Biomedical subjects

R C Newton

Publications and source records attributed to R C Newton.

At least 19 recordsLinked to original sources

PubMed1992

Activation and distribution of inflammatory cells in the mouse uterus during the preimplantation period.

Northern blot analysis of mouse uterine RNA showed that IL-1 (alpha and beta), and TNF-alpha mRNA were abundant on day (D) 1 of pregnancy, reduced on D2, and remained basal throughout the remainder of the preimplantation period (D3 and D4). Elevated IL-1 beta and TNF-alpha mRNA levels on D1 were accompanied by increased levels of immunoreactive protein in uterine cytosol preparations as determined by ELISA. In situ hybridization detected IL-1 beta mRNA in cells located in the endometrial stroma and concentrated in subepithelial regions on D1. Immunocytochemical localization of IL-1 beta and TNF-alpha identified cells scattered throughout the endometrial stroma, but more concentrated in the subepithelial region on D1. On D3 and D4, cytokine-immunopositive cells decreased in number and became located predominantly at the endometrial-myometrial junction. Histochemical localization of peroxidase as a marker predominantly for eosinophils showed an abundance of these cells in the D1 uterus. The distribution of peroxidase-positive cells in the uterus followed the same temporal and spatial changes as cytokine-immunopositive cells during the preimplantation period. These data document the occurrence of an inflammatory response in the uterus on D1 of pregnancy, and demonstrate that as the preimplantation period progresses the distribution of inflammatory cells changes from the subepithelial region of the endometrial stroma to the periphery of the uterus at the endometrial-myometrial junction. Mechanisms regulating the uterine inflammatory response on D1 were investigated. Cytokine mRNA levels were not significantly elevated during the estrous cycle or after treatment of adult ovariectomized mice with estradiol-17 beta. In contrast, mating with vasectomized males resulted in an inflammatory response on D1 of pseudopregnancy similar to that on D1 of normal pregnancy, whereas mechanical stimulation of the uterine cervix failed to elicit such a response. These results strongly suggest a role for some factor(s) in the ejaculate, other than spermatozoa, in the initiation of a uterine inflammatory response after mating, but an effect of the act of mating cannot be excluded.

Animals↗

PubMed1992

Strongyloides stercoralis hyperinfection in a carrier of HTLV-I virus with evidence of selective immunosuppression.

A patient with near fatal Strongyloides hyperinfection syndrome is briefly described. Investigation for possible risk factors for this parasitic infection disclosed that he was a carrier of human T-cell leukemia virus type I (HTLV-I), but without evidence of disease due to this retrovirus. Over the next few years, the patient's serum antibody levels of IgG to S. stercoralis larvae declined and became undetectable despite continued infection with the parasite. Repeated courses of appropriate treatment cleared the parasitic infection only temporarily. The patient was also found to have undetectable total serum IgE and a negative immediate hypersensitivity skin test to S. stercoralis antigens. Five of six other patients with HTLV-I-associated disease and with or without strongyloidiasis were also found to have very low total serum IgE levels. It is postulated that HTLV-I infection in certain individuals may selectively impair immune responses that are critical in controlling strongyloidiasis.

Antibodies, Helminth↗

PubMed1992

Type I interleukin-1 receptors in the mouse brain-endocrine-immune axis labelled with [125I]recombinant human interleukin-1 receptor antagonist.

Iodine-125-labelled recombinant human interleukin-1 (IL-1) receptor antagonist ([125I]IL-1ra) was utilized to further determine the characteristics of IL-1 receptors in the brain-endocrine-immune axis. The binding of [125I]IL-1ra in homogenates of mouse hippocampus, spleen and testis was linear over a broad range of membrane protein concentrations, saturable, reversible, and of high affinity (KD, 20-30 pM). In competition studies, IL-1ra, recombinant human IL-1 alpha, IL-1 beta and a weak IL-1 beta analog inhibited [125I]IL-1ra binding to mouse tissues in parallel with their biological activities. In autoradiographic studies, [125I]IL-1ra and [125I]IL-1 alpha binding showed comparable distribution patterns with highest densities of binding sites present in the dentate gyrus of the hippocampus, choroid plexus, anterior pituitary, marginal zones and red pulp regions of the spleen, epididymis and interstitial area of the testis. The binding characteristics and distribution of [125I]IL-1ra are comparable to those of previously characterized Type I IL-1 receptors. These data provide further support for a role for IL-1 in coordinating brain-endocrine-immune responses to physiological and pharmacological stimuli.

