Overexpression of human catalase inhibits proliferation and promotes apoptosis in vascular smooth muscle cells.

The role of reactive oxygen species, such as superoxide anions (O(2). (-)) and hydrogen peroxide (H(2)O(2)), in modulating vascular smooth muscle cell proliferation and viability is controversial. To investigate the role of endogenously produced H(2)O(2), rat aortic smooth muscle cells were infected with adenoviral vectors containing cDNA for human catalase (AdCat) or a control gene, beta-galactosidase (AdLacZ). Infection with AdCat resulted in dose-dependent increases in intracellular catalase protein, which was predominantly localized to peroxisomes. After infection with 100 multiplicity of infection (MOI) of AdCat, cellular catalase activity was increased by 50- to 100-fold, and intracellular H(2)O(2) concentration was reduced, as compared with control. Infection with AdCat reduced [(3)H]thymidine uptake, an index of DNA synthesis, in cells maintained in medium supplemented with 2% serum (0.37+/-0.09 disintegrations per minute per cell [AdLacZ] versus 0.22+/-0.08 disintegrations per minute per cell [AdCat], P<0.05). Five days after infection with 100 MOI of AdCat, cell numbers were reduced as compared with noninfected or AdLacZ-infected cells (157 780+/-8413 [AdCat], P<0.05 versus 233 700+/-3032 [noninfected] or 222 410+/-5332 [AdLacZ]). Furthermore, the number of apoptotic cells was increased 5-fold after infection with 100 MOI of AdCat as compared with control. Infection with AdCat resulted in induction of cyclooxygenase (COX)-2, and treatment with a COX-2 inhibitor overcame the AdCat-induced reduction in cell numbers. These findings indicate that overexpression of catalase inhibited smooth muscle proliferation while increasing the rate of apoptosis, possibly through a COX-2-dependent mechanism. Our results suggest that endogenously produced H(2)O(2) importantly modulates survival and proliferation of vascular smooth muscle cells.

The reappearance of polio. Postpolio syndrome.

Although polio is often considered a disease of the past, new symptoms are appearing in patients infected with the polio virus many years ago. Many patients who contracted a paralytic form of poliomyelitis 3, 4, or even 7 decades ago are now relieving their childhood symptoms in what is known as postpolio syndrome.

Awareness of congestive heart failure in the podiatric practice.

The authors review congestive heart failure and present a case report. The basic signs, symptoms, and treatment modalities are discussed in order to provide more complete knowledge of a condition commonly seen by the podiatrist. Interaction between the family physician and the podiatric physician create the necessary team to deal with cardiac decompensation.