Filariasis due to Loa loa and Mansonella perstans: distribution in the region of Okondja, Haut-Ogooué Province, Gabon, with parasitological and serological follow-up over one year

The prevalence of Loa loa and Mansonella perstans filariasis has been determined in 6 rural villages in eastern Gabon. Between 18.9 and 27.2% of people carry L. loa microfilariae with an overall microfilarial rate of 25.1%. The microfilarial rate for M. perstans was more variable, between 33.3 and 62.2% (average 49.1%). No significant difference was seen in the microfilarial rate with age over 15 years for either parasite, but men were infected more frequently than women. Anti-L. loa antibody titres were measured, using a homologous microfilarial antigen in ELISA. Taking the parasitological and immunological evaluations together, only 10% of the sample population appear to be free of these filarial infections. L. loa and M. perstans microfilaraemia and corresponding serology were also investigated twice in 150 people at a one-year interval. 99.1% of the cases who had no circulating L. loa microfilaria in March 1984 still did not show any 12 months later. Similarly, 97.1% of the untreated, microfilaraemic cases still harboured this parasite a year later. The same was not observed for M. perstans, since microfilariae appeared or disappeared in 26.7% of the cases. This suggests different dynamics for the two filarial infections. Variation in individual anti-L. loa antibody titres was low. The possibility of a genetic influence on the expression of loiasis is discussed.     

Cardioprotective effects of acute normovolemic hemodilution in patients with severe aortic stenosis undergoing valve replacement

BACKGROUND: After acute normovolemic hemodilution (ANH), improvement of the rheologic conditions may contribute to optimize tissue oxygen delivery and attenuate ischemia-reperfusion injuries. It was hypothesized that ANH would confer additional cardioprotection in patients with ventricular hypertrophy undergoing open heart surgery. STUDY DESIGN AND METHODS: This study was a randomized controlled trial. Forty patients scheduled for elective aortic valve replacement were randomly assigned to a control group (standard care) or an ANH group (target hematocrit level of 28%). All patients were managed with standard myocardial preservation techniques (cold blood cardioplegia, anesthetic preconditioning). The outcome measures included the release of myocardial enzymes, perioperative hemodynamic changes, the need for pharmacologic cardiovascular support, and cardiac complications. RESULTS: In the ANH group, the postoperative release of troponin I (mean peak plasma concentrations, 1.7 ng/mL; 95% confidence interval, 1.4-2.1 ng/mL) and myocardial fraction of creatine kinase (22 U/L; range, 18-24 U/L) was significantly lower than in the control group (3.6 [range, 3.0-4.2] ng/mL and 45 [range, 39-51] U/L, respectively). In addition, requirement for inotropic support was significantly lower and fewer hemodiluted patients presented adverse cardiac events. After ANH, there was a significant decrease in heart rate (-11 +/- 6%) and rate-pressure product (-16 +/- 8%) until the aortic cross-clamping time and, at the end of surgery, the circulating levels of erythropoietin (EPO) were higher than in control patients (13.6 +/- 4.2 mUI/mL vs. 7.3 +/- 2.4 mUI/mL; p < 0.05). CONCLUSIONS: Besides conventional cardiac preservation techniques, preoperative ANH further attenuates myocardial injuries. Optimization of preischemic myocardial oxygen delivery and/or consumption and the postconditioning effects of endogenous EPO are potential mechanisms for ANH-induced cardioprotection.     

Virtual memory CD8 T cells display unique functional properties

Previous studies revealed the existence of foreign antigen-specific memory phenotype CD8 T cells in unimmunized mice. Considerable evidence suggests this population, termed “virtual memory” (VM) CD8 T cells, arise via physiological homeostatic mechanisms. However, the antigen-specific function of VM cells is poorly characterized, and hence their potential contribution to immune responses against pathogens is unclear. Here we show that naturally occurring, polyclonal VM cells have unique functional properties, distinct from either naïve or antigen-primed memory CD8 T cells. In striking contrast to conventional memory cells, VM cells showed poor T cell receptor-induced IFN-γ synthesis and preferentially differentiated into central memory phenotype cells after priming. Importantly, VM cells showed efficient control of Listeria monocytogenes infection, indicating memory-like capacity to eliminate certain pathogens. These data suggest naturally arising VM cells display unique functional traits, allowing them to form a bridge between the innate and adaptive phase of a response to pathogens.     

