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Biomedical subjects

J Lowe

Publications and source records attributed to J Lowe.

At least 217 records · Page 12Linked to original sources
PubMed1986

Studies on the reappearance of MHC class II antigens on cells of a variant human lymphoblastoid line.

EB4 lymphoblastoid cell line cells were cultured for 32 days with a ricin A chain-conjugated monoclonal antibody (McAb) to a beta chain determinant present on DP and DR antigens. A single colony of cells which survived this treatment was grown up and surface expression of MHC class II and B cell antigens measured. All class II antigens (DQ as well as DP and DR, alpha as well as beta chains) were initially greatly diminished, but substantial recovery of expression occurred within 20-100 days of culture (approx. 21-105 generations), although recovery was still incomplete. The CD19 (p95) B cell antigen was present in greater amount and the CD22 B cell antigen and surface immunoglobulin in lower amount on the variant line cells. It was confirmed that unconjugated anti-class II McAb binds to surface antigens but is unable to induce modulation even over an 8-day culture period. Evidence is presented that the gradual re-expression of class II antigens on the variant line cells is not due to the appearance of a mutant or to recovery from modulation. It is suggested that the variant line cells produce an excess of a regulatory molecule when grown in the conjugate.

Antibodies, Monoclonal↗
PubMed1986

Cerebral and orbital Aspergillus infection due to invasive aspergillosis of ethmoid sinus.

Aspergillus fumigatus infection due to primary infection of the ethmoid sinus affected the brain and orbit of an otherwise healthy elderly woman. Primary nasal sinus infection may be a chronic process analogous to aspergilloma of the lung: it may, however, assume a locally invasive course and spread to the orbit or brain, as in the case described. This form of Aspergillus infection is rare in Europe but common in hot dry areas like the Sudan. The infection was probably contracted by our patient while on holiday in South Africa. Histological recognition of the condition is important in these unusual sites--many cases are clinically diagnosed as a tumour and undergo biopsy.

Aged↗
PubMed1986

Primary intracranial lymphoma. An important differential diagnosis in magnetic resonance imaging of the brain.

The magnetic resonance (MR) appearances are described in 6 pathologically verified cases of primary intracranial lymphoma, and comparison is made with the appearances on computed tomography (CT). In 5 cases, atypical CT appearances were seen and in these cases more extensive and multiple abnormalities were demonstrated by MRI. The importance of differentiating this condition from other pathologies affecting the white matter is discussed.

Adult↗
PubMed1986

The relative contribution of magnetic resonance imaging to the assessment and differential diagnosis of cerebellopontine angle mass lesions.

Forty-nine patients with a space occupying lesion in the cerebellopontine angle cistern were examined by computed tomography (CT), magnetic imaging (MRI) and, where appropriate, conventional neuroradiologic techniques. The presence of an intracanalicular extension and a high signal on T2 weighted sequences were typical of acoustic neuroma and allowed separation from meningioma. Contrast enhancement with gadolinium DTPA was particularly valuable in recurrent acoustic neuroma. Typically epidermoids had long T1 and T2 values. Sequences which highlight flow allow vascular lesions to be identified without the use of contrast media. In separating the several pathologies MRI was superior to CT and also gave information on tissue composition in acoustic neuroma.

Cerebellar Neoplasms↗
PubMed1985

A new assay for IgG rheumatoid factor activity and its use to analyse rheumatoid factor reactivity with human IgG isotypes.

A new assay for IgGRF activity is described which employs human IgGFc as the antigen and a radiolabelled monoclonal antibody directed against human IgG (CHI domain) as the developing antibody. Using this assay IgGRF activity against human IgG isotypes was measured and most sera from RA patients were shown to react predominantly with IgG1 and IgG2 but few reacted with IgG3 and IgG4. The same sera were tested for IgMRF to the IgG isotypes. IgG2 was the best antigen, IgG1 and IgG4 were less so and reactivity with IgG3 was the lowest. IgGRF without associated IgMRF was obtained, its specificity compared to that of IgMRF, and found to be broadly similar. With the new assay high levels of serum IgGRF were found in those RA patients with extraarticular disease but not in RA patients with synovitis alone.

Antibodies, Monoclonal↗
PubMed1985

Evaluation of monoclonal antibodies having specificity for human IgG sub-classes: results of an IUIS/WHO collaborative study.

Seventy-four monoclonal antibodies (McAb) of putative specificity for human IgG (11), the IgG sub-classes (59) or Gm allotypes (4) have been evaluated for reactivity and specificity in eight laboratories employing different assay techniques or protocols. For the IgG, IgG3, IgG4, G1m(f) and G3m(u) specificities McAb have been produced that can be satisfactorily applied in most methodologies employed and have potential as reference reagents. The IgG1 and particularly IgG2 specificities proved problematical with all McAb evaluated demonstrating apparent assay restriction and whilst performing well in some assays proved to be poor or inactive reagents in others. However, the study identifies McAb individually suited to application within most commonly employed methodologies. Epitope display is the probable variability rather than capricious behaviour by the McAb. IgG1 and IgG2 were the least immunogenic of the sub-class proteins and there is evidence that epitope display is influenced by the physical and chemical procedures used to immobilize or fix antigen - a common requirement in the assay systems studied.

