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Biomedical subjects

G Desmonts

Publications and source records attributed to G Desmonts.

At least 19 recordsLinked to original sources
PubMed1990

[Congenital toxoplasmosis. 5 cases of mother-to-child transmission of pre-pregnancy infection].

Five cases of congenital toxoplasmosis consecutive to a maternal toxoplasma infection that had preceded pregnancy were observed. One woman with normal immune system had developed a well-documented lymph node toxoplasmosis 2 months before conceiving. Four women had chronic toxoplasmosis diagnosed in the course of an immunosuppressive disease: Hodgkin's disease in 1 case, systemic lupus erythematosus in 2 cases and pancytopenia in 1 case. Toxoplasmosis had been recognized 3, 5 and 10 years respectively before conception in 3 women, and at an uncertain date in 1 woman. Three women had received corticosteroids during pregnancy, and 2 had undergone splenectomy. Among the 6 children (2 were twins), 1 presented with severe foetal disease at birth, 1 developed lethal systemic toxoplasmosis after birth, 1 showed hydrocephalus with therapeutically well-controlled chorioretinitis, 1 had isolated eye lesion and 2 had asymptomatic infection. The parasite seems to have been transmitted after the 20th week of pregnancy in all cases. The physiopathology of mother-to child toxoplasma transmission, the role played by maternal immunodeficiency and the practical implications of these exceptional cases are discussed.

Female↗
PubMed1988

Prophylaxis of congenital toxoplasmosis. Effects of spiramycin on placental infection.

The results of parasitological investigation of the placenta for toxoplasma in 223 cases with documented congenital toxoplasmosis were analysed according to whether the mother had been treated, or not, with spiramycin during pregnancy. The investigation was negative in 10-11% of the cases when the mother had not been treated or had been inadequately treated; in 25% of the cases with a treatment of 3 g spiramycin day; and in 50% with spiramycin plus the combination of pyrimethamine with sulphonamide. This series is compared with a previous group of 321 women whose placental investigation was negative in 50% of untreated cases and 81% of treated women. The treatment categories are not directly comparable, because it is not possible to have a randomly assigned 'no treatment' group, for ethical reasons. Correlation between spiramycin treatment and negative results of mouse inoculation of placental material suggests that spiramycin might decrease the risk of materno-fetal transmission of toxoplasma by reducing the severity and duration of toxoplasmic placentitis. Current use of spiramycin in infected pregnant women is recommended because of its activity and lack of side effects. The dosage must not be lower than 3 g/day. Additional pyrimethamine plus sulphonamide should be restricted to selected cases with fetal abnormality diagnosed during pregnancy. Some data on pharmacology of spiramycin in mothers, placentas and fetuses are reviewed. They suggest that monitoring of maternal serum antibody titres for a dosage more adapted to individual cases may be desirable.

Female↗
PubMed1988

Antigen(s) responsible for immunoglobulin G responses specific for the acute stage of Toxoplasma infection in humans.

An agglutination test for immunoglobulin G (IgG) Toxoplasma antibodies with acetone-fixed tachyzoites (AC antigens; AC agglutination test) was positive only with sera from patients during the acute stage of their infection. In contrast, when the test was performed with Formalin-fixed tachyzoites (HS antigens; HS agglutination test), positive results were obtained during both the acute and chronic (latent) stages of the infection. Studies were performed to define the antigen(s) of T. gondii which are detected by IgG antibodies present only during the acute stage of the infection. Sera of mice immunized with AC antigens recognized predominantly 10 antigens of tachyzoites by immunoblot analysis. Sera from individuals with the acute but not chronic infection reacted strongly with these same 10 antigens in immunoblots. Sera of mice immunized with HS antigens recognized more Toxoplasma antigens on immunoblots than did mouse AC antibodies. Absorption of the latter with HS antigens removed detectable reactivity of AC antibodies in immunoblots and in the AC and HS agglutination tests, suggesting that AC antigens are a selected portion of HS antigens. AC antigens were specific for tachyzoites in that AC antibodies reacted with the cell membranes of both forms of the organism in an indirect fluorescent-antibody test. Tachyzoite-specific antigen(s) appear to be useful in differentiating between the acute and chronic stages of Toxoplasma infection through their detection by IgG antibodies.

Acute Disease↗
PubMed1987

Toxoplasma gondii antigens recognized by sequential samples of serum obtained from congenitally infected infants.

