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Biomedical subjects

N Brown

Publications and source records attributed to N Brown.

At least 199 records · Page 11Linked to original sources
PubMed1987

Measurement of hand bone mineral content using single-photon absorptiometry.

A single photon absorption imaging technique has been developed to assess the bone mass of the hand, especially in patients with rheumatoid arthritis or bronchial asthma. A modified rectilinear scanner images the hand by transmission scanning in a water bath with a 7.4 GBq 125I source. A microcomputer is used to calculate the bone mineral distribution, and the total bone mineral content (BMC) of the hand is determined from that distribution. The precision (coefficient of variation) of the measurement is 1.9%. A control population of 20 men and 58 women has been studied to determine normal variations in hand bone mineral content with age, sex, body size, hand volume and years since menopause. The normal men are found to have an average hand BMC of 25.1 g with a coefficient of variation (CV) of 22%, which is reduced to 12% by normalising for body size using span. The normal women had an average hand BMC of 18.0 g +/- 15%. The CV is reduced to 13% by normalising for span and years post-menopause.

Adult↗
PubMed1987

Evidence for peripheral blood B lymphocyte but not T lymphocyte involvement in multiple myeloma.

Because there is controversy regarding whether subsets of peripheral blood lymphocytes (PBLs) are part of the malignant clone in patients with multiple myeloma, we studied this question by immunoglobulin and T cell receptor gene analysis. Southern blot analysis with antibody probes demonstrated clonal immunoglobulin gene rearrangements in PBLs of seven of nine patients that were identical to those seen in their marrow plasma cells. Circulating plasma cells were not detected in any of these patients. In contrast, no patient demonstrated clonally rearranged T cell receptor genes. In one sequentially studied patient, PBLs obtained at diagnosis when he had stage I (Durie-Salmon) contained only germline DNA, while analysis of PBLs at relapse (stage III) revealed a clonally rearranged band. These data confirm the notion that circulating lymphocytes in patients with myeloma are part of the malignant clone and, furthermore, these malignant cells are of B cell rather than T cell lineage.

Aged↗
PubMed1987

The molluscicidal properties of Ambrosia maritima L. (Compositae). 3. A comparative field trial using dry and freshly-harvested plant material.

A comparative trial of freshly-harvested and dry forms of the plant molluscicide, Ambrosia maritima is described. The plant was grown near Alexandria, Egypt and gave a weight ratio of 4:1 for fresh: dry, mature plants. Applications of plant material were made to irrigation watercourses at dosage levels of 560 mg . l-1 fresh and 70 and 140 mg . l-1 dry in May and 280 mg . l-1 fresh and 70 mg . l-1 dry in June. Snail numbers were reduced to low levels after two weeks in all treatments. Statistically significant differences could not be detected between the molluscicidal effects of fresh and dry material or their use in May and June. The cultivated plant has a similar order of activity to that collected from the wild. The snail number reduction was maintained to the end of the year in all treatments. This confirms an earlier finding that a correctly-timed, single application of the plant is capable of controlling snails throughout the entire schistosomiasis transmission season in Lower Egypt.

Animals↗
PubMed1986

Cloning and expression of a cDNA encoding a catalytically active fragment of calf thymus DNA polymerase alpha.

A calf thymus cDNA expression library was constructed in the EcoRI site of lambda gt11 and probed with an antibody raised against calf thymus DNA polymerase alpha. Three classes of antibody-reactive clones were isolated. The largest class carried a 1.9 kilobase calf cDNA insert and expressed a 165-175 kilodalton beta-galactosidase:calf fusion protein which displayed DNA polymerase activity. The characteristic responses of the polymerase activity to alpha-specific inhibitors and antibodies identified the 1.9 kilobase cDNA as a sequence specifically derived from the structural gene encoding the pol alpha catalytic core.

Base Sequence↗
PubMed1986

Bone loss in rheumatoid arthritis and primary generalized osteoarthrosis: effects of corticosteroids, suppressive antirheumatic drugs and calcium supplements.

The annual rate of bone loss in rheumatoid arthritis (RA) and primary generalized osteoarthrosis (PGOA) was determined by measurement of total body calcium (TBCa). The mean annual rate of bone loss in 24 patients with RA treated with nonsteroidal anti-inflammatory drugs (NSAIDs) alone was 3.4%. This rate of bone loss was not reduced in ten RA patients responding to suppressive antirheumatic drugs (4.3%) or seven patients receiving oral calcium supplements (4.5%). The mean annual rate of loss of TBCa in 19 patients with PGOA was 1.6%, a figure which probably represents age-associated bone loss. The rate of bone loss in PGOA was significantly less than that in RA patients not receiving corticosteroids. The mean annual rate of change of TBCa in 30 RA patients receiving corticosteroids (+0.7%) was significantly less than that in any of the other RA groups despite an initial normalized bone mass which was significantly less than in those RA patients receiving NSAIDs alone. The data supported the hypothesis that bone loss occurred early in the course of corticosteroid therapy and thereafter the drugs might have a protective effect on the loss of bone in RA.

