Effect of the host specific treatment in the phagocytosis of Trypanosoma cruzi blood forms by mouse peritoneal macrophages

Single doses of drugs active aginst Trypanosoma cruzi (megazol, nifurtimox and benznidazole) induce a rapid clearence of the blood parasites in experimentally infected mice. Furthermore, the in vitro phagocytosis and intracellular destruction by mouse peritoneal macrophage of blood forms collected from the treatment animals is strongly enhanced as compared with parasites from untreated controls. The uptake of the blood forms by macrophages is significantly higher with megazol than with benznidazole and nifurtimox, a finding that concurs with data showing that megazol is also the most active compound in the living host. The possibility that macrophages participate in a synergic effect between the host immune response and chemotherapeutic effect is discussed.

Problèmes d'échantillonnage lors d'une enquête sur la plombémie d'enfants citadin [Sampling problems in a survey of blood lead levels in city children].

A study on lead pollution was carried out on a sample of ca. 300 city children. This paper presents the errors producing bias in the sample. It is emphasized that, in Switzerland, the difference between the Swiss and the migrant population (the latter being mainly Italian and Spanish) must be taken into account.

Lectin receptors distribution in the surface membrane of Trypanosoma cruzi blood forms collected from mice submitted to specific treatment

The author investigated the distribution of lectin receptors on Trypanosoma cruzi blood forms collected from mice inoculated with, respectively, the drug-resistant and drug-sensitive strains VL-10 and CL, and treated with the two standard active nitroheterocyclic compounds nifurtimox and benznidazole used for treatment of human Chagas' disease. Blood trypomastigotes purified in Fycoll-Hypaque were incubated with fluorescein-labelled lectins Con A, WGA, EE, WFA, TPA and PNA and then microscopically examined. Neither qualitative or quantitative differences in the fluorescence intensity could be detected between parasites from VL-10 and CL strains submitted or not to treatment. The results suggest that both strains do not differ in their surface membrane carbohydrate moieties. Moreover, the rapid clearance of blood forms the drug-sensitive strain in animals treated with singlo doses of both compounds is not likely to depend on membrane alterations expressed by changes in the carbohydrate components. furthermore, resistance or sensitivity to drugs is not apparently related to carbohydrate distribution on T. cruzi blood forms.

Cholestérol, pression artérielle et fumée de cigarette dans la population en Suisse: le projet MONICA. [Cholesterol, blood-pressure and cigarette-smoking in switzerland - the MONICA-project].

Elevated plasma cholesterol, high blood pressure and cigarette smoking are three major risk factors for coronary heart disease. Within the framework of Switzerland's participation in the multicenter study MONICA (MONItoring of trends and determinants in CArdiovascular disease), proposed by the WHO, a first risk factor survey was conducted in a representative sample of the population (25-74 years) of two reporting units (cantons of Vaud and Fribourg, canton of Tessin). A high blood cholesterol level (>6,7 mmol/l) is the most common risk factor for coronary heart disease among the studied population. Among men, about 13% have elevated blood pressure, the proportion being about one in ten among women; these proportions increase with age and are slightly above these values in Tessin. Cigarette smoking is still a common behavior; between 25 and 45 years one third of the population (male and female) regularly smoke cigarettes.

Éthique et transfusion sanguine [Ethics and blood transfusion.]

Le don de sang représente un acte solidaire. Il est le plus souvent bénévole et, selon les pays et les circonstances, non rémunéré. Les éléments de la réflexion éthique sont, entre autres, l'augmentation des besoins, les critères d'exclusion de plus en plus nombreux, l'exigence sécuritaire et les modifications des structures de nos sociétés. Compte tenu de cela, les acteurs de la chaîne transfusionnelle doivent s'interroger sur certains paramètres : la valeur du don, le sens du bénévolat, l'opportunité de rémunérer l'acte de livrer une partie de soi, non plus comme un don et comme une expression d'altruisme et de solidarité, mais comme une prestation commerciale définie par des règles économiques. Blood donation is an act of solidarity. Most often, this act is done on a volunteer basis and, depending on countries and circumstances, is not remunerated. The increase in need, the always-greater number of deferral criteria, the safety issues and the changes in the structures of our societies are among the many subjects for ethical debates. Taking these into account, the actors of the transfusion must analyze certain parameters: the value of a donation, the meaning of volunteering, the appropriateness of remunerating the act of giving a part of one's self, no longer as a donation or an expression of altruism and solidarity, but as a commercial act regimented by economic laws.

