PubMed Health⌕ Search

Biomedical subjects

R W Janson

Publications and source records attributed to R W Janson.

13 recordsLinked to original sources
PubMed1997

Rheumatologic view of the rheumatoid foot.

Rheumatoid arthritis is a common systemic disease that affects between 0.3% and 1.5% of the general population worldwide. In 1988, it was estimated by the National Arthritis Foundation that there were 4 to 6 million cases of rheumatoid arthritis in the United States. There is general agreement that the feet are a major source of pain and disability at some point in the course of the illness. The frequency of involvement of the feet among 1000 patients with rheumatoid arthritis studied by Vainio was 91% in females and 85% in males. The clinical features and pathogenesis of the rheumatoid foot and an approach to initial nonsurgical treatment will be discussed.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1995

Human alveolar macrophages produce predominantly the 35-kD pro-forms of interleukin-1 alpha and interleukin-1 beta when stimulated with lipopolysaccharide.

Alveolar macrophages (AM) play a key role in local immunoregulation. The objective of these studies was to compare the production of the pro- and mature forms of both interleukin-1 alpha (IL-1 alpha) and interleukin-1 beta (IL-1 beta) by AM from nine nonsmoking control subjects, six asymptomatic smokers, and nine patients with interstitial lung disease (ILD). IL-1 alpha and IL-1 beta steady-state mRNA levels in AM cultured over 20 h were determined using specific cDNA probes. IL-1 alpha, 35-kD pro-IL-1 beta, and 17-kD mature IL-1 beta protein levels in cell lysates and supernatants were determined by individual specific ELISAs. Before culture, the isolated AM contained no IL-1 alpha or IL-1 beta mRNA. AM from nonsmoking control subjects and asymptomatic smokers produced comparable levels of IL-1 alpha protein, 5.01 +/- 1.02 ng/ml and 4.54 +/- 1.07 ng/ml, respectively, only after stimulation with lipopolysaccharide (LPS) and not with granulocyte-macrophage colony-stimulating factor (GM-CSF). The majority of the IL-1 alpha was present in the cell lysates as 35-kD pro-IL-1 alpha, as determined by Western blot analysis. AM from patients with ILD produced higher levels of LPS-induced cell-associated IL-1 alpha protein (9.78 +/- 1.80 ng/ml, p = 0.031). LPS-induced IL-1 beta production by AM from nonsmoking control subjects (5.22 +/- 1.89 ng/ml) and asymptomatic smokers (4.39 +/- 0.66 ng/ml) was equivalent to total IL-1 alpha protein production.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Enhanced production of IL-1 receptor antagonist by alveolar macrophages from patients with interstitial lung disease.

Alveolar macrophages (AM) produce various inflammatory and immunomodulatory cytokines. The objective of these experiments was to evaluate the production of IL-1ra, a specific receptor antagonist of IL-1, by AM from nonsmoking control subjects (n = 9), smoking control subjects (n = 6), and patients with interstitial lung disease (ILD) (n = 9). IL-1ra protein levels in cultured AM lysates and supernatants were determined by a specific ELISA; relative steady-state IL-1ra mRNA levels were measured using a specific cDNA probe. Before culture the isolated AM from all subject groups contained undetectable IL-1ra mRNA and no IL-1ra protein in the cell lysates as determined by ELISA. AM from nonsmoking control subjects spontaneously produced IL-1ra protein after a 20 h culture in medium, approximately 12 ng/ml with around half in cell lysates. AM from smoking control subjects produced levels of IL-1ra that were similar to the levels in AM from nonsmokers. In contrast, AM from nonsmoking ILD patients (n = 6) produced high levels of IL-1ra spontaneously (approximately 28 ng/ml), with no enhancement observed when cultured on adherent IgG. Interestingly, AM from smoking ILD patients (n = 3) produced lower levels of IL-1ra protein (approximately 11 ng/ml) that were comparable to levels noted in smoking control subjects. AM from all three types of subjects produced decreased amounts of IL-1ra in response to LPS and enhanced amounts in response to GM-CSF. In general, IL-1ra steady-state mRNA levels correlated with protein production.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Receptor-targeted immunotherapy.

