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Biomedical subjects

B Ivanoff

Publications and source records attributed to B Ivanoff.

At least 55 records · Page 3Linked to original sources
PubMed1988

Antifilarial activity of CGP 20,376 in chimpanzees (Pan t. troglodytes) naturally infected with Dipetalonema vanhoofi.

CGP 20,376, a benzthiazole and new antifilarial agent, was investigated at CIRMF in eight wild born chimpanzees naturally infected with Dipetalonema vanhoofi. Single oral doses (3.75, 7.5, 11 and 15 mg/kg) were administered. Drug levels during the first hour after administration were assessed in seven chimpanzees at 10 minute intervals in the blood. Levels of unchanged drug (CGP 20,376) were higher than those of its metabolite (CGP 20,308). However, there was considerable variation between individuals, although the results for each animal were consistent. Because of investigational limitations a complete drug profile could not be established. Unsheathed microfilariae of D. vanhoofi were monitored during the first hour following drug administration in seven chimpanzees. In five the microfilaraemia dropped to low counts within 10 minutes and remained below the initial values for the next 50 minutes while in two other chimpanzees it showed a more irregular reduction. Periodic microfilarial counts over the next 20 months, at roughly 30 day intervals, showed that three chimpanzees, treated with 7.5, 11 and 15 mg/kg respectively, remained free of circulating microfilariae from Day 1 to Day 600, the chimpanzee treated with 3.75 mg/kg remained microfilaremic and, in three chimpanzees low numbers of microfilariae reappeared within one year, whereas in the remaining ape they reappeared after one year. No major clinical adverse effects were observed, but liver function tests showed mild reversible changes at the 11 and 15 mg/kg doses. CGP 20,376 was therefore microfilaricidal, except for the lowest dose, and it was possibly macrofilaricidal in those chimpanzees which remained free of microfilariae for 600 days. Clinically CGP 20,376 was well tolerated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Ophthalmia neonatorum in a semi-rural African community.

The incidence and aetiology of ophthalmia neonatorum have been estimated over a 7-month period in Franceville, a semi-rural community in south-eastern Gabon. Chlamydia trachomatis was the most frequently observed pathogen, being isolated from 17 babies (2.7% of births), and Neisseria gonorrhoeae was recovered from 12 (1.6% of births). 5 of 17 cases of chlamydial conjunctivitis were in infants less than 5 d old as opposed to 9 in the typical 5 to 10-days-old group. As expected, most cases of gonococcal ophthalmia neonatorum occurred in the first 5 d of life with cases in older infants often not accompanied by a granulocytic response. Chlamydial conjunctivitis was usually unilateral whereas other cases were most frequently bilateral.

Age Factors↗
PubMed1987

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.

Adolescent↗
PubMed1987

Human T-cell leukemia virus type I isolates from Gabon and Ghana: comparative analysis of proviral genomes.

Two isolates of human T-cell leukemia virus type I (HTLV-I) were obtained from lymphocyte cultures of a healthy carrier in Gabon and another in Ghana. Their proviruses were analyzed by Southern blot hybridization and compared with prototypical HTLV-I isolated in Japan and the United States. The provirus genomes of both strains were highly homologous to the prototype HTLV-I along the whole viral genome. The restriction endonuclease sites of the Ghanian isolate were almost identical with those of the prototype HTLV-I, but 10 of 26 sites of the Gabonese isolate were different from those of the prototype. Furthermore, the restriction map of the Gabonese isolate resembled those of a simian T-cell leukemia virus (STLV-I) isolated from a chimpanzee from Sierra Leone and a variant of HTLV-I from Zaire (HTLV-Ib) more closely than those of any other known HTLV-I. These results indicated the existence of some unique strains of HTLV-I transmitted among African people, and the importance of clarifying the origin and transmission of HTLV group viruses.

Biological Evolution↗
PubMed1987

The use of mebendazole in the treatment of filariases due to Loa loa and Mansonella perstans.

Patients harbouring Loa loa and/or Mansonella perstans infections, or presenting typical filarial symptomatology, were treated with mebendazole, a drug shown to be efficient in other parasitoses. Of the patients who took the drug during 21 days and provided regular blood samples, 84% showed a significant decrease in their L. loa microfilaraemia and 100% in their M. perstans microfilaraemia, with a concomitant improvement in the clinical manifestations and no side reaction to drug administration. Additionally, the long-lasting effect of the drug (up to day 200 in some cases) may suggest a positive action on the adult worm. Mebendazole may consequently be regarded as a safer alternative to diethylcarbamazine for the treatment of these two parasitoses.

