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Biomedical subjects

H Strauss

Publications and source records attributed to H Strauss.

At least 37 records · Page 2Linked to original sources
PubMed1984

Steps in the stabilization of newly packaged DNA during phage P22 morphogenesis.

The protein products of three adjacent P22 genes, 4, 10 and 26, are required for the stabilization of DNA newly packaged into P22 phage capsids. We have isolated unstable DNA containing capsids from cells infected with mutants defective in these genes. All three classes could be converted into mature phage in vitro, confirming that they represent intermediates in particle maturation. The first of the three proteins to add to the newly filled capsids is gp4, followed by gp10 and gp26. The active form of gp4 sediments at 3 S, while the active forms of both gp10 and gp26 sediment at 5 S. These soluble subunits appear to polymerize onto the newly filled capsids to form the neck of the mature phage, the channel for DNA injection. Since gp4 is the first protein to act after DNA packaging, the unstable DNA containing capsids from 4- -infected cells must represent the direct product of the packaging of DNA into procapsids. The major fraction of these capsids lost activity with a half-life of 1.1 minutes at 23 degrees C, though they were much more stable at 0 degree C. Electron microscopic observations indicated that the loss of activity was due to the DNA exiting from the incomplete capsids. The marginal stability of the condensed DNA molecules within capsids is consistent with models of ATP-driven condensation and spontaneous DNA ejection. The basis of the stability of these highly condensed molecules remains to be determined.

Capsid↗
PubMed1982

[Investigations in Bioavailability of resinates as peroral retard drug dosage forms. Part 1: Pharmaceutical availability of dihydrocodein-resinates (author's transl)].

The dissolution rate constants of dihydrocodein in two retard drug dosage forms based on synthetic ion exchange resin were determined with four dissolution methods. The usage of the flow cell, rotationsdisk method and half-change method with a new dissolution model gave comparable results. Using the paddle apparatus the dissolution is very quick. There is only a small influence on the dissolution rate by the pH. A higher ionic strength of the dissolution medium increases the dissolution rate.

Biological Availability↗
PubMed1981

Relationship between creativity, repression, and anxiety in first graders.

The present study dealt with the extent to which creativity may be identified in 71 first graders and raised the question of whether and how creativity is related to anxiety and repression at this young age. Furthermore, correlation of 0.62 was obtained between creativity and decrease in repression. The various subtests and the four dimensions of creativity were separately analyzed in relation to anxiety and repression, and the results were discussed. No relation was found between intelligence and the dynamic variables of anxiety and repression.

Anxiety↗
PubMed1979

Keratoacanthoma: case presentation and discussion.

Keratoacanthomas are rather common, rapid growing skin tumors, in which may occur as solitary lesions or in the form of multiple lesions. Multiple forms involve the palms of soles, and their source is unclear. On area where hair grows, these lesions originate from the infundibular areas. Many environmental and traumatic influences are implicated as potential etiologic factors. Keratoacanthomas should be differentiated clinically and histologically from squamous cell carcinomas, prurigo nodularis, and chronic paronychia. Treatment varies according to the type of lesions, but solitary lesions should be excised in toto.

Diagnosis, Differential↗
PubMed1976

Enzymatic hydrolysis of 1-monoacyl-SN-glycerol-3-phosphoryl-choline (1-lysolecithin) by phospholipases from peanut seeds.

Hydrolysis of 1-lysolecithin (1-acyl glycerophosphorylcholine [1-acyl GPC]) by preparations of phospholipase D from peanut seeds was investigated. 1-Lysolecithin was hydrolyzed at a much slower rate than phosphatidylcholine (lecithin). Although Ca+2 ions are required for the cleavage of lecithin by the enzyme, their effect on the hydrolysis of lysolecithin depended upon the concentration of the substrate: at 0.2 mM 1-lysolecithin, Ca+2 ions increased the reaction rates, whereas at concentrations of the substrate lower than 0.1 mM, Ca+2 ions were inhibitory. A broad pH activity curve between 5 and 8 was obtained with higher rates in the alkaline range, both in the absence and presence of Ca+2 ions. The increased hydrolysis of lysolecithin due to Ca+2 was noticed over the entire pH range. Upon storage of the enzyme solutions at 4 C, decreased rates of hydrolysis of lecithin were observed, with t 1/2 values of ca. 50 and 100 days depending on the purity of the preparation. During the same period, no reduction occurred in the activity of these preparations on lysolecithin as substrate. The effects of Ca+2 ions and the analysis of the products of 1-acyl GPC cleavage by the enzyme preparations revealed the presence of more than one enzyme and the formation of the following compounds: lysophosphatidic acids (1 acyl glycerophosphoric acids), free fatty acids, glycerophosphorylcholine, and choline. The possible pathways leading to the degradation of lysolecithin and the formation of these products include reactions catalyzed by lysophospholipase A1 (lysophosphatidylcholine 1-acyl hydrolase, E.C. 3.1.1.5) and a phosphodiesterase (L-3-glycerylphosphorylcholine glycerophosphohydrolase, E.C.3.1.4.2), in addition to phospholipase D (phosphatidyl-choline phosphatidohydrolase, E.C. 3.1.4.4).

Arachis↗