Biomedical subjects

G D Lappas

Publications and source records attributed to G D Lappas.

4 recordsLinked to original sources

PubMed1999

Prevalence of left ventricular diastolic filling abnormalities in adult cardiac surgical patients: an intraoperative echocardiographic study.

The incidence of left ventricular (LV) diastolic abnormalities in adult cardiac surgical patients has not previously been adequately investigated. The present study was performed to characterize LV diastolic filling patterns by performing transesophageal Doppler echocardiographic (TEE) studies in patients undergoing cardiac surgical procedures and thus indirectly assess diastolic function in these patients. Doppler TEE studies were performed and transmitral flow (TMF) and pulmonary venous flow (PVF) velocities were recorded in 104 patients intraoperatively. Peak early (E) and late (A) TMF velocities and systolic (S) and diastolic (D) forward PVF velocities were assessed and deceleration time (DT) was measured in all patients. For analysis, the study patients were classified into three groups according to the ratio of the TMF E to A velocity curves: group I with E/A ratio less than 1.0, group II with E/A ratio of 1.0 to less than 2.0, and group III with E/A ratio of 2.0 or greater. A filling pattern of abnormal LV relaxation was found in 73 patients (E/A < 1.0), a normal or pseudonormal pattern was present in 27 patients (1.0 < or = E/A < or = 2.0), and restrictive filling in 4 patients (E/A > 2.0). Patients with impaired relaxation had a greater incidence of recent myocardial infarction and congestive heart failure (CHF) than those with normal or pseudonormal filling patterns. Within group II, patients with CHF had higher TMF E deceleration rates and lower PVF S/D ratios compared with those without CHF (P < .05). Doppler echocardiographic examination of TMF and PVF velocities suggests that abnormalities in diastolic function are prevalent in adult cardiac surgical patients.

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PubMed1995

Swallowing dysfunction after cardiac operations. Associated adverse outcomes and risk factors including intraoperative transesophageal echocardiography.

The frequency, importance to patient outcomes, and independent predictors of postoperative swallowing dysfunction documented by barium cineradiography were examined in 869 patients undergoing cardiac operations over a 12-month period. Swallowing dysfunction was diagnosed in 34 patients (4% incidence) and was associated with documented pulmonary aspiration in 90% of these patients, increased frequency of pneumonia (p < 0.0001), need for tracheostomy (p = 0.0002), length of stay in the intensive care unit (p = 0.0001), and duration of hospitalization after the operation (p = 0.0001). Independent predictors of postoperative swallowing dysfunction determined by multivariate logistic regression included age (p < 0.001), length of tracheal intubation after the operation (p = 0.001), and intraoperative use of transesophageal echocardiography (p = 0.003). Dysfunctional swallowing after cardiac operations, a serious complication significantly related to postoperative respiratory morbidity and extended length of hospitalization, is more common in older patients. An association between intraoperative use of transesophageal echocardiography and swallowing dysfunction was also observed in our patients.

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PubMed1995

Calcium antagonists decrease plasma and tissue concentrations of tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-1 alpha in a mouse model of endotoxin.

Calcium plays an important role in the toxic effects of endotoxin, and calcium antagonists also have been shown to improve survival in animals challenged with endotoxin. Calcium may be involved in regulating cytokine production. Therefore, the protective effect of calcium-antagonists in endotoxin may be due to decreased cytokine formation and/or systemic release. In a mouse model of endotoxin, dantrolene (10 mg/kg) and azumolene (20 mg/kg), drugs that decrease calcium release from intracellular stores, or diltiazem (20 mg/kg), a calcium channel blocker, decreased plasma tumor necrosis factor-alpha (TNF-alpha), interleukin-1 alpha (IL-1 alpha), and IL-1 beta (47.2, 63.2, and 62.4%, respectively, p < .05) when the animals were injected intraperitoneally with endotoxin. Dantrolene and azumolene decreased IL-1 alpha by 56.6 and 65.4%, respectively, (p < .05) and IL-1 beta by 51.7 and 69.7%, respectively (p < .05). Diltiazem had no effect on IL-1 alpha or IL-1 beta. Dantrolene decreased TNF-alpha in lung (26.1%), liver (29.4%), and spleen (35.4%) (p < .05) and IL-1 alpha in lung (30.0%) and liver (25.4%) (p < .05). The present findings indicate that calcium-antagonists may be efficacious in treating cytokine mediated inflammatory disorders.

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PubMed1994

Effect of ethanol and sodium arsenite on HSP-72 formation and on survival in a murine endotoxin model.

Recently, investigators reported that prophylactic hyperthermia and induction of heat shock proteins (HSPs) decreased mortality from endotoxin. Although the mechanism by which hyperthermia protects is unknown, two possible etiologies are induction of HSPs and/or production of cytokines, interleukin-1 alpha (IL-1 alpha) or tumor necrosis factor-alpha (TNF-alpha). The purpose of this study was to determine if in vivo administration of sodium arsenite (NaAsO2) or ethanol, inducers of HSPs in isolated cells, induced HSP-72 production in lung, liver, kidney, and duodenum (organs known to induce HSP-72 by heat) and improved survival from endotoxin. Female ND4 mice were injected intraperitoneally with either NaAsO2 (5.25 mg/kg body weight) or ethanol (4.0 g/kg), immediately, 8 or 18 h prior to Escherichia coli endotoxin injection (20 mg/kg). Both compounds improved short-term (24 h) survival twofold (p < .01), but failed to improve long-term (7 days) survival. Simultaneous injection of ethanol with endotoxin improved both short-term survival twofold (p < .01), and long-term survival 5-fold (p < .001). Ethanol induced HSP-72 in kidney, 50% that of the standard (i.e., pooled livers isolated from heat-treated mice); NaAsO2 induced HSP-72 in kidney (approximately 50% of standard) and liver (approximately 21% of standard). Neither ethanol nor NaAsO2 alone increased circulating concentrations of IL-1 alpha or TNF-alpha. However, ethanol given concurrently with endotoxin produced a significant decrease in TNF-alpha compared to endotoxin alone (p < .01).(ABSTRACT TRUNCATED AT 250 WORDS)

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