Adolescent↗
PubMed1987

Changing antibiotic susceptibility of Neisseria gonorrhoeae in Franceville, Gabon.

Susceptibilities to penicillin, cefotaxime, kanamycin, tetracycline, and spectinomycin were measured for 5 reference strains and 302 Neisseria gonorrhoeae isolates collected between 1980 and 1985. After an initial rise, the number of penicillinase-producing strains decreased. A gradual decrease in susceptibility to spectinomycin and the appearance of tetracycline-resistant strains were also documented.

Anti-Bacterial Agents↗
PubMed1987

Detection of human antibodies against Plasmodium falciparum sporozoites using synthetic peptides.

A large peptide consisting of about 40 (Asn-Ala-Asn-Pro) repeats of Plasmodium falciparum circumsporozoite protein, (NANP)40, was synthesized. It was recognized specifically by monoclonal antibodies produced against P. falciparum sporozoites. Moreover, this peptide strongly inhibited the binding of such monoclonal antibodies to antigens present in a sporozoite extract. The (NANP)40 peptide was employed without any carrier to develop an enzyme-linked immunosorbent assay to detect sporozoite-specific serum antibodies arising after natural malaria infections. Antibodies were detected in a high percentage (43.1%) of European patients suffering from acute P. falciparum malaria and in Africans living in an area of Gabon endemic for malaria. In the latter group, the frequency of antisporozoite antibodies increased with age, reaching 65.9% in individuals more than 40 years old. There was a significant correlation between the results obtained with an immunofluorescence assay with glutaraldehyde-fixed sporozoites and those obtained by enzyme-linked immunosorbent assay with (NANP)40. Therefore, such synthetic peptides representing the repetitive epitope of P. falciparum circumsporozoite protein can be used for the detection of antisporozoite antibodies and for the epidemiological studies required to obtain base-line data concerning the immune status of individuals before their participation in a sporozoite vaccine trial.

Adolescent↗
PubMed1987

Importance of chlamydial antibodies in acute salpingitis in central Africa.

Of 35 women with acute salpingitis on laparoscopy, 86% had chlamydial antibodies at a titre of 1/16 or higher and 49% at a titre of 1/512 or higher. Geometric mean titres of chlamydial antibodies correlated significantly with a laparoscopic observation of chronic salpingitis (p less than 0.001), with a history of infertility (p less than 0.05), and with severe inflammation (p less than 0.10), but not with a history of salpingitis or a positive cervical culture for Chlamydia trachomatis. In the subgroup of infertile women, the geometric mean titre of antibodies to chlamydiae correlated significantly with the presence of chronic salpingitis (p less than 0.005). These data indicate that chlamydial infections play a major part in salpingitis and infertility in central Africa. In this area, which is known as the "infertility belt", programmes to control chlamydial infections should be implemented.

Acute Disease↗
PubMed1986

A rapid, simple method for isolation of viable microfilariae.

We describe a rapid, efficient method for purifying Loa loa microfilariae from blood that does not affect their longterm motility. It is based on the separation of microfilariae on a performed discontinuous Percoll gradient, followed by filtration on cellulose ester membranes. The parasite population, after isolation, is close to 100% pure, 100% viable and remains motile for at least 20 days. Recovery from original blood samples is typically around 90%. The method, because of its simplicity and minimal material requirements, could be used with up to 210 ml of blood. It also allows the isolation of Mansonella perstans microfilariae.

Animals↗
PubMed1985

Rotavirus prevalence and relationships with climatological factors in Gabon, Africa.

A one-year study of rotavirus prevalence was carried out using electron microscopy in Gabon, equatorial Africa. One hundred fifty-six nonhospitalized diarrheic children up to 10 years of age and 115 age-matched controls were investigated together with diarrheic adults and children over 10 years of age. Rotaviruses were observed only in diarrheic children under 10 years of age (10.2%). Rotaviruses were more prevalent in the dry-season months (19.2% versus 1.3%, P less than .001). Rotaviruses were the most commonly found among all the viral, bacterial, and parasitic agents we detected, with the exception of the coronaviruslike particles, which are the subject of another paper [Sitbon, 1985].

