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Biomedical subjects

R R Coombs

Publications and source records attributed to R R Coombs.

At least 19 recordsLinked to original sources
PubMed1990

Fusidic acid in staphylococcal bone and joint infection.

Over 25 years experience with fusidic acid in the treatment of bone and joint infections is reviewed. Fusidic acid, usually given concurrently with another antibiotic, has proved effective in a wide variety of staphylococcal infections, including acute osteomyelitis and septic arthritis. It is a valuable adjunct to surgery in patients with chronic osteomyelitis. Oral therapy is generally well tolerated, apart from gastrointestinal side effects in a small proportion of cases. Use of fusidic acid in other orthopaedic situations is considered in the light of recent information.

Bone Diseases↗
PubMed1988

Interleukin-2-induced production of interferon-gamma by resting human T cells and large granular lymphocytes: requirement for accessory cell factors, including interleukin-1.

Between 5 and 20% of normal human lymphocytes were found to synthesize interferon-gamma (IFN-gamma) in primary cultures with recombinant interleukin-2 (rIL-2). After 22 hr, IFN-gamma-producing cells included CD5+ T lymphocytes, CD16+ large granular lymphocytes (LGL), and a population of CD5-, CD16- blast cells. Only a small proportion (0-7%) of IFN-gamma-synthesizing cells expressed HLA-DR. The production of IFN-gamma by all rIL-2-responding lymphocyte subsets was shown to require the presence of DR+ accessory cells, probably including nonadherent, esterase-negative monocytes and/or dendritic cells. Accessory cell function in lymphocyte preparations depleted of DR+ cells, or in purified (greater than or equal to 95%) suspensions of LGL, was fully replaced either by addition of 2% autologous, adherent monocytes or by monocyte culture supernatant. The activity of monocyte supernatant was greatly reduced by treatment with antiserum specific for human interleukin-1 beta (IL-1 beta), although a combination of rIL-1 beta and rIL-2 failed to stimulate IFN-gamma production in DR- lymphocytes. These results indicate that rIL-2-induced IFN-gamma synthesis in both T cells and LGL requires the synergistic activity of IL-1, and possibly of one or more other monokines, as yet unidentified.

Antigen-Presenting Cells↗
PubMed1988

Red-cell IgM-antibody capture assay for the detection of Mycoplasma pneumoniae-specific IgM.

A red-cell IgM-antibody capture assay has been developed for detecting Mycoplasma pneumoniae-specific IgM, which is based on the adsorption or 'capture' of IgM from patients' sera onto so-called 'inagglutinable' bovine red cells, chemically linked with anti-human mu. When M. pneumoniae antigen is added to the system, the red cells agglutinate in the presence of M. pneumoniae-specific IgM. The test was compared with the mu-capture ELISA described by Wreghitt & Sillis (1985), and was found to give comparable results. The two tests had similar sensitivity and specificity and could detect M. pneumoniae-specific IgM for a similar time (up to 6 months) after proven M. pneumoniae infection. However, the red-cell antibody capture assay is a much more simple and rapid test, taking only 1 h to perform (compared to 24 h for mu-capture ELISA). The red-cell IgM-antibody capture assay is therefore amenable to rapid diagnosis of M. pneumoniae infection and the institution of early appropriate antibiotic therapy.

Antibodies, Bacterial↗
PubMed1988

Does 'sugar' permeability reflect macromolecular absorption? A comparison of the gastro-intestinal uptake of lactulose and beta-lactoglobulin in the neonatal guinea pig.

Intestinal closure to cow's milk beta-lactoglobulin occurs within 6 days of birth in the guinea pig. Passive intestinal permeability to lactulose persists through the suckling period. The uptake of small water-soluble markers does not reflect macromolecular absorption, and has no place in the measurement of immunologic protein handling by the gut.

Animals↗
PubMed1988

Experimental studies on red cell-based assays for total IgE and allergen-specific IgE.

The potential of red cell-based assays for IgE and allergen-specific IgE has been examined using mouse monoclonal anti-human IgE antibodies and chimaeric human IgE anti-4-hydroxy-3-iodo-5-nitrophenacetyl. Experiments concerned with developing a red cell IgE antibody-capture assay for allergen-specific IgE have pointed to the advantages of presenting the allergen on a second agglutinable red cell.

Allergens↗
PubMed1988

Progesterone assay by inhibition of reverse passive haemagglutination.

