Biomedical subjects

Yu-Kyoung Oh

Publications and source records attributed to Yu-Kyoung Oh.

At least 37 records · Page 2Linked to original sources

PubMed2004

Skin permeation, biodistribution, and expression of topically applied plasmid DNA.

BACKGROUND: Topical application is emerging as a new route of gene delivery. However, the extent of skin permeation and the in vivo fate of topically applied plasmid DNA are not fully understood. METHODS: In vitro permeation of plasmid DNA across human skin and keratinocyte layers was tested using Franz diffusion cells. In vivo absorption and biodistribution of topically applied plasmid in mice were determined using quantitative polymerase chain reaction (PCR). The expression levels of plasmid DNA in various tissues were measured by semiquantitative reverse transcription PCR. RESULTS: In vitro, topically applied DNA was capable of penetrating human skin and keratinocyte layers. Following topical application of plasmid DNA onto murine skin, the levels of plasmid DNA in the serum peaked at 4 hr. At 24 hr post-dose, topically applied DNA existed at higher levels than intravenously administered DNA in almost all tissues, and induced 11.4- and 22-fold higher mRNA expression in muscle and skin, respectively. Moreover, the topical route showed sustained expression of plasmid DNA in the regional lymph nodes over 5 days, whereas the intravenous route did not. CONCLUSIONS: Taken together, our results show that topically applied plasmid DNA is capable of permeating the skin and being expressed for prolonged periods in various tissues including lymph nodes. This suggests that skin may provide an appealing, noninvasive route of delivery for DNA vaccines and other therapeutic genes.

Administration, Topical↗

PubMed2004

Preparation of ibuprofen-loaded liquid suppository using eutectic mixture system with menthol.

To prepare an ibuprofen-loaded liquid suppository using eutectic mixture with menthol, the effects of menthol and poloxamer 188 (P 188) on the aqueous solubility of ibuprofen were investigated. The physicochemical properties such as gelation temperature, gel strength and bioadhesive force of various formulations composed of ibuprofen, menthol and P 188 were investigated. Then, the pharmacokinetic study of ibuprofen delivered by the liquid suppositories composed of P 188 and menthol were then performed. In the absence of P 188, the solubility of ibuprofen increased until the ratio of menthol to ibuprofen increased from 0:10 to 4:6 followed by an abrupt decrease in solubility above the ratio of 4:6, indicating that four parts of ibuprofen formed eutectic mixture with six parts of menthol. In the presence of P 188, the solutions with the same ratio showed abrupt increase in the solubility of ibuprofen. Furthermore, the solution with ratio of 4:6 showed more than 2.5- and 6-fold increase in the solubility of ibuprofen compared with that without additives and that without menthol, respectively. The poloxamer gel with menthol/ibuprofen ratio of 1:9 and higher than 15% poloxamer 188 showed the maximum solubility of ibuprofen, 1.2mg/ml. Ibuprofen increased the gelation temperature and weakened the gel strength and bioadhesive force of liquid suppositories. However, menthol did the opposite due to forming the eutectic mixture with ibuprofen. The ibuprofen-loaded liquid suppository [P 188/menthol/ibuprofen (15/0.25/2.5%)] with the maximum ibuprofen solubility of 1.2mg/ml was administered easily to the anus and to remain at the administered site without leakage after the dose. Furthermore, it gave significantly higher initial plasma concentrations, Cmax and AUC of ibuprofen than did solid suppository, indicating that the drug from poloxamer gel could be more absorbed than that from solid one in rats. Thus, the liquid suppository system with P 188 and menthol, a more convenient and effective rectal dosage form for ibuprofen will be expected to enhance the rectal bioavailability of ibuprofen.

Animals↗

PubMed2004

Studying changes in the incidence, diagnosis and management of GTD: the South Korean model.

