PubMed Health⌕ Search

Biomedical subjects

N Rice

Publications and source records attributed to N Rice.

At least 37 records · Page 2Linked to original sources
PubMed1996

Regulation of NF-kappa B activation in T helper 1 and T helper 2 cells.

In most cell types, NF-kappa B is activated by release from a cytoplasmic inhibitor protein, I kappa B, followed by its translocation to the nucleus where it binds to the regulatory regions of many genes, including the IL-2 gene in T lymphocytes. We have previously shown by electrophoretic mobility shift assays that nuclear extracts prepared from activated, non-IL-2-producing Th2 cell clones. We show here that Th-1 and Th2 cells have similar levels of cytoplasmic p65(RelA) and p50, but TCR stimulation fails to induce the nuclear translocation of p65(RelA) in Th2 cells. Nuclear translocation of p65(RelA) can be induced by IL-1 stimulation of Th2 cells, indicating that a basic mechanism of NF-Kappa B activation common to many cells is intact in Th2 cells. We demonstrate that IL-1 and TNF induce rapid nuclear translocation of p65(RelA) in T cell clones, whereas TCR-induced NF-Kappa B activation in Th1 cells is delayed and may be longer in duration. This suggests that the TCR pathway of NF-Kappa B activation is different from the cytokine pathway. Furthermore, we show that Th1 and Th2 cells express different levels and/or different forms of I kappa B alpha, and that cytokines, but not TCR stimuli, significantly modulate detectable levels of cytoplasmic I kappa B alpha.

Animals↗
PubMed1996

Multilevel models: applications to health data.

This paper presents an introductory account of multilevel models, highlighting the potential benefits that may be gained by the use of these methods. It draws on recent applications in health services research that have appeared in the literature. Methodological advances in these statistical techniques have taken place in the field of education, where empirical studies have mainly been concerned with comparing pupil achievement across different schools by exploring the relationship between individual and institutional factors. Although recent widespread availability of suitable software packages has enabled other disciplines to adopt these methods, to date they have received little attention in the health services research literature (the investigation of effects of geographical areas on health being a possible exception) despite their obvious application in many areas of current interest. Key areas that could benefit greatly from these techniques include the exploration of variations in clinical practice, comparisons of institutional performance and resource allocation.

Health Behavior↗
PubMed1995

Establishment of lipopolysaccharide-dependent nuclear factor kappa B activation in a cell-free system.

Nuclear factor kappa B (NF-kappa B), consisting of p50 and p65, is bound to a cytoplasmic retention protein, I kappa B, in a resting state, and the stimulation of cells with a variety of inflammatory stimuli induces the dissociation of NF-kappa B from I kappa B and the nuclear translocation of NF-kappa B, thereby activating several genes involved in inflammatory responses, such as interleukin (IL)-6, IL-8, and tumor necrosis factor alpha. In order to elucidate the precise mechanism of NF-kappa B activation, we have established lipopolysaccharide (LPS)-dependent NF-kappa B activation in a cell-free system using plasma membrane-enriched, cytosol, and nuclear fractions extracted from a human monocytic cell line, THP-1, by disruption with sonication followed by a differential centrifugation. The combination of plasma membrane-enriched fraction and cytosol was sufficient to activate NF-kappa B in a LPS/CD14-dependent manner only in the presence of ATP as judged by the binding of NF-kappa B to the IL-8 gene kappa B site on an electrophoretic mobility shift assay. LPS-dependent NF-kappa B activation was inhibited by protein kinase inhibitors, such as staurosporine, herbimycin A, tyrphostin, and genistein, but not mitogen-activated protein kinase substrate, cGMP-dependent protein kinase, cAMP-dependent protein kinase, protein kinase C, and calmodulin-dependent protein kinase II inhibitory peptides, suggesting that staurosporine-sensitive kinase(s) as well as tyrosine kinase(s) are involved in LPS-mediated NF-kappa B activation. In addition, LPS induced the phosphorylation of I kappa B-alpha, starting at 5 min after the stimulation in a cell-free system. Moreover, the phosphorylation was inhibited by herbimycin A and tyrphostin, but not staurosporine, suggesting that these protein kinase inhibitors act at distinct steps of signal transmission. Establishment of ligand-dependent activation of NF-kappa B in a cell-free system will facilitate identification of protein kinase(s) and its substrate(s) involved in LPS-mediated NF-kappa B activation.

Amino Acid Sequence↗
PubMed1995

N- and C-terminal sequences control degradation of MAD3/I kappa B alpha in response to inducers of NF-kappa B activity.

