No abstract

We developed an assay to quantify LDL transcytosis across endothelial cells and discovered an unexpected role for SR-BI. Elucidating the mechanisms of LDL transcytosis may identify novel targets for the prevention or therapy of atherosclerosis.

We have used an extremely accurate, dedicated, real time computerized image analysis system to facilitate the manual quantification of changes in the prevalence of mitotic figures and apoptotic bodies in male rat pituitary following surgical adrenalectomy and, 14 days later, dexamethasone treatment. Under basal conditions, the prevalence of mitotic figures and apoptotic bodies was 0.066+/-0.016% and 0.030+/-0.012% (mean+/-SE) respectively. Dexamethasone treatment reduced the prevalence of mitotic figures and, in adrenalectomized animals, produced a highly significant and reproducible burst of apoptotic activity that peaked 48 h after the beginning of treatment (0.261+/-0.022%) before falling sharply to control levels within a further 8 h. Two weeks after the start of dexamethasone treatment, total pituitary cell numbers continued to decline. The rate of accumulation of mitotic figures in vivo after colchicine treatment indicates that mitosis is histologically overt in 2 microm thick hematoxylin and eosin stained sections under the light microscope for around 80 min; that apoptosis--identified as classical apoptotic bodies--is overt for 44 min and that, on average, a young, adult, male rat anterior pituitary cell either dies or divides as frequently as once every 60-70 days. These data show that transient and apparently trivial fluctuations in the prevalence of apoptotic and mitotic events have a profound effect on pituitary cell population dynamics, and demonstrate that dexamethasone treatment of adrenalectomized rats produces a decline in total anterior pituitary cell numbers that continues for at least 2 weeks after the start of glucocorticoid treatment.

Hypertension is characterized by elevated blood pressure (BP) and autonomic dysfunction, both thought to be improved with exercise training. Isometric handgrip (IHG) training may represent a beneficial, time-effective exercise therapy. We investigated the effects of IHG training on BP and traditional and nonlinear measures of heart rate variability (HRV). Pre- and post-measurements of BP and HRV were determined in 23 medicated hypertensive participants (mean ± SEM, 66 ± 2 years) following either 8 weeks of IHG training (n = 13) or control (n = 10). IHG exercise consisted of four unilateral 2-min isometric contractions at 30% of maximal voluntary contraction, each separated by 4 min of rest. IHG training was performed 3 days/week for 8 weeks. IHG training decreased systolic BP (125 ± 3 mmHg to 120 ± 2 mmHg, P < 0.05) and mean BP (90 ± 2 mmHg to 87 ± 2 mmHg, P < 0.05), while sample entropy was increased (1.07 ± 0.1 to 1.35 ± 0.1, P < 0.05) and the fractal scaling distance score was decreased (0.34 ± 0.1 to 0.19 ± 0.1, P < 0.05). No significant changes were observed in traditional spectral or time-domain measures of HRV or control participants. IHG training improves nonlinear HRV, but not traditional HRV, while reducing systolic and mean BP. These results may highlight the benefits of IHG training for patients with primary hypertension.

This study reports on the diagnosis and treatment of chondral delamination in the knees of soccer players. The authors attempted to provide a clinical standard for comparison with emerging cartilage repair techniques. Twenty-three consecutive chondral fractures in a homogeneous population of athletes were evaluated using physical examination, magnetic resonance imaging, and arthroscopic examination. All knees were treated with debridement to a stable border and removal of the calcified cartilage base. Results were graded using the scoring system advocated by proponents of chondral transplant. All patients reported pain that limited soccer activities. Effusions occurred in 48%, joint line tenderness in 33%, and crepitus in 19% of the knees. Results from magnetic resonance imaging correlated with arthroscopic examination in 21% of the knees. Arthroscopic examinations revealed lesions on the medial femoral condyle in eight patients, the patella in six, the lateral femoral condyle in six, and the trochlea in three. Athletes returned to play at an average of 10.8 weeks. Repeat arthroscopic procedures in eight cases revealed fibrocartilage at the initial site. There were 6 excellent, 9 good, 0 fair, and 0 poor results at their 1-year followup examinations (15 knees). The definitive diagnosis of chondral delamination relies on a thorough arthroscopic probing of the articular surface. The early functional results of this treatment compare favorably with the autologous transplantation technique. Caution, however, is recommended when treating articular cartilage injuries because no long-term data exists on whether any treatment modality can prevent the development of degenerative joint disease.