Chemical Hazards in Foods

This extensive chapter focuses on chemical hazards that have increased dramatically because of the economic development in various sectors including agriculture, food processing, industry and transport. Chemical hazards in food chain pose a wide range of health risks varying from irritation to chronic diseases and cancer. Moreover, exposure to a combination of chemical hazards may be associated with additive, antagonistic, and synergistic interactions. Thus it is necessary to monitor their concentrations in food and reduce exposure to consumers. The well compiled chapter includes occurrence, detection, legislation, toxicity and risk assessment of a variety of chemicals of both natural and man-made origin

Novacor left ventricular assist system versus heartmate vented electric left ventricular assist system as a long-term mechanical circulatory support device in bridging patients: A prospective study

AbstractObjective: Long-term mechanical circulatory support as a bridge-to-transplantation procedure and bridge to recovery is of increasing importance. The implantable left ventricular assist devices, Novacor N100 left ventricular assist system (Baxter Healthcare Corporation, Berkeley, Calif) and TCI HeartMate vented electric left ventricular assist system (Thermo Cardiosystems Inc, Woburn, Mass), have proved to be efficient devices in bridge-to-transplantation settings and for prolonged support. The two systems were compared with regard to reliability and morbidity. Methods: Between October 1996 and March 1998, a prospective, single-center study was done that included 40 patients, 20 of whom were treated with the Novacor system and 20 of whom were treated with the HeartMate device. The diseases were mainly dilated cardiomyopathy (13/9) and ischemic cardiomyopathy (6/10). There were no statistically significant differences between the two groups regarding age, sex, preoperative clinical blood chemistry values, hemodynamic data, or risk factors. Results: There were no statistically significant differences between the two groups with regard to postoperative hemodynamics, organ recovery, out-of-hospital support, and survival to heart transplantation. Mean duration of support was 235.3 ± 210 days for the Novacor group and 174.6 ± 175 days for the HeartMate group and mean out-of-hospital support was 241 ± 179 days and 166 ± 152 days for the two groups, respectively. Neurologic complications occurred significantly more often among the Novacor group, whereas the HeartMate group had a higher prevalence of infections and technical problems, which was statistically significant. Survival to transplantation was 65% for the Novacor group and 60% for the HeartMate group. Conclusions: Most patients had organ recovery with left ventricular assist system support, and a considerable number of patients in both groups underwent transplantation. However, both devices need revision to address the current problems, that is, thromboembolism for the Novacor device and infection and reliability for the HeartMate device. (J Thorac Cardiovasc Surg 2000;119:581-7

IgG classification of anti-PF4/heparin antibodies to identify patients with heparin-induced thrombocytopenia during mechanical circulatory support

Commercial immunoassays frequently detect anti-PF4/heparin antibodies during mechanical circulatory support (MCS), but only a small minority of patients develops heparin-induced thrombocytopenia (HIT). Whereas platelet functional tests can distinguish between platelet-activating and non-platelet-activating antibodies, commercial PF4-dependent immunoassays do not. Between 2003 and 2004, 113 patients were placed on MCS. Blood samples were obtained on postimplant day 5-7 for analyses by antibody assays and the functional heparin-induced platelet activation (HIPA) assay. Three distinct groups of patient sera were identified: platelet-activating anti-PF4/heparin antibodies (n = 10), non-platelet-activating anti-PF4/heparin antibodies (n = 53), and anti-PF4/heparin antibody negative (n = 50). Patients with platelet-activating antibodies had the highest risk for thromboembolic events (P &lt; 0.005), whereas those with non-platelet-activating antibodies did not differ from antibody negative patients (P = 0.369). The enzyme-immunoassay and column agglutination assays, which cover all immunoglobulin classes, demonstrated adequate sensitivity and negative predictive value; yet, both lacked specificity with respect to the platelet-activating antibodies. If all antibody positive patients were further classified by an IgG-specific anti-PF4/heparin enzyme-immuno assay, specificity for platelet-activating antibodies increased. Whereas IgG-specific optical density (OD) values below 1.0 were likely for non-platelet-activating anti-PF4/heparin antibodies, higher values were progressively predictive for pathogenic platelet activation. The probability of the development of clinical HIT also increased steeply. In conclusion, platelet-activating anti-PF4/heparin antibodies are relatively common (about 9%) in patients on MCS and are associated with significantly higher thrombotic event rates. Low IgG-specific OD values (&lt; 1.0) in the enzyme-immunoassay indicate low likelihood for the presence of platelet-activating antibodies. These results justify further validation so that anticoagulation during MCS becomes safer and adequate.</p

The structural examination of myocardial samples from patients with end-stage heart failure supported by ventricular assist devices using electron-microscopy and amino acid analysis reveals low degree of reverse remodeling

Milting H, Jacob M, Kassner A, et al. The structural examination of myocardial samples from patients with end-stage heart failure supported by ventricular assist devices using electron-microscopy and amino acid analysis reveals low degree of reverse remodeling. JOURNAL OF HEART AND LUNG TRANSPLANTATION. 2004;23(4):396-404.Background: Chronic heart failure is a multifactorial, progressive disease of many causes and is associated with complex ventricular remodeling. Deposition of extracellular matrix proteins and sarcomeric disarray of the myocytes occur in end-stage heart failure. Ventricular assist devices (VAD), implanted as bridge to transplantation, may reverse ventricular remodeling. Although successfully weaning patients from VAD support has been reported, it is not clear to what degree reversal of remodeling,occurs in unloaded failing hearts. Because collagen deposition, and ultrastructural disarray are hallmarks of myocardial remodeling, we analyzed the myocardial ultrastructure and collagen content of VAD-supported hearts before and after mechanical unloading. Methods: We used amino acid analysis to measure collagen content (4-hydroxyproline content) in 24 transplant candidates receiving VAD support. We used transmission electron microscopy to examine the ultrastructure in 6 patients receiving VAD support. Results: The 4-hydroxyprohne content increased significantly at VAD implantation and was not altered by mechanical unloading. The ultrastructure showed signs of persisting. cardiomyopathy. Conclusion: Mechanical unloading does not alter the total collagen content of the supported, failing heart. Thus, structural reversal of the remodeling process associated with heart failure is not a general phenomenon in mechanically unloaded hearts