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Biomedical subjects

S Geerts

Publications and source records attributed to S Geerts.

At least 91 records · Page 5Linked to original sources
PubMed1994

Influence of priming and inoculation dose on the production of monoclonal antibodies in two age groups of BALB/c mice.

An experiment was set up to assess the influence of some parameters on the production of ascites and monoclonal antibodies against circulating excretory-secretory antigens of Taenia saginata cysticerci in mice. The following parameters were examined: time lapse between priming and the inoculation of hybridoma cells, age and body weight of the mice at the time of inoculation, number of cells injected IP, and the resulting antibody titers of the ascites. In this experiment the method used to prime the mice was the only factor having an influence on the amount of ascites produced. Injection of a higher number of hybridoma cells (2-4 x 10(6) cells) coincided with higher antibody titers and resulted in an earlier ascites production. The antibody titer of the ascites was increasing with time.

Aging↗
PubMed1994

Moclobemide versus fluoxetine for major depressive episodes.

The efficacy and tolerability of moclobemide (300 or 600 mg daily) and fluoxetine (20 or 40 mg daily) were compared in a 6-week, double-blind study of 25 inpatients and 24 outpatients who had major depressive episodes without psychotic features (DSM-III-R). Although the clinical results of this study suggest better efficacy with moclobemide and better tolerability with fluoxetine, a statistically significant difference between treatment groups was noted only with respect to Clinical Global Impressions recorded after 10 days of therapy; these were significantly better in the moclobemide group. A daily dosage of 300 mg of moclobemide and 20 mg of fluoxetine would thus appear to be comparable both in antidepressant efficacy and tolerability.

Acute Disease↗
PubMed1993

Field trials to control schistosome intermediate hosts by the plant molluscicide Ambrosia maritima L. in the Senegal River Basin.

Several field experiments were carried out in Senegal to evaluate the molluscicidal activity of Ambrosia maritima L. Applications of 400 mg L-1 of dry leaves of the plant in creeks of the Lampsar river did result in a reduction of Bulinus spp of 54-56% 2 weeks after treatment. Treatment of a closed irrigation canal caused a reduction of the density of Biomphalaria pfeifferi up to 77% 2 weeks after the application of 150 mg L-1 and 300 mg L-1. In both trials, however, a quick increase in the snail density was observed after treatment. It is concluded that the large amounts of crude plant material required to achieve snail reductions of less than 80% compromise the use of A. maritima in schistosomiasis control programmes.

Animals↗
PubMed1993

Evaluation of the efficacy of a slow release device containing homidium bromide in rabbits infected with Trypanosoma congolense.

The subcutaneous implantation of a slow release device (SRD) containing 1 mg kg-1 homidium bromide (Ethidium) protected 95% of the rabbits for at least 3 months against reinfection with different stocks of Trypanosoma congolense. Only 30.8% of the animals, which received the classical intramuscular injection of 1 mg kg-1 homidium bromide, were protected for more than 1 month. The advantages of an SRD against injection of homidium bromide are a longer protection period, less variation in the percentage of protected animals and the possibility to recover the implants at slaughter. The possible effects on the development of resistance have to be examined further.

Animals↗
PubMed1992

Experimental infection of pigs with a Taenia species from Korea: parasitological and serological aspects.

Belgian Landrace piglets were experimentally infected with eggs of a Taenia sp. of Korean origin. At autopsy, metacestodes were present only in the livers. The proportion of degenerated metacestodes increased from 12%-39% at 5 weeks to 94%-100% at 10 weeks after infection. A sandwich enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies raised against the excretory-secretory products of T. saginata metacestodes detected circulating antigen in the sera of the pigs at 1 week post-infection. A good correlation was found between the presence of viable metacestodes and the detection of circulating antigen; the latter disappeared as the metacestodes died off. However, the antibodies were detected only after 3 weeks of infection and onwards until the necropsy of the pigs.

Animals↗
PubMed1992

A monoclonal antibody-based ELISA for the detection of circulating excretory-secretory antigens in Taenia saginata cysticercosis.

