Differences in coagulation among Asians and Caucasians and the implication for reconstructive microsurgery

Microvascular reconstructive surgery has seen a revival with the introduction of muscle-sparing perforator flaps. Recognition of potential ethnic differences in coagulation profiles would be important to a microvascular surgeon. Based on clinical observations, we hypothesize that Asian patients have a less thrombogenic coagulation profile than Caucasians. An extensive retrospective review was performed. The annual incidence of venous thromboembolism in the United States is generally accepted to range from 70 to 120 events per 100,000 people versus 16 to 17 events per 100,000 persons in Asia. Autopsy analysis of pulmonary embolism incidence was noted to be 15% in North Americans and less than 1% in Asian populations. Thromboelastography analysis of Asian and Caucasian patients undergoing cholecystectomy revealed different hemostatic mechanisms. Comparison of Asians and Caucasians undergoing the Fontan procedure revealed significantly lower postoperative factor levels in Asians than Caucasians. Baseline comparison of factor and serum levels revealed Asians with the least thrombogenic profiles compared with other ethnic groups. Asians and Caucasians demonstrate different baseline rates of deep vein thrombosis and pulmonary embolism, different hemostatic responses to surgery, and different baseline levels of clotting factors. Further study may lead to better pre-, intra-, and postoperative care of the free flap patient based on their ethnic coagulation profile.     

Pressure wave reflections, central blood pressure, and aortic stiffness in patients with Adamantiades-Behcet's disease: a cross-sectional case-control study underlining the role of chronic corticosteroid treatment

BACKGROUND: Adamantiades-Behcet's disease (ABD) is a multisystemic inflammatory/autoimmune disease involving both microcirculation and macrocirculation. Aortic stiffness index and aortic augmentation index (AI) are indices for the estimation of arterial stiffness and pressure wave reflections, respectively. The effect of anti-inflammatory and immunosuppressive drugs used in ABD on these indices is unknown. METHODS: In this cross-sectional study we examined 74 subjects with ABD (aged 40.1 +/- 12.5 years, 24 men) and 24 control subjects by using the noninvasive technique of radial artery applanation tonometry and pulse wave analysis for assessment of aortic AI by application of transfer functions. Echocardiography was used for assessment of aortic stiffness index. Classic cardiovascular (CV) risk factors, left ventricular and endothelial function of the brachial artery, as well as intima-media thickness of carotid artery, were also assessed. RESULTS: Corticosteroids were the only drug having a negative and independent effect on aortic AI, but not on aortic stiffness. Patients taking corticosteroids had lower aortic AI and central systolic blood pressure (BP), but not aortic stiffness and peripheral systolic BP, when compared to those without corticosteroids (21+/-14% v 12+/-14%, P < .050). Medication, traditional CV risk factors, and functional or structural CV parameters were all comparable among the two groups. The AI was similar between the control group and patients with ABD taking corticosteroids. CONCLUSIONS: The AI, but not aortic stiffness, is lower in patients with ABD taking corticosteroids compared to patients not taking corticosteroids and similar to the control group. These results imply a role of inflammation or immunomodulatory mechanisms in the regulation of pressure wave reflections.     

Endothelial activation and inflammation biomarkers in children and adolescents with sickle cell disease

Sickle cell disease pathogenesis is a complex interplay of multiple factors associated with vascular endothelial activation, intense oxidative stress, and increased sickle cell adhesion. The aim of this study was to determine and compare three panels of plasma circulating biomarkers at ‘steady state’ and during veno-occlusive crises (VOC) in a cohort of children and adolescents with SCD and healthy controls. The following biomarkers were assessed: acute phase reactants, endothelial factors, and adhesion molecules. Forty-one SCD pediatric patients and 28 healthy children were enrolled. Patients at ‘steady state’ presented significantly elevated plasma levels of endothelin-1 (ET-1), soluble-VCAM-1 (sVCAM-1), soluble P-selectin (sP-selectin), and d-dimers compared to the control group. ET-1, sP-selectin, platelet-derived growth factor (PDGF), von Willebrand factor (vWf), d-dimers, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) seems to represent additional, but not independent, prognostic markers of VOC crisis. Elevated plasma levels of sP-selectin, ET-1, and sVCAM-1 were associated with VOC frequency. The present study provides preliminary evidence of a possible association between these biomarkers and the endothelial activation at steady state and VOC in childhood SCD. Further prospective studies are required to confirm the potential independent prognostic value of these markers in different stages of pediatric SCD.     

Determination of the exercise intensity corresponding with maximal lactate steady state in high-level basketball players

The purpose of the present study was to define the maximal lactate steady state (MLSS_meas) in high-level male basketball players and to compare it with the lactate turnpoint (LTP) and the respective point derived form a prediction method (MLSS_cal). Twelve high-level basketball players underwent one maximal and several submaximal tests on a treadmill on different days where MLSS and LTP were measured. MLSS_meas was observed at 75% of the maximal treadmill speed, at 77% of VO_2max, at 88% of HR_max and at [La^-] of 3.7 mmol.l^?1. No differences were observed between MLSS_meas and LTP in any of the measured variables. A good agreement was observed between MLSS_meas and LTP, as well as between MLSS_meas and MLSS_cal. Therefore, LTP and MLSS_cal are offered as acceptable approaches to predict MLSS, but not all the indices used to define MLSS presents high agreement between the methods used.     

Distinct neuronal circuits mediate experience-dependent, non-associative osmotactic responses in Drosophila

Osmotactic responses can be modified in an experience-dependent manner and have been used to condition animals in negative or positive associative paradigms. Experience-dependent non-associative defects in avoidance of aversive odors were reported in Drosophila learning mutants. This prompted an examination of the contribution of the mushroom bodies and inner antenoglomerular tract, the two neuronal populations implicated in processing olfactory information to experience-dependent non-associative osmotactic responses. Silencing inner antenoglomerular tract synapses results in defective osmotaxis after experiencing a different odor, but not electric shock. Conversely, structural or functional perturbation of the mushroom bodies precipitates osmotactic deficits after prior experience of electric shock but not odors. These effects on osmotaxis are specific, long lasting and independent of the aversive or attractive properties of the odors. Deficient osmotactic responses only after electric shock stimulation were exhibited by mutants with altered cAMP levels, but all other mutants in genes preferentially expressed in the mushroom bodies responded normally. Our results suggest that the mushroom bodies and inner antenoglomerular tract are essential for normal osmotactic responses after prior stimulation with electric shock or another odor respectively. Finally, these experience-dependent non-associative paradigms are excellent methods of functionally ascertaining normal activity of the mushroom bodies and inner antenoglomerular tract in putative leaning and memory mutants.