The effects of transferring tumor suppressor gene p16INK4A to p16INK4A-deleted cancer cells

OBJECTIVES

p16 is known to be an important tumor suppressor gene and is also called MTS1 (multiple tumor suppressive gene 1). Especially in the case of non-small cell lung cancer, it was not expressed in more than 70% of cell lines examined. To determine changes in cell-cycle related proteins and the tumorigenic effect, we, therefore, transfected p16INK4A gene into lung cancer cell lines.

METHODS

We transfected p16INK4A gene into lung cancer cell lines which do not express p16 protein. We evaluated the effect by clonogenic assay and observed the changes of cell-cycle related proteins.

RESULTS

The newly-expressed p16 formed a complex with cdk4, and phosphorylated pRB was decreased, although cyclin D1 and pRB:cyclin D1 complex were unchanged. Clonogenic assay after selection with G418 showed that, in the cell lines transfected with p16, tumorigenicity was significantly less than in the control.

CONCLUSION

These results suggest that the p16INK4A gene can be a candidate for gene therapy in cases of NSCLC in which p16INK4A gene is inactivated.

The effects of oxygen radicals on the activity of nitric oxide synthase and guanylate cyclase

Reactive oxygen species such as superoxides, hydrogen peroxide (H2O2) and hydroxyl radicals have been suggested to be involved in the catalytic action of nitric oxide synthase (NOS) to produce NO from L-arginine. An examination was conducted on the effects of oxygen radical scavengers and oxygen radical-generating systems on the activity of neuronal NOS and guanylate cyclase (GC) in rat brains and NOS from the activated murine macrophage cell line J774. Catalase and superoxide dismutase (SOD) showed no significant effects on NOS or GC activity. Nitroblue tetrazolium (NBT, known as a superoxide radical scavenger) and peroxidase (POD) inhibited NOS, but their inhibitory actions were removed by increasing the concentration of arginine or NADPH respectively, in the reaction mixture. NOS and NO-dependent GC were inactivated by ascorbate/FeSO4 (a metal-catalyzed oxidation system), 2'2'-azobis-amidinopropane (a peroxy radical producer), and xanthine/xanthine oxidase (a superoxide generating system). The effects of oxygen radicals or antioxidants on the two isoforms of NOS were almost similar. However, H2O2 activated GC in a dose-dependent manner from 100 microM to 1 mM without significant effects on NOS. H2O2-induced GC activation was blocked by catalase. These results suggested that oxygen radicals inhibited NOS and GC, but H2O2 could activate GC directly.

Cloning and expression of cDNA for a human Sia alpha 2,3Gal beta 1, 4GlcNA:alpha 2,8-sialyltransferase (hST8Sia III)

The cDNA encoding human Sia-alpha2,3-Gal-beta1,4-GlcNAc-R:alpha2, 8-sialyltransferase, hST8Sia III, was isolated by screening of a human brain cDNA library with polymerase chain reaction-amplified DNA probe generated from the sequence of mouse ST8Sia III (mST8Sia III) and by 5' rapid amplification of cDNA ends of mRNA isolated from human brain tissues. Comparative analysis of the predicted protein-coding region between our cloned hST8Sia III and mST8Sia III showed 92 and 96% identities in the nucleotide and the amino acid sequence, respectively. The soluble hST8Sia III protein expressed in COS-7 showed an extremely high catalytic activity of transferring sialic acid through alpha2,8-linkage to intact fetuin glycoprotein, whereas the transferring activity was completely undetectable toward either alpha2,6-sialylated glycoprotein or desialylated glycoprotein acceptors. Northern analysis of hST8Sia III showed that the transcript corresponding to 11 kb was expressed in both human fetal and adult brain, while the expression of the 5.5-kb transcript was restricted to fetal liver, indicating that the expression of hST8Sia III is developmentally and tissue-specifically regulated.

Blood eosinophils and serum IgE as predictors for prognosis of interferon-gamma therapy in atopic dermatitis

BACKGROUND

Interferon-gamma (IFN-gamma) therapy has been reported to be effective in atopic dermatitis. However, IFN-gamma therapy in atopic dermatitis has not yet been well established. In this study, immunologic variables were evaluated as predictors for the prognosis of IFN-gamma therapy in atopic dermatitis.

