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Biomedical subjects

J Shields

Publications and source records attributed to J Shields.

At least 19 recordsLinked to original sources
PubMed1992

Purification and characterization of biologically active human recombinant 37 kDa soluble CD23 (sFc epsilon RII) expressed in insect cells.

Human recombinant soluble 37 kDa CD23 has been expressed in insect cells and secreted into the culture medium using the IL-2 leader sequence. The 37 kDa CD23 was purified 600-fold to homogeneity by monoclonal antibody affinity chromatography and gel filtration. The pure protein is monomeric, glycosylated, depleted of one N terminal amino acid and contains four disulphide bonds. It degrades into smaller fragments of 33, 29 and 25 kDa if purified in the absence of protease inhibitors. The same pattern of proteolytic fragments is observed when the pure preparation is incubated at room temperature for 3 weeks. Physical characterization of the 37 kDa CD23 by circular dichroism indicates that the protein contains mainly beta sheet and 20% of alpha helical structures. Specific binding of IgE to natural CD23 (low affinity IgE receptor) was inhibited by purified recombinant 37 kDa CD23. Moreover, purified recombinant 37kDa CD23 and interleukin-1 promoted the survival of germinal centre B cells.

Amino Acid Sequence↗
PubMed1992

Consolidation hemibody radiotherapy following induction combination chemotherapy in high-tumor-burden multiple myeloma.

PURPOSE: Curative therapy for multiple myeloma continues to be an elusive goal. This report discusses the Northern California Oncology Group (NCOG) phase I and II trial in high-tumor-burden disease that used a strategy that consisted of induction chemotherapy (vincristine, melphalan, cyclophosphamide, and prednisone [VMCP]) for eight cycles followed by sequential hemibody radiation therapy (RT) and subsequent chemotherapy for an additional eight cycles. PATIENTS AND METHODS: Seventy-two previously untreated stage III myeloma patients were entered onto the study. Sixty-nine received induction chemotherapy, 40 received induction chemotherapy and hemibody RT, and 23 received induction chemotherapy, hemibody RT, and consolidative chemotherapy. RESULTS: Twenty-two complete responses (CRs) were obtained by induction chemotherapy, with four additional CRs after RT and consolidative chemotherapy. Nineteen patients developed grade 4 hematologic toxicity primarily after upper hemibody RT. Eight of these developed long-standing neutropenia or thrombocytopenia. Median survival of the group was 134 weeks, which was not significantly different from other approaches. CONCLUSIONS: Hemibody RT can be combined with chemotherapy as induction therapy and can be safely administered in a community setting. However, as administered here no survival advantage was demonstrated.

Adult↗
PubMed1991

Growth regulation of the AML-193 leukemic cell line: evidence for autocrine production of granulocyte-macrophage colony-stimulating factor (GM-CSF), and inhibition of GM-CSF-dependent cell proliferation by interleukin-1 (IL-1) and tumor necrosis factor (TNF alpha).

The human leukemic cell line AML-193 was tested for its proliferative response to endogenously produced autocrine factors and to a variety of cytokines and colony-stimulating factors. Cells grown in the absence of GM-CSF incorporated tritiated thymidine, and this was partially reversed by adding neutralizing anti-GM-CSF antibodies to the culture medium, suggesting that it was due, at least in part, to autocrine GM-CSF production. This was confirmed by immunopurification of a GM-CSF-like activity from cell supernatant of AML-193 cells grown in serum free medium in the absence of exogenous GM-CSF. When AML-193 cells were cultured with GM-CSF in combination with other cytokines, Interleukin-1 alpha and beta (IL-1 alpha and beta), Interleukin-3 (IL-3), Interleukin-6 (IL-6), granulocyte colony-stimulating factor (G-CSF) and tumor necrosis factor alpha (TNF alpha), none of them affected the concentration of GM-CSF required to induce 50% of maximum proliferation (D50). However, the maximum proliferation induced by GM-CSF alone was drastically decreased by IL-1 alpha, IL-1 beta and TNF alpha. Inhibition caused by exposure of the AML-193 to IL-1 for up to 24 hr was reversible, ruling out a direct cytotoxic effect.

Cell Division↗
PubMed1991

Ambient air arsenic levels along the Texas-Mexico border.

The Texas-Mexico border region is one of the most rapidly developing areas in the state. Unprecedented economic and demographic growth is placing stress on a system already overburdened with air, water, waste, and public health problems. This paper reports the results of an initial survey of the past and present ambient air levels of arsenic along the Texas side of the border. Ambient air arsenic levels have increased over time, exhibit seasonal variations, and are higher in specific areas when compared to the rest of the state. Five of the 20 areas in Texas having the highest 24-hour levels of arsenic are found along the border. In areas where emissions have been significantly reduced at the source, arsenic levels remained high in the environment for over two years. This provides a potential continuum for human exposure. The results of this study emphasize the need for bi-national development and implementation of air quality control programs along the Texas-Mexico border.

Air Pollutants, Occupational↗
PubMed1991

Expression of human recombinant CD23 in insect cells.

