Search PubMed⌕ Search

Biomedical subjects

A Voller

Publications and source records attributed to A Voller.

At least 37 records · Page 2Linked to original sources
PubMed1984

Serum C-reactive protein levels and falciparum malaria.

A microplate ELISA was developed to measure C-reactive protein (CRP) and it was used to establish the relationship between CRP levels and malaria. Highest serum CRP levels were found in African patients with high Plasmodium falciparum parastaemia. However, even African children with lower parasitaemia had higher CRP levels than others without parasitaemia. All African groups studied had CRP levels above those of a control UK group.

Adolescent↗
PubMed1983

Purified Trypanosoma cruzi specific glycoprotein for discriminative serological diagnosis of South American trypanosomiasis (Chagas' disease).

Chagas' disease, leishmaniasis, and Trypanosoma rangeli infection are endemic and their distributions overlap in vast regions of South and Central America. Serological cross-reactivities can confuse epidemiological studies of these infections, and their differential diagnosis has been assigned a high priority by the World Health Organisation. A lectin-affinity-purified, 90,000 molecular weight glycoprotein (GP90) is present in the known principal strains (zymodemes) of Trypanosoma cruzi and absent from Leishmania and T rangeli. Patients with T cruzi infection have antibody to GP90, whereas patients with leishmaniasis do not and the two infections can be distinguished in an ELISA system using this antigen. In a mouse model, the same test can differentiate between T cruzi and T rangeli infections. Antigens purified by affinity chromatography clearly provide a practical basis for very precise, even strain-specific, diagnostic tests.

Antibodies↗
PubMed1983

Coxsackie-B-virus-specific IgM responses in children with insulin-dependent (juvenile-onset; type I) diabetes mellitus.

Coxsackie B1-6 virus IgM responses were detected by an enzyme-linked immunosorbent assay (ELISA) in 11 of 28 (39%) children aged 3-14 years in whom insulin-dependent (juvenile onset; type I) diabetes mellitus (IDDM) developed in 1982. 5 patients had a homotypic response to Coxsackie B4 and 1 had a homotypic response to B5. A serum sample had been obtained from each patient 2 to 16 weeks after onset of IDDM symptoms. Islet-cell cytoplasmic antibodies (IgG) and complement fixing islet cell antibodies were detected in 15 of 18 sera tested, but only 6 of these sera were positive for Coxsackie-B-virus-specific IgM which suggests that Coxsackie-B-virus and islet-cell antibodies are not cross-reactive. Coxsackie-B-virus-specific IgM responses were present in only 16 of 290 (5.5%) age-matched non-diabetic London children whose sera were also collected during 1982. Sera from children with virologically confirmed Coxsackie-B-virus infections showed that development of homotypic or heterotypic Coxsackie B1-6 responses was age-related. 29 of 36 (81%) children aged 6 months to 4 years had a homotypic response, whereas 44 of 57 (77%) persons aged 15 years had heterotypic responses. Mothers of 2 children with Coxsackie-B-virus-induced neonatal myocarditis had Coxsackie-B-virus-specific IgM responses directed against serotypes 3 and 4, whereas their infants had a response to Coxsackie B2 virus alone.

Adolescent↗
PubMed1983

An enzyme-linked immunosorbent assay (ELISA) for field diagnosis of visceral leishmaniasis.

A simplified enzyme-linked immunosorbent assay (ELISA) was evaluated as a diagnostic test for visceral leishmaniasis in the field on 222 individuals with splenomegaly and 110 controls. The test was shown to have a sensitivity of 98.4% and specificity of 100% when compared with parasite identification by splenic aspiration. The data indicate that the ELISA is an accurate, safe, and economical alternative to splenic aspiration for the diagnosis of visceral leishmaniasis.

Enzyme-Linked Immunosorbent Assay↗
PubMed1982

A comparison of thin layer immunoassay (TIA) and enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to Trypanosoma cruzi.

The enzyme-linked immunosorbent assay (ELISA) was compared with a new solid phase method, thin layer immunoassay (TIA) for the serodiagnosis of Chagas's disease. 156 sera from Brazilian adult patients who were subject to investigation for chronic Chagas's disease, and 100 sera from healthy Swedish blood donors were analysed. There was a very good agreement between the methods with regard to positive and negative results and it is concluded that either method could be used for sero-diagnosis of Chagas's disease depending upon the choice and facilities of the particular laboratory.

Adult↗
PubMed1982

A serological study on primary hepatocellular carcinoma in Zambia.

The enzyme linked immunosorbent assay (ELISA) was used to measure alpha-foetoprotein (AFP) levels and to detect Hepatitis B surface antigen (HBsAg) and antibody to Hepatitis B surface antigen (anti-HBs) in patients with primary hepatocellular carcinoma and in controls free of the disease in Zambia. Virtually all the patients with primary hepatocellular carcinoma had grossly elevated AFP levels and about two thirds of them were positive for HBsAg. All the controls had much lower AFP levels and one sixth were positive for HBsAg.

