PubMed Health⌕ Search

Biomedical subjects

K Suk

Publications and source records attributed to K Suk.

At least 37 records · Page 2Linked to original sources
PubMed1997

Enhancement of B-cell translocation gene-1 expression by prostaglandin E2 in macrophages and the relationship to proliferation.

Although prostaglandin (PG) E2 is known to suppress various macrophage functions, the molecular mechanisms by which that occurs are largely unknown. To understand better those mechanisms, differential screening of a cDNA library from PGE2-treated macrophages was performed. Subsequently, the DNA sequence of a differentially expressed cDNA clone was determined and the cDNA was identified as B-cell translocation gene-1 (BTG1), a recently cloned antiproliferative gene. A two-to threefold increase in macrophage BTG1 expression was observed after PGE2 treatment. PGE1 and platelet-activating factor, but not leukotrienes B4, and C4, or lipopolysaccharide, also enhanced BTG1 expression. Furthermore, this effect ws mimicked by dibutyryl cAMP which indicated the involvement of elevated cAMP in the PGE2-mediated enhancement of BTG1. Moreover, there was an inverse correlation between BTG1 mRNA expression and macrophage proliferation; however, BTG1 alteration was not associated with macrophage tumoricidal activation. Thus, BTG1 may play a role in PGE2-mediated inhibition of macrophage proliferation and not activation.

Animals↗
PubMed1997

Synergistic stimulation of fibrinogen gelation by casein kinase II and polycationic compounds.

The processes of thrombin-induced gelation of the fibrinogen may be influenced by a variety of factors including phosphorylational state of the fibrinogen. Casein kinase II (CKII) has been shown to phosphorylate fibrinogen in vitro and accelerate gelation of the fibrinogen. In this work, we have demonstrated that CKII and polycationic compounds such as polylysine, spermine, and spermidine synergistically stimulate thrombin-induced gelation of the fibrinogen. These polycationic compounds were also found to increase the stimulatory effects of CKII on the platelet aggregation. Current findings suggest potential role of CKII and polycationic compounds in the process of hemostasis.

Adult↗
PubMed1996

Differential regulation of tumour necrosis factor-alpha mRNA degradation in macrophages by interleukin-4 and interferon-gamma.

Interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) have been reported previously to mediate similar as well as antagonistic effects on murine macrophage functions. One effect common to both is the enhancement of tumour necrosis factor-alpha (TNF-alpha) secretion in macrophages. To assess further the effects of these two lymphokines on macrophage TNF-alpha production, we investigated the role of these lymphokines in the induction and stability of TNF-alpha messages along with interleukin-1 (IL-1) as a comparison. IFN-gamma and IL-4 increased lipopolysaccharide (LPS)-induced TNF-alpha, IL-1 steady-state message levels. In contrast to IL-1 messages, whose degradation was not significantly affected by either lymphokine, the stability of TNF-alpha messages differed after IFN-gamma and IL-4 treatment. Although IL-4 treatment increased the TNF-alpha transcription rate, an increase in the degradation rate of TNF-alpha mRNA in the IL-4-treated cells resulted in a lower level of steady-state mRNA than in the IFN-gamma-treated cells. Additionally, a 18,000 MW cytoplasmic factor was found to have specific binding activity to the AU-rich sequences of the TNF-alpha message in peritoneal macrophages. Although the binding activity of this factor was not affected by either IFN-gamma or IL-4, the binding of the factor to AU-rich sequences appeared to be important in the rapid degradation of TNF-alpha messages. Thus IFN-gamma and IL-4 may differentially affect the post-transcriptional control of TNF-alpha gene expression. And this lymphokine-mediated post-transcriptional control of the TNF-alpha gene does not appear to involve the alteration of binding activity of the 18,000 MW AU-rich sequence binding factor.

Animals↗
PubMed1995

Borrelia burgdorferi genes selectively expressed in the infected host.

An immunological screening strategy was used to select microbial genes expressed only in the host. Differential screening of a Borrelia burgdorferi (the Lyme disease agent) expression library identified a gene (p21) encoding a 20.7-kDa antigen that reacted with antibodies in serum from actively infected mice but not serum from mice immunized with heat-killed B. burgdorferi. Selective expression of p21 in the infected host was confirmed by Northern blot analysis and RNA PCR. Further differential screening of the expression library identified at least five additional B. burgdorferi genes are selectively expressed in vivo. This screening method can be used to identify genes induced in vivo in a wide variety of pathogenic microorganisms for which a gene transfer system is not currently available.

Amino Acid Sequence↗
PubMed1993

Regulation of murine macrophage function by IL-4: IL-4 and IFN-gamma differentially regulate macrophage tumoricidal activation.

To understand the differential role of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) in the process of macrophage tumoricidal activation, we investigated the production of tumor necrosis factor-alpha (TNF-alpha) and nitric oxide in activated murine macrophages and the effects of those lymphokines on prostaglandin E2 (PGE2)-mediated down-regulation. IFN-gamma and IL-4 increased lipopolysaccharide (LPS)-induced TNF-alpha production by different mechanisms because IL-4, unlike IFN-gamma, failed to overcome the LPS-hyporesponsiveness in C3H/HeJ mice. Moreover, only IFN-gamma synergized with LPS to induce nitric oxide production and blocked eicosanoid-mediated down-regulation. These differential effects of IFN-gamma and IL-4 on the select efferent cytolytic activities may be the result of an altered or different signal transduction pathway. Because potentiation of protein kinase C (PKC) activity by IFN-gamma has been previously documented, we next studied the role of IFN-gamma and IL-4 in alteration of enzymatic activity of PKC. Two lymphokines caused translocation of PKC from cytosol to membrane with different levels, providing a biochemical basis for explaining how two lymphokines lead to different phenotypic responses. Although treatment of macrophages with IFN-gamma and IL-4 gave rise to a similar enhancing effect on macrophage TNF-alpha production, these two lymphokines appeared to differentially regulate the overall functional state of macrophages for tumour cell killing capability. Additionally, this differential regulation seems to be accomplished in part by different biochemical events.

Animals↗
PubMed1982

[Spiral cesarean section--hysterography].

Spiral caesarean section is a new technique to open the uterus. The following benefits are claimed for the new method, with reference being made to experience obtained separately at two hospitals:--1. The effect of uterus opening to expose the head of the foetus was higher by something between 19 and 38 per cent, as compared to all other methods. 2. Delivery was possible even from mid-pelvic level, and it was also possible at any stage of labour from breech and transverse positions. 3. Incisions would not further open towards the edge of the uterus, and larger blood loss was thus prevented. 4. The uterus scar was solid, as confirmed by hysterography in this report.

Cesarean Section↗