Biomedical subjects
Publications and source records attributed to P A Valen.
We have reported a case of septic sternoclavicular arthritis illustrating a rare complication of infection with a relatively common pathogen, Haemophilus influenze. Early identification of the infecting organism and appropriate antibiotic therapy are essential to prevent further morbidity from the complications of this unusual pyoarthritis.
Myoadenylate deaminase (MADA) deficiency has been associated with symptoms of postexertional aches, cramps, weakness, and skeletal muscle dysfunction. Measurement of plasma lactate and ammonia concentrations after forearm ischemic exercise has been suggested as a screening test for this disorder. We performed forearm ischemic tests on 3 patients with histochemically defined MADA deficiency and 13 healthy control subjects, in a standardized fashion. Our results demonstrated that subject effort and/or performance during the exercise portion of testing is a critical variable. In addition to lactate and ammonia, plasma purine compounds (adenosine, inosine, and hypoxanthine) were measured. The finding of decreased purine release after exercise in MADA-deficient patients compared with that in normal individuals increases the specificity of the test and supports the hypothesis that disordered purine metabolism occurs in MADA deficiency.
These results indicate that measuring venous ammonia concentrations after forearm ischemic exercise is an effective means of screening for MADA deficiency but that submaximal exercise performance, whether due to weakness, pain or poor effort, can provide false positive results. Measurements of purine compounds released after exercise may increase the specificity of forearm ischemic exercise testing for MADA deficiency. The low level of purines released after exercise in MADA-deficient subjects supports the hypothesis that disordered purine metabolisms occurs when MADA activity is absent.