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Biomedical subjects

H Zahner

Publications and source records attributed to H Zahner.

At least 91 records · Page 5Linked to original sources
PubMed1987

Morphological alterations in female litomosoides carinii after treatment with two benzthiazole derivatives in vivo.

Multimammate rats (Mastomys natalensis) infected with Litomosoides carinii were treated 65 days after infection with a single oral dose of 50 mg/kg of CGP 20308 or CGP 20376 (Ciba Geigy Limited, Basel). Autopsies were performed between 1 and 28 days after treatment. The numbers of worms and the numbers and condition of intrauterine developmental stages in the females were determined. Other female filariae were investigated by transmission electron microscopy (TEM). Female filariae were observed to be immobile on Day 2, later became encapsulated, and had almost disappeared on Day 28. The number of embryos had decreased on Day 6 and even more on Day 14, when only 5-10% appeared light-microscopically unaffected. TEM examination of the filarial midbody regions revealed, that the fine structures of all somatic muscle cells began to disintegrate as early as Day 4 after treatment with either drug. The breakdown of these cells was increased on Day 6 and Day 14. The cytoplasm of the nerve fibres was more electron-dense in treated than in untreated worms. No alterations were observed in the hypodermis, the cuticle, the intestine and the uterine epithelia. Sections from anterior and posterior regions of the parasites were studied after treatment with CGP 20308 only. Degenerating nerve fibres were found in the nerve rings of these filariae 4 days after treatment.

Animals↗
PubMed1987

Effect of ivermectin in Dipetalonema viteae and Litomosoides carinii infections of Mastomys natalensis.

In D. viteae infected M. natalensis oral or subcutaneous (s.c.) treatment with ivermectin on 5 consecutive days with at least 0.05 mg/kg and single dose treatment with 0.1 mg/kg caused a 100% reduction of microfilaraemia throughout the investigation period of 42 days. Using lower doses (lowest dose used 5 X 0.003 mg/kg) animals were free from circulating microfilariae at least until day 7. The drug was active against adult worms. Treatment with doses of 5 X 0.2 mg/kg and above resulted in 81-93% and 38-83% reductions of male and female worms, respectively. Lower doses caused inconsistent macrofilaricidal effects but mainly male worms were affected. After treatment with 5 X 3.25 mg/kg and above increased rates of pathologically altered intrauterine stages were found in surviving female worms. After treatment of L. carinii infected Mastomys with doses of at least 5 X 1.5 mg/kg animals remained amicrofilaraemic until autopsy on day 42 and in case of lower doses (lowest dose used 5 X 0.006 mg/kg) at least until day 7. After single dose treatment (s.c.) with 0.2 mg/kg and above animals were free from microfilariae in the blood throughout the observation period. Single dose treatment with 0.05 and 0.0125 mg/kg removed all microfilariae from the blood until 8 and 48 hours, respectively but microfilariae occurred in the blood again after 14 days. Ivermectin did not affect the numbers of adult L. carinii but female worms isolated 42 days after treatment with 5 X 0.78 mg/kg and above were free from motile, normally shaped microfilariae and contained increased rates of pathologically altered embryonic stages.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Immunity to Litomosoides carinii in Mastomys natalensis. II. Effects of chemotherapeutically abbreviated and postpatent primary infections on challenges with various stages of the parasite.

Naive Mastomys natalensis, Litomosoides carinii-infected M. natalensis at a postpatent stage of the infection and L. carinii-infected M. natalensis treated chemotherapeutically with furazolidone (FUR), FUR and diethylcarbamazine (FUR/DEC) or amoscanate (AMOS) were challenged by either injection or implantation of 40 third stage larvae (L3, s.c.), 40 fourth stage larvae (L4, 16 days old, i.p.), 20 male and 20 female preadult worms (36 days old, i.p.), 12 adult female worms (i.p.) or 6 X 10(6) microfilariae/kg (i.v.). Microfilaraemia in animals challenged at a postpatent stage (independent of the kind of challenge), was either totally suppressed or at least greatly reduced. Necropsy of L3-challenged animals showed that neither the length of the worms nor their content of morphologically intact, intrauterine stages was affected. Infected, treated animals challenged with developing stages (L3, L4 and preadult worms) showed reduced levels of microfilaraemia (by up to 75%). Dissection of AMOS-treated, L3-challenged animals showed that both the developmental rate and the fertility of the worms were affected. Microfilaraemia was also reduced after implantation of adult worms into treated animals. This was independent of the interval between treatment and challenge (44-150 days) except in animals challenged 10 days after AMOS-treatment, which showed no difference from naive controls. However, infected, treated M. natalensis, cotton rats and gerbils did not develop immunity against intravenously injected blood microfilariae.