Contentious matters between doctors and patients in the orthopaedic and traumatology surgery activity of a regional university hospital

The medical art is more and more legally regulated. The case-law about civil medical liability has widely changed these past years. The reversal of the burden of proof regarding patient’s information, the presumption of responsibility in case of nosocomial infection, the medical liability without fault, the therapeutic risk and finally the law of 4 March 2002 are just a few examples of these changes. Regarding this judicial tendency of the medical practice, it appears interesting to study the contentious matters between doctors and patients in the orthopaedic and traumatologic surgery activity of a regional university hospital. Over a 20-year-period activity, at a rate of 3,000 patients per year, we found 20 files. The first complaints occurred 12 years after the medical event; they have become more frequent in the past 3 years. The most frequent reasons of complaint are the nosocomial infections and the lack of information to the patients. The rare medical errors could have had less effect if discussed beforehand with the patients. Nowadays fact sheets are available to the public and the committee for the prevention of nosocomial infection (CLIN) is positively involved. The complaints’ handling process is still slow, and therefore delays the compensation of victims. The increasing number of complaints made to the Regional commission for conciliation and compensation (CRCI) could be a solution to address those delays.     

Natural antibodies against three distinct and defined antigens of Plasmodium falciparum in residents of a mesoendemic area in Gabon

The magnitude of the antibody response to three distinct and defined antigens of Plasmodium falciparum was assessed in 144 inhabitants of the Kassa district (Haut Ogooué Province, Gabon), a region where malaria is mesoendemic. Antibodies against a polypeptide consisting of 40 (Asn-Ala-Asn-Pro) repeats of P. falciparum circumsporozoite protein [(NANP)40] were detected by ELISA. Antibodies against the fusion peptide 31.1, which consists of the N-terminal portion of the 190-200 kDa glycoprotein, were also detected by ELISA. Antibodies against ring-infected erythrocyte surface antigens (RESA), mainly the P. falciparum 155 kDa antigen (Pf 155), were detected by IFA on glutaraldehyde-fixed P. falciparum infected red blood cells (IRBC). In addition, a standard IFA employing air-dried P. falciparum IRBC was used to detect antibodies against intraerythrocytic asexual forms. Parasitemia and spleen enlargement were also recorded. The frequency of sera positive for specific antibodies increased with age for all the antigens tested. Plateau antibody levels were reached at different ages for the different antigens. Individual antibody responses varied in titer to the different antigens. Subjects with parasite-negative thick smears showed higher titers of anti-31.1 as well as an increased frequency of anti-RESA antibodies compared to subjects having positive smears. No differences in the titer and in the prevalence of anti-(NANP)40 antibodies were found between these groups. The results suggest that the antibody response against asexual blood stage antigens, especially anti-RESA and anti-31.1, may play a role in controlling parasitemia.     

Expression of filarial-specific IgG subclasses under different transmission intensities in a region endemic for loiasis

Specific IgG subclasses were investigated in two villages (Okoumbi and Ndjokaye) in southeast Gabon with different Loa loa transmission intensities of approximately 9,000 and 1,300 infective larvae (L3) per person per year, respectively. IgG subclasses were measured by an enzyme-linked immunosorbent assay (ELISA) using extracts of L. loa L3, microfilariae (MF), or adult worms. Levels of L3-specific IgG3 were significantly higher in the village with low transmission (Ndjokaye) (P = 0.006). In contrast, MF-specific IgG2 was significantly higher in Okoumbi than in Ndjokaye (P = 0.0009). In the high-transmission village (Okoumbi), levels of both MF- and adult-specific IgG4 were significantly increased in MF carriers compared with amicrofilaremic subjects (P = 0.0015 and P = 0.003, respectively), while levels of L3- and MF-specific IgG1 were significantly higher in amicrofilaremic individuals compared with MF carriers (P = 0.04 and P = 0.03, respectively). Furthermore, among microfilaremic individuals, the level of the specific IgG1 subclass was much lower in Okoumbi than in Ndjokaye (P = 0.036). These results suggest that the expression of antigen-specific IgG3 and IgG2 is more likely to vary with transmission intensity, whereas antigen-specific IgG4 and IgG1 varies with adult worm and MF burden.     