Impact of the C2/C6 ratio of high-molecular-weight hydroxyethyl starch on pharmacokinetics and blood coagulation in pigs

Rapport de synthèse : Contexte: l'hydroxyéthylamidon (HEA) est largement utilisé comme expanseur volémique en anesthésiologie et réanimation. Cependant, cette classe de produits perturbe le system de la coagulation. Des améliorations restent possibles dans le choix de la combinaison optimale de poids moléculaire, de degré de substitution en radicaux éthyle et de localisation de ces radicaux sur le squelette glucidique des polymères, afin d'optimiser leur efficacité et leur tolérance. L'HEA de poids moléculaire élevé et faiblement substitué n'affecte pas plus la coagulation sanguine que de l'HEA de bas poids moléculaire faiblement substitué. Nous examinons in vivo l'effet d'un abaissement du rapport C2/C6 sur les caractéristiques pharmacocinétiques et l'impact sur la coagulation sanguine d'un HEA de haut poids moléculaire faiblement substitué. Matériels et méthode: nous comparons dans une étude prospective, randomisée et parallèle l'HEA 650/0.42/2.8 avec l'HEA 650/0.42/5.6 auprès de 30 cochons. Avant, pendant et jusqu'à 630 minutes après une perfusion de 30 ml/kg d'HEA, des échantillons sanguins ont été collectés pour mesurer les concentrations d'HEA, les tests de coagulation plasmatique classiques et la coagulation sanguine par thrombélastographie (TEG®, Haemoscope Corporation, Niles, II, U.S.). Les paramètres pharmacocinétiques ont été estimés en adaptant un modèle à deux compartiments. Résultats: la constante d'élimination est de 0.009 ± 0.001 (min-1) pour l'HEA 650/0.42/2.8 et 0.007 ± 0.001 (min-1) pour l'HEA 650/0.42/5.6 (p<0.001); la surface sous la courbe de concentration est de 1374 ± 340 min*g/L pour l'HEA 650/0.42/2.8 et 1697 ± 411 min*g/L pour l'HEA 650/0.42/5.6 (p=0.026). Les concentrations mesurées d'HEA ne montrent pas de différence entre l'HEA 650/0.42/2.8 et l'HEA 650/0.42/5.6. Les deux solutions d'HEA affectent de façon identique la coagulation sanguine: l'index de coagulation thrombélastographique diminue pareillement à ta fin de la perfusion d'HEA 650/0.42/2.8 et d'HEA 650/0.42/5.6 (p=0.29). De même, le temps de thromboplastine partielle activée et le temps de prothrombine augmentent de manière similaire pour l'HEA 650/0.42/2.8 et l'HEA 650/0.42/5.6 (p=0.83). Conclusion: la réduction du rapport C2/C6 de l'HEA de poids moléculaire élevé et faiblement substitué aboutit à une élimination légèrement accélérée d'HEA. Cependant, elle ne modifie pas l'effet perturbateur sur la coagulation.

Investigation of Postmortem Gases: A Forensic Imaging and Analytical Chemistry Approach

Background: Distinguishing postmortem gas accumulations in the body due to natural decomposition and other phenomena such as gas embolism can prove a difficult task using purely Multi-Detector Computed Tomography (MDCT). The Radiological Alteration Index (RAI) was created with the intention to be able to identify bodies undergoing the putrefaction process based on the quantity of gas detected within the body. The flaw in this approach is the inability to absolutely determine putrefaction as the origin of gas volumes in cases of moderate alteration. The aim of the current study is to identify percentage compositions of O2, N2, CO2 and the presence of gases such as H2 and H2S within these sampling sites in order to resolve this complication. Materials and methods: All cases investigated in our University Center of Legal Medicine are undergoing a Post-Mortem Computed Tomography (PMCT)-scan before external examination or autopsy as a routine investigation. In the obtained images, areas of gas were characterized as 0, I, II or III based on the amount of gas present according to the RAI (1). The criteria for these characterizations were dependent of the site of gas, for example thoracic and abdominal cavities were graded as I (1 - 3cm gas), II (3 - 5cm gas) and III (>5cm gas). Cases showing gaseous sites with grade II or III were selected for this study. The sampling was performed under CT-guidance to target the regions to be punctured. Luer-lock PTFE syringes equipped with a three-way valve and needles were used to sample the gas directly (2). Gaseous samples were then analysed using gas chromatography coupled to a thermal conductivity detector (GC-TCD). The components present in the samples were expressed as a percentage of the overall gas present. Results: Up to now, we have investigated more than 40 cases using our standardized procedure for sampling and analysis of gas. O2, N2 and CO2 were present in most samples. The following distributions were found to correlate to gas origins of gas embolism/scuba diving accidents, trauma and putrefaction: ? Putrefaction → O2 = 1 - 5%; CO2 > 15%; N2 = 10 - 70%; H2 / H2S / CH4 variable presence ? Gas embolism/Scuba diving accidents → O2 and N2= varying percentages; CO2 > 20% ? Trauma → O2 = small percentage; CO2 < 15%; N2 > 65% H2 and H2S indicated levels of putrefaction along with methane which can also gauge environmental conditions or conditions of body storage/burial. Many cases showing large RAI values (advanced alteration) did reveal a radiological diagnosis which was in concordance with the interpretation of the gas composition. However, in certain cases (gas embolism, scuba divers) radiological interpretation was not possible and only chemical gas analysis was found to lead to the correct diagnosis, meaning that it provided complementary information to the radiological diagnosis. Conclusion: Investigation of postmortem gases is a useful tool to determine origin of gas generation which can aid the diagnosis of the cause of death. Levels of gas can provide information on stage of putrefaction and help to perform essential medico-legal diagnosis such as vital gas embolism.