OBJECTIVE: To evaluate the changing epidemiologic picture and clinical characteristics of gestational trophoblastic disease (GTD) in South Korea over the past 5 decades. STUDY DESIGN: Patient data were collected from 37 hospitals nationwide, the Korean Research Institute of Trophoblastic Disease registry and CHA University Comprehensive Gynecologic Cancer Center from the years of 1970s through the year 2002. Demographic data, pretreatment evaluation, treatment modality, chemotherapeutic regimen and their results according to the clinical International Federation of Gynecology and Obstetrics classification and World Health Organization prognostic score were analyzed. Management of high-risk gestational trophoblastic tumor (GTT) was reviewed in depth. RESULTS: The nationwide incidence of hydatidiform mole and GTT dropped from 40.0 per 1,000 deliveries and 5.0 per 1,000 deliveries, respectively, in the 1970s to 2.0 per 1,000 deliveries and 0.5 per 1,000 deliveries, respectively, in the 1990s. The rate of decline was slower in 2000-2002. Significant changes were also noted in age distribution, interval between the preceding pregnancy and disease, gravidity and parity, and distribution of low- and high-risk groups of GTT. CONCLUSION: The dramatic improvement in GTD over the past 5 decades in South Korea can be attributed to the following factors: refinement in terminology and classification, advances in pretreatment evaluation, development of effective chemotherapeutic agents, application of multimodal treatment and novel chemoagents for high-risk GTT.

Adult↗

PubMed2003

Effect of sodium chloride on the release, absorption and safety of diclofenac sodium delivered by poloxamer gel.

Poloxamer solutions prepared with poloxamers and sodium chloride were previously reported to undergo a phase transition to bioadhesive gels at body temperature. For the development of a thermosensitive diclofenac sodium-loaded poloxamer gel, here we investigated the effect of sodium chloride on the release, safety and rectal absorption in rats of diclofenac sodium delivered by the poloxamer gels. P 188 delayed the release rates of diclofenac sodium from poloxamer gels. However, sodium chloride showed no significant effect on the release rates of diclofenac sodium from poloxamer gels. Release mechanism analysis showed the release of diclofenac sodium was proportional to the time. The initial plasma concentrations of diclofenac sodium in the rectal formulation [diclofenac sodium/poloxamer 407 (P 407)/poloxamer 188 (P 188)/sodium chloride (2.5/15/17/0.8%)] were significantly higher compared with those in semi-solid suppository. Furthermore, it gave significantly faster Tmax of diclofenac sodium than did semi-solid suppository, indicating that the diclofenac sodium from poloxamer gel could be absorbed faster than that from semi-solid one in rats. It did not cause any morphological damage to the rectal tissues. These results suggested that poloxamer gel with sodium chloride could be a more effective and safe rectal delivery system of diclofenac sodium.

Absorption↗

PubMed2003

Enhanced immunogenicity of DNA fusion vaccine encoding secreted hepatitis B surface antigen and chemokine RANTES.

To increase the potency of DNA vaccines, we constructed genetic fusion vaccines encoding antigen, secretion signal, and/or chemokine RANTES. The DNA vaccines encoding secreted hepatitis B surface antigen (HBsAg) were constructed by inserting HBsAg gene into an expression vector with an endoplasmic reticulum (ER)-targeting secretory signal sequence. The plasmid encoding secretory HBsAg (pER/HBs) was fused to cDNA of RANTES, generating pER/HBs/R. For comparison, HBsAg genes were cloned into pVAX1 vector with no signal sequence (pHBs), and further linked to the N-terminus of RANTES (pHBs/R). Immunofluorescence study showed the cytoplasmic localization of HBsAg protein expressed from pHBs and pHBs/R, but not from pER/HBs and pER/HBs/R at 48 h after transfection. In mice, RANTES-fused DNA vaccines more effectively elicited the levels of HBsAg-specific IgG antibodies than pHBs. All the DNA vaccines induced higher levels of IgG(2a) rather than IgG(1) antibodies. Of RANTES-fused vaccines, pER/HBs/R encoding the secreted fusion protein revealed much higher humoral and CD8(+) T cell-stimulating responses compared to pHBs/R. These results suggest that the immunogenicity of DNA vaccines could be enhanced by genetic fusion to a secretory signal peptide sequence and RANTES.

Animals↗

PubMed2003

Helicobacter pylori infection activates NF-kappaB signaling pathway to induce iNOS and protect human gastric epithelial cells from apoptosis.