The Sabin-Feldman dye test, the immunoglobulin M (IgM) immunosorbent agglutination assay, and the immunoblot technique were used to study the evolution of the antibody response to Toxoplasma gondii and to examine antigens of the organism recognized by antibodies in the sera of 12 congenitally infected infants and 7 mothers. In the sera of eight infants, a significant rise was noted in the dye test titers, while the serum of only one infant demonstrated a late increase in the IgM immunosorbent agglutination assay titer. In each infant and mother, antigens with approximate masses of 35,000 and 115,000 daltons were strongly recognized by IgG antibodies. An antigen(s) with an approximate mass of 4,000 daltons was recognized by IgM antibodies in the sera of each of the mothers but was recognized by antibodies in the sera of only two of the infants.

Adult↗
PubMed1987

Serodiagnosis of postnatally and prenatally induced toxoplasmosis in sheep.

Nineteen pregnant (45 to 90 days of gestation) and 9 nonpregnant ewes were inoculated orally with 1,000 or 10,000 oocysts of Toxoplasma gondii. Pregnant ewes were euthanatized at days 14 (2 ewes), 21 (1 ewe), 23 (1 ewe), 28 (2 ewes), 35 to 42 (6 ewes), and 49 to 62 (6 ewes), and antibody titers in fetal and maternal sera were assayed, using the modified agglutination, latex agglutination, indirect hemagglutination, and dye tests. Although all ewes developed antibody titers of greater than or equal to 1,024 within 28 days after inoculation, fetuses were seronegative up to 28 days, using the modified agglutination test. Toxoplasma gondii antibodies were found in fetuses, using the modified agglutination and dye tests 35 days after ewes were inoculated. Latex agglutination and indirect hemagglutination tests were insensitive for detection of T gondii antibodies in ovine fetal sera. Toxoplasma gondii antibody titers in nonpregnant ewes were similar to those in pregnant ewes. Passively acquired T gondii antibodies from the colostrum decreased from 1,024 to less than 16 between 49 and 56 days of age in 1 lamb and between 62 and 106 days in its twin.

Animals↗
PubMed1986

Toxoplasma gondii-induced abortion in dairy goats.

Three of 8 goats on a Maryland farm aborted or had dystocia associated with toxoplasmosis during the winter of 1984. Doe 1 aborted a decomposed fetus 30 days before term. Modified agglutination test (MAT) antibody titers against Toxoplasma gondii were found in pleural fluid of the fetus (1:1,024) and in serum of doe (1:4,096 at 31 days after abortion). Doe 2 aborted a fetus 5 days before term; MAT antibody was found in the pleural fluid of the fetus (1:16,384) and in the doe's serum (1:4,096 on the day of abortion). Placenta from both does had foci of necrosis characteristic of toxoplasmosis, and T gondii was identified in lesions. Doe 3 had dystocia 7 days before term and a partially decomposed fetus was delivered by cesarian section; MAT was found in pleural fluid of the fetus (1:1,024) and in serum from the doe (1:4,096 on the day of abortion). Focal gliosis and calcification were seen in brain specimens from 2 of the 3 fetuses. None of the does produced milk after abortion. Two other does (No. 4 and 5) delivered apparently healthy kids transplacentally infected with T gondii; MAT in serum of both does was 1:4,096. Doe 4 delivered 3 kids; MAT titer in a serum from each kid 38 days after birth was 1:16,384. Doe 5 delivered 1 kid with a serum MAT titer of 1:1,024 at 38 days after birth. The 3 remaining does had MAT titers of 1:256, 1:16, and 1:16, and all delivered healthy kids. Epizootiologic evidence suggested that the does acquired T gondii infection from oocysts passed in feces of domestic cats on the farm. The MAT titers of 4 cats on the farm were 1:65,356; 1:1,024; 1:16; and 1:1,024.

Abortion, Veterinary↗
PubMed1986

Analysis of Toxoplasma gondii antigens recognized by human sera obtained before and after acute infection.

The antibody response to Toxoplasma gondii was studied in human serum samples obtained before and during acute infection with T. gondii. Analysis was by the Sabin-Feldman dye test, double-sandwich IgM ELISA, agglutination test, and protein blots of toxoplasma antigens. Seventeen patients were studied: 12 pregnant women, 2 heart transplant recipients, and 3 symptomatic but immunologically normal individuals. Both IgM and IgG protein blots of the first serologically positive serum sample from each patient revealed new bands, as well as intensified staining of bands noted with the serologically negative serum samples. In each patient, bands corresponding to antigens of approximately 4 kilodaltons (kDa; IgM blots) and of approximately 35 kDa (IgG) were the most intensely stained. In one patient, IgM antibodies to the 4-kDa antigen(s) were demonstrable by protein blots before they were demonstrable by IgM ELISA. IgG protein blots of sera from individuals with chronic infection with T. gondii revealed weakly reactive antibodies to both the 4-kDa and 35-kDa antigens; these bands were not demonstrable in the IgM blots.

