Contractility in Humans after Coronary Artery Surgery: Echocardiographic Assessment with Preload-adjusted Maximal Power

Background: Propofol's unique pharmacokinetic profile offers advantages for titration and rapid emergence in patients after coronary artery bypass graft (CABG) surgery, but concern for negative inotropic properties potentially limits its use in these patients. The current study analyzed the effect of various propofol plasma concentrations on left ventricular (LV) contractility by means of a single-beat contractile index based on LV maximal power (PWRmax).

Methods: The study was conducted in 30 patients after CABG surgery. Immediately after admission to the intensive care unit (ICU), four different plasma concentrations of propofol, 0.65, 1.30, 1.95, and 2.60 [micro sign]g/ml, were established. At each concentration level, the cardiac and vascular effects of propofol were studied by combining echocardiographic data with invasively derived aortic root pressure. Preload was characterized by LV end-diastolic dimensions. Afterload was indicated in terms of indexed systemic vascular resistance (SVRI), LV end-systolic meridional wall stress (LV-ESWS), and arterial elastance (Ea). Quantification of effects on contractility was achieved by preload-adjusted PWRmax.

Results: Myocardial contractility did not change during a fourfold increase in propofol plasma concentration. Preload-adjusted PWRmax amounted to 3.90 +/- 1.75 W [middle dot] ml-2 [middle dot] 104, 3.98 +/- 1.69, 3.94 +/- 1.70, and 3.88 +/- 1.72, respectively (mean +/- SD). With respect to ventricular loading conditions, propofol caused a significant reduction in both pre- and afterload.     

Parvovirus 4 in French in-patients: a study of hemodialysis and lung transplant cohorts

The epidemiology and the clinical implication of human parvovirus 4 (PARV4) in human populations is still under evaluation. The distribution of PARV4 DNA was determined in cohorts of French hemodialysis and lung transplant patients. Plasma samples (n=289) were tested for PARV4 by real-time PCR assay (ORF2), and amplification products selected at random were sequenced. Analysis of available serological and biological markers was also undertaken. Fifty-seven samples out of 185 (30.8%) were positive for PARV4 DNA in the cohort of hemodialysis patients. A higher prevalence of the virus was identified in patients with markers of HBV infection. PARV4 was also identified in 14 out of 104 samples (13.5%) from lung transplant recipients, with no clear-cut association with available clinical markers. Point mutations located on the zone of real-time detection were identified for some amplification products. This study describes the detection of PARV4 in the blood of hemodialysis and lung transplanted patients with significant difference in prevalence in these two cohorts. Further studies will be needed in order to understand better both the potential implication in host health and the natural history of this virus.     

Genome-wide linkage analysis for circulating levels of adipokines and C-reactive protein in the Quebec family study (QFS)

Adipose tissue synthesizes and secretes a wide range of biologically active molecules considered as inflammatory markers whose dysregulation in obesity plays a role in the development of insulin resistance and vascular disorders. Thus, finding genes that influence circulating levels of inflammatory biomarkers may provide insights into the genetic determinants of obesity-related metabolic diseases. We performed linkage analyses for fasting plasma levels of adiponectin, C-reactive protein (CRP), interleukin-6 (IL-6) and tumor-necrosis factor-alpha (TNF-alpha) in 764 subjects enrolled in the Quebec family study (QFS). A maximum of 393 pairs of siblings from 211 nuclear families were available for analyses. A total of 443 markers spanning the 22 autosomal chromosomes with an average inter-marker distance of 6.24 Mb were genotyped. Linkage was tested using both allele-sharing (SIBPAL) and variance component linkage methods (MERLIN). We showed suggestive evidence of linkage for plasma adiponectin levels on chromosome 15q21.1 [D15S659; logarithm of the odds (LOD) score = 2.23], 3q13.33 (D3S3023; LOD = 2.09), 20q13.2 (D20S197; LOD = 1.96) and 14q32.2 (D14S1426; LOD = 1.79). Evidence of linkage (SIBPAL) was also found for CRP on 12p11.23 (P = 0.001) and 12q15 (P = 0.0005) and for IL-6 on 14q12 (P = 0.002). None of these linkages remained significant after adjustment for body mass index. No evidence of linkage was found for TNF-alpha plasma levels. These results suggest that several QTLs can influence plasma levels of adiponectin and CRP, partly via their effects on adiposity.     