Hip paraosteoarthropathy after sciatica nerve injury by quinine intramuscular injection]

INTRODUCTION: Often occurring in central nerve injuries, paraosteoarthropathic conditions are revealed by a stiffness or ankylosis of the joint. Their occurring during peripheral nerve injuries is rare. OBJECTIVE: To report a case of hip paraosteoarthropathy features after sciatica nerve injury by quinine intramuscular injection. MATERIALS AND METHOD: We report a case of a 24-year-old patient presenting with pain, oedema of the left buttock, limitation of bending of the left hip, and antalgic limping associated with a small step because of axonal left sciatic nerve injury. Initial pelvis X-ray and laboratory findings were normal. Reviewed 4 months later with important stiffness of the left hip, a second X-ray showed an atypical paraosteoarthropathy (POA). Chemotherapy and physiotherapy alleviated neurological muscle weakness but did not have any effect on the hip functionality. Surgical excision was the only treatment that improved the amplitude of movements. Evolution 7 years later showed the disappearance of the peripheral nerve-injury signs and the conservation of the movement amplitude obtained after excision, without a return to normal. CONCLUSION-DISCUSSION: Factors pointing to this POA were initial oedema, immobilization because of pain, and trauma by quinine intramuscular injection. The interest is the exceptional occurrence of POA on a peripheral nerve injury (sciatica nerve injury by quinine injection) outside the context of length resuscitation and that sciatica nerve injury is frequent in tropical countries but anachronistic in a developed one.     

Age-related prevalence of antibody response against three different, defined Plasmodium falciparum antigens in children from the Haut-Ogooué province in Gabon

The kinetics of the humoral response to defined Plasmodium falciparum antigens was studied in 543 children, 1 month to 15 years old, living in an area endemic for malaria. The antigens used for enzyme-linked immunosorbent assay were (i) the synthetic peptide (NANP)40 representing the immunodominant repeated region of the circumsporozoite protein, and (ii) the fusion peptide 31.1, representing the N-terminal portion of the 83 kDa polypeptide expressed at the surface of merozoites which is a processed product of the 190-200 kDa glycoprotein. In addition, glutaraldehyde-fixed infected red blood cells (RBC) were used to detect ring-infected erythrocyte surface antigen (RESA) and unfixed infected RBC to detect intra-erythrocytic asexual form (IEF) antigens by immunofluorescence. In the 1 to 2 months age group, 50%, 26% and 21% of the children had antibodies for IEF, (NANP)40 and 31.1 respectively, but none had anti-RESA antibodies. The proportions of positive subjects decreased until 3 to 6 months and then increased progressively for the 4 antigens, approaching, but not reaching, adult values by the age of 15 years. Antibodies against specific antigens were acquired concomitantly. Children born from (NANP)40-positive mothers showed enhanced anti-(NANP)40 IgG responses.     

Étude sérologique de la toxoplasmose chez les femmes enceintes de Franceville, Gabon

The serological prevalence of Toxoplasma gondii was studied among 839 pregnant women in two hospitals from Franceville (Gabon), between May 2007 and December 2007. Specific T. gondii IgG and IgM were measured by Enzyme Linked Fluorescent Assay (ELFA). Datation of the infection was carried out by avidity test. Fifty-six percent of women in this study were immunised compare to the 71% who were found as immunised in a previous study carried out fifteen years ago. 2.6% were found to be IgM positive. However, from the avidity test it was found that these infections occurred before pregnancy contact with cats and age increase this prevalence. The lack of information for pregnant women, the lack of continuous training for health personnel and lack of awareness about interpretation of laboratory diagnostic tests like avidity test in these hospitals reduce the level of counselling for women about T. gondii.