METHODS

Sixty-eight atopic dermatitis patients were each treated 18 times with 2 x 10(6) units/m2 IFN-gamma. Blood IgE level, eosinophil percentage, eosinophil count, and levels of IFN-gamma, interleukin-4 (IL-4), IL-5, and IL-10 were investigated. According to clinical responses, patients were classified into three groups: patients with improved clinical severity scores of over 20% were included in group A; those with improved scores of 20% or less in group B; and those with no improvement in group C.

RESULTS

Serum IgE levels and blood eosinophil percentages were the lowest in group A. Most atopic dermatitis patients with an eosinophil percentage over 9% and IgE level over 1500 IU/ml did not respond to IFN-gamma therapy. Initial IL-10 levels were the highest in group A. IL-4 levels in group A, and IL-5 and IL-10 levels in all groups were significantly decreased by IFN-gamma therapy.

CONCLUSIONS

IFN-gamma therapy may be recommended for atopic dermatitis patients with blood eosinophil percentages less than 9% and serum IgE levels less than 1500 IU/ml.

Fractional allelic loss in gastric carcinoma correlates with growth patterns

To gain an insight into the genetic events underlying morphological phenotypes, we analysed 58 gastric carcinoma tissues for the genome-wide allelotype study using microsatellite markers. Based on a binomial distribution, loss of heterozygosity (LOH) that was significantly more frequent than expected (P<0.05) thus interpreted as nonrandom LOH selected during tumorigenesis. The overall extent of chromosomes undergoing LOH i.e. fractional allelic loss (FAL, the ratio of LOH-positive markers to the total number of informative markers) was measured in each tumor patient. Nonrandom LOH was found on 17p (48.0%), 18q (38.4%), 13q (38.1%) and 9p (36.4%). Overall, there were no significant phenotypes correlated with allelic loss on specific chromosome regions. Based on a bimodal distribution of FAL values with two peaks bordered by a mean of 0.233, tumors were classified into LOH-related (>0.233) and LOH-unrelated (<0.233) types. Among 24 patients with LOH-related tumors, increase in the infiltrative type of growth pattern was found to correspond with a significant trend of increasing FAL values. This study shows that the growth pattern of gastric carcinoma is correlated with FAL, suggesting that a malignant phenotype is influenced by LOH event.

Regulation of exit from quiescence by p27 and cyclin D1-CDK4

The synthesis of cyclin D1 and its assembly with cyclin-dependent kinase 4 (CDK4) to form an active complex is a rate-limiting step in progression through the G1 phase of the cell cycle. Using an activated allele of mitogen-activated protein kinase kinase 1 (MEK1), we show that this kinase plays a significant role in positively regulating the expression of cyclin D1. This was found both in quiescent serum-starved cells and in cells expressing dominant-negative Ras. Despite the observation that cyclin D1 is a target of MEK1, in cycling cells, activated MEK1, but not cyclin D1, is capable of overcoming a G1 arrest induced by Ras inactivation. Either wild-type or catalytically inactive CDK4 cooperates with cyclin D1 in reversing the G1 arrest induced by inhibition of Ras activity. In quiescent NIH 3T3 cells expressing either ectopic cyclin D1 or activated MEK1, cyclin D1 is able to efficiently associate with CDK4; however, the complex is inactive. A significant percentage of the cyclin D1-CDK4 complexes are associated with p27 in serum-starved activated MEK1 or cyclin D1 cell lines. Reduction of p27 levels by expression of antisense p27 allows for S-phase entry from quiescence in NIH 3T3 cells expressing ectopic cyclin D1, but not in parental cells.

Continuous wavelet analysis as an aid in the representation and interpretation of electrogastrographic signals

This paper presents an application of the continuous wavelet transform (CWT) in the analysis of electrogastrographic (EGG) signals. Due to the nonstationary nature of EGG signals, the CWT method, which uses multiresolution scaled windows, gives a better time-frequency resolution than the short-time Fourier transform, which uses a fixed window. Spike activity due to gastric contraction was investigated through experiments on dogs. During spike activity we observed an increase in magnitude of the slow wave and the appearance of a low frequency component with half the frequency of the slow wave. Studies of the EGG signals from the small intestine are also presented to investigate the hypothesis that its slow wave might be confounded with spike activity in the stomach due to the similarity of their frequency ranges.

