In-hospital and long-term outcomes of patients with acute myocardial infarction undergoing direct angioplasty during regular and after hours.

Off-hours presentation resulted in a significant increase in the onset of pain to balloon inflation time (approximately 1.3 hours) as well as the emergency room to balloon inflation time (approximately 54 minutes). However, this delay to reperfusion did not result in a difference in clinical outcomes (in-hospital or long-term) in patients undergoing direct percutaneous transluminal coronary angioplasty within 12 hours of the onset of acute myocardial infarction.

Adjunctive therapies in the cath lab. Successful thrombolysis using the combination of tissue plasminogen activator and abciximab in an adult with Kawasaki's disease.

Kawasaki's disease is an acute systemic vasculitic syndrome that primarily affects children. Coronary aneurysms are common vasculitic sequelae of Kawasaki's disease. Intracoronary thrombosis and embolization are potential consequences of coronary aneurysms. We describe our experience of successful thrombolysis using the combination of reduced-dose intravenous tissue plasminogen activator and abciximab as described in the Thrombolysis in Myocardial Infarction 14 trial (TIMI 14) to treat a patient found to have intracoronary thrombus at the site of aneurysm formation due to Kawasaki's disease.

Excimer laser facilitated percutaneous coronary intervention of a nondilatable coronary stent.

A patient is described in which excimer laser percutaneous coronary intervention is performed inside a suboptimally expanded stent due to nondilatable calcified plaque. The use of excimer laser facilitated full expansion of the stent with a balloon.

Oxidative stress and mitochondrial function in skeletal muscle: Effects of aging and exercise training.

The rate of oxidative phosphorylation was investigated in isolated mitochondria from hindlimb muscles of young (4.5 mo) and old (26.5 mo) male Fischer 344 rats with or without endurance training. Further, the susceptibility of the muscle mitochondria to exogenous reactive oxygen species was examined. State 3 and 4 respiration, as well as the respiratory control index (RCI), were significantly lower in muscle mitochondria from aged vs. young rats (P<0.05), using either the site 1 substrates malate-pyruvate (M-P) and 2-oxoglutarate (2-OG), or the site 2 substrate succinate. In both young and old rats, training increased state 4 respiration with M-P, but had no effect on state 3 respiration, resulting in a reduction of RCI. Training also increased state 4 respiration with 2-OG and decreased RCI in young rats. When muscle mitochondria were exposed to superoxide radicals (O2 (·-)) and hydrogen peroxide (H2O2) generated by xanthine oxidase and hypoxanthine, or H2O2 alone in vitro, state 3 respiration and RCI in both age groups were severely hampered, but those from the old rats were inhibited to a less extent than the young rats. In contrast, state 4 respiration was impaired by O2 (·-) and/or H2O2 to a greater extent in the old rats. Muscle mitochondria from trained young rats showed a greater resistance to the O2 (· -) and/or H2O2-induced state 3 and RCI inhibition than those from untrained young rats. Muscle from aged rats had significantly higher total activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX), and glutathione reductase than that from young rats, however, training increased SOD and GPX activities in young but not old rats. The results of this study suggest that mitochondrial capacity for oxidative phosphorylation is compromised in aging skeletal muscle. Further, the increased mitochondrial resistance to reactive oxygen species demonstrated in aged and young trained muscles may be attributed to enhanced antioxidant enzyme activities.

Contrast echocardiography displays increased subendocardial perfusion after nitroglycerin administration.

A mechanism proposed to contribute to the antianginal effect of nitroglycerin is a redistribution of coronary blood flow to the subendocardium. Contrast echocardiography combines ultrasound with echogenic contrast agents to assess regional myocardial perfusion. This study aims to assess the effect of nitroglycerin on myocardial transmural perfusion with contrast echocardiography in humans. Nine patients scheduled for coronary angiography received 300 microg intracoronary nitroglycerin. Contrast echocardiographic studies were performed before and immediately after the administration of intracoronary nitroglycerin. Videodensitometric analysis was performed off-line to measure subendocardial and subepicardial opacification. Subendocardial opacification greater than subepicardial opacification increased from six of 13 patients before nitroglycerin administration to 11 of 13 after nitroglycerin administration (p <0.05). Similarly, these observations increased from nine of 13 patients to 13 of 13 after nitroglycerin administration during diastole (p <0.05). Contrast echocardiography demonstrates increased subendocardial perfusion after the administration of nitroglycerin in these patients.

