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Biomedical subjects

D Shimbo

Publications and source records attributed to D Shimbo.

6 recordsLinked to original sources
PubMed2005

Negative impact of depression on outcomes in patients with coronary artery disease: mechanisms, treatment considerations, and future directions.

Depressive symptoms are common in coronary artery disease (CAD) patients, and are associated with increased cardiac risk. Although an important relation exists between depression and CAD prognosis, the underlying pathophysiological mechanisms are poorly understood. Additionally, evidence including the recently published ENRICHD (Enhancing Recovery in Coronary Heart Disease Patients) trial suggests that depression treatments do not lower recurrent cardiac risk. The reason for the observed lack of benefit with depression treatment in CAD patients is unclear. In this review, we discuss the impact of depression in CAD patients, the possible mechanisms involved, the studies that have examined the effects of psychological and antidepressant therapies on recurrent cardiac events, and the direction that future research should take.

Antidepressive Agents↗
PubMed2004

Antithrombotic effects of S 18886, a novel orally active thromboxane A2 receptor antagonist.

Platelet activation and thrombus formation play a critical role in the onset of acute coronary syndromes. Thromboxane A2 (TxA2) is among the different chemical modulators released by activated platelets. TxA2 is considered one of the most powerful agonists for platelet activation. In addition, TxA2 exerts a vasoconstrictor effect by serving as an agonist of the thromboxane receptor (TP) on the vascular smooth muscle cell membranes. The putative effect of TxA2 on thrombosis is demonstrated by the clinical effectiveness of acetylsalicylic acid (ASA) in the prevention of acute coronary syndromes. Among the clinically used antiplatelet agents, clopidogrel has shown to be slightly more effective than ASA in the prevention of atherothrombotic events in patients with peripheral arterial disease, and is one of the most widely used after aspirin. The aims of the study were to study the antithrombotic effects of escalating doses of the TP-receptor antagonist, S 18886 and to compare its effects with those achieved by the administration of ASA (5 mg kg-1 day-1), and clopidogrel (3 mg kg-1 day-1). The study was undertaken at high and low shear rate conditions using the Badimon perfusion chamber in a porcine model. Antithrombotic effects were assessed as changes on platelet and fibrin(ogen) deposition. The doses of 30 and 100 micro g kg-1 day-1 were selected based on a previous platelet aggregation study. S 18886 shows a dose-dependent antithrombotic response. The dose of S-100 develops similar antithrombotic effects to those of clopidogrel and superior to those of aspirin. The antithrombotic effects were statistically significant at both studied shear rate conditions. Therefore, the orally active TP-receptor antagonist, S 18886, appears to be a new and effective agent to prevent atherothrombotic complications.

Animals↗
PubMed2001

Testing platelet activation with a shear-dependent platelet function test versus aggregation-based tests: relevance for monitoring long-term glycoprotein IIb/IIIa inhibition.

BACKGROUND: Tests developed to monitor glycoprotein (GP) IIb/IIIa blockade do not properly reflect platelet function in vivo and need a baseline (pretreatment) value. Because GP IIb/IIIa is essential in platelet aggregation and thrombosis under shear conditions, a flow-dependent approach to monitor its inhibition can be used. METHODS AND RESULTS: We compared a test based on flow-dependent platelet deposition, the Cone and Platelet Analyzer (CPA), with in vitro platelet aggregometry and the Rapid Platelet Function Assay (RPFA) on platelet function after GP IIb/IIIa inhibition. In vitro, increasing concentrations of abciximab (0% to 100% receptor occupancy) were tested. Ex vivo, platelet function was monitored with the CPA and with aggregometry for up to 1 week after abciximab administration. The CPA was better correlated with the percentage of free GP IIb/IIIa receptors than was aggregometry or the RPFA. Only the RPFA, when expressed as a ratio over baseline (pretreatment), was comparable to the CPA. Ex vivo, the CPA, but not aggregometry, showed prolonged platelet inhibition with gradual recovery from GP IIb/IIIa receptor blockade in the first week after abciximab administration. CONCLUSIONS: Platelet function assessment by shear-induced deposition is a reliable test to monitor a wide range of GP IIb/IIIa inhibition. Its accuracy does not require a baseline reference. The effects of GP IIb/IIIa blockade on platelet function should be examined under high shear conditions.

Abciximab↗