Modern techniques of genetic engineering have led to the development of novel receptor-targeted immunotherapies for human diseases. These new approaches include mAbs to the CD4+ subset of T cells, immunotoxins for CD5+ T cells, a diphtheria toxin coupled to IL-2, and antibodies to specific TCRs. Additional approaches include a specific IL-1 receptor antagonist and soluble receptors for IL-1 or TNF. Although initially promising, these new approaches to altering immune and inflammatory events need to be thoroughly and carefully evaluated in further clinical trials in human diseases. Perhaps these novel forms of receptor-targeted immunotherapy will eventually prove to be most effective when employed in combination with more conventional anti-inflammatory and immunosuppressive medications.

Arthritis, Rheumatoid↗
PubMed1991

Production of IL-1 receptor antagonist by human in vitro-derived macrophages. Effects of lipopolysaccharide and granulocyte-macrophage colony-stimulating factor.

The objective of these experiments was to evaluate the production of IL-1ra, a specific receptor antagonist of IL-1, by human in vitro-derived macrophages, a model for differentiated macrophages. IL-1ra protein levels in supernatants and lysates of cultured cells were determined by a specific ELISA. Relative steady-state IL-1ra mRNA levels were measured using a specific cDNA probe. Human monocytes were differentiated by 6 days culture in either medium or granulocyte-macrophage colony-stimulating factor (GM-CSF), after which the effects of subsequent LPS and/or GM-CSF on the production of IL-1ra were evaluated. In vitro-derived macrophages cultured in medium for 6 days constitutively produced IL-1ra protein during the 24-h period of the 7th day in culture. The constitutive production of IL-1ra by medium-aged cells correlated with low steady-state IL-1ra mRNA levels determined over this same time period. In contrast, cells cultured for 6 days in GM-CSF synthesized significantly increased levels of IL-1ra protein during the 7th day in culture but the secreted levels remained unchanged. Cells differentiated in GM-CSF displayed enhanced steady-state levels of IL-1ra mRNA in comparison with cells aged in medium. Stimulation of in vitro-derived macrophages aged for 6 days in medium or in GM-CSF, with LPS or adherent IgG, did not result in increased levels of IL-1ra protein production in comparison with non-LPS stimulated cells. The IL-1ra protein detected in the supernatants of cells differentiated in GM-CSF was biologically active in the IL-1-augmented murine thymocyte proliferation assay. By Western blot analysis, the IL-1ra protein in the in vitro-derived macrophage supernatants was predominantly the 22- to 24-kDa glycosylated species, whereas the lysates contained additional lower molecular weight forms. These results suggest that as monocytes differentiate in vitro into macrophages, they constitutively produce IL-1ra protein and that this production is enhanced by the continuous presence of GM-CSF.

Blotting, Western↗
PubMed1991

IL-1 receptor antagonist and IL-1 beta production in human monocytes are regulated differently.

Human monocytes may synthesize simultaneously both the agonist IL-1 beta and a specific receptor antagonist of IL-1 (IL-1ra). These studies examined whether monocyte production of these two structurally related cytokines was regulated differently. IL-1ra and IL-1 beta protein levels in cell supernatants and lysates were measured with specific ELISA. Relative steady-state mRNA levels, relative transcriptional rates as determined by the nuclear run-on technique, and mRNA stability were all assessed using specific cDNA probes. Monocytes were stimulated with LPS alone, adherent IgG, or both LPS and adherent IgG. Monocytes stimulated with LPS produced near equivalent amounts of IL-1ra and IL-1 beta proteins over 22 h; relative steady-state mRNA levels paralleled the protein levels. In addition, LPS-induced monocytes exhibited enhanced rates of transcription for both IL-1ra and IL-1 beta, in comparison to adherent control cells without LPS. mRNA half-lives in LPS-induced monocytes also were similar for IL-1ra and IL-1 beta. Monocytes cultured on adherent IgG exhibited a low level of IL-1 beta transcription with an absence of protein production. In contrast, adherent IgG led to a high and prolonged rate of IL-1ra protein production. Furthermore, monocytes cultured on adherent IgG exhibited a specific induction of IL-1ra transcription and a marked prolongation in IL-1ra mRNA stability. However, LPS in a high concentration, 1 microgram/ml, reversed the IgG induction of IL-1ra production by decreasing both transcriptional rate and mRNA stability. These results indicate that production of IL-1ra by human monocytes is characterized by different patterns of regulation in comparison with IL-1 beta. LPS induces production of both proteins whereas adherent IgG stimulates only IL-1ra production. The effects of IgG and LPS on induction of IL-1ra production in human monocytes are mediated at both transcriptional and post-transcriptional levels.