Animals↗
PubMed1986

IgE responses of Wistar rats to Schistosoma mansoni infections.

Using the Wistar rat as experimental animal for Schistosoma mansoni infections it was shown that reaginic antibody response to S. mansoni antigens depends on the infection dose in a way that low infection doses induce persistent titres whereas high doses provoke transient titres. Repeated infections strongly favoured the reagins. In contrast, total serum IgE levels measured by ELISA followed a rather constant time course, independent from the mode of infection. Antigen-specific IgE antibodies followed none of the time courses and reached maximum levels about 12-15 weeks post infectionem. The data allow to suppose that different types of IgE occurred possessing different capacities to sensitize mast cells.

Animals↗
PubMed1985

Immunity to Litomosoides carinii in Mastomys natalensis. I. Effect of immunization with microfilariae and existing primary infections on the parasitaemia after microfilariae injection and challenge infection.

Subcutaneous injections of intrauterine stages of Litomosoides carinii into Mastomys natalensis induced strong immunity to i.v. injected blood microfilariae. Immunity, developed after boostering with an i.p. and an i.v. injection of microfilariae, did not totally suppress the parasitaemia of a challenge infection but reduced significantly the microfilaraemia level. No effect was found on number and size of the worms of the challenge infection, the number of microfilariae or the number of leucocytes in the pleural cavity. Delayed type hypersensitivity reactions in challenged animals were similar to those in non-immunized, infected controls. Sera of immunized animals agglutinated microfilariae and mediated cell attachment to microfilariae. Challenge infections did not change this until the end of the fourth week post infection but sera taken 32 days after challenge and later failed to induce such reactions. Challenge infections performed 120 or 240 days after a primary infection did not increase the parasitaemia of recipients. Dissections carried out 130 days after the challenge showed that (a) the developmental rate of the challenge infection was reduced by about 50%; (b) the size of the challenge parasites was reduced; and (c) that these worms produced significantly less embryonic stages in comparison to worms of primary infections, of which about 90% were abnormal.

Agglutination Tests↗
PubMed1985

Reaginic and homocytotropic IgG antibodies in Schistosoma mansoni infected Mastomys natalensis: time courses in untreated infections and after chemoprophylactic and chemotherapeutic treatment.

Mastomys natalensis were infected percutaneously with 250 cercariae of Schistosoma mansoni and treated effectively with 5 X 50 mg amoscanate/kg body-weight 12-16 (I), 28-32 (II), 56-60 (III) and 101-105 days p.i. (IV) respectively. Levels of reaginic antibodies (RAb) and homocytotropic IgG antibodies (GAb) were assessed by passive cutaneous anaphylaxis tests (PCA) and compared with those in infected, untreated animals. In untreated animals RAb were first detected in the 6th week p.i. Maximum titres around 1:80 were reached after 100 days. High levels persisted until the end of the experiment 185 days p.i. RAb did not develop after treatment I. After treatment II only low PCA titres occurred. After treatment III the time course was similar to the controls but levels were reduced. Treatment IV did not interfere with the occurrence of specific RAb. In the case of GAb, independent of any treatment, after a first peak of PCA titres in the 5th week either a negative pattern or only very low titres were found in week 7. In untreated infected Mastomys GAb levels increased thereafter to maximum titres of about 1:80 at day 70. Later than 100 days p.i. relatively constant titres were observed. The second rise of antibody levels did not occur after early treatment. After treatment II only low transient titres developed. Animals treated in the early patency (III) showed reduced PCA titres and were negative at the end of the observation period. Treatment given 101 to 105 days p.i. rather enhanced the development of GAb.

