The average roughness and fractal dimension of articular cartilage during drying.

Cartilage is a unique material in part because of it biphasic properties. The structure of cartilage is a porous matrix of collagen fibers, permeated with synovial fluid which creates a gliding and near frictionless motion in articulating joints. However, during in vitro testing or surgery, there exists potential for cartilage to dehydrate, or dry out. The effects of this drying can influence experimental results. It is likely that drying also changes joint performance in vivo. In in vitro testing of equine cartilage explants exposed to open air, the average roughness of cartilage changes from 1.85 ± 0.78 to 3.66 ± 1.41 µm SD in a 5-h period. Significant changes in roughness in individual samples are seen within 10 min of exposure to open air. However, the multi-scale nature of cartilage, characterized by the fractal dimension, does not significantly change during the same period. The current study attempts to quantify the magnitude of error that is introduced when cartilage is removed from its native environment.

Variable clinical and hormonal manifestations of hyperandrogenemia.

This study was undertaken to contrast the hormonal profiles in patients with various hyperandrogenemic states in an attempt to correlate clinical manifestations with specific hormonal abnormalities. Patients with idiopathic hirsutism, polycystic ovaries, and a syndrome recently described by us, amenorrhea with cryptic hyperandrogenemia, ie, without hirsutism, participated. Total testosterone, the testosterone: sex-hormone-binding globulin (SHBG) ratio, and androstenedione levels were elevated in each group of patients. SHBG levels were suppressed in patients with idiopathic hirsutism and in patients with polycystic ovaries. In patients with polycystic ovaries or cryptic hyperandrogenemia, plasma estrone levels were elevated and the luteinizing hormone (LH) responses to luteinizing-hormone-releasing hormone (LH-RH) were exaggerated. Estrone is derived from androstenedione under the influence of the enzyme, aromatase. While elevated androstenedione occurred in both patients with polycystic ovaries or idiopathic hirsutism, estrone levels were only elevated in patients with polycystic ovaries. Reduced aromatase activity may have protected patients with idiopathic hirsutism from elevated estrone values and, thereby, from menstrual disturbances. The hormonal profiles in polycystic ovary syndrome and in patients with amenorrhea with cryptic hyperandrogenemia were very similar, with the exception that SHBG levels were high normal in three of five patients with cryptic hyperandrogenemia while estrone values were markedly elevated in these patients. Elevated estrone levels may explain the normal SHBG values, which are usually suppressed in hyperandrogenemic states. While each of the hyperandrogenemic disorders studied has a characteristic hormonal profile, the various clinical manifestations cannot be accounted for solely by abnormalities in circulating hormonal levels.(ABSTRACT TRUNCATED AT 250 WORDS)