Helicobacter pylori infection induces apoptosis and inducible nitric oxide synthase (iNOS) expression in gastric epithelial cells. In this study, we investigated the effects of NF-kappaB activation and iNOS expression on apoptosis in H. pylori-infected gastric epithelial cells. The suppression of NF-kappaB significantly increased caspase-3 activity and apoptosis in H. pylori-infected MKN-45 and Hs746T gastric epithelial cell lines as well as primary gastric epithelial cells. An NF-kappaB signaling pathway via NF-kappaB-inducing kinase and IkappaB kinase-beta activation was found to be involved in the inhibition of apoptosis in H. pylori-infected gastric epithelial cells. In gastric epithelial cells transfected with retrovirus containing IkappaBalpha superrepressor, iNOS mRNA and protein levels were reduced, indicating that H. pylori infection induced the expression of iNOS by activating NF-kappaB. Moreover, a NO donor, S-nitroso-N-acetylpenicillamine (100 microM), decreased caspase-3 activity and apoptosis in NF-kappaB-suppressed cells infected with H. pylori. These results suggest that NF-kappaB activation may play a role in protecting gastric epithelial cells from H. pylori-induced apoptosis by upregulating endogenous iNOS.

Apoptosis↗

PubMed2003

Enhanced adjuvanticity of interleukin-2 plasmid DNA administered in polyethylenimine complexes.

We report here the enhanced adjuvant effect of murine interleukin-2 plasmid DNA (mIL-2) by complexation with a cationic polymer polyethylenimine (PEI). The mRNA expression of mIL-2 was observed at C2C12 cells after treatment with pVAXmIL-2 in PEI-complexed form, but not in naked plasmid DNA. In vivo, the plasmid DNA levels of mIL-2 at the administered muscle tissues were prolonged up to 14 days after intramuscular administration in PEI complexes. Moreover, the mRNA expression level in the muscle was 54-fold higher in PEI-complexed pVAXmIL-2 than in naked pVAXmIL-2 at 14 days after intramuscular administration. Mice were immunized on Days 0 and 28 by intramuscular administration of hepatitis B surface antigen (HBsAg) alone or with pVAXmIL-2 in naked or PEI complexes. At 8 weeks after the first immunization, mice coadministered with HBsAg plus pVAXmIL-2 in PEI complexes showed the serum IgG titer 72- and 208-fold higher as compared to those treated with HBsAg plus naked pVAXmIL-2 and with HBsAg alone, respectively. Though both HBsAg-specific IgG(1) and IgG(2a) immune responses were increased upon complexation of pVAXmIL-2 with PEI, IgG(2a) was more effectively induced relative to IgG(1). These results suggest that the complexation with PEI could be useful for prolonging in vivo expression of genetic cytokine adjuvants and enhancing their adjuvanticity for subunit vaccines.

Adjuvants, Immunologic↗

PubMed2003

Enhanced mucosal and systemic immune responses to a vaginal vaccine coadministered with RANTES-expressing plasmid DNA using in situ-gelling mucoadhesive delivery system.

To develop more potent and convenient mucosal vaccines, we investigated the effect of an in situ-gelling mucoadhesive vaginal vaccine delivery system and a genetic chemokine adjuvant on the local and systemic immune responses. The in situ-gelling mucoadhesive delivery system of hepatitis B surface antigen (HBsAg), composed of poloxamers and polycarbophil, showed the prolonged retention at the vaginal tissues. Following intravaginal administration to mice, HBsAg-specific IgA was induced in the vagina and saliva, and IgG was produced in the serum. RANTES-expressing plasmid (pRANTES) intravaginally coadministered with HBsAg showed the expression at the vaginal tissues, and more effectively induced the vaginal IgA and serum IgG immune responses than did cholera toxin (CT). The intramuscular coadministration of pRANTES with HBsAg also increased both serum IgG levels and mucosal IgA levels. Regardless of the adjuvants, the in situ-gelling mucoadhesive HBsAg delivery system enhanced the mucosal and systemic immune responses. At 42 days after the first immunization, the highest vaginal IgA levels were induced after intravaginal immunization of HBsAg plus pRANTES using the in situ-gelling mucoadhesive delivery system, showing 182- and 1035-fold higher titer compared to the groups receiving HBsAg alone in PBS by intravaginal and intramuscular routes, respectively. Our results indicate that the use of in situ-gelling mucoadhesive delivery systems with the genetic chemokine adjuvant pRANTES would be advantageous for more effective induction of mucosal and systemic immune responses to intravaginally administered vaccines.