Risk factors for Trypanosoma cruzi infection among blood donors in Central Brazil

Characteristics and possible risk factors associated with Trypanosoma cruzi infection among blood donors were assessed within a routine screening programme in blood banks in an endemic area of Chagas disease. 6,172 voluntary blood donors were interviewed and tested for anti-T. cruzi antibodies by Haemagglutination and Complement Fixation tests in six blood banks in Goiânia-Central Brazil from October 1988 to April 1989. An overall prevalence of 2.3% for T. cruzi infection was obtained, being 3.3% for first-time blood donors, and 1.9% for regular ones (p < 0.01). Considering this seropositivity among regular blood donors, selection of candidates relying only on the history of previous donation was found to be inadequate. The risk of infection increased inversely with the degrees of education and monthly income. There was a 9.2 risk of infection (95% CI 3.8-22.6) for those who had lived more than 21 years in an endemic area compared to subjects who had never lived in rural settings, after multivariate analysis. These informations may help to review the criteria of selection of donors in order to improve quality of blood products in endemic areas.

Is intra-operative blood flow predictive for early failure of radiocephalic arteriovenous fistula?

BACKGROUND: For over 50 years, radiocephalic wrist arteriovenous fistulae (RCAVF) have been the primary and best vascular access for haemodialysis. Nevertheless, early failure due to thrombosis or non-maturation is a major complication resulting in their abandonment. This prospective study was designed to investigate the predictive value of intra-operative blood flow on early failure of primary RCAVF before the first effective dialysis. METHODS: We enrolled patients undergoing creation of primary RCAVF for haemodialysis based on the pre-operative ultrasound vascular mapping discussed in a multidisciplinary approach. Intra-operative blood flow measurement was systematically performed once the anastomosis had been completed using a transit-time ultrasonic flowmeter. During the follow-up, blood flow was estimated by colour flow ultrasound at various intervals. Any events related to the RCAVF were recorded. RESULTS: Autogenous RCAVFs (n = 58) in 58 patients were constructed and followed up for an average of 30 days. Thrombosis and non-maturation occurred in eight (14%) and four (7%) patients, respectively. The intra-operative blood flow in functioning RCAVFs was significantly higher compared to non-functioning RCAVFs (230 vs 98 mL/min; P = 0.007), as well as 1 week (753 vs 228 mL/min; P = 0.0008) and 4 weeks (915 vs 245 mL/min, P < 0.0001) later. Blood flow volume measurements with a cut-off value of 120 mL/min had a sensitivity of 67%, specificity of 75% and positive predictive value of 91%. CONCLUSIONS: Blood flow <120 mL has a good predictive value for early failure in RCAVF. During the procedure, this cut-off value may be used to select appropriately which RCAVF should be investigated in the operation theatre in order to correct in real time any abnormality.

Temperature effect upon blood consumption in Triatoma infestans

Different blood consumption speed was observed in Triatoma infestans - nymphs and adults - exposed to 12 degrees C and 28 degrees C. Exposure to optimal temperature (28 degrees C) allows the insects to consume blood at a rate of 9% per day. Significative relationship between blood amount present in the promesenteron and consumed blood was found at 28 degrees. Consumption of blood was drastically reduced at the lowest temperature. Accordingly, lack of ovaric development, oviposition and mating behaviour was observed in insects kept at 12 degrees C. Relationship between laboratory and field observations are discussed.

Use of glass beads and CF 11 cellulose for removal of leukocytes from malaria-infected human blood in field settings

Passage of malaria infected blood through a two-layered column composed of acid-washed glass beads and CF 11 cellulose removes white cells from parasitized blood. However, because use of glass beads and CF 11 cellulose requires filtration of infected blood separately through these two resins and the addition of ADP, the procedure is time-consuming and may be inapropriate for use in the field, especially when large numbers of blood samples are to be treated. Our modification of this process yields parasitized cells free of contaminating leukocytes, and because of its operational simplicity, large numbers of blood samples can be processed. Our procedure also compares well with those using expensive commercial Sepacell resins in its ability to separate leukocytes from whole blood. As a test of usefulness in molecular biologic investigations, the parasites obtained from the blood of malaria-infected patients using the modified procedure yield genomic DNA whose single copy gene, the circumsporozite gene, efficiently amplifies by polymerase chain reaction.