Animals↗

PubMed1992

Permuteins of interleukin 1 beta--a simplified approach for the construction of permutated proteins having new termini.

A technique for the rapid and simple generation of permutated versions of the interleukin-1 beta (IL-1 beta) gene is described. In this method, the human IL-1 beta cDNA is twice amplified by the polymerase chain reaction (PCR) and the resulting DNA fragments are ligated in tandem. Between the two genes, the DNA sequence encodes a short four amino acid loop to link the native N- and C-terminal ends of the IL-1 beta protein. By using PCR amplification from this starting template, a new version of the IL-1 beta cDNA was obtained that encodes a permutated form of the IL-1 beta protein where the new N- and C-terminal amino acids correspond to residues 65 and 64 of the native IL-1 beta sequence, respectively. The name 'permutein' is proposed to describe proteins generated by this technology. The molecular profile (IL-1 receptor binding, biologic activity and solution properties) of the IL-1 permutein produced by this technology, permutein 65/64, is shown to be identical to that of native IL-1 beta. The approach should be useful to define further the structural features of this protein that are important for its function.

Amino Acid Sequence↗

PubMed1992

Effects of intracellular ions on interleukin-1 beta production by lipopolysaccharide-activated human monocytes.

Following the observation that interleukin 1 beta (IL-1 beta) production in lipopolysaccharide (LPS)activated monocytes increases in concert with a rise in intracellular pH (pHi), the role of ion transport in IL-1 beta production was investigated. The amiloride analogue 5-(N-ethyl-N-isopropyl)amiloride (EIPA), an inhibitor of the Na(+)-H+ antiporter, inhibited extracellular IL-1 beta. The replacement of Na+ in the culture medium with sucrose or choline chloride also prevented monocyte activation. The sodium ionophore monensin, in doses from 100 pM to 1 microM, potentiated LPS-stimulated extracellular IL-1 beta when compared with LPS alone. In the absence of LPS activation, monensin by itself at 10 nM stimulated IL-1 beta production to 63%. EIPA at 10 microM inhibited the Na+ influx, the rise in pHi, and intra- and extracellular IL-1 beta production in activated monocytes; this inhibition was reversed by 10 nM monensin. In the absence of bicarbonate, or in the presence of 10 microM 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, the pHi of activated monocytes and the total protein synthesis did not change, but the production of IL-1 beta was inhibited. The data suggest that the stimulated influx of Na+ via the Na(+)-H+ antiporter regulates both pHi and IL-1 beta production in LPS-activated monocytes. The requirement for bicarbonate indicates an additional mechanism(s), separate from the modulation of pHi and intracellular Na+.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed1991

Modulation of synovial fibroblast plasminogen activator and plasminogen activator inhibitor production by protein kinase C.

Phorbol myristate acetate (PMA) added to human synovial fibroblast cultures caused a dose-dependent increase in the production of plasminogen activator inhibitor-type 1 (PAI-1). In addition, PMA inhibited endogenous and interleukin-1 (IL-1) induced plasminogen activator (PA) activity, while increasing mRNA PAI-1 levels. Other protein kinase C (PKC) activators, mezerein and teleocidin B4, caused similar effects. The simultaneous addition of the PKC antagonists, H-7 or staurosporine, prevented the inhibition of PA activity by PMA. This study shows that activation of PKC inhibits PA and stimulates PAI production in human synovial fibroblasts. These results suggest that activation of PKC may play an important role in regulating increased PA production associated with joint destruction in rheumatoid arthritis (RA).

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1991

Internalization and nuclear localization of interleukin 1 are not sufficient for function.

The human fibroblast interleukin 1 (IL-1) receptor is a glycosylated transmembrane protein with a cytoplasmic domain of 213 amino acids. We have constructed a series of deletion mutants of the cytoplasmic region of the IL 1 receptor and have used these mutants to examine its role in ligand binding, internalization, signal transduction, and nuclear localization of IL-1. Mutant receptors lacking most of the cytoplasmic domain are expressed at the cell surface and can bind, internalize, and localize IL-1 at the nucleus, but they do not allow IL-1-mediated induction of interleukin 2 and SV40 promoters. We have localized a critical region for signal transduction to a 50-amino acid segment of the cytoplasmic domain of the receptor. These studies demonstrate that IL-1 internalization and nuclear localization are not sufficient to trigger IL-1 activation of gene expression in T-cells.