Administration, Intravaginal↗

PubMed2003

Enhanced mucosal and systemic immune responses following intravaginal immunization with human papillomavirus 16 L1 virus-like particle vaccine in thermosensitive mucoadhesive delivery systems.

To develop more potent and convenient mucosal human papillomavirus (HPV) vaccines, we tested the effect of thermosensitive mucoadhesive vaginal vaccine delivery systems on the local and systemic antibody responses to HPV 16 L1 virus-like particles (VLP). HPV 16 L1 VLP expressed from recombinant baculovirus-infected Sf21 insect cells were delivered in phosphate-buffered saline (PBS) or thermosensitive mucoadhesive delivery systems, composed of poloxamers (Pol) and varying amounts of polyethylene oxide (PEO). Pol/PEO-based vaginal vaccine delivery systems existed in liquid form at room temperature, but gelled at 37 degrees C. The mucoadhesiveness of Pol/PEO-based delivery systems increased with PEO, but the formulations with PEO higher than 1.0% were too viscous to be administered into the vagina. Vaccine vehicles affected the vaginal and salivary immune responses to HPV 16 L1 VLP intravaginally administered into mice. At 42 days after the first intravaginal immunization of HPV 16 L1 VLP with cholera toxin, vaginal and salivary IgA titers were the highest in the group given in Pol/PEO 1.0% vehicle followed by Pol/PEO 0.4% and PBS vehicles. Intravaginal coadministration of HPV 16 L1 VLP and cholera toxin in Pol/PEO 1.0% showed 31- and 39-fold higher titers compared to the PBS-based HPV 16 L1 VLP groups administered by intravaginal and intramuscular routes, respectively. Following intravaginal administration, Pol/PEO 1.0%, but not Pol/PEO 0.4%, showed significantly higher HPV 16 L1 VLP-specific serum IgG titers as compared to the PBS vehicle. Our results indicate that the use of in situ-gelling vaginal vaccine delivery systems with increased mucoadhesiveness would be beneficial for more effective induction of mucosal and systemic immune responses to intravaginally administered HPV 16 L1 VLP vaccines.

Administration, Intravaginal↗

PubMed2003

Altered imprinting, promoter usage, and expression of insulin-like growth factor-II gene in gestational trophoblastic diseases.

OBJECTIVE: We aimed to understand the involvement of imprinted genes in the pathogenesis of gestational trophoblastic diseases (GTD) such as hydatidiform mole (H-mole) and gestational trophoblastic tumors (GTT). METHODS: An allelic-typing assay was performed using a PCR-RFLP-based method for identification of heterozygous informative cases. The usage of insulin-like growth factor-II (IGF2) promoters was examined by RT-PCR using promoter-specific primers. The mRNA expression of IGF2 and H19 was quantified using a densitometer. RESULTS: The imprinting of IGF2 and H19 was maintained in all normal placenta tissues (n = 15) but relaxed in GTD (n = 47). Loss of imprinting (LOI) of IGF2 was in the order of GTT (57%) > complete H-mole (43%) > partial H-mole (25%). Similarly, LOI of H19 was in the order of GTT (40%) > complete H-mole (18%) > partial H-mole (0%). Promoter usage pattern of IGF2 changed with gestation stage of normal placentae and GTD. In normal placentae, the usage of promoter P1 was higher than that of P4 in the first trimester but lowered in the full term. H-mole and GTT predominantly used promoter P1 with relative silencing of promoter P4. Although normal early placenta and various GTD tissues showed the similar usage of IGF2 promoter P1, GTT tissues revealed the higher expression levels of IGF2 but a down-regulation of H19 relative to the normal early placentae. CONCLUSIONS: These results suggest that LOI, deregulation of IGF2 promoters, and the altered expression levels of IGF2 and H19 genes might be associated with the progression of GTD.

