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Biomedical subjects

A Weber

Publications and source records attributed to A Weber.

At least 649 records · Page 36Linked to original sources
PubMed1975

Calcium binding to rabbit skeletal myosin under physiological conditions.

At a free Mg2+ concentration of 1.0 mM, myosin binds one Ca2+ per molecule when the Ca2+ concentration is 20 muM, a value in the concentration range expected during contraction of skeletal muscle. Mg2+ alters Ca2+ binding in a complex manner, not by simple competition. In the range from 20 to 100 muM Mg2+ it produces positive cooperativity between the high-affinity Ca2+ binding sites, in addition to shifting binding to higher Ca2+ concentrations. High-affinity Ca2+ binding is not significantly affected by the addition of ATP, increase in ionic strength to 0.1 and changes in temperature. Ca2+ binding did not increase actin-activated ATPase activity in the absence of regulatory proteins, but rather inhibited it.

Actins↗
PubMed1975

Correction of the malabsorption of the preterm infant with a medium-chain triglyceride formula.

After receiving milk-based formula for one week, 16 preterm infants, weighing 1,300 to 1,800 gm, were fed two isocaloric formulas containing either medium-chain or long-chain triglycerides for 15 days; the alternate formula was given for a second period of identical duration. While receiving MCT, the infants had greater (P smaller than 0.01) percent fat absorption (83.4 leads to 97.1%) and weight gain (7.5 leads to 11.5 gm/kg/100 calories). Because metabolic acidosis occurred with the LCT formula, the chloride content was adjusted to that of the MCT were confirmed and, in addition, there was a higher (P smaller than .01) percent retention of nitrogen (67.3 leads to 82.1).

Body Weight↗
PubMed1975

Conformational change and cooperativity in actin filaments free of tropomyosin.

The decrease in amplitude of the electron spin resonance spectrum of the cysteine-bound spin-label, 3-(maleimidomethyl)-2,2,5,5-tetramethyl-1-pyrrolidinoxyl, brought about by the magnetic interaction with tightly bound manganous ion, was used as a probe of conformational change in actin on binding myosin. The magnitude of this "spin--spin" interaction first decreased then increased on increasing saturation of the actin filament with heavy meromyosin subfragment-1. That the "spin--spin" interaction occurred between spins of adjacent monomers was demonstrated by the observation that the change in magnitude of the "spin--spin" interaction was maintained on binding of heavy meromyosin subfragment-1 to copolymers in which actin monomers containing both manganous ion and spin label were diluted 7-fold with native actin monomers. These data provide evidence for a conformational change in actin on interacting with heavy meromyosin subfragment-1. Further, the fact that not only the magnitude but also the sense of the change in the "spin--spin" interaction is a function of increasing saturation with heavy meromyosin subfragment-1 indicates that the monomers of the actin filament are capable of cooperative interaction in the absence of tropomyosin.

Actins↗
PubMed1975

[Results of hallux valgus operations in young adults (author's transl)].

Compared were the results of three different hallux valgus operations (operations according to: Hohmann, Du Vries and Brandes) of young patients. As expected, the 2/3-resection according to Brandes showed unsatisfactory results, cosmetically and functionally. For this reason, this method should only be used with hallux valgus with a metatarso-phalangial joint with athrotic changes and with the polyarthritis foot. On the other hand, there can be obtained in most cases quite good results or at least satisfactory ones by the subcapital osteotomy according to Hohmann and Du Vries. The risk of a posterior metatarso-phalangial joint arthrosis seems us to be higher with the method according to Du Vries as according to Hohmann.

Adolescent↗