Animals↗
PubMed1984

Enzyme-linked crossed immunoelectrophoresis: a technique for detection of allergens and their respective antibodies in human schistosomiasis.

A method is described which allows the demonstration of allergens in complex antigens and their respective antibodies. Schistosoma mansoni antigens are separated in agarose by 2-dimensional electrophoresis, using an anti-S. mansoni serum from goats in the second dimension. After extensive washing test serum is spread over the gel and allowed to bind to the precipitated antigens. After further extensive washing, horseradish peroxidase-coupled anti-IgE antibodies are put on the plate and allowed to react. Bound antiserum is visualized with tetramethylbenzidine as a substrate. In pooled sera from schistosomiasis patients at least 7 antigen fractions of adult S. mansoni and 2 of cercarial antigen reacted with IgE antibodies. No reaction was found in normal sera.

Allergens↗
PubMed1984

Detection of IgE in the sera of rodents: comparison of the applicability of ELISA and RIA.

RIA and ELISA were compared for their ability to detect IgE in different rodent species. With a sheep anti-rat IgE antibody good correlation (P less than 0.001) between the 2 assay methods for IgE was found in rats. RIA failed to detect the IgE of Mastomys natalensis while ELISA proved to be a suitable test. However, both tests failed to measure IgE in sera of Nile rats.

Animals↗
PubMed1984

Different suitability of 3 filarial antigens (Litomosoides carinii, Dipetalonema viteae, Dirofilaria immitis) to act as allergens in the Passive Cutaneous Anaphylaxis Test and to serve as antigens in an ELISA in the course of experimental filarial infections (L. carinii, D. viteae, Brugia malayi, B. pahangi) of Mastomys natalensis.

Crude extracts of adult worms of 3 different filariae (Litomosoides carinii, Dipetalonema viteae, Dirofilaria immitis) were evaluated for their suitability to serve as allergens in the Passive Cutaneous Anaphylaxis Test (PCA) and as antigens in an ELISA which detected mainly IgG antibodies. Studies were done in the course of 4 different filarial infections (L. carinii, D. viteae, Brugia malayi, B. pahangi) of Mastomys natalensis, using sera from different times after infection up to 350 days p.i.--In the PCA L. carinii and D. viteae antigens, apart from L. carinii infection caused reactions to a similar degree. In the L. carinii infection the homologous antigen was more effective. The D. immitis antigen was clearly less effective: high titres were found only during the early prepatency of D. viteae and Brugia infections and during the early patency of L. carinii and D. viteae infections. In all other cases, if at all, it led to weak reactions only.--In the ELISA different time courses were obtained as well. In Brugia infections values obtained with D. viteae and D. immitis antigens were significantly correlated but were not related to those obtained by the L. carinii antigen. However, the L. carinii antigen detected high levels of antibodies especially during prepatency of B. malayi, B. pahangi and D. viteae infections. No relations were found between the antigens for the D. viteae infection. In the case of the L. carinii infection the values of all 3 antigens were significantly correlated.

Allergens↗
PubMed1984

Serodiagnosis of human onchocerciasis: evaluation of sensitivity and specificity of a purified Litomosoides carinii adult worm antigen.

Sensitivity and specificity of a Litomosoides carinii macrofilariae aqueous crude extract and a purified antigen which was isolated by preparative flat bed electrofocusing, were evaluated for the immunodiagnosis of human onchocerciasis in 3 serological tests: Double diffusion test (DT), latex agglutination test (LAT) and ELISA. Testing sera from proven cases of onchocerciasis (n = 28), loiasis (n = 4) filariasis bancrofti (n = 4), and other non filarial helminth infections (n = 29) in all tests the purified antigen was clearly more sensitive and specific. Testing onchocerciasis sera highest sensitivity was found by ELISA (92.9%) followed by latex agglutination test (89.3%) and double diffusion test (82.1%). Specificity controls of the purified antigen with sera from patients with helminth infections others than filariases led to 0% (DT), 6.9% (LAT) and 10.3% (ELISA) false positive reactions. When the 3 tests were used in combination in a way that at least two positive reactions in different tests were regarded as necessary to declare a serum as positive, sensitivity increased to 100% and unspecific reactions were found only testing one serum (3.4%) originating from a case of cystic echinococcosis.