Alleles↗

PubMed2003

Inhibition of Helicobacter pylori-induced nuclear factor-kappa B activation and interleukin-8 gene expression by ecabet sodium in gastric epithelial cells.

BACKGROUND: Helicobacter pylori stimulates nuclear factor-kappa B (NF-kappa B) activation and chemokine interleukin-8 (IL-8) expression in gastric epithelial cells. Ecabet sodium (ecabet), a locally acting antiulcer drug, is known to have anti-H. pylori activity. However, there is little understanding of how ecabet induces anti-inflammatory activity in gastric epithelial cells infected with H. pylori. The aim of this study was to investigate the effects of ecabet on IL-8 gene expression and NF-kappa B activation in human gastric epithelial cells infected with H. pylori. MATERIALS AND METHODS: After Hs746T, MKN-45, or SNU-5 gastric epithelial cell lines had been infected with cagA+cytotoxin+H. pylori in the presence of ecabet, IL-8 mRNA expression was assessed by quantitative reverse transcription-polymerase chain reaction, and IL-8 secretion was measured by enzyme-linked immunosorbent assay. NF-kappa B and inhibitory kappa B-alpha (I kappa B alpha) signals were assayed by electrophoretic mobility shift assay and Western blot, respectively. The activation of NF-kappa B and IL-8 reporter genes was determined by luciferase assay. RESULTS: Ecabet showed no antimicrobial activiy against Gram-positive or -negative bacteria. However, ecabet inhibited transcription of the IL-8 gene and secretion of IL-8 by gastric epithelial cells infected with H. pylori at a concentration of 5 micro g/ml. Moreover, ecabet inhibited the activation of NF- kappa B and the degradation of I kappa B alpha in gastric epithelial cells in response to H. pylori infection. In addition, the NF-kappa B signal inhibited by ecabet was comprised predominantly of heterodimers of p65/p50. CONCLUSIONS: Ecabet inhibited H. pylori-induced IL-8 gene transcription and secretion by suppressing the NF-kappa B signal. This inhibition might be one pathway by which ecabet exerts its anti-inflammatory effect on H. pylori-induced gastric inflammation.

Abietanes↗

PubMed2002

Comparative binding of antitumor drugs to DNA containing the telomere repeat sequence.

Telomeres are the ends of the linear chromosomes of eukaryotes and consist of tandem GT-rich repeats in telomere sequence i.e. 500-3000 repeats of 5'-TTAGGG-3' in human somatic cells, which are shortened gradually with age. The G-rich overhang of telomere sequence can adopt different intramolecular fold-backs and tetra-stranded DNA structures, in vitro, which inhibit telomerase activity. In this report, DNA binding agents to telomere sequence were studied novel therapeutic possibility to destabilize telomeric DNA sequences. Oligonucleotides containing the guanine repeats in human telomere sequence were synthesized and used for screening potential antitumor drugs. Telomeric DNA sequence was characterized using spectral measurements and CD spectroscopy. CD spectrum indicated that the double-stranded telomeric DNA is in a right-handed conformation. Polyacrylamide gel electrophoresis was performed for binding behaviors of antitumor compounds with telomeric DNA sequence. Drugs interacted with DNA sequence caused changes in the electrophoretic mobility and band intensity of the gels. Depending on the binding mode of the anticancer drugs, telomeric DNA sequence was differently recognized and the efficiency of cleavage of DNA varies in the bleomycin-treated samples under different conditions. DNA cleavage occurred at about 1% by the increments of 1 micromM bleomycin-Fe(III). These results imply that the stability of human telomere sequence is important in conjunction with the cancer treatment and aging process.

Antineoplastic Agents↗

PubMed2002

Prolonged antifungal effects of clotrimazole-containing mucoadhesive thermosensitive gels on vaginitis.

