Biomedical subjects

A Berg

Publications and source records attributed to A Berg.

At least 307 records · Page 17Linked to original sources

PubMed1976

Resting muscle levels and the influence of exercise on serum amino acid-arylpeptidase activity in man.

Activities of amino acid arylamidases in skeletal muscle and serum of healthy male subjects were investigated using various substrates (Ala-, Leu-, Phe- and S-benxylcysteine-4-nitroanilides). At rest, there is no agreement between muscle and serum activity patterns. After physical exercise, the serum increase of Ala-, Leu- and Phe-AP activities is closely correleated to their respective activities in resting muscles. Since there is no relationship of the postexercise increase of amino acid arylpeptidase activitiy and exercise-induced intrasvascular haemolysis, it appears highly probable that the origin of the serum activity increase after physical work is skeletal muscle.

Adolescent↗

PubMed1976

Characterization of a cytochrome P-450-dependent steroid hydroxylase system present in Bacillus megaterium.

Cell-free extracts from sonically disrupted Bacillus megaterium ATCC 13368 hydroxylated a variety of 3-oxo-delta4-steroids in position 15beta in the presence of NADPH and O2. Ring A-reduced, aromatic and 3beta-hydroxy-delta5-steroids did not serve as substrates for the 15beta-hydroxylase system. Using ion exchange chromatography on DEAE-cellulose and gel filtration on Ultrogel ACA-54 it was possible to resolve the hydroxylase system into three proteins: a strictly NADPH-dependent FMN-containing (megaredoxin reductase), an iron-sulfur protein (megaredoxin), and cytochrome P-450 (P-450meg). The activity of the 15beta-hydroxylase system was fully reconstituted upon combination of these three proteins and addition of NADPH. Megaredoxin had an apparent sulfur to iron ration of 0.98 and showed g-signals at 1.90, 1.93, and 2.06 when analyzed by electron paramagnetic reso0 times and the preparation contained 1 to 2 nmol of cytochrome P-450 per mg of protein. This preparation of cytochrome P-450meg sedimented as a homogeneous zone on sucrose gradients with a sedimentation coefficient of 3.3 S and contained 0.94 nmol of heme per nmol of cytochrome P-450. The oxidized form of cytochrome P-450meg showed absolute absorption maxima at 416, 528, and 565 nm whereas the reduced form showed maxima at 411 and 542 nm. The following scheme is suggested for the electron transport in the 15beta-hydroxylase system in B. megaterium: NADPH leads to megaredoxin reductase leads to megaredoxin leads to cytochrome P-450meg.

Bacillus megaterium↗

PubMed1976

Fear of trying.

Unless the nutrition community intervenes in national and international policymaking, the world could well be headed for serious trouble with deaths from starvation on a consequential scale. There has been near-total dissociation between agricultural planning policies and food distribution and nutritional needs of populations. Unfortunately, the nutrition community is out of the mainstream of forces which affect nutritional status and which produce the macro-decisions. Why? Perhaps the professionals have too narrow a view of their role; although malnutrition is a health problem, the solution is not necessarily one of health delivery. Perhaps they don't seriously wish to be involved with policy change and the work it entails. Perhaps, by being unable to achieve consensus within their own ranks, they have generated a lack of credibility. The nutrition community needs to recognize a broader scope for nutrition and to take new approaches in advocacy directed to education policy-makers. No one else can play this role with authority.

Agriculture↗

PubMed1975