Humans↗
PubMed1991

The biological role of naturally-occurring cytokine inhibitors.

Four different mechanisms of cytokine inhibition might be involved in regulation of cytokine effects in vivo. Different cytokines may exhibit opposing biological effects on a specific target cell or in a particular disease. Autoantibodies to cytokines may block cytokine effects in vivo or may function as carriers to deliver cytokines to tissues. Soluble receptors of cytokines, particularly for IL-2 and TNF alpha, may be released by cell activation. Lastly, a specific receptor antagonist of IL-1, IL-1ra, is synthesized by human monocytes and macrophages, particularly under the influence of GM-CSF. IL-1ra is the first described naturally-occurring receptor antagonist of any cytokine or hormone-like molecule. It is not yet known whether IL-1ra is produced in tissues in human diseases as an endogenous anti-inflammatory factor. Whether any of these potential mechanisms to regulate cytokine effects will be of value in the treatment of human diseases remains to be determined.

Autoantibodies↗
PubMed1990

The effects of differentiating agents on IL-1 beta production in cultured human monocytes.

Human monocytes aged in medium exhibit a decrease in LPS-induced IL-1 beta production in comparison with fresh cells. The objective of these experiments was to evaluate the effects of differentiation for 1 or 6 days in IFN-gamma, 1,25-(OH)2-vitamin D3, granulocyte-macrophage CSF, or in various combinations of these agents on both steady state IL-1 beta mRNA levels and protein production in LPS-stimulated monocytes. Monocytes preincubated in IFN-gamma for 1 day, then cultured for 24 h with LPS, exhibited similar kinetics of IL-1 beta mRNA production, but a higher peak mRNA level at 8 h after LPS stimulation, in comparison with cells cultured in medium before LPS stimulation. An increase in IL-1 beta protein production with variable secretion was noted in monocytes preincubated in IFN-gamma before stimulation with LPS. Monocytes preincubated for 1 day in 1,25-(OH)2-D3 alone or in both IFN-gamma and 1,25-(OH)2-D3 exhibited similar kinetics and peak expression of LPS-induced IL-1 beta mRNA levels as cells cultured in medium. However, monocytes preincubated for 1 day in both agents displayed a 50% or greater restoration in LPS-induced IL-1 beta synthesis and secretion in comparison with fresh cells. Granulocyte-macrophage-CSF did not augment the effects of the other differentiating agents on IL-1 beta production. Monocytes cultured over 6 days in differentiating agents failed to exhibit any restoration in LPS-induced IL-1 beta production. These in vitro-derived macrophages exhibited very low levels of both IL-1 beta mRNA and protein production under any culture condition. These results suggest that the effects of differentiating agents on LPS-induced IL-1 beta production may in part be related to the state of maturation of the monocyte. Furthermore, a repression in IL-1 beta transcription that is not reversed by exposure to differentiating agents may be acquired by monocytes as they mature into macrophages in vitro.

Cells, Cultured↗
PubMed1989

IL-1 beta production in cultured human monocytes is regulated at multiple levels.