Autoradiography↗

PubMed1990

Identification of soluble interleukin-1 binding protein in cell-free supernatants. Evidence for soluble interleukin-1 receptor.

This study describes the identification and characterization of a soluble interleukin-1 (IL-1) binding protein in the conditioned media from Raji human B-lymphoma cells. The soluble IL-1 binding material was isolated by IL-1 affinity chromatography, and treatment with trypsin decreased its ability to bind to IL-1 demonstrating its protein nature. The soluble IL-1 binding protein was specific for IL-1 and was able to discriminate between Il-1 alpha and IL-1 beta in a manner analogous to the membrane-bound Raji IL-1 receptor. The specificity of the IL-1 binding protein was further established in two ways. 1) Cell-free supernatants from Raji "receptor-negative" cells did not contain any IL-1 binding protein, thus ruling out nonspecific interactions between IL-1 and a serum or other protein present in the conditioned medium; and 2) the soluble binding protein inhibited IL-1 binding to Raji cells in a dose-dependent manner. Scatchard analysis of IL-1 beta binding showed the dissociation constant (KD) to be 5.1 nM for the soluble IL-1 binding protein compared with 0.8 nM for the membrane-bound IL-1 receptor. Gel chromatography of the soluble binding protein yielded a major peak of IL-1 binding activity with a molecular mass of 35-45 kDa. The characteristics of the soluble IL-1 binding protein described above are consistent with those of the extracellular binding domain of the membrane-bound Raji IL-1 receptor.

Cell Line↗

PubMed1990

A clinical trial of topical terbinafine (a new allylamine antifungal) in the treatment of tinea pedis.

Twenty-three patients were enrolled in a randomized, double-blind trial of terbinafine 1% cream compared with placebo vehicle in the treatment of tinea pedis. Of the 20 patients who were evaluated for efficacy, 10 received terbinafine and 10 received placebo. Except for the terbinafine-treated patients being an average of 11 years older than the patients receiving placebo and the median duration of disease being 6 weeks longer in the placebo group, the two groups were demographically and clinically similar. Results of mycologic tests and clinical findings showed terbinafine to be significantly more effective than placebo in the treatment of tinea pedis. Significantly more terbinafine-treated patients than placebo-treated patients showed conversion to negative culture and microscopy at end of therapy and a significant reduction in scored signs and symptoms. Overall efficacy at follow-up (combined mycologic and clinical findings) was also significantly greater in the terbinafine group (78%) than in the placebo group (zero) (p less than 0.001). Unexplained elevation of liver function test results was noted in three placebo-treated patients and in one terbinafine-treated patient, but these changes were not considered clinically relevant or drug related.

Administration, Cutaneous↗

PubMed1990

Human N-terminal analogs of interleukin 1 beta demonstrate altered binding and function in hematopoiesis.

This study describes the structure-function relationship of interleukin 1 beta (IL-1 beta) using two amino-terminal muteins of human IL-1 beta. One mutein, clone 18, which substitutes a threonine and methionine for the alanine and proline at positions 1 and 2 of the N-terminus of fully processed and active IL-1 beta, demonstrated similar activity to that of native IL-1 beta in inducing granulocyte-macrophage colony-stimulating activity (GM-CSA) from cultured fibroblasts. Clone 18 also demonstrated similar binding to IL-1 beta receptors on fibroblasts when using a competitive binding assay. The second mutein was GLU-4, which in addition to substituting alanine and proline by threonine and methionine also substituted glutamine for arginine at position 4 of the processed IL-1 beta molecule. GLU-4 required a 3-log increase in concentration to obtain the same GM-CSA release from fibroblasts and to produce the same amount of competitive binding inhibition as clone 18 and native IL-1 beta. In addition, preincubation of bone marrow cells with clone 18 and native IL-1 beta demonstrated a greater ability to protect early hematopoietic progenitors from the lethal effects of 4-hydroperoxycyclophosphamide when compared to similar concentrations of GLU-4. A greater number of large granulocyte-macrophage, erythroid, and mixed colonies as well as blast cell colonies were observed when bone marrow cells were preincubated for 20 h with clone 18 or native IL-1 beta as compared to preincubation with GLU-4 or medium alone. Therefore, arginine at position 4 of the processed IL-1 beta molecule was shown to be a key residue in the function of IL-1 beta as a hematopoietic regulator. These results also suggest that minor changes in the N-terminal sequence of IL-1 beta result in decreased interaction with its receptor and a subsequent reduction in biological activity.