Inhibition of midgut ion transport by allatotropin (Mas-AT) and Manduca FLRFamides in the tobacco hornworm Manduca sexta

Short-circuit current (Isc) across the posterior midgut of day 2 fifth-instar tobacco hornworms (Manduca sexta) is inhibited by Manduca allatotropin (Mas-AT) and two Manduca FLRFamides (F7G and F7D). Another FLRFamide, F10, and the related molluscan tetrapeptide FMRFamide elicited only a modest inhibition of Isc. Mas-AT, F7G and F7D inhibited the Isc in a dose-dependent manner. Maximal inhibition of Isc by Mas-AT was achieved at a concentration of 50 nmol l-1. At 100 nmol l-1, Mas-AT produced a significantly greater inhibition of Isc than did F7G and F7D. The inhibition caused by Mas-AT was reversed by removing the peptide. Furthermore, the action of Mas-AT could be blocked by preabsorption with its antiserum. When F7G or F7D was added after the Isc had been inhibited by Mas-AT, a further reduction in the Isc was observed. No additive effects were seen when F7G and F7D were added together. In comparison with the anterior and middle regions, the posterior section of the midgut was the most sensitive to these three peptides. The Isc of midguts dissected from feeding fourth instars was inhibited by Mas-AT, F7D and F7G, whereas the Isc of midguts dissected from pharate fifth instars or wandering fifth instars was virtually unaffected by these peptides. Active ion transport across the posterior midgut of the silk moths Hyalophora cecropia and Bombyx mori was unaffected by these peptides.

Circulating soluble CD5 in atopic dermatitis

The CD5/Leu-1 is involved in the activation of the T-cell helper function through T/B-cell collaboration by CD5/CD72 interaction. T-cell function is known to be dysregulated in atopic dermatitis. However, to date, the role of CD5 has not been investigated in atopic dermatitis, nor has the presence of circulating soluble CD5 been reported in atopic dermatitis. Five patients with atopic dermatitis who showed typical symptoms, 5 acute febrile patients and 5 normal subjects were tested. Peripheral blood mononuclear cells and plasma were separated. The T- and B-cells were separated using immunomagnetic beads. Reverse transcription polymerase chain reaction was performed using CD5 specific primers. Immunoblotting with the mouse antiCD5 monoclonal antibody was done. Circulating soluble CD5 was present only in 4 out of 5 atopic patients. However, it was not detected in acute febrile patients nor in normal subjects. CD5 mRNA expression was detected in all atopic patients and acute febrile patients. CD5 mRNA expression in T- and B-cells was tested in patients with atopic dermatitis and was detected only in the T-cells. In this study, circulating soluble CD5 was detected in atopic patients and soluble CD5 was suspected to participate in the pathogenesis of atopic dermatitis. CD5 mRNA expression was detected only in T-cells, which suggests that circulating soluble CD5 might be produced from T-cells.

IgE binding patterns to German cockroach whole body extract in Korean atopic asthmatic children

It is widely known that the cockroach is an inhalant allergen in atopic asthma and allergic rhinitis. Even though Bla g I and Bla g II are considered as the major allergens, several relatively high-molecular weight (MW) cockroach allergens have also been recently identified by IgE-immunoblot in western countries. However, the environmental control and diagnostic tests mainly focussed on Bla g I and Bla g II. Furthermore there is no data about major IgE-binding cockroach antigens in Korea. We performed this study to identify the major German cockroach allergens in Korean atopic children. By the results of allergy skin tests, 14 children with atopic asthma (9 were cockroach-sensitive and 5 were cockroach-nonsensitive atopics) were enrolled in this study. We conducted IgE immunoblot and autoradiographic analysis using Yonsei-extract of German cockroach antigen produced in our laboratory, individual sera from 9 cockroach-sensitive children, and the pooled sera of 5 house-dust-mites-only-sensitive children. We performed an allergic skin test to cockroach mix, and a radioallergosorbent test (RAST) using German cockroach crude extract on all subjects. German cockroach-specific IgE was detected in 6 out of 9 subjects by RAST. We identified at least 15 IgE-binding protein bands, and among them, the components of MWs of 76, 64, 50, 38, and < 14 kilodaltons (kDa) were the major German cockroach allergens in study subjects. Therefore, Bla g I (25-30 kDa) and Bla g II (36 kDa) could not be the absolute indicators of German cockroach sensitization and parameters of environmental control.

