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Biomedical subjects

E I Lev

Publications and source records attributed to E I Lev.

9 recordsLinked to original sources
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↗
PubMed2000

Acute antithrombotic effect of a front-loaded regimen of clopidogrel in patients with atherosclerosis on aspirin.

There is a need for a rapid antithrombotic effect after the administration of antiplatelet drugs in the setting of acute coronary syndromes and percutaneous interventions. Clopidogrel, a new thienopyridine derivative, is an efficient antiplatelet agent. However, the standard regimen of clopidogrel (75 mg/d) requires 2 to 3 days before significant antithrombotic effects. Patients with stable arterial disease on chronic aspirin therapy (n=20) were treated with clopidogrel either with a front-loaded regimen, 300 mg the first day and 75 mg/d the next 7 days, or with a standard regimen, 75 mg/d for 8 days. Blood thrombogenicity was assessed by quantification of platelet-thrombus formation in an ex vivo perfusion chamber, by ADP-induced platelet aggregation, and by ADP-induced fibrinogen binding. At 2 hours, mean total thrombus area with the standard regimen was not significantly reduced. In contrast, at 2 hours, the mean total thrombus area with the front-loaded regimen was significantly decreased by 23.1+/-8.5% versus baseline (P<0.05). ADP-induced platelet aggregation (with 5 and 10 micromol/L) was also significantly (P<0.05) reduced with the front-loaded regimen at 2 hours, with the mean platelet aggregation being 82.2+/-4.4% and 81.8+/-4.5%, respectively, versus baseline. Similarly, flow cytometry demonstrated a significant decrease (P<0. 05) in the ADP-induced fibrinogen binding (with 0.12 and 0.6 micromol/L) at 2 hours in this front-loaded regimen group (36.1+/-2. 0% and 53.2+/-9.3%). With the standard regimen, platelet activity was not significantly reduced at 2 hours. Our data suggest that a front-loaded regimen of clopidogrel added to aspirin achieves a significant antithrombotic effect at 2 hours in patients with known atherosclerotic disease on chronic aspirin therapy. This provides a rationale for using front-loaded clopidogrel in combination with aspirin in percutaneous coronary interventions.

Adenosine Diphosphate↗
PubMed1999

Distribution of serum creatine kinase activity in young healthy persons.

The normal distribution of serum creatine kinase (CK) was determined in 428 men (mean age = 21.5) and 540 women (mean age = 20.2). The bootstrap method was employed to obtain statistical parameters of CK reference range and correlations with physical activity habits, BMI, cigarette smoking and alcohol consumption. CK distribution was non-Gaussian and skewed toward the higher values; 18.9% of the men and 4.6% of the women had values above the upper reference limits defined for the commercial assay kit. The median 97.5 percentile value was 532 u/l for men and 248 u/l for women (95% confidence interval of 384-738 u/l and 184-340 u/l, respectively). A significant correlation was found only between CK and alcohol consumption in men. Myoglobin level in a representative group of subjects correlated well with CK activity for both genders. Our findings define the range of CK values in a healthy, young, heterogeneous population. We suggest that only CK levels above the determined 97.5 percentile should warrant further clinical investigation.

Adult↗
PubMed1999

Preparing hospitals for toxicological mass casualties events.

OBJECTIVE: For most hospital staffs, treatment of chemical casualties presents an obscure and even frightening situation. We report our unique experience from hospital drills in order to improve hospital preparedness for patient management under mass casualty conditions involving hazardous chemicals. SETTING: Twenty-one major hospitals in Israel. INTERVENTIONS: A unique hospital deployment plan for the management of chemical casualties was developed, and hospitals were required to have a full chemical practice drill every 3 to 5 yrs. These drills were designed as realistically as possible, and all included the use of personal protective equipment, decontamination, and treatment of simulated patients. Twenty-five percent of these patients, simulating children and adults, required intensive care and ventilation support. Hospitals were inspected and reviewed on the quality of treatment given and the overall continuity of care as well as on their administrative performance. RESULTS: Between 1986 to 1994, 30 full chemical practice drills were conducted in 21 major hospitals. Each drill included treatment of 100 to 400 simulated patients. The lessons from the hospital drills are described and were incorporated in the proposed revised hospital deployment plan. All hospitals significantly improved their ability to respond appropriately to these incidents. CONCLUSIONS: The level of preparedness for a chemical mass casualty scenario should be established according to the existing threat and the available resources. The proposed plan can serve as a basis for hospital planning and staff training worldwide, thus facilitating optimal care in the event of an incident involving toxic chemicals. A cost-effective scale for hospital preparation levels according to the existing threat is suggested.

Adult↗
PubMed1998

Exercise-induced aortic flow parameters in early postmenopausal women and middle-aged men.

OBJECTIVE: Exercise Doppler echocardiography has been recognised as an accurate method for the assessment of left ventricular function in patients with coronary artery disease. Gender differences in aortic flow parameters during exercise have not been well established. The aims of this study were to compare basal ejection Doppler indexes in healthy early postmenopausal women with those of men, and to assess the effects of both isometric and dynamic exercises on these parameters. DESIGN: Intergroup comparison between early postmenopausal women and middle-aged men. SUBJECTS: Fifteen healthy women with a mean age of 55 (SD 5) years and 15 healthy men aged 52 (SD 4) were evaluated. SETTING: Women were recruited from a menopause clinic and men from a primary cardiovascular prevention program at a cardiac rehabilitation institute. INTERVENTIONS: Isometric exercise was performed with a 2-hand bar dynamometer, and dynamic exercise with a supine ergometer. Echo Doppler examination was performed at rest and at peak isometric and dynamic exercise with a pulsed Doppler transducer. RESULTS: Both types of exercise resulted in higher values of hemodynamic parameters in the women, with most figures reaching statistical significance. Most aortic flow parameters during rest and exercise were also significantly higher in the women. CONCLUSIONS: The unexpected higher values in hemodynamic and aortic flow parameters in early postmenopausal women as compared with middle aged men may shed light on a peculiar aspect of gender differences in cardiovascular function, perhaps specific to this age group and related to menopausal transition.

Aorta↗
PubMedDate not supplied

Hemophilus influenzae biotype III cellulitis in an adult.

The case of a patient with systemic lupus erythematosus presenting with severe leg cellulitis caused by Hemophilus influenzae non-B biotype III is reported. Skin infections caused by H. influenzae in general, and of the extremities in particular, seem to be rare in adults. This is the first reported case of cellulitis caused by H. influenzae biotype III. The infection was treated successfully with antibiotics. This case highlights the importance of blood cultures and prompt antimicrobial treatment in febrile adults with cellulitis, especially immunocompromised patients.

Adult↗
PubMedDate not supplied

Creatine kinase activity decrease with short-term freezing.

Freezing of serum samples at -30 degrees C without protective agents is the simplest and least expensive method of storage in serum banks. We investigated the stability of creatine kinase (CK) in human sera after freezer storage under such conditions for 24 h (n = 30) or for 2 or 4 weeks (n = 99). CK activity was measured in fresh sera and compared to matched thawed sera after freezer storage at the designated time intervals. The enzyme's median activity decreased significantly after 24 h, 2 weeks, and 4 weeks of freezer storage by 2.6, 5.9, and 8.3%, respectively (p < 0.0001, r = 0.99). Sex or high CK initial values had no significant effect on these results. We conclude that freezer storage of serum at -30 degrees C, even for short periods, causes a steady and significant decline in CK activity. These results should be taken into consideration when analyzing CK activity in frozen sera for research or clinical purposes.

Blood Banks↗