The proteolytic degradation of the inhibitory protein MAD3/I kappa B alpha in response to extracellular stimulation is a prerequisite step in the activation of the transcription factor NF-kappa B. Analysis of the expression of human I kappa B alpha protein in stable transfectants of mouse 70Z/3 cells shows that, as for the endogenous murine protein, exogenous I kappa B alpha is degraded in response to inducers of NF-kappa B activity, such as phorbol myristate acetate or lipopolysaccharide. In addition, pretreatment of the cells with the proteasome inhibitor N-Ac-Leu-Leu-norleucinal inhibits this ligand-induced degradation and, in agreement with previous studies, stabilizes a hyperphosphorylated form of the human I kappa B alpha protein. By expressing mutant forms of the human protein in this cell line, we have been able to delineate the sequences responsible for both the ligand-induced phosphorylation and the degradation of I kappa B alpha. Our results show that deletion of the C terminus of the I kappa B alpha molecule up to amino acid 279 abolishes constitutive but not ligand-inducible phosphorylation and inhibits ligand-inducible degradation. Further analysis reveals that the inducible phosphorylation of I kappa B alpha maps to two serines in the N terminus of the protein (residues 32 and 36) and that the mutation of either residue is sufficient to abolish ligand-induced degradation, whereas both residues must be mutated to abolish inducible phosphorylation of the protein. We propose that treatment of 70Z/3 cells with either phorbol myristate acetate or lipopolysaccharide induces a kinase activity which phosphorylates serines 32 and that these phosphorylations target the protein for rapid proteolytic degradation, possibly by the ubiquitin-26S proteasome pathway, thus allowing NF-kappa B to translocate to the nucleus and to activate gene expression.

Amino Acid Sequence↗
PubMed1995

Is enumeration district level an improvement on ward level analysis in studies of deprivation and health?

AIM: To investigate whether enumeration district (ED) level data reflect the aggregate characteristics of people living in that district better than ward level analysis. DESIGN AND SETTING: Reanalysis of the fourth national morbidity survey in general practice (MSGP4). Socioeconomic data on patients who had consulted 60 practices over one year were linked via postcode to ED and thence to small area statistics data for that ED and to the corresponding electoral ward. RESULTS AND CONCLUSIONS: There was no evidence that patients were likely to be more representative samples of the population of an ED than of a ward.

Data Interpretation, Statistical↗
PubMed1994

Novel mechanism of glucocorticoid-mediated gene repression. Nuclear factor-kappa B is target for glucocorticoid-mediated interleukin 8 gene repression.

A glucocorticoid, dexamethasone, inhibited the production of a leukocyte chemotactic cytokine, interleukin 8 (IL-8), as well as mRNA expression by a glioblastoma cell line, T98G, stimulated with interleukin 1 (IL-1). Dexamethasone also inhibited IL-8 promoter-driven chloramphenicol acetyltransferase (CAT) activities induced by IL-1, suggesting that dexamethasone inhibited IL-8 production mainly at the transcriptional level. Moreover, CAT assay revealed that the nuclear factor-kappa B (NF-kappa B) binding site was the crucial cis-element required for conferring IL-1 responsiveness in conjunction with the CCAAT enhancer binding protein/nuclear factor-IL-6 (NF-IL6) and/or the AP-1 binding site(s). Mutation of either the AP-1 or NF-IL6 binding site did not abolish IL-8 gene repression by dexamethasone, suggesting that these sites were not targets for dexamethasone. Trimerized kappa B sequence in the IL-8 gene was enough for conferring the induction by IL-1 and inhibition by dexamethasone of CAT activity. Finally, dexamethasone diminished the IL-1-induced formation of NF-kappa B complexes, which were identified immunochemically to consist of p50 and p65, without reducing the amount of translocated factors. Collectively, dexamethasone interfered with the binding of the most essential transcription factor, NF-kappa B, to its cognate cis-element, thereby suppressing the transcription of IL-8 gene.

Amino Acid Sequence↗
PubMed1994

The interleukin-8 AP-1 and kappa B-like sites are genetic end targets of FK506-sensitive pathway accompanied by calcium mobilization.

