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G A Nicholson

Publications and source records attributed to G A Nicholson.

99 records · Page 6Linked to original sources
PubMed1977

Pedigree testing in Duchenne muscular dystrophy.

Female relatives of 41 Duchenne muscular dystrophy proband cases were studied with a panel of carrier-detection tests. A total of 277 relatives were tested in order to determine which mothers had affected sons as a result of new mutation. In 39 of 41 pedigrees the data demonstrate that a mutation cannot be postulated; the 2 megative pedigrees were inadequately tested. Our data suggest that all mothers of affected sons should be considered genetic carriers (heterozygotes) until proved otherwise. Our findings also raise questions concerning what mechanisms skew the indirect statistical estimates of mutation that are in common use.

Adolescent↗
PubMed1977

Is there acetylcholine receptor in human thymus?

Recent studies have suggested that thymus tissue of the calf may bear nicotinic acetylcholine receptors. The presence of similar receptors in thymus tissue of man could thereby serve as a source of antigen for the production of antibody to the acetylcholine receptor in patients with myasthenia gravis. In the present experiments, human thymus tissue was examined for the presence of acetylcholine receptor. Both [125I] alpha-bungarotoxin binding and antiserum to the human acetylcholine receptor were used in tests for acetylcholine receptor in thymus glands from normal individuals and from patients with myasthenia gravis. Neither normal nor myasthenic thymus tissue were found to possess the [125I] alpha-bungarotoxin binding or the antigenic properties of the acetylcholine receptor.

Antibodies↗
PubMed1977

Some properties of human skeletal muscle creatine kinase.

Creatine kinase has been purified from human skeletal muscle. The properties of the human enzyme are similar to those of the enzyme from rabbit muscle. The molecular weight was determined as approximately 80000 with a probable two reactive sulphydryl groups per molecule. Manganous (II) ion was almost as effective as magnesium as the activating metal ion, and calcium and cobalt could also act in this capacity. Under standardized conditions the nucleotide specificity was ADP greater than dADP greater than IDP greater than GDP greater than UDP greater than XDP in the reverse reaction. No hydrolytic activity was observed with ATP. Initial velocity and product inhibition studies were used to determine various kinetic constants for the substrates of the enzyme. It was concluded that, as for the rabbit muscle enzyme, the reaction probably followed a rapid equilibrium random mechanism. Anomalous kinetic behaviour, however, was observed for the forward reaction for MgATP2- but not for creatine, when measurements were extended over a much wider range than normally used. The reciprocal plot of velocity as a function of substrate concentration gave a curve, concave downwards, instead of a straight line.

Creatine Kinase↗
PubMed1977

Lactate dehydrogenase isoenzyme in detecting carriers of Duchenne muscular dystrophy.

Thirty mothers of patients with Duchenne muscular dystrophy were studied with serum enzyme tests, including serum glutamic-oxaloacetic transminase, creatine kinase, and lactate dehydrogenase isoenzymes. In addition, females from the mothers' pedigrees were studied. Lactate dehydrogenase isoenzyme 5 determinations were as senitive an indicator of carrier status as creatine kinase and also identified several mothers who had normal dehydrogenase isoenzyme 5 determinations, as well as extensive pedigree testing, identified 28 to 30 mothers as probable heterozygotes. These data independently support the suggestion that cases of Duchenne muscular dystrophy as a result of spontaneous mutation are more uncommon than currently accepted.

Adult↗
PubMedDate not supplied

The effect of aerobic exercise on serum creatine kinase activities.

Aerobic exercise is now a common form of recreational exercise among young women. In a previous study, more than a third of a group of young mothers volunteering blood samples to establish a creatine kinase (CK) reference range for Duchenne muscular dystrophy (DMD) carrier detection regularly participated in aerobic exercise programs. Aerobic exercise programs include eccentric exercises. As eccentric exercise is known to produce a delayed CK peak, this study was carried out to determine the effect of aerobic exercise on serum CK activities. The postexercise serum CK activity peak was monitored in 15 young women (age range 20-23 years) following aerobic exercise classes (45 minutes on 3 consecutive days). Peak values at 24-48 hours following the last class ranged from 90 to 3473 U/liter, or 1.55 to 34.71 times resting values. It is concluded that aerobic exercise programs should be excluded in order to obtain accurate resting serum CK values for muscle disease diagnosis.

Creatine Kinase↗