Adrenal Cortex Hormones↗
PubMed1986

Anti-idiotypic sera against monoclonal anti-progesterone antibodies: production in rabbits and rats and characterization of specificity.

Antisera were raised in rabbits and rats against three mouse monoclonal anti-progesterone IgG1 antibodies. Anti-idiotypic antibodies were isolated from rabbit sera by successive passage over immunoadsorbent columns of normal mouse Ig and the specific immunizing monoclonal, with elution from the latter. Radioimmunoassays for anti-idiotype and free idiotype were established, enabling detection of idiotype in sera of mice immunized with progesterone-BSA conjugate. Binding of rabbit anti-idiotype to anti-progesterone monoclonals was partially inhibitable by free progesterone-hemisuccinate or progesterone-ovalbumin conjugate. While showing considerable specificity for their respective inducing monoclonals, the anti-idiotypes also cross-reacted in varying degrees with the other anti-progesterone monoclonals, demonstrating the presence of IdI and IdX determinants. The patterns of cross-reactivity showed some correlation with the relative isoelectric points and combining-site specificities of the anti-progesterones. The specificities of rat and rabbit anti-idiotypes were similar, but not identical.

Animals↗
PubMed1985

Tumor of the heart diagnosed by magnetic resonance imaging.

A case of liposarcoma metastatic to the heart is presented. This is a very rare entity and only three prior case reports could be found. Magnetic resonance imaging was successfully used to visualize the tumor. These images compared favorably with a two-dimensional echocardiographic study and postmortem examination.

Echocardiography↗
PubMed1984

The Drosophila position-specific antigens are a family of cell surface glycoprotein complexes.

Position-specific (PS)1 and PS2 monoclonal antibodies bind non-uniformly to the mature wing imaginal disc of Drosophila with respect to the boundary separating the dorsal and ventral developmental compartments. PS1 antibodies preferentially recognize dorsal cells, PS2 antibodies ventral cells. Antibodies of the two classes extract distinct sets of glycoproteins from an imaginal disc lysate. PS3 antibodies bind to both dorsal and ventral disc cells and extract both PS1 and PS2 glycoprotein sets together with an additional component. We show that the PS antigens are related multimeric glycoprotein complexes on the cell surface. PS3 antibodies recognize a glycoprotein present in all complexes, while PS1 and PS2 antibodies recognize unique components of their own complexes. Spatial and temporal correlations suggest the molecules may have a function in development.

Animals↗
PubMed1984

Sequential changes in the mechanical properties of viable articular cartilage stored in vitro.

Viable articular cartilage from the medial femoral condyles of rabbits was stored in vitro in tissue culture medium with various additives and the same site of each specimen was mechanically tested sequentially throughout a 12-day storage period. Indentation testing was performed with instantaneous and sustained loads. Preservation of sustained-load carrying capacity was observed in the condyles stored with additives, indicating maintenance of an intact cartilage matrix. However, initial testing with small sustained loads (preload) showed changes not observed at higher load levels. The changes noted at small sustained initial loads may reflect alterations in cartilage surface structure and may be an early indicator of its mechanical integrity. Chondrocyte viability and proteoglycan content, as measured by 35S incorporation and hexosamine concentration, were unchanged in comparison to fresh articular cartilage.

Animals↗
PubMed1984

Infectious mononucleosis: a polyclonal B cell transformation in vivo.

We obtained spontaneous formation of Epstein-Barr virus-transformed B lymphocyte colonies from the blood of four patients with mononucleosis with the use of soft-agar medium. The colonies were propagated into separate cell lines and analyzed for their immunoglobulin secretion. Of 52 such lines, 44 produced immunoglobulin composed of a single class of heavy chain and single type of light chain. Among these clonal transformants, 27 (62%) of 44 produced mu-chain, 13 (29%) of 44 produced gamma-chain, and 4 (9%) of 44 produced alpha-chain. Analysis of light-chain secretion revealed that of the 44 cell clones secreting complete, monoclonal immunoglobulin products, 31 produced kappa-chain and 13 produced gamma-chain. One clone secreted mu-heavy chain and no light chain, an observation suggesting the clone is a pre-B cell phenotype. Seven lines derived from clones had aberrant patterns of immunoglobulin secretion that produced either two heavy chains or two light chains. B lymphocytes in different states of immunoglobulin gene expression are, therefore, transformed in vivo by Epstein-Barr virus.

Antibodies, Viral↗