FK506, an immunosuppressant, inhibits the production of several cytokines in T lymphocytes. We observed that FK506 suppressed the transcription of a chemotactic cytokine, interleukin-8 (IL-8) in a human T cell line, Jurkat cells, activated by phorbol 12-myristate 13-acetate (PMA) and calcium (Ca2+) ionophore (ionomycin). By deleted and mutated analysis of the IL-8 promoters, the AP-1 and kappa B-like sites were identified as the responsive elements for PMA and ionomycin. FK506 suppressed the transcriptions through the AP-1 or kappa B-like sites induced by PMA plus Ca(2+)-mobilizing agents, but not those induced by Ca(2+)-independent stimuli. In gel retardation analysis, FK506 had little effect on the binding to the AP-1 site of PMA/ionomycin-induced nuclear factors, which were recognized with anti-JunD or c-Fos antibody. In contrast, FK506 or EGTA (Ca2+ chelator) similarly affected the formation of kappa B-like site binding complexes, which were not recognized by any antibodies against the human Rel family proteins (c-Rel, p65, p50, and p49). Furthermore, we confirmed the previous report that FK506 suppressed the PMA/ionomycin-induced activation through authentic kappa B site of immunoglobulin (Ig) gene, to which NF-kappa B binding was also decreased by FK506, indicating that both IL-8 kappa B-like site and Ig kappa B site are FK506-sensitive in spite of the difference of binding factors. Our results indicate that not only the reported IL-2 NF-AT and NFIL-2A sites and Ig kappa B site, but also the IL-8 AP-1 and kappa B-like sites are terminals of FK506-sensitive pathway involving Ca2+ mobilization.

Base Sequence↗
PubMed1994

Equine infectious anemia virus trans-regulatory protein Rev controls viral mRNA stability, accumulation, and alternative splicing.

The cis- and trans-acting components of the Rev regulatory pathway employed by equine infectious anemia virus (EIAV) to regulate and coordinate viral gene expression were examined in complementation experiments. Viral protein expression and mRNA expression were compared in cells transiently transfected with wild-type or mutant proviruses in combination with Rev expression plasmids. Mutation of the predicted rev gene abolished Gag protein synthesis, and this defect was complemented, in trans, by Rev. Analysis of viral mRNAs from transfected cells confirmed that EIAV expresses five major mRNAs: the full-length and singly spliced mRNAs contain introns and encode viral structural proteins while the three fully spliced mRNAs, encoding nonstructural genes, are generated by alternative splicing. Compared to cells transfected with the wild-type provirus, the intron-containing mRNAs produced from the rev-minus mutant were present at reduced levels in the nuclear RNA fraction and were not detected in the cytoplasm. This pattern of viral mRNA synthesis was restored to the wild-type pattern by providing Rev in trans. In contrast to the intron-containing mRNAs, cytoplasmic accumulation of the multiply spliced class of mRNAs was independent of Rev. Closer examination of the multiply spliced class of viral mRNAs by reverse transcriptase-PCR analysis revealed a Rev-dependent alternative splicing phenomenon. In the absence of Rev, proviruses expressed a four-exon mRNA at high levels; the addition of Rev caused both a decrease in the levels of the four-exon mRNA and the appearance of a related mRNA lacking exon 3. The cis-acting RNA elements that mediate Rev responsiveness were studied with deleted proviruses, which revealed that EIAV contains at least two elements located near the ends of envelope gene. Unlike the Rev-responsive elements in other retroviruses, the cis-acting regions of EIAV do not appear to form complex secondary structures.

Alternative Splicing↗
PubMed1994

Overproduction of NFKB2 (lyt-10) and c-Rel: a mechanism for HTLV-I Tax-mediated trans-activation via the NF-kappa B signalling pathway.

Molecular, biochemical and epidemiological evidence implicate HTLV-I as an etiologic agent of adult T cell leukemia (ATL). The Tax protein of HTLV-I, a positive transcriptional activator of HTLV-I gene expression, is a viral oncogene that also increases transcription of cellular genes including GM-CSF, IL-2R alpha and IL-2. One of the cellular targets of the trans-activating effects of Tax is the NF-kappa B/Rel family of transcription factors, pleiotropic regulators of immunoregulatory, cytokine and viral gene expression. In this report, we demonstrate that NFKB2 (lyt-10) and c-Rel are overexpressed in HTLV-I infected and Tax-expressing cells and, together, account for the majority of the constitutive NF-kappa B binding activity in these cells before and after PMA stimulation. Most importantly, we show a Tax-dependent correlation between expression of NFKB2(p100) and processing to the DNA binding NFKB2(p52) form, induction of c-Rel, and trans-activation of NF-kappa B-mediated gene expression. Furthermore, the NFKB2 precursor is physically associated with c-Rel and with Tax in HTLV-I infected cells. We propose that NFKB2 synthesis and processing allows continuous nuclear expression of an otherwise cytoplasmic protein and, in conjunction with overexpression of c-Rel, NFKB2 alters the NF-kappa B signalling pathway and contributes to leukemic transformation of T cells by HTLV-I.