An assay for the steroid hormone progesterone is described based on the inhibition of the agglutination by progesterone-bovine serum albumin conjugate of red cells coupled with monoclonal antiprogesterone antibody (reverse passive haemagglutination). A low-affinity agglutination system produced the optimal sensitivity, capable of detecting less than 1 ng/ml steroid. This assay has the simplicity and sensitivity for a potential clinical test for placental or corpus luteum function. It also serves as a model for detection of other small ligands (drugs, hormones) by inhibition of reverse passive haemagglutination.

Animals↗
PubMed1988

Measurement of gamma-interferon in culture supernatants of antigen-stimulated lymphocytes from patients with Schistosoma mansoni infections by a reverse passive haemagglutination assay.

An assay for gamma-interferon (IFN gamma) in human lymphocyte culture supernatants, based on reverse passive haemagglutination (RPH) of red cells bearing a monoclonal anti-IFN gamma antibody, was developed and compared with a conventional virus inhibition assay. Test samples comprised supernatants of lymphocytes from patients with Schistosoma mansoni infections, cultured with or without a soluble worm antigen preparation. The two assays gave comparable results, the correlations for individual samples being good. The RPH assay was both specific and sensitive, allowing the detection of IFN gamma at 13 u/ml (1 ng/ml) or less. The advantages of the RPH assay were that it was quick, relatively inexpensive and suitable for testing large numbers of samples. In particular, between-experiment variation was very low, allowing the assay of different samples on different occasions.

Adolescent↗
PubMed1987

The detection of heat-aggregated IgG (as a model for immune complexes) by reverse passive haemagglutination using a human monoclonal rheumatoid factor coupled to erythrocytes.

A human monoclonal IgM rheumatoid factor (RF) produced in vitro by an Epstein-Barr virus (EBV)-immortalized cell line was purified by protein A-Sepharose adsorption and coupled by the chromic chloride method to human erythrocytes. The RF-coupled cells were incorporated in reverse passive haemagglutination (RPH) assays to detect immune complexes (IC) using heat-aggregated human IgG as a model system. The sensitivity of the RPH was comparable to an enzyme-linked immunosorbent assay (ELISA) using sheep C1q for the detection of ICs.

Antibodies, Monoclonal↗
PubMed1987

Isolation of low-frequency class-switch variants from rat hybrid myelomas.

Class-switch variants have been isolated from rat-rat hybrid myelomas by sib selection using a simple assay based on red cell-labelled antiglobulins. The variants detected are consistent with the gene order deduced from molecular cloning. They appear to arise spontaneously at a rate approximately ten-fold lower than for mouse cell lines but the rate of switching back to the parental isotype is substantial in comparison. An IgG2b variant antibody having the same specificity as CAMPATH-1 for human lymphocytes and monocytes is active in antibody-dependent cell-mediated killing (unlike the parental IgG2a) and may prove to be a valuable therapeutic antibody for immunosuppression and treatment of leukaemia and lymphoma.

Animals↗
PubMed1987

Detection of ecto-5'-nucleotidase on rat B and T lymphocyte subpopulations using a monoclonal antibody in rosetting reactions.

A mouse monoclonal antibody to rat 5'-nucleotidase (5N 4-2 McAb) was used in the direct anti-determinant rosetting reaction (DARR) to demonstrate the ecto-5'-nucleotidase molecule in preparations of rat lymphocytes. Results indicated that 35.5 +/- 7.5% of peripheral blood lymphocytes (PBL), 37.3 +/- 4.8% of lymph node cells (LN) and 37.0 +/- 8.5% of spleen lymphocytes expressed the 5N 4-2 antigen. Depletion studies and mixed rosetting reactions (MRR) showed that the 5N 4-2 antigen was mainly expressed on rat T lymphocytes rather than on B lymphocytes: In fact 59.6 +/- 3.2% (in PBL), 76.5 +/- 0.6% (in LN) and 67.1 +/- 1.3% (in spleen) of T lymphocytes exhibited the 5N 4-2 antigen compared to only 26.5 +/- 2.6% (in PBL), 34.0 +/- 2.1% (in LN) and 46.1 +/- 12.0% (in spleen) of B lymphocytes. As expected a strong association was found between the expression of 5N 4-2 antigen and 5'-nucleotidase enzyme activity on lymphocytes. Both 5N 4-2 positive cells and enzyme activity were preferentially exhibited in the T lymphocyte subpopulation, and 92% of the enzyme activity was observed in a 5N 4-2 antigen positive subpopulation.

5'-Nucleotidase↗