Adult↗
PubMed1986

[A new agglutination reaction for the diagnosis of the developmental stage of acquired toxoplasmosis].

Agglutination of acetone treated toxoplasma (AC) is different from that one of formalin fixed parasites (HS). Sera from patients with a recently acquired ("acute") infection agglutinate both HS and AC parasites suspensions as well; contrary to sera from patients with past infection ("chronic stage") in which high titers of HS agglutination are often present, while the titres of AC agglutination are lower even negative. This is markedly observed in patients with local lesions (relapsing chorioretinitis, patients with AIDS and brain abscesses). The reason might be that different membrane toxoplasma antigens may induce the synthesis of agglutinating IgG. For example, antigens 35 KD and 27 KD described by E. Handman et al. The antibody specific for 27 KD is apparently present mainly during acute infection, contrary to the antibody specific for 35 KD which might be responsible of the high HS agglutination titre in sera from patients with chronic infection. Even if these hypotheses were not confirmed in the future, comparison of the titre in the HS and AC agglutination test might actually be helpful for practical diagnosis of the stage of toxoplasma infection.

Acute Disease↗
PubMed1985

Prenatal diagnosis of congenital toxoplasmosis.

Prenatal diagnosis of congenital toxoplasmosis was attempted by means of fetal blood sampling at 20-24 weeks' gestation. It was possible to detect in fetal blood samples non-specific laboratory signs of fetal infection, specific antibodies of fetal origin (IgM), and parasitaemia by inoculation of the sample into mice. Amniotic-fluid samples were also inoculated into mice and parasites were often present when the fetus was infected. Ultrasound examination of the fetus was done repeatedly, mainly to detect any enlargement of the cerebral ventricles. Together the results of these examinations allowed a reliable diagnosis, which was confirmed by the presence of necrotic foci of toxoplasmic encephalitis in the fetus in every case. Only 1 case of congenital toxoplasmosis occurred among 209 cases with negative prenatal diagnoses.

Antibodies↗
PubMed1985

An anti-human mu chain monoclonal antibody: use for detection of IgM antibodies to Toxoplasma gondii by reverse immunosorbent assay.

A precipitating anti-human mu chain monoclonal antibody (designated Tibi 82 McAb) was produced by the cell fusion technique. This McAb (isotype: IgG1 kappa) reacted by radioimmunoassay with all 10 human IgM proteins tested. In contrast, no reactivity was observed with IgG, IgA, IgE, lambda and kappa chains. 19 S IgM proteins were precipitated by Tibi 82 McAb using the Ouchterlony method under standard conditions. Hence specificity of this McAb for the C mu 2 domain was characterized by inhibition of precipitin reactions using human IgM fragments. Despite its narrow specificity for the C mu 2 domain, such a McAb could be used for IgM capture in the detection of specific IgM to Toxoplasma gondii employing the IgM immunosorbent agglutination assay (IgM-ISAGA). Tibi 82 McAb was compared with 3 anti-human IgM polyclonal reagents in the routine analysis of 117 sera. With 2 of them, a correlation coefficient of 0.976 was obtained and Tibi 82 McAb was more sensitive than the third polyclonal reagent tested. The IgM-ISAGA technique was shown to be reproducible using Tibi 82 McAb and similar anti-human mu chain McAbs could permit the wider development of reverse immunosorbent methods for the detection of specific IgM in various infectious diseases.

Antibodies, Anti-Idiotypic↗
PubMed1985

Recognition of different Toxoplasma antigens by IgM and IgG antibodies in mothers and their congenitally infected newborns.

The protein-blotting technique was used to determine the antigens of Toxoplasma gondii that were recognized by IgG and IgM antibodies in sera of congenitally infected newborns and their mothers. Patterns of IgG and IgM blots with sera from newborns revealed antigen-antibody reactions (bands) that were not present in the respective blots obtained with sera from their mothers. This was true for 50% of 24 congenitally infected newborns. In contrast, such a difference was noted in only one (5%) of 21 newborns who were not congenitally infected but whose mothers had serological evidence of acute infection with T. gondii acquired during gestation. Our results suggest that the protein-blotting method or an adaptation may be valuable for study of the immune response of the mother, fetus, and newborn to various antigens of infectious organisms and for diagnosis of congenital infections in the newborn.

Antigen-Antibody Reactions↗