Carcinoma, Hepatocellular↗
PubMed1982

The measurement of human erythrocyte carbonic anhydrase I by the enzyme linked immunosorbent assay (ELISA).

A method is described for the assay of human erythrocyte (RBC) carbonic anhydrase I (HCAI) by the enzyme linked immunosorbent assay. The method was found to be a simple, reliable and precise technique and gave a mean C.V. for 40 samples, assayed in quadruplicate, of 3.32% and a range of 0.84-5.9. The mean erythrocyte HCAI value and standard deviation for 20 normal men and women were respectively 16.9 +/- 3.4 and 15.4 +/- 2.1 mg HCAI/g haemoglobin. The use of heparin as an anticoagulant interfered with the assay resulting in apparent HCAI concentrations as low as 60% of those obtained using EDTA.

Animals↗
PubMed1982

Anti-ssDNA and antinuclear antibodies in human malaria.

The incidence of serum antinuclear antibodies and serum antibodies to single stranded (ss) and double stranded (ds) DNA was investigated following acute malaria in 58 Caucasians visiting tropical countries but resident in Britain and in 24 Ghanaians resident in Ghana. In Caucasians this infection was associated with a significant increase in the incidence of speckled antinuclear antibodies (38% compared to 3% in controls; P less than 0.001) and a significant rise in antibody levels against ssDNA (14% compared to 5%; P less than 0.05), but no rise in antibodies against dsDNA. Acute malaria in Ghanaians was associated with an incidence of 25% of antinuclear antibodies and 4% of antibodies to ssDNA; these were similar to those found in healthy Ghanaians who are chronically exposed to malaria. Antibodies against dsDNA were not detected. The incidence of antinuclear antibodies and levels of anti-ssDNA antibodies was higher in the Ghanaian healthy population than in normal Caucasians. These observations indicate that malaria is associated with the development of antinuclear and anti-ssDNA antibodies. Ghanaian patients with a tropical splenomegaly syndrome or with a nephrotic syndrome, both of which conditions are suspected of having a malarial aetiology, had serum levels of anti-ssDNA higher than healthy controls. This observation adds further circumstantial evidence to the role of malaria in causing anti-DNA antibodies.

Adult↗
PubMed1981

Malaria diagnosis by enzyme-linked immunosorbent assays.

Enzyme-linked immunosorbent assays (ELISA) for detecting malarial parasites in blood were tested on uninfected monkeys and in monkeys infected with Plasmodium falciparum. A double antibody sandwich ELISA detected one malarial cell per 10(3) uninfected cells, and an inhibition ELISA detected on infected cell per 10(4) uninfected erythrocytes. These methods are not yet as sensitive as conventional blood-film examinations, in which a well-trained microscopist might be expected to detect one malarial cell per 10(6) erythrocytes. Nevertheless, ELISA offers an objective means of detecting malaria and is particularly advantageous since up to 100 samples may be processed simultaneously.

Animals↗
PubMed1980

Detection of Neisseria meningitidis cell envelope antigen by enzyme-linked immunosorbent assay in patients with meningococcal disease.

Sera from various populations and cerebrospinal fluid (CSF) from meningitis patients were tested for Neisseria meningitidis cell envelope antigen by an enzyme-linked immunosorbent assay (ELISA) sandwich system. The minimum optical density (OD) for antigen detection in CSF was defined as the mean value obtained with specimens from a group of tuberculous meningitis patients plus two standard deviations. By this criterion, antigen was detected by ELISA in four of five CSF specimens from group A meningococcal meningitis patients. Very high ELISA values were obtained with sera from fulminating cases but control sera and sera obtained from meningococcal meningitis non-fulminating cases could not be clearly differentiated by this technique. The possible reasons for this are discussed. The results of this study show that as little as 15 ng/ml (protein) of cell envelope antigen can be detected by the ELISA sandwich test and suggest that the technique may be of value in clinical diagnosis of meningococcal disease.

Antigens, Bacterial↗
PubMed1980

The communication of ELISA data from laboratory to clinician.

The data generated by quantitative enzyme-immunoassay of antibody activity are unsuitable for direct communication from the laboratory to clinician. In this paper, the fundamental problems of reporting ELISA results are highlighted and a list of desirable characteristics is set out for such reports. The available methods for processing ELISA data are reviewed in relation to these ideal requirements and the deficiencies and advantages of each method are discussed. The performance of each method is demonstrated by the use of actual test data from a model ELISA system. No single method has been found which satisfies all criteria.

Absorption↗