipases of the meat starter culture organisms Staphylococcus xylosus and Debaryomyces hansenii.

The effects of environmental conditions on lipolysis by cell-free extracts from the meat starter culture organisms Staphylococcus xylosus and Debaryomyces hansenii were studied using pork fat emulsions as model systems. For the individual effects of temperature and pH it was found that the optimal conditions for the lipolysis by S. xylosus lipase were 37 degrees C and pH 7.0, and 37 degrees C and pH 6.5 for the lipolysis by D. hansenii lipase. For the combined effects of conditions relevant to meat fermentation, i.e. 10-30 degrees C, pH 4.7-6.0, 2.5-7.5% (w/v) NaCl and incubation times of 2-6 days, the empirical models indicated that temperature, pH and incubation time had important effects on total lipolysis whereas NaCl concentration had little effect. For both cultures lipolysis was strongly inhibited at conditions of meat fermentation compared to optimal conditions. For any set of the conditions which were examined the total lipolysis caused by D. hansenii lipase was lower than that caused by S. xylosus lipase.

Animals↗
PubMed1991

Purification of a 20 kD allergen from Aspergillus fumigatus.

Sera from patients sensitized to Aspergillus fumigatus (A.f.) were screened for specific IgE using sodiumdodecylsulphate-gradient-polyacrylamidegelelectrophoresis (SDSgPAGE) followed by immunoblotting to nitrocellulose. Approximately 25 IgE-binding components were detected. The components of molecular weight 20, 31, 44, 50, 53, 77 and 90 kD were reacting with more than 50% of the patients. The 90, 77 and 20-kD components showed up as the strongest IgE-binding bands. The 20-kD component, called Ag 20 kD, was purified and further characterized. Ag 20 kD was purified to apparent homogeneity. using a combination of size-exclusion chromatography on a Sephacryl S-200 column, preparative isoelectric focusing in a pI 2.5-6.5 gradient, and a Sephadex G-50 Superfine column. Fractions were characterized with protein and carbohydrate analyses, RAST and SDSgPAGE followed by immunoblotting to nitrocellulose. Ag 20 kD was found to be a glycoprotein as it stained with both Coomassie Brilliant Blue and PAS. However, it did not bind Con A, and thus, did probably not contain any terminal alpha-D mannopyranosyl end groups. The relation between mannose, galactose and glucose was found to be 2:1:0.5. The isoelectric point was heterogeneous within pH range 5-6, and the molecular weight was estimated to approximately 20 kD. An increased RAST response was shown for the purified component compared with crude extract using patient sera reacting with Ag 20. The antigen was shown not to be identical with the previously described Ag 3. Neither did it fit the description of Ag 5, 7 or 13 earlier described by the same group. The antigen is going to be used for further immunochemical and clinical investigations, and coupling to other systems for antigen characterization.

Allergens↗