Cultured human monocytes and tissue macrophages exhibit a marked decrease in LPS-stimulated IL-1 production. Preincubation of monocytes in 100 U/ml IFN-gamma or in 0.25 microgram/ml cycloheximide (Cx) leads to a partial maintenance of the ability to produce IL-1 in response to subsequent stimulation with LPS, whereas preincubation in both reagents leads to a near complete maintenance of this response. These studies were performed to determine the mechanisms of these alterations in regulation of IL-1 production in cultured monocytes. In comparison to LPS-induced fresh monocytes, cells preincubated in medium for 1 day, then stimulated for 24 h with 100 ng/ml LPS, exhibited a 50% or more decrease in steady-state IL-1 beta mRNA levels. This reduction was accompanied by a four- to fivefold decrease in relative transcriptional rate, as determined by the nuclear run-on technique. The medium-aged cells also displayed greatly decreased IL-1 beta production with deficient secretion. Monocytes preincubated in IFN-gamma for 1 day before LPS stimulation exhibited a variable maintenance in IL-1 beta production, secondary both to prolonged duration of transcription and to increased IL-1 beta mRNA stability. Monocytes were preincubated for 1 day in Cx alone or in both IFN-gamma and cycloheximide, then these substances were washed out before a subsequent 24-h culture in LPS. Cx preincubation led to increases in both the peak and duration of transcription as well as to enhanced secretion of IL-1 beta protein. Monocytes preincubated in both IFN-gamma and Cx exhibited increased IL-1 beta mRNA levels due to both enhanced transcription and mRNA stability; more IL-1 beta protein secretion also was present in these cells. In summary, IFN-gamma and Cx may maintain LPS-induced IL-1 beta production in cultured human monocytes through multiple mechanisms. These alterations in regulation of IL-1 beta production during monocyte differentiation may be relevant to tissue macrophages where impaired IL-1 production may be present.

Blood Proteins↗
PubMed1989

A method for recovery of native, clonally-restricted immunoglobulins from agarose gels.

Multiple low level, clonally-restricted, immunoglobulins (Ig) are commonly encountered on routine serum protein electrophoresis by clinical laboratories using high resolution zone electrophoresis on agarose. We sought a method for recovering the clonally-restricted Ig, in native configuration, from clinical laboratory gels as a first step in the investigation of its clinical significance. We found that a two-stage electrophoretic procedure gave consistently good recoveries. After routine agarose gel electrophoresis, portions of the electropherogram, containing clonally-restricted Ig, were excised and subjected to flatbed isoelectric focusing in agarose to enhance separation of the individual antibody clonotypes. Multiple slabs, containing the same clonally-restricted Ig, could be cut from adjacent tracks (i.e., tracks loaded with the same specimen) on the zone electropherogram and applied to a single track on the focusing gel to improve separation and increase yields. The focused gels were cut to isolate slabs containing individual clonotypes. These slabs were washed to remove carrier ampholytes and held at -20 degrees C overnight. Ig was extracted from the thawed gels, with 61-68% recovery, by ultracentrifugation following physical disruption of the gel. Antigen binding activity of the recovered Ig was verified by rate nephelometry. Clonally-restricted antibodies were successfully isolated from an immune animal serum by this procedure and biotinylated for use as probes on Western blots.

Electrophoresis↗
PubMed1980

The effect of hydralazine on arachidonic acid metabolism in isolated, washed human platelets.

The effects of hydralazine on arachidonic acid metabolism were studied in isolated washed human platelets. The washed platelets (10(9)/ml) were exposed to 14C-arachidonic acid and incubated for 15 minutes in a platelet aggregometer (37 degrees C). The media was then extracted and the reaction products separated by means of reversed phase high pressure liquid chromatography. In this system, hydralazine inhibited the production of TXB2 (the stable metabolite of TXA2) and enhanced the production of PGF2 alpha and PGE2 in a dose dependent fashion. Indomethacin, blocked the production of all prostaglandin compounds normally synthesized by platelets. These results suggest that hydralazine is a specific thromboxane synthetase inhibitor and that its vasodilatory effects might be related to its ability to block the production of an endogenous vasoconstrictor (i.e. TXA2).

Arachidonic Acids↗