To develop more effective treatment for vaginal candidasis, clotrimazole (CT) was formulated in mucoadhesive thermosensitive gels (MTG). Several MTG formulations composed of poloxamers (P) 407, 188, and polycarbophil (PC) were prepared. P188 and PC increased the mucoadhesiveness but reduced the syringebility of liquid forms of the gels. Based on the balance between the mucoadhesiveness and syringebility, MTG composed of P407/P188/PC (15/15/0.2 or 15/20/0.2) were further studied. Of the two MTG, the formulation with 15% of P188 gelled at higher temperature and revealed lower elastic modulus. In vitro, sustained release of CT from MTG was observed. In vivo antifungal activity of CT, tested against Candida albicans vaginitis in female rats, was significantly prolonged after vaginal delivery using MTG. At 10 days post-dose, the c.f.u. of C. albicans was more than 10(4)-fold decreased in MTG-treated groups. Moreover, the vaginal delivery of CT in MTG enhanced the viability of epithelial cells without affecting the morphology of vaginal mucosa. These results indicate that CT-containing vaginal MTG might be further developed for safe, convenient, and effective treatment of vaginal candidasis with reduced dosing interval.

Adhesives↗

PubMed2002

Alterations in promoter usage and expression levels of insulin-like growth factor-II and H19 genes in cervical carcinoma exhibiting biallelic expression of IGF-II.

Biallelic expression of insulin-like growth factor-II (IGF2) has been reported to be associated with progression of several tumors. Here, we report that the promoter usage and expression levels of IGF2 and H19 were altered in cervical carcinoma showing loss of imprinting. The imprinting status was examined in 32 cervical carcinomas and their matched normal tissues. Loss of imprinting (LOI) of IGF2 was observed in seven of 18 (39%) informative cases. LOI of H19 gene was detected in five of 14 informative cases. The usage of promoter P1 was observed in LOI tumors of IGF2, but not in the tumors showing maintenance of IGF2 imprinting (MOI) and in the normal cervical tissues. Unlike MOI tumors, some LOI tumors revealed the lack of IGF2 transcription from promoter P3. LOI tumors of IGF2 showed an increased expression level of IGF2 but a down-regulation of H19 relative to the normal tissues whereas MOI tumors did not reveal significant alterations. These results suggest that promoter P1 could be involved in the biallelic expression of IGF2 and that the altered expression levels of IGF2 and H19 gene might be associated with the progression of cervical carcinoma showing biallelic expression of IGF2.

Alleles↗

PubMed2002

Mimosine prevents the death of glucose-deprived immunostimulated astrocytes by scavenging peroxynitrite.

Immunostimulated astrocytes become highly vulnerable to glucose deprivation (Choi and Kim: J Neurosci Res 54:870-875, 1998a). The increased vulnerability is caused by the enhanced level of peroxynitrite endogenously produced in glucose-deprived immunostimulated astrocytes. In the present study, we report that the plant amino acid mimosine can attenuate the increased death by scavenging peroxynitrite. Treatment with mimosine blocked the increase of nitrotyrosine immunoreactivity, a marker of peroxynitrite, in glucose-deprived immunostimulated astrocytes. Furthermore, mimosine directly inhibited the nitration of tyrosine residues of bovine serum albumin and the oxidation of dihydrorhodamine-123 to rhodamine-123 by peroxynitrite. Mimosine has been used experimentally as a cell cycle G1/S phase transition blocker (Lalande: Exp Cell Res 186:332-339, 1990; Hoffman et al.: Cytometry 12:26-32, 1991). Flow cytometry analysis, however, showed that the cytoprotective effect of mimosine was not attributed to its inhibition of cell cycle progression. Furthermore, under our experimental conditions, mimosine did not alter the levels of cell cycle regulatory proteins, including p21(WAF1/CIP1), cyclins D1 and E, and proliferating cell nuclear antigen. In addition, cyclin-dependent kinase inhibitors olomoucine and roscovitine did not block the increased death. These results indicate that mimosine inhibits the augmented death of glucose-deprived immunostimulated astrocytes by scavenging peroxynitrite rather than suppressing the cell cycle progression.

Adjuvants, Immunologic↗

PubMed2002

In situ gelling and mucoadhesive polymer vehicles for controlled intranasal delivery of plasmid DNA.

