Biomedical subjects

E Schonberger

Publications and source records attributed to E Schonberger.

3 recordsLinked to original sources

PubMed1989

Delayed metabolic changes after strenuous exertion in trained young men.

Twenty apparently healthy, young male volunteers, aged 18-25 (mean 19.3, SD 1.4) years received a 6 months standardized, graded outdoor physical training and were screened for serum magnesium concentration (S-Mg), serum calcium concentration (S-Ca), serum aspartate amino transferase (S-AST), serum alanine amino transferase (S-ALT), serum creatine kinase activity (S-CK), other laboratory variables, weight, and VO2 ml.kg-1.min-1 [corrected] (VO2 max), before a 70 km march, as well as at 1, 24 and 72 h and 18 days after. Maximal aerobic power, body weight, haemoglobin, haematocrit, serum creatinine, total protein and albumin remained unchanged throughout. Immediately after the march, S-Mg did not change, S-AST, S-ALT and S-CK rose, but the rise was not statistically significant, while small but significant rises in S-Ca (P less than 0.05, Student's t-test) and serum cholesterol (P less than 0.01) normalized at 24 h. At 72 h after the march, a significant fall in S-Mg was found (P less than 0.01), together with a second significant rise in S-Ca (P less than 0.05). After 18 days, with no intervening marches or dietary changes, S-Mg remained significantly lowered (P less than 0.05), mean S-ALT and S-CK became significantly raised for the first time (P less than 0.001 and P less than 0.01 respectively), whereas S-Ca normalized. Concomitantly, for the first time there was now a significant rise in blood sugar (P less than 0.001), serum triglycerides (P less than 0.01), and a second rise of serum cholesterol (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1988

Magnesium fluxes in ventricular fibrillation and defibrillation in untreated and dibenzepine HC1 pretreated cats.

Serum magnesium concentration (S-Mg) was estimated in 12 anesthetized cats before and after central thoracotomy, during an electrically induced ventricular fibrillation (VF) and after defibrillation (DEF), and again, in the same experimental animals, after the administration of 3 mg/kg of dibenzepine HC1--a tricyclic antidepressant reported to facilitate spontaneous DEF--as well as during a subsequently induced VF and after the spontaneous DEF which followed. In the first part of the experiment, the surgery and the induction of VF caused no significant change of mean serum magnesium concentration (S-Mg) or serum calcium concentration (S-Ca), whereas the DEF was accompanied by Mg efflux (a significant increase of mean S-Mg from 0.824 mmol/l, SD 0.182, n = 12 to 0.991 mmol/l, SD 0.182, n = 12; P less than 0.05). In the second part of the experiment, following the administration of dibenzepine HCl there was Mg influx (a lowering of mean S-Mg to 0.891 mmol/l, SD 0.160, n = 12; P less than 0.05). During VF in the pretreated cats, S-Mg remained unchanged, while S-Ca decreased significantly (P less than 0.05), followed by a rebound Ca++ efflux (a systematic rise of S-Ca) as the animals defibrilated spontaneously. Concomitantly, there was Mg efflux (a systematic rise of S-MG), the mean S-Mg rising from 0.879 mmol/l, SD 0.143, n = 9 to 1.083 mmol/l, SD 0.257, n = 7, ie to virtually the same value as that obtained after electrically induced DEF.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Changes in serum magnesium concentration after strenuous exercise.

Serum magnesium concentration (S-Mg) was measured in 20 highly trained young men (mean age 19.5, +/- 0.5, range 18-20.5) before, and at 1 hour, 24 hours, 72 hours, and 3 months after a 120 km hike. As found in previous studies, S-Mg was significantly decreased at the end of the hike (p less than 0.001, [corrected] Student's t-test). In this group S-Mg had risen significantly after 24 hours in relation to the value at 1 hour (but not to starting value); yet, at 72 hours and 3 months later, it was once more significantly lower than the starting value (p less than 0.001 and p less than 0.05, respectively, Student's t-test). A marked elevation in serum creatine kinase activity (CK) suggests that the rise in S-Mg observed at 24 hours is the result of either exertional rhabdomyolysis or loss of membrane integrity, as a result of the strenuous exertion, since the CK had fallen sharply by 72 hours after the hike. The biphasic, statistically significant, lowering of S-Mg which persisted after 3 months suggests that strenuous exertion induces magnesium deficiency.

Adolescent↗