Experimental and theoretical models of flow during forced expiration: pressure and pressure history dependence of flow rate

Flow characteristics have been studied in elastic mono- and bialveolar lung models made from tubes and balloons in series. Flow rate variation is explained on the basis of two successive limiting factors governed by the mutual interaction of tube mechanical properties and flow characteristics, i.e. wave-speed and viscous limitations induced by the tube collapse. A numerical model of flow in an elastic monoalveolar structure has been developed. It is generally admitted that a remarkable feature of forced expiration is that the flow rate is ‘effort independent’ for approximately the lower 80 per cent of vital capacity. The present results, which describe a continuous process, suggest that the flow rate depends mostly on the external pressure and pressure history. between the 15th August 1987 and the 31st August 1988, and at other periods to him at INSERM U. 296, Faculté de Médecine, 8 av Gl Sarrail, 94010 Creteil Cedex, France.     

Recognition of activities in children by two uniaxial accelerometers in free-living conditions

The aim of this study was to develop a classification procedure for accelerometer data to recognize the mode of children’s physical activity (PA) in free-living conditions and to compare it with an established cutoff method. Hip and wrist accelerometer data with an epoch interval of 1 s were collected for 7 days from 24 girls (age: 10.7 ± 1.7 years) and 17 boys (age: 10.6 ± 1.6 years). Videos were recorded during the same 7 days at several points of time at school and during leisure time. Each second of video data was labeled as one of nine activity classes. A classification procedure based on pattern recognition algorithms was trained with the accelerometer data relating to respective video labels of half of the children and tested against the data from the other half of the children. The overall recognition rate of the classification procedure was 67%. The procedure was able to classify 90% of stationary activities, 83% of walking, 81% of running and 61% of jumping activities. The remaining activities could not be recognized by the main classifier. This study developed a classification procedure based on well-accepted accelerometers and video recordings to recognize children’s PA in free-living conditions. It has been shown to be valid for the activities of being stationary, walking, running and jumping. In contrast to former measurement and analysis procedures, this method is able to determine the modes of specific activities among children. Consequently, the presented classification procedure provides additional information on the PA behavior in children registered by established accelerometers.     

Preclinical investigations of a medium-chain triglyceride:fish oil emulsion III. Experiments in cultured endothelial cells

The bolus intravenous injection of a novel medium-chain triglyceride:fish oil emulsion was recently reported to provoke a rapid and sustained increase in the cell phospholipid content of long-chain polyunsaturated omega3 fatty acids in both rats and human subjects. This report deals mainly with a comparison between this and other emulsions, as well as albumin-bound omega3 fatty acids, in terms of the time course, reversibility and concentration dependency for the incorporation of the omega3 fatty acids in the phospholipids of cultured endothelial cells. The results document that the new emulsion is quite efficient for a rapid and sustained enrichment of phospholipids in long-chain polyunsaturated omega3 fatty acids. The potential beneficial effects of such an enrichment in terms of aortic endothelial and cardiac function are emphasized.     

Evaluation ofprimary blood monocyte and bone marrow cell culture for the isolation of Rickettsia rickettsii.

Rickettsia rickettsii was isolated from experimentally infected guinea pigs by culture of blood monocytes and bone marrow cells, and from experimentally infected rhesus monkeys by blood monocyte culture. Rickettsiae were identified in monocyte-macrophage monolayers stained by Giménez or flourescent antibody techniques. A total of 78 culture attempts were made from 20 guinea pigs and 16 monkeys. The success of isolation of R. rickettsii in culture was positively correlated with the numbers of rickettsiae present in the blood and bone marrow. in cultures derived from infected guinea pigs, rickettsiae were usually observed after 5 to 7 days of culture, and in monkeys monocyte cultures they were usually observed within 3 to 5 days. Positive cultures were derived from guinea pigs and monkeys as early as the first day of fever and 1 to 3 days before the appearance of other clinical signs. Monocyte cultures became negative with the resolution of rickettsemia and concomitantly with the appearance of serum antibody. Monocyte culture isolation of R. rickettsii may be as sensitive for the detection of rickettsiae in blood and marrow as the intraperitoneal inoculation of guinea pigs or the plaque assay technique. Because of the simplicity of the method and because rickettsiae were often identified within 3 to 5 days after initiation, the monocyte culture technique may be useful in the early diagnois of human rickettsial disease.