Base Sequence↗
PubMed1993

Uroflowmetry in the puerperium.

One hundred women underwent uroflowmetry once per day for the first 3 days after delivery, and the results compared to those of 53 nonpregnant controls in an effort to determine 1) whether urinary flow in the puerperium is different to that found without pregnancy, 2) whether uroflow parameters change as the puerperium progresses, and 3) which characteristics of a patient or her labour bear most influence upon the results of uroflowmetry. Urinary flow in the puerperium was seen to be different from that of the nonpregnant female in that mean flow rates were lower. In addition to this, voided volume, total flow time, and time to peak flow were all significantly increased on day 1, but were comparable on days 2 and 3. Other than for falling voided volumes, uroflow parameters did not alter significantly as the puerperium progressed. Correlation of the variables age, parity, baby weight, length of first and second stage, use of epidural and perineal suturing with the parameters of urinary flow failed to show any significant relationship.

Adult↗
PubMed1993

The prevalence and severity of cyclosporin and nifedipine-induced gingival overgrowth.

The gingival health of 32 renal transplant patients who were medicated with cyclosporin was compared with a similar cohort of 23 renal transplant patients medicated with both cyclosporin and nifedipine. Both groups of patients had been taking the above medication for at least 3 months. Plaque scores, gingival inflammation and probing depths were similar for both groups. Patients medicated with the combination of nifedipine and cyclosporin had a significantly higher gingival overgrowth score (p = 0.046) when compared with the group receiving cyclosporin alone. The incidence of clinically significant overgrowth (i.e., overgrowth > 30% which would require surgical intervention) was similar in both groups. Gingival overgrowth was not related to cyclosporin dosage. It is concluded that patients taking cyclosporin or cyclosporin and nifedipine experience gingival overgrowth and that the severity of the overgrowth is greater in patients taking the combined therapy. The levels of plaque and gingival inflammation appear to be associated with this phenomenon.

Adult↗
PubMed1993

Chronic human immunodeficiency virus type 1 infection stimulates distinct NF-kappa B/rel DNA binding activities in myelomonoblastic cells.

The relationship between human immunodeficiency virus type 1 (HIV-1) infection and the induction of NF-kappa B binding activity was examined in a myeloid cell model of HIV-1 infection derived from the PLB-985 cell line. Chronic infection of PLB-985 cells led to increased monocyte-specific surface marker expression, increased c-fms gene transcription, and morphological alterations consistent with differentiation along the monocytic pathway. PLB-IIIB cells displayed a constitutive NF-kappa B-like binding activity that was distinct from that induced by tumor necrosis factor alpha or phorbol 12-myristate 13-acetate treatment of the parental PLB-985 cell line. This unique DNA binding activity consisted of proteins of 70, 90, and 100 kDa with a high degree of binding specificity for the NF-kappa B site within the PRDII domain of beta interferon. In this report, we characterize the nature of these proteins and demonstrate that binding of these proteins is also induced following Sendai paramyxovirus infection. The 70-kDa protein corresponds to the NF-kappa B RelA (p65) subunit, which is activated in response to an acute paramyxovirus infection or a chronic HIV-1 infection. Virus infection does not appear to alter the amount of RelA (p65) or NFKB1 (p50) but rather affects the capacity of I kappa B alpha to sequester RelA (p65), therefore leading to constitutive levels of RelA DNA binding activity and to increased levels of NF-kappa B-dependent gene activity. The virally induced 90- to 100-kDa proteins have a distinct binding specificity for the PRDII domain and an AT-rich sequence but do not cross-react with NF-kappa B subunit-specific antisera directed against NFKB1 (p105 or p50), NFKB2 (p100 or p52), RelA (p65), or c-rel. DNA binding of the 90- to 100-kDa proteins was not inhibited by recombinant I kappa B alpha/MAD-3 and was resistant to tryptic digestion, suggesting that these proteins may not be NF-kappa B related. Transient cotransfection experiments demonstrated that RelA and NFKB1 expression maximally stimulated HIV-1 LTR- and NF-kappa B-dependent reporter genes; differences in NF-kappa B-like binding activity were also reflected in higher constitutive levels of NF-kappa B-regulated gene expression in HIV-1-infected myeloid cells.