Ischaemia-reperfusion induced alterations of mitochondrial function in hypertrophied rat heart.

The impact of in vivo ischaemia and ischaemia-reperfusion (I-R) on mitochondrial respiratory function was investigated in hypertrophied (HP) hearts with aortic constriction compared with control hearts using an open-chest rat surgical model. Moreover, mitochondrial susceptibility to superoxide radicals (O2-.) in vitro was examined in HP and control hearts with or without I-R. With the site I substrates pyruvate-malate, mitochondrial state 4 (basal) respiration and the respiratory control index (RCI) were not affected by either ischaemia alone or I-R in both HP and control hearts. State 3 (ADP-stimulated) respiration was increased with I-R in control hearts, but showed a reduction after I-R in the HP hearts. Exposure of mitochondria to O2-. (20 nM hypoxanthine in the presence of 0.13 unit mL-1 xanthine oxidase) significantly increased state 4 respiration, whereas state 3 respiration and RCI were decreased in all treatment groups. I-R hearts in both HP and control showed greater increases in state 4 respiration with O2-. than either sham or ischaemic hearts. HP hearts exhibited a significantly lesser extent of inhibition in state 3 respiration and RCI by O2-. compared with control hearts. These changes in mitochondrial respiratory properties were not observed with the site II substrate succinate. Myocardial reduced vs. oxidized glutathione ratio was significantly decreased after I-R in both control and HP hearts. Malondialdehyde content showed an increase with I-R, but the increase was significant only in control hearts. These data indicate that short-term in vivo I-R does not impair heart mitochondrial respiratory function, but renders the organelles more vulnerable to imposed oxidative stress. Mitochondria from the HP hearts are more resistant to free radical damage under normal and ischaemic conditions; however, this advantage is severely compromised after reperfusion.

Aging and exercise training in skeletal muscle: responses of glutathione and antioxidant enzyme systems.

Glutathione (GSH) content and antioxidant enzyme activities were investigated in skeletal muscle of young, adult, and old male Fischer 344 rats. Furthermore, the effect of 10 wk of exercise training on these antioxidant systems was evaluated at all ages. In the soleus muscle, GSH concentration increased markedly with age, with no significant change in glutathione disulfide (GSSG) content. Training caused a 30% decrease of GSH (P < 0.05) in the soleus of young rats and a reduction of the GSH-to-GSSG ratio at all ages. Activity of gamma-glutamyl transpeptidase (GGT), a key enzyme for GSH uptake by muscle, was also significantly decreased with training. GSH, GSSG, and the GSH-to-GSSG ratio were not altered with aging or training in the deep portion of vastus lateralis muscle (DVL). Activities of GSH peroxidase (GPX), GSSG reductase (GR), superoxide dismutase (SOD), catalase (CAT), and GSH sulfur-transferase were increased significantly with aging in both soleus and DVL. In DVL, training increased GPX and SOD activities in the young rats, whereas in soleus, training decreased GR and CAT activities in the adult rats and GGT and CAT activities in the old rats. Muscle lipid peroxidation was significantly increased with aging in both DVL and soleus but was not affected by training. These data indicate that aging may cause not only an overall elevation of antioxidant enzyme activities but also a fiber-specific adaptation of GSH system in skeletal muscle. Exercise training, although increasing selective antioxidant enzymes in the young rats, does not offer additional protection against oxidative stress in the senescent muscle.

Contrast echocardiography.

Myocardial contrast echocardiography (MCE) is an ultrasound imaging technique which promises to provide a safe, noninvasive means of assessing myocardial perfusion. A contrast agent, consisting of a suspension of air-filled microspheres, serves as an ultrasound tracer. When these microspheres are injected intravascularly, the acoustic interface created between the blood and the microspheres enhances the reflected ultrasound signals. Thus, the flow pattern of the microspheres represent the actual blood flow patterns. This paper will review the field of contrast echocardiography, its background and history, the development of ultrasound contrast agents, and a variety of experimental as well as clinical uses. Contrast echocardiography has been utilized in the cardiac catheterization laboratory for the assessment of "risk area," assessment of collateral blood flow and assessment of coronary blood reserve. In the operating room, contrast echo is utilized for the determination of cardioplegic perfusion, assessment of graft patency and evaluation of valvular regurgitation. In the future, with the technical advancement in ultrasound imaging and the active interest and growth in the field of myocardial perfusion imaging using contrast echocardiography, the ability to provide routine real-time perfusion imaging may become a reality.