Adolescent↗
PubMed1985

Loa loa: a simple method for isolation of microfilariae from blood with production of antigen in extraction medium.

A simple method for isolating Loa loa microfilariae from the blood of patients is described. This involves sedimentation on Ficoll followed by migration of the microfilariae into an extraction medium. During migration the microfilariae release antigen-rich excretory or secretory products. The procedure thus yields two products: pure microfilariae and large amounts of antigen in the extraction medium.

Antigens, Helminth↗
PubMed1985

Prepartal infection of the placenta with Neisseria gonorrhoeae.

Placentas from 191 consecutive deliveries were cultured for Neisseria gonorrhoeae and other bacteria before being examined histologically. N gonorrhoeae was seen on direct microscopical examination and cultured from two placentas, one of which had chorioamnionitis and the other had a granulocytic invasion of the membranes. In both patients, rupture of the membranes had occurred two hours or less before delivery, and thus after infection. A third patient was also found to have light gonococcal infection of the placenta. Six infections with group B streptococci were identified, but only one correlated with chorioamnionitis. Chorioamnionitis was observed in 16 (8.4%) and granulocytic infiltration of the membranes in 18 (9.4%) of the deliveries.

Adolescent↗
PubMed1985

Auxotypes and serogroups of penicillinase producing and non-producing strains of Neisseria gonorrhoeae isolated in Franceville, Gabon.

The auxotypes and serogroups of 250 consecutive isolates of Neisseria gonorrhoeae from Franceville, Gabon, including 33 penicillinase producing (PPNG) strains, were identified and the results tabulated for four periods. The PPNG and certain non-PPNG strains were isolated in clusters against a relatively stable pattern of non-PPNG biotypes. Most of the non-PPNG strains were non-requiring or proline requiring strains of serogroup WII or non-requiring strains that could not be grouped with commercially available antisera. No strain requiring arginine, hypoxanthine, and uracil was observed. The PPNG strains were all serogroup WI or ungroupable and non-requiring or proline or arginine dependent auxotypes. Only one non-PPNG strain required proline or arginine and was not serogroup WII.

Culture Media↗
PubMed1985

[Etiology of acute infantile gastroenteritis in Gabon].

Rotaviruses are the main etiology of acute diarrhoeas in gabonese children (11 to 30% according to age). Salmonellae (11.4%), Shigellae (7.1%) and E. histolytica (7.1%), isolated or associated with enterobacteria, E. coli (3%), Giardia and Strongyloides stercoralis (1.4%), Yersinia enterocolitica (1%) and Balantidium coli (0.5%) were also found, without cholera.

Adolescent↗
PubMed1984

Age of appearance of IgG, IgM, and IgE antibodies specific for Loa loa in Gabonese children.

IgG, IgM, and IgE antibodies against the filaria Loa loa were measured in umbilical cord blood and in blood from young Gabonese children by an ELISA technique using a homologous metabolic antigen. For children in eight consecutive age groups and adults the percentage of the population positive for each of the antibody classes was determined. The number of children with maternal IgG decreased until one year of age when new synthesis began to become apparent. IgM antibodies were detected only after six months, probably indicating an early infancy as opposed to a fetal infection. The percentage of individuals positive for IgM or IgE reached a peak between two and three years old, followed by a slight decline. Over half of the individuals over one year of age had IgM antibody against L. loa, indicating long-term synthesis of this class of immunoglobulin in many people. In the first two years of life, IgE antibodies were usually accompanied by L. loa-specific IgM. This specific IgE did not appear to trigger the synthesis of nonspecific IgE. By the age of two, 95% of the population had some antibodies against L. loa and by five the percentage of individuals positive for each antibody class had reached adult levels.

Adult↗
PubMed1984

[Current aspects of the ELISA technic applied to the serological diagnosis of helminthiasis].

The authors reviewed the data acquired in ELISA technique for serological diagnosis of parasitosis. They reviewed the literature on Schistosomisis, Fasciolasis, Cestode infections (hydatidoses and cysticercoses) and nematode infections. They described their adaptation of the technique for detection of antimicrofilaria Loa loa antibodies and concluded that ELISA technique is reliable in the diagnosis of parasitic diseases even in areas where they are endemic.

Cestode Infections↗