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Biomedical subjects

A Voller

Publications and source records attributed to A Voller.

At least 73 records · Page 4Linked to original sources
PubMed1976

[Renal involvement in malaria (author's transl)].

Malaria infection leads to renal involvement. Reversible proteinuria accompanies many plasmodial infections. Chronic malarial nephrotic syndrome is specifically associated with quartan malaria. Acute renal failure is restricted to infections with Plasmodium falciparum. The pathogenesis of renal involvement during malarial infections includes immunological mechanisms. It is now realized that there exist at least two types of immunological processes: acute transient immune-complex glomerulonephritis with reversible proteinuria and chronic immune-complex glomerulonephritis with irreversible nephrotic syndrome.

Acute Kidney Injury↗
PubMed1976

Factor-VIII-related antigen: measurement by enzyme immunoassay.

Factor-VIII-related antigen was measured, both by an enzyme immunoassay using a microplate method and by the Laurell technique, in normal people, patients with von Willebrand's disease, haemophiliacs, and obligatory haemophilia carriers. The enzyme immunoassay was simpler to perform and gave equally reliable and reproducible results. Many more assays could be carried out at any one time.

Antigens↗
PubMed1976

Tumorigenicity of Epstein-Barr virus (EBV)-transformed lymphoid line cells in autologous squirrel monkeys.

Eight squirrel monkeys (Saimiri sciureus) challenged with EBV or EBV-transformed SLCL were naturally or experimentally infected with Plasmodium knowlesi or Pl. brasilianum. Most of the animals had been splenectomized and unilaterally nephrectomized. Three of these monkeys received one dose of 6 to 12 X 10(8) autologous SLCL. These lines were derived from saimiri lymphoid cells permanently transformed by B-EBV in vitro. All three animals developed multiple undifferentiated malignant lymphomas and died 8 to 10 days post inoculation. Necropsy tumor specimens were EBNA-positive and contained 7 to 21 EBV genome equivalents per cell. EBNA- and EA-positive SLCL were established in vitro from four tumor explants of two monkeys. These results demonstrate that in vitro EBV-transformed SLCL are able to cause tumor formation in autologous squirrel monkeys. Five monkeys received high transforming doses of B-EBV or S-EBV, derived from one of the tumorigenic SLCL. None of the animals developed any sign of tumor formation during an observation period of up to 130 days. Three of these monkeys showed no detectable EBV-related seroconversion while the sera of two monkeys had become anti-EBNA-positive when tested at days 28 and 130 respectively post inoculation. Two additional monkeys received neither EBV nor SLCL. They showed no clinical evidence of tumor development or spontaneous seroconversion over a period of more than 1 year.

Animals↗
PubMed1976

Experimental Trypanosoma cruzi infections in rhesus monkeys. II. The early chronic phase.

Information on the acute and early chronic phases of infection with Trypanosoma cruzi in eight rhesus monkeys is reported with particular reference to the pattern of subpatent parasitaemia and serology. Xenodiagnosis was superior to animal inoculation and blood culture in its capacity to detect subpatent parasitaemia. Each monkey showed an individual, relatively constant pattern of this not related to the nature of the inoculum. Levels of indirect fluorescent and indirect haemagglutinating antibodies remained elevated during a year of observations. One monkey died with a megaoesophagus. Another monkey after challenge with a heterologous strain by orbital inoculation failed to develop Romana's sign and showed no change in serum antibody levels or degree of xenopositivity.

Animals↗
PubMed1976

The effect of human immune IgG on the in vitro development of Plasmodium falciparum.

Plasmodium falciparum parasites infecting Aotus trivirgatus erythrocytes were cultured in media (Harvard and TC199) augmented with human, foetal calf, or other sera. Conditions were established which supported growth of parasites and allowed cyclical multiplication when fresh erythrocytes (from Aotus or Homo) were added in sub-culture (mean multiplication rate: X3). Immunoglobulin G pools, prepared from plasma collected in endemic malarious areas in Africa and from unexposed Britons, were tested for effects on the in vitro growth (measured by incorporation of tritiated leucine) and multiplication of parasites. Whilst non-immune IgG was without effect, IgG from both East and West Africa inhibited the multiplication of East African (Uganda-Palo Alto strain) parasites.