A series of monoclonal antibodies (MoAb) produced against excretory and secretory products from 10- and 20-week-old Taenia saginata cysticerci were tested for their ability to detect circulating antigen in a double antibody sandwich enzyme-linked immunosorbent assay (ELISA). Two MoAb, 12G5 and 2H8, proved to be highly reactive with the tegument of viable T. saginata cysticerci and recognized antigenic components of 65, 87 and 100 kDa in immunoblotting. The detection limit of the assay using 12G5 as trapping antibody and 2H8 as a biotinylated indicator antibody was 0.1 ng protein per ml. Although the sensitivity of the test varied from one animal to another, the minimum number of living cysticerci, which could be detected by the ELISA, was 88. Animals harbouring only dead cysticerci gave similar reactions as non-infected control animals. Cross-reactions were only observed with taeniid parasites. The test was able to detect circulating antigen also in sheep and pigs, respectively infected with T. ovis and T. solium and in the serum samples of confirmed cases of human T. solium cysticercosis.

Animals↗
PubMed1992

Studies on an Ostertagia ostertagi strain suspected to be resistant to benzimidazoles.

Four calves were infected with a susceptible (laboratory) strain of Ostertagia ostertagi and four with a field strain suspected to be resistant to benzimidazoles. After 25 days two calves from each group were treated with 3.5 mg kg-1 fenbendazole. Egg output fell to zero in all treated calves. Treated calves did not harbour worms at slaughter 35 days after infection. Significant differences between the strains were shown for ED50 values for thiabendazole in the egg hatch assay, but not in the tubulin binding assay. It is concluded that benzimidazole resistance in the suspected strain cannot be confirmed.

Animals↗
PubMed1992

World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) methods for the detection of anthelmintic resistance in nematodes of veterinary importance.

Methods have been described to assist in the detection of anthelmintic resistance in strongylid nematodes of ruminants, horses and pigs. Two tests are recommended, an in vivo test, the faecal egg count reduction test for use in infected animals, and an in vitro test, the egg hatch test for detection of benzimidazole resistance in nematodes that hatch shortly after embryonation. Anaerobic storage for submission of faecal samples from the field for use in the in vitro test is of value and the procedure is described. The tests should enable comparable data to be obtained in surveys in all parts of the world.

Animals↗
PubMed1992

Experimental infection of pigs and cattle with eggs of Asian Taenia saginata with special reference to its extrahepatic viscerotropism.

Asian Taenia saginata, tentatively called Taenia saginata taiwanensis, has been described to be infected in its metacestode stage only in the liver of intermediate host animals. Experimentally, however, we found that the metacestodes of the Asian Taenia saginata are also infected in other viscera than the liver of pigs (Landrace-Duroc-Hampshire) 4 days to 4 months postinoculation (PI). Viscerotropism of cysticercosis was apparent because a majority (70.7%) of the non-calcified cysticerci were found in the livers while a minority were found in extrahepatic organs such as the omentum (19.2%), lungs (8.1%) and serosa of colon (2.0%). When experimentally infected to cattle, Asian T. saginata cysticerci were also observed calcified in the livers. On the other hand, classical Taenia saginata metacestodes infected the muscles and viscera of the Holstein-Friesian cattle whereas no infection was observed in experimental pigs. Extrahepatic metacestodes of Asian T. saginata, which were obtained from an experimental pig were confirmed to be infective to a male volunteer. This extrahepatic viscerotropism of Asian T. saginata metacestodes in experimental pigs explains well the transmission modes of Asian T. saginata among people considering the eating habits.

Animals↗
PubMed1992

[Immunodiagnosis of Taenia saginata cysticercosis].

Many different serological tests have been investigated in order to replace the current "knife and eye" method at the slaughterhouse, which detects only a small fraction of the cattle infected with cysticercosis. Among the assays for the detection of antibodies against the cysticerci of Taenia saginata, the ELISA is certainly the most sensitive, although it is unable to detect lightly infected animals. Consequently it only allows a group diagnosis in naturally infected cattle. The use of purified antigens of T. saginata, T. crassiceps and T. hydatigena did not improve significantly the reliability of these antibody detection tests. Recently monoclonal antibodies have been developed against surface or excretory- and secretory antigens of T. saginata metacestodes, allowing the detection of circulating antigens in the serum of infected cattle. Furthermore these monoclonal antibodies can distinguish animals carrying living, infectious cysticerci from those harbouring only dead cysticerci. Research is currently going on in order to improve the sensitivity of this antigen detection test, so that it can replace the current unreliable meat inspection methods in the slaughterhouse.

Animals↗
PubMed1991

[Toxicity of the molluscicidal plant, Ambrosia maritima L., to aquatic non-target organisms].