Binding, Competitive↗

PubMed1990

The production of human interleukin-1 beta by blood monocytes.

Human peripheral blood monocytes can produce interleukin-1 (IL-1) beta following the addition of picogram amounts of bacterial lipopolysaccharides (LPS). The activation of IL-1 production by these cells can be mimicked by manipulation of specific biochemical pathways which appear to be independent of, and synergistic with, the pathways activated by LPS. Such pathways may be used by other physiological systems to modulate the production of IL-1. Both negative and positive modulation of IL-1 production can be described. Selected chemical antagonists of the arachidonic acid cascade have been shown to inhibit IL-1 production. The activity of such compounds does not appear to be related to their activity as inhibitors of cyclooxygenase or lipooxygenase enzymes or to activity as antioxidants. The intracellular form of IL-1 beta is limited to the precursor, which is found cytoplasmically. The release of IL-1 by activated cells appears to be regulated, in part, by the integrity of the microtubule system of the cells.

5,8,11,14-Eicosatetraynoic Acid↗

PubMed1989

Identification of IL-1 receptors on human monocytes.

The expression and functional analysis of IL-1 beta R on human monocytes were investigated. Binding of 125I-IL-1 to human monocytes was found to be specific and saturable. Scatchard plot analysis revealed a single class of receptors with a binding constant of 600 pM and a receptor density of approximately 100 binding sites per cell. At 37 degrees C 54% of the labeled ligand was internalized over 2 h of incubation. Addition of 0.2% sodium azide to the cells reduced ligand internalization to 9% of total bound. Cross-linking studies revealed that the IL-1R in human monocytes had a Mr of 80 kDa. The addition of IL-1 to monocytes caused changes in membrane Ag expression as assessed by flow cytometric analysis. The results of this study identify IL-1 receptors on monocytes and suggest that IL-1 may act as an effector molecule for monocytes by enhancing expression of Ag correlated with cell differentiation and immune function.

Antigens, Differentiation, B-Lymphocyte↗

PubMed1989

Systemic interleukin I administration suppresses arachidonic acid-induced ear oedema in the mouse.

Recombinant human interleukin 1 beta (IL-1 beta), given intraperitoneally to mice as a single injection, significantly suppressed the development of arachidonic acid (AA)-induced ear oedema. This effect was noted 2 h after administration and for at least 5 days afterwards. IL-1 beta was effective in the dose range of 250 ng-20 micrograms/mouse. Injection of IL-1 beta per se resulted in erythema of the ears, and thus, IL-1 beta has the capacity not only to induce and augment but also to suppress inflammatory responses. Indomethacin administered as subcutaneously-implanted pellets did not influence the IL-1 beta induced-ear erythema, but suppressed to some extent the effect of IL-1 beta on the AA-induced ear oedema.

Animals↗

PubMed1989

A surgical treatment for vitiligo: autologous cultured-epithelial grafts.

Medical treatment of vitiligo has been disappointing; therefore surgical treatments using autologous grafts have been tried. We investigated a new technique in which normally pigmented epidermal cells from a vitiligo patient were cultured on a collagen-coated membrane in MCDB-153, a media that supports melanocytes and keratinocytes. The cell/collagen-coated membrane was used to cover a superficially dermabraded vitiliginous area. Clinical repigmentation, though incomplete, was evident in three of four patients in 4 weeks. Immunofluorescence and electron microscopy were performed on the grafted areas (involved and uninvolved controls). These studies demonstrate the reappearance of melanocytes and melanosomes within the grafted area. All three patients who were successfully repigmented retained their pigment at 1 year follow-up. Further investigation of this promising treatment for vitiligo is warranted.

Adult↗

PubMed1989

Flow cytometric analysis of the effect of interleukin-1 administration on bone marrow populations in mice.