Human CD23 (low affinity receptor for IgE) has been expressed in insect cells (Sf9) using the baculovirus expression system and the baculovirus transfer vector pAc373. Insect cells infected with a recombinant baculovirus coding for CD23 synthesized a polypeptide not found in wild-type infected insect cells that had antigenic properties similar to natural CD23 produced in RPMI 8866 cells. Surface expression of recombinant CD23 was demonstrated by its ability to bind IgE. Recombinant CD23 expressed in insect cells had a slightly lower molecular weight (43 kDa) than that of natural CD23 (45 kDa) from RPMI 8866 cells as detected by SDS-PAGE followed by Western-blotting. Affinity-purified recombinant CD23 from infected insect cells showed B-cell growth promoting activitiy. These observations demonstrate for the first time that biologically active recombinant CD23 can be produced by the baculovirus expression system, thus providing a useful source of recombinant material to elucidate the biological functions of CD23.

Animals↗
PubMed1991

Semantic-pragmatic disorder: a right hemisphere syndrome?

Following right hemisphere lesions, adults' speech can become copious and inappropriate, with abnormal prosody, and they may be unable to comprehend metaphor or humour. Their symptoms resemble those of children with semantic-pragmatic language disorder, who use fluent, grammatically complex language, but with poor sensitivity to the communicative situation. The hyperlexia found in some of these children reflects an underlying cognitive problem in integrating semantic information with knowledge of the world. Both groups of patients fail comprehend inferential meaning or to make use of paralinguistic features. It is hypothesised that the disorders of communication and cognition found in semantic-pragmatic language disorder may be linked to right hemisphere dysfunction, but this has yet to be confirmed by research.

Autistic Disorder↗
PubMed1990

Inhibition of human interleukin 4-induced IgE synthesis by a subset of anti-CD23/Fc epsilon RII monoclonal antibodies.

Specific monoclonal antibodies (mAb) directed against the CD23 antigen were used to study human interleukin 4 (hIL4)-induced IgE production by blood and tonsillar mononuclear cells. Both peripheral blood and tonsillar mononuclear cells stimulated by hIL4 expressed membrane CD23 as detected by the binding of all anti-CD23 mAb. Nevertheless, two sets of anti-CD23 mAb could be distinguished. The first set, including mAb 25, was able to decrease significantly hIL4-induced IgE synthesis by mononuclear cells. The second set, including EBVCS#1, did not affect hIL4-induced IgE synthesis. All the anti-CD23 mAb were able to bind specifically to a human B cell line expressing recombinant CD23. Inhibition experiments revealed that the two sets of anti-CD23 mAb did not recognize the same epitope on the CD23 antigen. In fact, all the anti-CD23 mAb, except EBVCS#1, were able to inhibit IgE binding to CD23 on RPMI 8866 cells. Moreover, the first set of antibodies, which decreased IgE production, was able to up-regulate membrane CD23 expression on hIL4-stimulated tonsillar mononuclear cells. Conversely, EBVCS#1, which had no effect on IgE production, did not affect hIL4-induced CD23 expression. These results indicate that CD23 plays a key role in human IgE synthesis.

Antibodies, Monoclonal↗
PubMed1990

Production of a 26,000-dalton interleukin 1 inhibitor by human monocytes is regulated by granulocyte-macrophage colony-stimulating factor.

An interleukin 1 (IL 1) inhibitor is secreted into culture medium by a human promyelocytic cell line, H-161, upon stimulation with (PMA) and recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF). Since the morphological characteristics of this cell line were macrophage-like, human monocytes were tested for their ability to produce similar activity using the same induction conditions. Upon induction of adherent peripheral blood monocytes with rhGM-CSF and/or PMA, an IL 1 antagonistic activity was found in the cell supernatants, as determined by IL 1 receptor binding assay, using the murine EL-4.6.1C10 cell line as the cell target. Most of the inhibition of IL 1 binding induced by PMA or by PMA/rhGM-CSF was shown to be caused by IL 1, since it was neutralized by a mixture of anti-IL 1 alpha/beta antibodies and was active in the murine thymocyte proliferation assay (LAF). The activity induced by GM-CSF alone was not neutralized by anti-IL 1 alpha/beta antibodies and showed no LAF activity. The IL 1 inhibitor activity was induced by rhGM-CSF with a D50 around 40 pg/ml. The activity was produced for more than 3 wk in the presence of GM-CSF; removal of GM-CSF was followed by a rapid decrease of IL 1 antagonistic activity. The specific binding of biosynthetically labeled IL 1 inhibitor to target cells (EL-4.6.1C10) showed a protein of 26 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This molecule shares biological and physical characteristics with the urinary IL 1 inhibitor and the promyelocytic H-161-derived IL 1 inhibitor.(ABSTRACT TRUNCATED AT 250 WORDS)

Culture Media↗
PubMed1976

Pelvic lipomatosis.

Three cases of pelvic lipomatosis are presented. Excretory urogram revealed characteristic elevation and elongation of urinary bladder base and relative hyperlucency of pelvic cavity. Associated varying degrees of hydronephrosis and hydroureters are seen secondary to distal ureteral obstruction. Barium enema showed elongation and elevation of rectosigmoid colon.

Female↗