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Biomedical subjects

D Samuel

Publications and source records attributed to D Samuel.

At least 199 records · Page 11Linked to original sources
PubMed1990

The use of enzyme immunoassay (EIA) and radiobinding assay to investigate the cross-reactivity of Klebsiella antigens and HLA B27 in ankylosing spondylitis patients and healthy controls.

The binding of rabbit anti-Klebsiella antibodies to tissue-typed lymphocytes obtained from 30 ankylosing spondylitis (AS) patients and 54 healthy subjects has been measured by an enzyme immunoassay method. HLA B27 positive lymphocytes obtained from either AS patients (t = 3.60; p less than 0.001) or healthy subjects (t = 3.77; p less than 0.001) were found to bind Klebsiella antibodies to a significantly greater extent than non-B27 lymphocytes obtained from healthy controls. Absorption studies demonstrated that HLA B27 positive lymphocytes absorbed out significantly more anti-Klebsiella antibodies than HLA B27-negative lymphocytes (t = 6.76; p less than 0.005). These results are compatible with cross-reactivity or molecular mimicry between HLA B27 and epitopes on some Gram-negative bacteria such as Klebsiella.

Antigens, Bacterial↗
PubMed1990

[Rapid diagnosis of cytomegalovirus hepatitis after liver transplantation. Use of monoclonal antibody E13 directed against an early viral antigen].

Liver biopsies obtained from 10 liver transplant patients for whom a cytomegalovirus (CMV) hepatitis was suspected on the basis of clinical and biological abnormalities have been studied by an immunohistological method using the monoclonal antibody E-13 directed against an early viral antigen. Biopsies were performed between the 30th and the 77th day after transplantation. In 7 of the 10 cases, CMV hepatitis was diagnosed by histological examination because of the association of lobular cytolysis, inflammatory infiltrate with neutrophils and intranuclear inclusions. Ten cases were positive with the E-13 antibody including the 3 cases in which histological examination was not conclusive. In all cases, positive results gave a nuclear staining pattern in hepatocytes (63%) or endothelial cells (40%), independently of the presence of inclusions. Rapid diagnosis of CMV hepatitis is of significant importance since anti-viral drugs, such as DHPG (Ganciclovir), are now efficient. The immunohistochemical method with E-13 could permit easy and rapid detection of CMV in liver specimens.

Adolescent↗
PubMed1989

The FITC-anti-FITC system is a sensitive alternative to biotin-streptavidin in ELISA.

In a model ELISA system alkaline phosphatase (AP) absorbed onto microtitre wells was employed as the target antigen. The antigen was then reacted with a monoclonal antibody to AP either unlabelled or labelled with (a) FITC and (b) biotin. The bound anti-AP was then detected with horseradish peroxidase (HRP) conjugates of polyvalent anti-mouse IgG, and the FITC and biotin anti-AP conjugates with HRP conjugates of a monoclonal anti-FITC or streptavidin respectively. The FITC-anti-FITC system proved to be of similar sensitivity to the biotin-streptavidin system detecting 140 amol compared to 350 amol of antigen. Both these methods of antigen detection were superior to the anti-mouse IgG reagent (2100 amol). In contrast to biotinylated antibodies, FITC-labelled antibodies are highly coloured and fluorescent. These features aid the preparation, purification and characterisation of conjugates. In addition, very low non-specific binding is encountered with enzyme conjugates of anti-FITC and this may confer an advantage over enzyme conjugates of avidin/streptavidin reagents.

Alkaline Phosphatase↗
PubMed1989

Enhanced chemiluminescence ELISA for the detection of antibody to hepatitis B virus surface antigen.

