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Biomedical subjects

W Albers

Publications and source records attributed to W Albers.

8 recordsLinked to original sources
PubMed1992

The production of fatty acid modifying enzyme (FAME) and lipase by various staphylococcal species.

Eighty-six strains encompassing 11 species of coagulase-negative staphylococci were examined for the production of fatty acid modifying enzyme (FAME) and lipase. Staphylococcus schleiferi and S. saprophyticus most closely resembled S. aureus in that 80% of the strains produced both enzymes. In contrast, no strains of S. lugdunensis and S. haemolyticus tested produced these enzymes. S. simulans was unusual in that eight of 10 strains produced FAME, but only one produced lipase. Among the other species the proportion of strains producing both enzymes ranged from 10 to 60%. Generally there was a strong correlation between FAME and lipase production.

Acyltransferases↗
PubMed1990

Design methods for some dose-response models.

A recently described design method for one-parameter biomedical models such as limiting or serial dilution assays is generalized to two-parameter models for which the dose-response relationship can be expressed as a linear regression model with parameters alpha (intercept) and beta (slope). Design formulae are proposed for three different cases in which prior information about the unknown regression parameters alpha and beta is available (alpha known, beta known and neither known, respectively). A suitable transformation of the two-parameter model enables the direct application of the one-parameter design method to the first two cases, while the third needs more advanced considerations. Two experimental designs, taken from the literature, are reproduced as closely as possible using the methods described, thus showing under which circumstances these designs are suitable.

Animals↗
PubMed1988

Using jackknife methods for estimating the parameter in dilution series.

Dilution assays are quantal dose-response assays that detect a positive or negative response in each individual culture within groups of replicate cultures that vary in the dose of cells/organisms tested. We propose three jackknife versions of the maximum likelihood estimator of the unknown parameter, i.e., the frequency of a well-defined cell within the context of limiting dilution assays or the density of organisms within the context of serial dilution assays. The methods have been evaluated with artificial data from extensive Monte Carlo experiments. As a result of these experiments and theoretical considerations, the jackknife version based on deleting one individual culture at a time is proposed as the statistical procedure of choice. The next best method is the jackknife version based on leaving out the same replicate from each of the culture groups at a time.

Biometry↗
PubMed1986

[Surgical treatment of recurrent ventral dislocation of the shoulder using the Weber rotation osteotomy].

There are different procedures for surgical treatment of a recidivating ventral dislocation of the shoulder. In our hospital the rotatory osteotomy according to Weber proved good; in accordance with the findings it can be combined with other procedures. The surgical procedures and our results are explained. In our opinion, this surgical treatment will effect, besides known results (rotation of head defect to lateral), an essential stabilisation of the joint, by means of strain exercised on M. infraspinatus and the upper part of M. teres minor.

Adolescent↗
PubMed1985

[Surgical treatment of osteochondrosis dissecans of the knee joint].

There are numerous methods for surgical treatment of osteochondrosis dissecans of the knee. These methods and their indications are pointed out. In our clinic screw-fixation of dissecates respectively of osteocartilaginous grafts proved good. Surgical procedure, after-treatment and results are reported.

Adolescent↗
PubMed1977

A-V block.

Explore the source record for details and available documents.

Atrioventricular Node↗
PubMed1975

Sodium + potassium-activated ATPase of mammalian brain. Regulation of phosphatase activity.

1. The K+-nitrophenylphosphatase activity associated with mammalian brain (Na+ + K+)-ATPase displays K+ activation curves that have intermediary plateaus and maxima in the presence of less than saturating concentrations of Na+. Zero Na+ and saturating Na+ produce sigmoid K+-activation curves with low and high K+ affinities respectively. 2. ATP inhibits K+-activated nitrophenylphosphatase through both competitive and non-competitive mechanisms. ATP is synergistic with Na+ in the mechanism which converts the enzyme from low to high K+ affinity. 3. The Na+ and K+ interactions can be accounted for by equations which describe a model with separate regulatory sites for Na+ and K+ and with K+- requiring catalytic site which is only accessible in one of the two principal conformational stages of the enzyme. 4. The effects of ATP can be accounted for by the same model through interactions at a single nucleotide binding site. Inhibition which is competitive with K+ and non-competitive with substrate arises from stabilization of the inactive enzyme conformation. Inhibition which is non-competitive with K+ and competitive with substrate results from interactions with the active enzyme conformation. The synergism between Na+ and ATP appears to arise as a consequence of the formation of phosphoryl enzyme. 5. A model for (Na+ + K+)-ATPase is discussed which involves in-phase coupling of subunit interactions as suggested by these studies.

Adenosine Diphosphate↗