The toxicity of the molluscicidal plant, Ambrosia maritima L., has been evaluated in fish, crustacea and algae. The LC50 for fries of the guppy, Lebistes reticulatus, was respectively 650 and 450 mg/litre using a powder or an ether-methanol-hexane extract from the leaves of the plant. This concentration is much higher than the molluscicidal concentration (LC90) of 35 to 70 mg/litre, which is used in the field (irrigation canals in Egypt). Preliminary tests showed that juveniles of L. reticulatus and Tilapia aurea were as sensitive as the fries. Using the same extract of A. maritima the LC50 for Daphnia magna was 766 mg/litre and no toxic effects could be observed in algae Selenastrum capricornutum at 1 g/litre. It can be concluded that A. maritima has a very low toxicity to aquatic non-target organisms. It is not toxic when used at the molluscicidal concentration of 35 to 70 mg/litre.

Animals↗
PubMed1991

Toxicity and mutagenicity of the molluscicidal plant Ambrosia maritima L.

The acute and subchronic toxicity of the molluscicidal plant, Ambrosia maritima L., has been tested on rats. No toxic signs could be detected neither after oral administration of 5 g/kg of dried leaves of the plant as a powder or as a methanolic extract, nor after the incorporation of 50,000 ppm powdered leaves in the feed during 4 weeks. Using an aqueous extract of the plant material of A. maritima or using ambrosin, one of the active molluscicidal components of the plant, no mutagenic activity could be detected in the S. typhimurium strains TA97, TA 98, TA1538, TA100 and TA1535.

Administration, Oral↗
PubMed1990

[Taenia saginata: an eternal problem?].

Although the official figures of the meat inspection services show that the number of Belgian slaughtering cattle, infected with cysticercosis decreased during the last 20 years from 0.3 to 0.03%, the data collected during this study, prove that the parasite is absolutely not dying out. Detailed examination of slaughtering cattle showed that 9.5% of them are infected with cysticerci of T. saginata. This discrepancy with the official figures is due i.a. to the inappropriate detection techniques used in the slaughterhouses. Contrary to Taenia solium, T. saginata in man is far from being eradicated. Based on the number of cestocidal drugs sold in Belgium since 1980, it can be assumed that T. saginata has an average annual incidence of 0.4%. In a second chapter some epidemiological features are examined, which might explain the remarkable stability of the taeniasis-cysticercosis complex in our modern society: i.a. the high biotic potential of the parasite, the efficient dissemination of T. saginata eggs in the environment and the role of the intermediate hosts. Finally it is shown that the eradication of T. saginata is not yet feasible for the moment. A series of specific control measures are proposed in order to avoid the infection of cattle with cysticerci as well as the infection of the final host with a tapeworm.

Animals↗
PubMed1989

Reliability and reproducibility of the larval paralysis test as an in vitro method for the detection of anthelmintic resistance of nematodes against levamisole and morantel tartrate.

In order to study the reliability of the larval paralysis test as an in vitro assay for the detection of resistance of nematodes to levamisole and morantel tartrate, the influence of different parameters was evaluated using resistant and susceptible Ostertagia ostertagi strains. The operator, the sample (10% of the larvae present in the suspension), the incubation time (24, 48 or 72 h), the incubation temperature (20 or 25 degrees C) and the observation period of the larvae (5 or 15 s) had no statistically significant influence on the test results. Statistical differences were obtained only when L3 larvae of different ages (1 or 2 months) were used. Reversibility of the paralysis did not occur when concentrations of levamisole of less than or equal to 200 micrograms ml-1 or morantel tartrate of less than 2000 micrograms ml-1 were used. The reproducibility of the test was fairly good, with a mean standard deviation of 21.3% for the LC50 values. Morantel resistance in a strain of O. ostertagi was not confirmed as such by the larval paralysis test. The resistance factor was less than or equal to 1, in spite of an efficacy of morantel of 77.4% as shown in vivo.

Animals↗
PubMed1989

Chemoprophylaxis of trypanosomiasis, due to Trypanosoma (Nannomonas) congolense, in rabbits using a slow release device containing homidium bromide.

The prophylactic activity of a subcutaneously implanted slow release device, containing homidium bromide, was assessed in rabbits, challenged with different stocks of T. congolense, and compared with the classical treatment of 1 mg homidium bromide/kg b.w. intramuscularly. The prophylactic activity of the intramuscular injection was less than a month, while the slow release device protected the rabbits against seven challenges with T. congolense during a period of more than 300 days.

Animals↗