Antibodies, Monoclonal↗
PubMed1985

The effects of spinal injury on the intensity of emotional experience.

Twenty-nine subjects with spinal lesions were asked whether the intensity of their experience of eight common emotions had decreased, increased or stayed the same since injury. Analysis of their responses produced no evidence of a decline in affective tone following spinal injury.

Adult↗
PubMed1985

Immunogenicity and antigenicity of immunoglobulins. XII. Intact light chain and heavy chain isotype-restricted Vk-associated epitopes.

Immunization with intact IgG has allowed the isolation of four hybridomas producing antibodies recognizing epitopes expressed within subpopulations of human kappa light chains unrelated to known polymorphisms (Km) and previously defined V-region subgroups. The V-region-associated epitopes recognized are conformation-dependent, being expressed on intact light chain but not on isolated VK or CK fragments. The frequency of expression within paraprotein panels of different heavy chain isotypes varied between individual antibodies. An epitope recognized by B2A6, expressed by greater than 85% IgGK paraproteins, was not represented in 16 IgM paraproteins tested, suggesting that association of VK with mu chains does not result in display of the epitope recognized, or alternatively, that selective association between VK and CH gene products occurs. These data contrast with the reactivity of other McAb for CK epitopes which were reactive with isolated CK fragments, and for all kappa-bearing paraproteins, regardless of heavy chain isotypes.

Antibodies, Monoclonal↗
PubMed1984

The separation of human serum IgG into subclass fractions by immunoaffinity chromatography and assessment of specific antibody activity.

Murine monoclonal antibodies ( McAbs ) with specificity for subclass-specific or subclass-restricted determinants on human IgG have been coupled to Sepharose to generate affinity columns. The judicial use of positive and negative chromatography and the exploitation of the special properties of individual McAb affinity columns has allowed the preparation of individual IgG subclasses from polyclonal IgG containing less than 1% contamination by any other IgG subclass. The specificity of the antibodies present in each polyclonal IgG subclass preparation has been assayed against a bacterial toxoid (tetanus), 2 bacterial cell wall antigens (E. coli and pneumococcal) and coat antigen(s) of a DNA virus (CMV). Antibodies were predominantly IgG1 to tetanus toxoid, IgG2 to pneumovax and E. coli cell walls, and IgG1, 2 and 3 to CMV coat antigens.

Adult↗
PubMed1984

Significance of bone scintigraphy in symptomatic spondylolysis.

In a prospective study, the authors evaluated the usefulness of bone scintigraphy in the work-up of young military personnel with lumbar spondylolysis and persistent low back pain. Ten out of 23 spondylolytic individuals with a recent history of low back pain had positive scintigrams, and none of a group of painless spondylolytic individuals had positive scans. We believe these results indicate that bone scintigraphy is of value in determining whether a spondylolysis in a young individual can be attributed to recent physical exertion or a specific recent traumatic incident.

Adult↗
PubMed1984

Monoclonal antibodies to an immunoglobulin allotype marker G1m(f).

The properties of a group of mouse monoclonal antibodies (McAbs) specific for the human G1m(f) allotype marker on immunoglobulin G are described. The specificity of all 5 McAbs was anti-Gm(f) in haemagglutination assays detecting the G1m(f) determinant on 6 ng of purified G1m(f) paraproteins. A high dilution (greater than or equal to 1/10(4)) could be used for the majority of McAbs in this assay. In Elisa the G1m(f) marker could be detected in homozygote G1m(f+z-) sera at a serum dilution of greater than or equal to 1/10(4). In Elisa assays the G1m(f) specificity was lost when IgG was bound directly to polystyrene but was restored when IgG was bound via anti-human IgG to the polystyrene plate. A possible conformational change in IgG to account for this loss of specificity is discussed. It is expected that these McAbs with their high titre and increased sensitivity over conventional Gm antisera will allow more detailed analysis of the Gm marker system.

Animals↗
PubMed1983

Methicillin induced drug-fever during treatment for acute post traumatic osteomyelitis and septic arthritis.

High dose intravenous methicillin therapy is a common form of treatment for post traumatic acute osteomyelitis and septic arthritis, with positive staphylococcus aureus cultures. A high and spiking fever, persisting in the face of adequate antibiotic therapy, presents a difficult diagnostic dilemma in such patients. In seven patients, methicillin induced drug fever was found to be the cause of such as persisting pyrexia, inspite of an adequate antibiotic regime. This diagnosis must be established by a cautious clinical evaluation and by a careful elimination of all other causes for fever. Upon discontinuation of methicillin, the body temperature reverted to normal within 24 h.

Accidents↗
PubMed1983

A comparison of the agar cloning and microtitration techniques for assaying cell survival and mutation frequency in L5178Y mouse lymphoma cells.

Microtitration methods for assaying cell survival and mutation frequency to ouabain resistance, 6-thioguanine resistance and 1-beta-D-arabinofuranosyl cytosine resistance in L5178Y mouse lymphoma cells were compared to the standard agar cloning technique. The two methods gave essentially similar results for untreated cells, and after treatment with ethyl methanesulphonate and 4-nitroquinoline 1-oxide. Potential advantages of the microtitration method as a routine assay system are discussed.

Agar↗