Animals↗
PubMed1976

The detection of viruses by enzyme-linked immunosorbent assay (ELISA).

The use of enzyme-linked antibodies for the detection of two morphologically different plant viruses is described. The technique is extremely sensitive, enabling assay of the viruses at concentrations as low as 10 to 100 ng/ml both in purified preparations and in crude plant extracts.

Alkaline Phosphatase↗
PubMed1976

A microplate enzyme-immunoassay for toxoplasma antibody.

A new test for the detection and measurement of toxoplasma antibody is described. Test sera are reacted with antigen-sensitized wells in micro-haemagglutination plates. Any attached antibody is shown by the addition of an enzyme-labelled antiglobulin followed by assay of the enzyme reaction with its substrate. The test is easy to carry out on a large scale, and there is a positive correlation between the results and dye test and haemagglutination test titres.

Alkaline Phosphatase↗
PubMed1976

Enzyme immunoassays in diagnostic medicine. Theory and practice.

Serological methods are playing an increasingly important role in the diagnosis and epidemiological assessment of diseases. Simple, inexpensive methods for large-scale application are urgently needed. The enzyme immunoassay methods developed recently and reviewed here hold great promise for application in a wide variety of conditions. Under laboratory conditions they can be as sensitive as radio-immunoassay, but they can also be adapted as simple field screening procedures. These methods are based on the use of antibodies or antigens that are linked to an insoluble carrier surface. This is then used to "capture" the relevant antigen or antibody in the test solution and the complex is detected by means of an enzyme-labelled antibody or antigen. The degradation of the enzyme substrate, measured photometrically, is proportional to the concentration of the unknown "antibody" or "antigen" in the test solution. The application of these techniques to endocrinology, immunopathology, haematology, microbiology, and parasitology is reviewed.

Humans↗
PubMed1976

Enzyme-immunoassays for antibodies in measles, cytomegalovirus infections and after rubella vaccination.

Enzyme-immunoassays using an indirect method with alkaline phosphatase conjugated antiglobulins were satisfactory for detection of antibody to Measles and Cytomegalovirus. The antigen was passively adsorbed to polystyrene micro-harmagglutination plates for the assays. IgM antibody to Rubella was also detected by enzyme-immunoassay at 7 and 28 days after vaccination in a person who had negative Rubella serology before vaccination. IgG antibody was detected at those times in another patient who had positive Rubella serology prior to vaccination. The enzyme immunoassays appear to have the potential for routine laboratory use for virological diagnosis.

Alkaline Phosphatase↗
PubMed1975

New serological test for malaria antibodies.

In an enzyme-linked immunosorbent assay test for malaria antibodies, antibodies to Plasmodium vivax and P. falciparum in man are detected using a crude antigen prepared from the simian malaria parasite P. knowlesi. The test may be suitable for epidemiological studies.

Adsorption↗
PubMed1975

Microplate enzyme-linked immunosorbent assay for chagas' disease.

A microscale immunosorbent assay (E.L.I.S.A.) for the measurement of antibody in Chagas' disease (American trypanosomiasis) is described. The test was assessed on plasma samples from people living in Bahia, Brazil. 98% of the individuals with positive Trypanosoma cruzi immunofluorescent-antibody (I.F.A.) tests gave E.L.I.S.A. reading considered as positive. Less than 2% of those with negative I.F.A. tests had positive E.L.I.S.A. reactions. This simple test may be suitable for use in large seroepidemiological surveys.

Adsorption↗
PubMed1975

Circulating soluble antigens and antibody in schistosomiasis.

Some patients with Schistosoma mansoni and S. haematobium infections were shown to have soluble schistosomal antigen in their plasma. Antibody to this antigen and to other antigens of adult worms were also present. These findings may be relevant to schistosomal-related immune-complex disease, especially the nephrotic syndrome.

Adolescent↗
PubMed1975

The distribution of enzyme variation in populations of Plasmodium falciparum in Africa.

Isolates of Plasmodium falciparum collected from the east and west coasts of tropical Africa and also from several inland regions have been examined for electrophoretic forms of the enzymes GPI, LDH and 6PGD. Variation within and between isolates was found in the parasite forms of all three enzymes. While not disproving the existence of genetic divisions between P. falciparum populations in Africa the distribution of this variation provides no evidence for such a hypothesis.

Africa, Eastern↗