Nasal administration of plasmid DNA is emerging as a new route of delivery for therapeutic genes and DNA vaccines. To improve the intranasal absorption of plasmid DNA, we designed delivery systems composed of in situ gelling and mucoadhesive polymers. Poloxamers (Pol) were used to provide in situ gelling property. Polycarbophil (PC) or polyethylene oxide (PEO) was used as mucoadhesive polymers. The gelation temperatures of the formulations slightly decreased by the mucoadhesive polymers, but not by plasmid DNA. The in vitro release of plasmid DNA from the gels followed Fickian diffusion. The absorption of plasmid DNA varied with the contents and type of mucoadhesive polymers. Of vehicles, Pol/PC 0.2% showed the highest absorption with an area under the curve value 11-fold higher than saline, the conventional vehicle. The nasal retention of plasmid DNA was highly prolonged by mucoadhesive polymers. At 3 h postdose, the nasal tissue levels of plasmid DNA given in Pol/PC and Pol/PEO 0.8% were 10- and 40-fold higher relative to saline. The histopathology of nasal tissues was not altered after repeated dosing over 2 weeks. The mRNA expression of plasmid DNA delivered by Pol or Pol/PEO 0.4% was observed in the nasal tissues. These results indicate that the nasal absorption of plasmid DNA can be effectively and safely enhanced by using in situ gelling and mucoadhesive polymer-based vehicles.

Adhesives↗

PubMed2002

Daunomycin binding to deoxypolynucleotides with alternating sequences: complete thermodynamic profiles of heterogeneous binding sites.

Complete thermodynamic binding profiles for the interaction of the anticancer drug, daunomycin with natural DNA and synthetic deoxypolynucleotides were described. Fluorescence titration method was used to estimate the equilibrium binding constants. Binding isotherms were found to be surprisingly complex in some cases, presumably because there were heterogeneous sites even in simple deoxypolynucleotides of repeating sequence. Some polynucleotides consisting of alternating sequence contain at least two different binding sites for daunomycin. The binding affinity of the primary binding sites of alternating and non-alternating sequences was found to differ by two orders of magnitude. An isothermal microtitration calorimeter was used to directly measure the binding enthalpy at 25 degrees C with a high sensitivity. The binding enthalpy of poly[d(A-T)] was found to be -5.5 Kcal/mol, which was much lower than any other polynucleotides, while the binding constant of the high affinity sites, was similar. In this report, the complete thermodynamic profiles of daunomycin binding to deoxypolynucleotides were reliably shown for the first time.

Antibiotics, Antineoplastic↗

PubMed2002

Differential expression and polarized secretion of CXC and CC chemokines by human intestinal epithelial cancer cell lines in response to Clostridium difficile toxin A.

Intestinal epithelial cells are the initial sites of host response to Clostridium difficile infection and can play a role in signaling the influx of inflammatory cells. To further explore this role, the regulated expression and polarized secretion of CXC and CC chemokines by human intestinal epithelial cells were investigated. An expression of the CXC chemokines, including IL-8 and growth-related oncogene (GRO)-alpha, and the CC chemokine monocyte chemoattractant protein (MCP)-1 from HT-29 cells increased in the 1-6 hr following C. difficile toxin A stimulation, assessed by quantitative RT-PCR. In contrast, the expression of neutrophil activating protein-78 (ENA-78) was delayed for 18 hr. The up-regulated mRNA expression of chemokines was paralleled by the increase of protein levels. However, the expression of macrophage inflammatory protein (MIP)-1alpha, RANTES (regulated on activation normal T cells expressed and secreted), and interferon-gamma-inducible protein-10 (IP-10) was not changed in HT-29 or Caco-2 cells stimulated with toxin A. Upon stimulation of the polarized Caco-2 epithelial cells in a transwell chamber with toxin A, CXC and CC chemokines were released predominantly into the basolateral compartment. Moreover, the addition of IFN-gamma and TNF-alpha to toxin A stimulated Caco-2 cells increased the basolateral release of CC chemokine MCP-1. In contrast, IFN-gamma and TNF-alpha had no effect on the expression of the CXC chemokines IL-8 and GRO-alpha. These results suggest that a CXC and CC chemokine expression from epithelial cells infected with C. difficile may be an important factor in the mucosal inflammatory response.

Bacterial Toxins↗