Antibodies↗
PubMed1983

Time courses of antibody levels in Mastomys natalensis after infections with Litomosoides carinii, Dipetalonema viteae, Brugia malayi or B. pahangi, Determined by ELISA.

Using a Litomosoides carinii adult antigen, time courses of antibody levels were followed by an ELISA in L. carinii, Dipetalonema viteae, Brugia malayi and B. pahangi infected Mastomys natalensis. Using various groups of infected animals, periods up to 400 days after infection were covered. In L. carinii infected Mastomys, antibodies were first detected 11 days p.i. and levels increased rapidly until day 40. Temporarily reduced levels about the beginning of patency were followed by increasing values until about 100 days p.i. Then the antibody content of the sera remained more or less constant until about 250 days p.i. although maximum levels were found at day 170. Thereafter, the antibody concentration in the sera declined slowly but high levels were still observed 390 days p.i. The antibody content was usually higher in animals with high microfilariae densities than in those with low microfilariae counts but relations could not be proven statistically. In D. viteae infected Mastomys, maximum antibody values were reached within the beginning of patency. Levels were not altered markedly until about 110 days p.i. Thereafter they decreased slightly but then remained constant until the end of the investigation period 350 days p.i. B. malayi infected animals showed a rapid increase of the antibody content in the sera; a maximum was reached by 20 days after the infection. Thereafter, somewhat constant levels were found for 4--5 months. After 300 days p.i. the antibody levels declined progressively, accompanied with increasing parasitaemia densities; after 380 days the levels reached about 2/3 of the maximum. However, despite this, no relation was found between the levels of parasitaemia and antibody in individual animals. In B. pahangi infections the main prepatent antibody increase occurred during week 5 p.i., when maximum values were observed. The beginning of patency and the early patency were accompanied with slightly declining antibody levels. From 150 days p.i. until the end of the investigation 400 days p.i., the antibody content of the sera was fairly constant.

Animals↗
PubMed1983

Isolation of antigen from Litomosoides carinii macrofilariae detecting serum antibodies due to Onchocerca volvulus.

Crude aqueous Litomosoides carinii adult worm extract was used as antigen for the detection of antibodies in sera from African patients with proven onchocerciasis (n = 45) resident in rural endemic areas of Togo and Sierra Leone. In 71% of cases this extract was found to produce 1 to 5 precipitation arcs in immunoelectrophoresis. Using a crude aqueous extract from adult Onchocerca volvulus, precipitation tests were positive in 75% of cases. The complexity of the L. carinii crude extract was shown by PAG-disc electrophoresis, PAG-electrofocusing, immunoelectrophoresis and crossed immunoelectrophoresis with the appropriate rabbit-antiserum. An antigen detecting onchocercal antibodies was isolated by two step preparative flat bed electrofocusing in granulated gel (PEGG). The antigen (pI 6.55, molecular weight 55 to 60 kd as estimated by SDS-PAG electrophoresis) was very suitable for antibody demonstration in double diffusion test and immunoelectrophoresis. Preliminary controls for specificity were performed by diffusing the antigen against sera from human and animal helminthoses including filarial infections. In contrast to the crude L. carinii extract no reaction was observed with sera from helminthic infections others than filariasis.

Animals↗
PubMed1983

Occurrence of microfilariae in various hollow organs and in the peritoneal cavity after treatment of Litomosoides carinii infected Mastomys natalensis with diethylcarbamazine and haloxon.