A chemiluminescent enzyme linked immunosorbent assay (ELISA) for the detection of antibody to hepatitis B virus surface antigen (anti-HBs) in human serum has been developed. Polystyrene microtitre plates were coated with recombinant, yeast-derived hepatitis B surface antigen (rec-HBsAg). Patient serum samples and appropriate controls were added to the rec-HBsAg-coated wells and incubated to bind anti-HBs. The wells were then washed and a fluorescein isothiocyanate (FITC) conjugate of a human plasma-derived hepatitis B surface antigen (HBsAg) was added. Following incubation and further washing, the bound FITC-labelled HBsAg was detected after addition of a horseradish peroxidase (HRP) conjugate of a monoclonal anti-FITC antibody and assaying for the enzyme. The activity of the HRP was measured using luminol and hydrogen peroxide as substrates and iodophenol as a chemiluminescence enhancer. The luminescence was recorded using a camera luminometer. Preliminary tests have shown the assay to be suitable for the detection of antibody in sera from both vaccinees and also from individuals with a past hepatitis B virus infection. The use of the FITC-anti-FITC system together with the measurement of a chemiluminescence signal makes possible the completion of this assay in a few hours. The assay has been shown to be both specific and sensitive and provides a permanent photographic record.

Colorimetry↗
PubMed1989

Emergency orthotopic liver transplantation in two patients using one donor liver.

Because of its anatomy, the liver can be divided into two hemilivers suitable for use as two grafts for liver transplantation. The line of division is the main scissure, giving the right hemiliver (segments 5-8) and the left hemiliver (segments 2-4). Segment 1 (caudate lobe) has to be resected. The vessels are divided between the two grafts: the vena cava remains on the right; on the left, the left hepatic vein is sutured into the vena cava of the recipient, which is retained intact. The left graft retains only the left branch of the portal vein, the bile duct and the hepatic artery. The right graft retains the portal trunk, the common bile duct and the right branch of the hepatic artery. This procedure was used for emergency grafting of two patients with fulminant hepatitis when only one donor was available. Both recipients recovered from coma and regained normal liver function. However, both died from causes not specifically related to the operative technique, one from multiple organ failure on the 20th day and the other from diffuse cytomegalovirus infection on the 45th day.

Adult↗
PubMed1989

An amplified ELISA for the detection of parvovirus B19 IgM using monoclonal antibody to FITC.

A new M-antibody capture ELISA for the detection of specific IgM against parvovirus B19 is described. The test uses a monoclonal anti-fluorescein isothiocyanate (FITC) antibody conjugated to horseradish peroxidase to amplify the positive reactions. Serum samples (N = 823) submitted for B19 IgM assay were tested in parallel in the new ELISA and the standard B19 M-antibody capture radioimmunoassay (MACRIA) test. By both tests B19 IgM was detected in 38 (4.6%) samples, and not detected in 771 (94%) samples. One sample was positive in the ELISA test but negative in the RIA and of the 13 sera giving 'equivocal' results in the MACRIA, 6 were positive and 7 negative. If the RIA equivocal results were excluded, the ELISA showed 100% (38/38) sensitivity and 99.9% (771/772) specificity compared to the MACRIA test. The B19 IgM ELISA is a sensitive and specific test with better discrimination between anti B19 IgM positive and negative specimens than MACRIA.

Animals↗
PubMed1989

The use of monoclonal antibodies to demonstrate Listeria monocytogenes in post mortem tissue using a direct immunofluorescence technique, and to detect a soluble antigen in CSF supernatants using an ELISA.

A direct immunofluorescence technique was developed using FITC conjugates of anti-listeria antibodies (CL2 and CL17). Using this technique Listeria monocytogenes (whole cells) were observed in post mortem tissue from 3 patients where listeriosis had been proven by the isolation of the bacterium, and also from a patient where listeriosis was suspected. Using one of these monoclonal antibodies (CL2) an indirect antigen capture ELISA was developed for the detection of soluble antigen. Soluble antigen was detected in cerebrospinal fluid (CSF) from 27% of patients infected with L. monocytogenes serogroup 4 and 2% of patients where listeriosis was suspected. The test was 100% specific in that antigen was not detected in 270 other CSF samples tested. Antigen was only detected in CSF samples taken within 7 days after onset of illness.

Adolescent↗
PubMed1989

Anterior sacral meningocele.

Anterior sacral meningocele is a rare congenital meningeal cyst herniating through a bony defect in the sacrum. Since its description by Bryant in 1837, only 154 cases have been reported in the world literature. The application of ultrasound and C.T. scan following myelography is discussed.

Back Pain↗