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Biomedical subjects

K Ekelund

Publications and source records attributed to K Ekelund.

16 recordsLinked to original sources
PubMed2000

Rectangular solid domains in ceramide-cholesterol monolayers - 2D crystals.

Very small rectangular domains were observed by atomic force microscopy in binary monolayers of synthetic ceramides and cholesterol. When the cholesterol content is increased the domains are bigger although the rectangular shape is retained. The almost perfect shape of the domains indicates two-dimensional single ceramide crystals. Lipid domains in monolayers of this particular shape and size have to our knowledge not been reported in the literature previously.

Ceramides↗
PubMed2000

The skin barrier from a lipid perspective.

This contribution summarises the results from a number of investigations undertaken in the spirit of the Domain Mosaic Model proposed by Forslind in 1994. Atomic Force Microscopy (AFM) studies on the two-dimensional phase behaviour of some stratum corneum lipids revealed phase separation of the lipids in the typical case and the ability of cholesterol to reduce the line tension between phases. A theoretical model was developed describing the response of an oriented stack of polar lipid bilayers in the presence of a gradient in water chemical potential (water solution to humid air). The gradient gives rise to an inhomogeneous water swelling, and presumably to a liquid crystal-to-gel transition in the lamellar region closest to humid air. Skin penetration enhancers such as Azone and oleic acid cause phase transformations in lipid bilayer systems which may be relevant in the context of skin permeation.

Air↗
PubMed1998

A RAPD-PCR method for large-scale typing of Bacillus cereus.

A robust RAPD-PCR procedure for large-scale typing of Bacillus cereus was developed. It is based on a simple DNA preparation, involving only freezing and boiling of cells in water with active carbon. By using a computerized system for data collection and processing, an efficient system for handling RAPD patterns for large-scale investigations was achieved. The procedure was highly discriminatory for Bacillus cereus strains and was found to give reproducible classification of RAPD fingerprints for five reference strains.

Animals↗
PubMed1980

Output of bile and pancreatic enzymes after test meals with different fat content. Influence of body weight on pancreatic enzyme composition.

The output of bile and pancreatic enzymes after two mixed meals with different fat content was studied in 16 healthy volunteers of normal body-weight. A quantitative multiple indicator dilution method was used. The delivery of more fat per time to the duodenum after the fat rich compared to the low fat meal was followed by the emptying of more bile but did not significantly increase the pancreatic response. The ratio between amylase and lipase was constant throughout the course of a single experiment but differed between the subjects. The ratio decreased with an increasing body weight, indicating a relative dominance of amylase over lipase in the lighter and the reverse in the heavy subjects. The same correlation was found when results from a previously reported series with a glucose containing mixed meal were reexamined. It is proposed that long time dietary differences might influence the enzyme composition of the postprandial pancreatic secretion.

Adult↗
PubMed1979

[Duovac 300--udder health and milking routines. A field experiment (author's transl)].

The effect on udder health and milking routine of two Alfa Laval milking units, the Duovac 300 with a normal (380 mm Hg) and a low (250 mm Hg) vacuum phase and the standard HP 100 unit with only the normal (380 mm Hg) vacuum phase, was investigated on six dairy farms. A total of 197 cows were involved in the study. Each herd was divided into two groups which were as similar as possible in terms of age, stage of parturition and milk yield. One group was milked with the Duovac unit, while the other was milked with the HP 100 units for a test period of 100 days. No differences in cell counts from the cow samples, the presence of subclinical mastitis or clinical condition of the teats were observed between the two test groups. The total milking machine time for the Duovac units was longer than for the HP 100 units. However, the time spent in the normal vacuum phase (380 mm Hg) for the Duovac units was shorter than the total milking machine time for the HP 100 units (380 mm Hg). The Duovac units had the shortest machine stripping time, but the "waiting time" for the milkers (the time between the various operations) was longer. These time studies showed that the number of cows milked per hour by one man using four or five Duovac units was equal to or greater than the number of cows milked per hour by one man using three HP 100 units. It was recommended that no more than three HP 100 units be managed by one man.

Animals↗
PubMed1976

Relation between body weight and the gastric and intestinal handling of an oral caloric load.

The gastric and intestinal handling of a standard liquid 300-ml meal (0.89 kcal/ml) was examined in 10 healthy, non-obese subjects by a quantitative multiple-indicator dilution technique. Such a meal contains about one-tenth of the daily energy requirements. The heavier the subject the more energy was transferred from the stomach to the intestine during the first 80 minutes after taking the meal. A high body weight was also associated with a rapid transit through the proximal 70 cm of intestine and the passing of a substantial part of the meal calories to the lower intestine. These circumstances favour a fast incorporation of fed calories. In subjects with lower body weights eneryg was delivered more slowly from the stomach. The absorbed an equal amount of energy in the proximal intestine as did the heavier subjects, but during the longer transit times. The percentage absorption in the investigated segment was therefore higher.

Adult↗
PubMed1976

Jejunitis with malaborption. A quantitative study of the gastric and intestinal handling of a meal during malabsorption and after recovery.

The gastric and intestinal response to a standard meal was examined with a quantitative multiple indicator dilution technique in a patient with jejunitis and malabsorption. Examinations were made during and after recovery from disease. The malabsorptive state was associated with a marked delay of the gastric emptying paralleled by a low gastric secretion rate. Despite the low delivery rate from the stomach, large fluid volumes passed at the investigated level 70 cm distal to the pyloric sphincter. This was due to a reduced absorption of nutrients and water during a rapid transit of the proximal intestine and to persistently high pancreatic and intestinal secretion rates. A comparison with data from the healthy experiment suggests that the strong gastric inhibition during malabsorption works as an effective compensation for the decreased absorptive capacity after the second hour from meal intake and onwards.

Adult↗
PubMed1975

Output of bilirubin and pancreatic enzymes in response to different liquid test meals in man.

The output of bilirubin and pancreatic enzymes was determined after ingestion of three different liquid test meals in man. Doubling the amount of protein in a composite meal was followed by a delivery of more protein per time unit to the intestine and by a higher output of bilirubin and enzymes than was recorded after a similar meal containing less protein. The ingestion of a 15% glucose solution awoke a considerable output of bilirubin and enzymes during the first hour, thereafter it was low and decreasing. The differences in enzyme and bilirubin output corresponded to differences in quality and quantity of the emptied food components.

Adult↗