Treatment of Litomosoides carinii infected Mastomys natalensis with diethylcarbamazine (DEC: 500 mg/kg p.o.) was followed by increased occurrence of microfilariae in the bronchi of the host after 40 min and lasting at least until 6 h after treatment. After 4 h, increased levels of larvae were observed in the gut. Only a few microfilariae occurred in the bladder and sputum. Accumulations of microfilariae were found furthermore in the Lnn. hepaticae whereas no changes were observed in the inguinal or jejunal and lung and pleura associated lymph nodes. Increased numbers of microfilariae were found in the peritoneal cavity only after 8 and continuing until at least 48 h after treatment. In contrast, after haloxon treatment (100 mg/kg p.o.) an accumulation of microfilariae was found in the peritoneal cavity only, following a time course similar to that after DEC.

Animals↗
PubMed1983

Diethylcarbamazine dependent, complement mediated, adherence and cytotoxicity of cells on microfilariae of Litomosoides carinii.

Diethylcarbamazine (DEC) induced dose dependent adherence of normal spleen cells from Mastomys natalensis to microfilariae of L. carinii in the presence of serum from Mastomys infected with L. carinii or normal serum. The effect could be also induced, using fresh, normal human serum and human blood leucocytes. The responsible serum factor was heat labile (56 degrees C, 30 min) and was eliminated from the sera by pretreatment with Inulin. The activity could be reconstituted by normal serum. Cell adhesion was inhibited by 0.004 MEDTA while 0.004 M EGTA had only a weak inhibitory effect. The addition of Mg++ led to high adherence rates in the presence of EGTA. The data indicate that DEC activates complement on the surface of the larval sheath by the alternate pathway. Adherent Mastomys cells or human cells had a cytotoxic effect on the larvae. The death of the microfilariae did not depend on the loss of the larval sheath.

Animals↗
PubMed1981

[A contribution to stepless antibody determination by the "enzyme linked immunosorbent assay" (ELISA) (author's transl)].

A simple method for the mathematical calculation of ELISA results is described. Using the formula (formula: see text) (Eu, En, Ep = extinction values of the unknown serum, the negative, and positive standard serum, respectively) an index value Iu is calculated for the testserum, whereby the optical density of the testserum is put in relation to the optical density of a negative and positive standardserum. Using three different ELISA test systems, the Iu values of a number of human, bovine and rabbit testsera were relatively uniform and reproducible in repeated investigations. A statistically calculated tolerance limit for the index values of negative sera can be introduced into the formula described, thus facilitating the decision "negative" or "positive" for unknown sera.

Animals↗
PubMed1980

[Immunization against Capillaria hepatica: the effects of primary infections, x-irradiated stages, non-embryonated eggs, and soluble egg extracts (author's transl)].

The influence of primary infections with embryonated infective eggs or with X-irradiated infective eggs, and of non-embryonated eggs, and egg homogenate extracts on challenge infections with Capillaria hepatica was investigated. The worm reproductivity was significantly suppressed in a sublethal challenge infection given 11 days after a primary infection of Mastomys natalensis with 50, 150, 400, and 800 eggs per animal. The administration of 600 X-irradiated (2.2 Krd) embryonated eggs 36 days before challenge as well as an intraperitoneal injection of non-embryonated eggs 12, 10, 8, 6, 4, and 2 days before challenge (simulating the egg production of a normal infection) also reduced significantly the egg production of a weak (50 eggs/ animal) infection. No effect was observed on a moderate challenge (300 eggs/animal). The effect was not markedly enhanced by the repeated administration of X-irradiated eggs or by the combination of X-irradiated infective eggs and non-embryonated eggs. Immunization of mice with soluble egg extracts resulted in significant reduction of egg production determined 60 days after challenge. Two hundred and thirty eggs of C. hepatica/g body weight proved to be a lethal infection dose for M. natalensis. The animals died between 20 and 35 days after infection. After single infections with 50, 150, 400, or 800 eggs per animal the mortality of Mastomys challenged 36 or 52 days later was reduced to 0--30%. Using X-irradiated embryonated eggs for immunization only repeated administration led to protection in 70 to 80% of the animals. About 40% of the animals could be protected by the intraperitoneal injection of non-embryonated eggs. If death occurred it was delayed. The combination of X-irradiated stages and eggs did not enhance the protection.

Animals↗