We have examined the effect of administration of human interleukin-1 (IL-1) beta on bone marrow populations in mice. The bone marrow population was characterized by flow cytometric analysis of cell volume, right angle light scatter, and cell surface markers. The bone marrow population demonstrated significant alterations following the injection of a single dose of IL-1. The earliest response was a loss of granulocytes, which was followed by an expansion of cells in this population. There was also an accumulation of kappa chain positive B cells 24 h following administration. These cells were lost from the marrow over the next 48 h, accompanied by an expansion of precursor cells. The changes in cell populations were not due to contaminating lipopolysaccharide (LPS), although the effects could be mimicked by injection of high doses of LPS. Significant effects could be detected with single dose administration of 10 micrograms to 10 ng of IL-1 per animal. The effects of a single high dose (10 micrograms) were mimicked with multiple injections of low doses (5 x 10 ng), suggesting that the intensity of the response is related to the pharmacokinetics of IL-1. These results indicate a potent effect of IL-1 administration on murine bone marrow granulocyte and B lymphocyte populations. The studies described offer a means for the analysis of the effects of IL-1 in vivo.

Animals↗

PubMed1989

The thyroid.

The integument contains many components whose function is influenced by thyroid hormone. Thus, an increase or decrease in hormone levels results in a variety of cutaneous, hair, and nail changes. These changes are important to recognize, as they may aid in the early diagnosis of thyroid disorders. Other cutaneous disorders are more prevalent in patients with thyroid disease, and their recognition may likewise be helpful. Finally, several syndrome complexes occur with which thyroid disorders are regularly associated.

Hair Diseases↗

PubMed1988

Interleukin 1-induced, T cell-mediated regression of immunogenic murine tumors. Requirement for an adequate level of already acquired host concomitant immunity.

Intraperitoneal injection of human rIL-1 in a dose of 0.5 microgram daily for 5 d, or 1 microgram daily for 3 d, was capable of causing complete regression of immunogenic SA1 sarcoma growing subcutaneously in syngeneic or semisyngeneic mice. Higher doses of IL-1 were not more therapeutic against the SA1 sarcoma, but needed to be given to cause complete regression of the immunogenic L5178Y lymphoma. On the other hand, the P815 mastocytoma was much less responsive to IL-1 therapy, in that it failed to undergo complete regression in response to doses of IL-1 capable of causing regression of the L5178Y lymphoma. IL-1 caused regression of the SA1 sarcoma when given on days 6-8 of tumor growth, but not when given on days 1-3. This refractoriness of a small tumor to IL-1 therapy suggests that the antitumor action of IL-1 is based on an underlying host-immune response that is not generated until after day 3 of tumor growth. Direct evidence for the participation of host immunity in IL-1-induced tumor regression was supplied by results showing that IL-1 was not therapeutic against the SA1 sarcoma growing in T cell-deficient (TXB) mice, unless these mice were first infused with Ly-2+ and L3T4+ T cells from donor mice bearing an established SA1 sarcoma. In contrast, normal T cells, or T cells from donor mice bearing a YAC-1 lymphoma, failed to provide TXB recipients with the ability to cause regression of their SA-1 sarcoma in response to IL-1 treatment. The results are in keeping with the interpretation that exogenous IL-1, by augmenting the production of tumor-sensitized T cells, converts a subtherapeutic level of host immunity to a therapeutic level. The results suggest, in addition, that IL-1 only stimulates the replication of T cells that are already engaged in the antitumor immune response.

Animals↗

PubMed1988

Characterization of murine IL-1 beta. Isolation, expression, and purification.

One cDNA clone encoding a truncated murine IL-1 beta (M IL-1 beta) sequence was isolated from a murine macrophage cDNA library. We reconstituted the coding sequence of the 152-residue mature protein and expressed it in Escherichia coli. rM IL-1 beta was purified to homogeneity and characterized by oligonucleotide and NH2-terminal sequence analysis. Purified rM IL-1 beta exhibited biologic activity equivalent to 7.8 x 10(7) units/mg in the murine thymocyte proliferation assay and 9.9 x 10(3) units/mg in the human gingival fibroblast PGE2 production assay, indicative of species specificity. The isoelectric point of rM IL-1 was found to be 8.85. The circular dichroism spectrum revealed that the secondary structure of M IL-1 is indistinguishable from that of the human protein. Receptor binding studies indicated the rM IL-1 bound to murine EL-4.1 thymoma cells in a specific and dose-dependent fashion with an affinity of 32 pM. Competition binding data suggested that murine and human IL-1 compete for a single class of receptor. Antisera were generated in rabbits against both murine and human IL-1. Results of ELISA binding and antisera neutralization assays indicated that there are common antigenic sites between the two IL-1 beta molecules. These domains are of functional importance because they are capable of mediating the neutralization of biologic activity.

Amino Acid Sequence↗