Base Sequence↗
PubMed1992

The c-rel protooncogene product c-Rel but not NF-kappa B binds to the intronic region of the human interferon-gamma gene at a site related to an interferon-stimulable response element.

Interferon-gamma (IFN-gamma) is an important immunoregulatory protein that is expressed usually only in large granular lymphocytes and T cells. The gene encoding IFN-gamma was previously found to contain an intronic enhancer element that was not tissue-specific in its activity, despite the restricted expression of the intact IFN-gamma-encoding gene. Using nuclear extracts from the human T-cell line Jurkat, we have now identified two protein-binding regions in this intronic enhancer element. One of the protected regions has strong partial identify to the NF-kappa B site present in the promoter region of the human interleukin 2-encoding gene. Based on this observation and recent reports of the interaction of the c-rel protooncogene product (c-Rel) with NF-kappa B sites, we determined whether c-Rel could interact with the intronic enhancer element in the human IFN-gamma genomic DNA. Most surprisingly, gel-shift analysis, using c-Rel expressed in Escherichia coli established that c-Rel binds specifically to the IFN-gamma intronic DNA but not to the interleukin 2-like NF-kappa B site. Additional studies with antibodies prepared against c-Rel peptides verified specificity of the interaction of c-Rel with this binding site. In addition, using an affinity-purified p50 subunit of the NF-kappa B complex, we observed that the p50 protein did not bind to this additional c-Rel-binding site. Furthermore, nucleotide sequence analysis of this DNA region revealed a strong similarity of the additional c-Rel-binding site to a previously identified IFN-stimulable response element. These data show that c-Rel can interact with DNA regions distinct from that recognized by NF-kappa B and may, in fact, be involved in transcriptional regulation of the IFN-stimulable genes via the IFN-stimulable response element.

Base Sequence↗
PubMed1992

The effect of indomethacin on anthralin inflammation.

The effect of prostaglandin inhibition, using topical indomethacin, on anthralin inflammation was studied. Indomethacin gel and gel base were applied to opposite flexor forearm skin sites of 11 volunteers for 2 h and then washed off. Anthralin and UVB were then applied to the gel-treated skin and the anthralin- and UVB-induced erythema and oedema were measured at 2, 6, 24 and 48 h using Harpenden callipers and a reflectance erythrometer. Prostaglandin inhibition was demonstrated by a significant reduction of UVB erythema at the indomethacin-treated sites compared to the gel-base-treated sites. There was a small but significant reduction in anthralin erythema, but not oedema, at the indomethacin-treated sites compared to the gel-base sites. This study demonstrates that prostaglandins, and other inflammatory mediators because the inhibitory effect was small, are involved in anthralin inflammation.

Administration, Topical↗
PubMed1985

Genetic characterization of human c-rel sequences.

We isolated and sequenced a human genomic-DNA segment that is homologous to a portion of v-rel, the transforming gene of reticuloendotheliosis virus (strain T). We also localized the human rel sequences to human chromosome 2 by screening a panel of rodent X human somatic-cell hybrids with the newly described human rel segment.

Base Sequence↗
PubMed1983

Outbreak of central-nervous-system toxoplasmosis in western Europe and North America.

Acute encephalitis caused by Toxoplasma gondii was diagnosed in ten patients in Belgium, the U.S.A., and Canada. None had underlying conditions usually associated with toxoplasmosis. Three had evidence of extraneural infection at necropsy. Nine patients died. Only two of the patients had a history of homosexuality, and one was a heroin addict. Five were Haitian, and four of them had lived in North America for 2-5 years. Eight of the patients had pronounced lymphopenia. Diagnosis of toxoplasmosis was hampered by a lack of suspicion that Toxoplasma could be the agent causing necrotising encephalitis in the non-immunocompromised host, the protean manifestations of the encephalitis, and a lack of a specific antibody response. The large number of cases appearing in western Europe and North America emphasise the necessity of including toxoplasmosis in the differential diagnosis of encephalitis of unknown aetiology.

Acute Disease↗
PubMed1982

The hydrolysis of dolichyl palmitate by intestinal mucosa.

A dolichyl palmitate esterase was found in cell-free extracts of both pancreas and intestinal mucosa. The substrate for the reaction was dolichyl palmitate that was synthesized with labeled fatty acid. The reaction was monitored by the liberation of the free fatty acid and HPLC. All polyprenol esters studied were hydrolyzed despite differences in chain length. The role of this enzyme might be to promote the absorption of dolichol from the diet.

Animals↗