Role of serine-19 phosphorylation in regulating tyrosine hydroxylase studied with site- and phosphospecific antibodies and site-directed mutagenesis

The effects of depolarization by elevated potassium concentrations were studied in PC12 cells and in stably transfected AtT-20 cells expressing wild-type or [Leu19]-recombinant tyrosine hydroxylase (rTH). Changes in the phosphorylation states of Ser19 and Ser40 in tyrosine hydroxylase (TH) were determined immunochemically using antibodies specific for the phosphorylated state of each site and compared with changes in TH activity in PC12 cell lysates and with changes in L-DOPA biosynthesis rates in intact AtT-20 cells. Treatment of either PC12 cells or AtT-20 cells expressing wild-type rTH with elevated potassium produced a transient increase in the phosphorylation state of Ser19 (up to 0.7 mol of phosphate/mol of subunit) in concert with a more gradual and sustained increase in Ser40 phosphorylation. Elevated potassium treatment also increased TH activity in PC12 cell lysates, but these increases paralleled the temporal course of Ser40, as opposed to Ser19, phosphorylation. Similarly, increases in DOPA accumulation produced by elevated potassium in AtT-20 cells expressing wild-type rTH paralleled the increases in the phosphorylation state of Ser40 but not Ser19. Moreover, elevated potassium produced comparable increases in DOPA accumulation in AtT-20 cells expressing rTH in which Ser19 phosphorylation had been eliminated (by substitution of Leu for Ser19). Thus, depolarization-induced increases in the stoichiometry of Ser19 phosphorylation do not appear to influence directly the activity of TH in situ.

Hepatocellular carcinoma: power Doppler US with a contrast agent--preliminary results

PURPOSE

To investigate the value of contrast material-enhanced power Doppler ultrasonography (US) in the demonstration and characterization of tumor vascularity in hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Twenty patients with HCC were prospectively evaluated with power Doppler US before and after injection of the contrast agent SH U 508 A. The grade and pattern of tumor vascularity at power Doppler US were analyzed, along with the degree of tumor staining at angiography.

RESULTS

Intra- and peritumoral flow signals were detected in 19 HCCs (95%) at unenhanced power Doppler US. After injection of contrast agent, flow signals increased in 19 lesions (95%). At contrast-enhanced power Doppler US, two tumors demonstrated grade 1 vascularity; four, grade 2; three, grade 3; and 11, grade 4. At angiography, two tumors demonstrated grade 1 staining; four, grade 2; eight, grade 3; and six, grade 4. The correlation between vascularity grades at contrast-enhanced power Doppler US and at angiography was statistically significant (P < .0001). Seventeen HCCs (85%) showed the intratumoral or basket pattern of vascularity at unenhanced power Doppler US; after injection of contrast material, 15 HCCs (75%) showed the mixed pattern.

CONCLUSION

Contrast-enhanced power Doppler US is superior to unenhanced power Doppler US in the demonstration and characterization of tumor vascularity in HCC.

Effect of surface properties on the antithrombogenicity of silk fibroin/S-carboxymethyl kerateine blend films

Polymeric blends of silk fibroin (SF) and S-carboxymethyl kerateine (SCMK) were prepared by the solvent casting method to study the effect of surface properties on the antithrombogenicity. The films of SF/SCMK showed better antithrombogenic properties than SF or SCMK alone. Among them, the film containing 50 wt% SCMK showed the best antithrombogenicity. When the SF/SCMK films were treated with methanol, the antithrombogenicity of the films was scarcely affected except the SF-rich ones. The enhanced antithrombogenic properties were explained in terms of polarity of the surface. The blend films showed an enhancement of polar contribution to surface free energy (gamma(P)S and polar stabilization energy (I(SW)). SF-rich films showed high gamma(P)S and I(SW) values when treated with methanol. This change of surface properties was considered to be due to the fact that the conformational transition from random coil structure to beta-structure of proteins may have affected the surface properties, especially the polar properties.

Ginsenoside Rg1 down-regulates glucocorticoid receptor and displays synergistic effects with cAMP

Ginsenoside-Rg1 (G-Rg1) from the roots of Panax ginseng C. A. Meyer has been shown to bind to the glucocorticoid receptor (GR). To further explore the effect of G-Rg1 binding to GR, a luciferase reporter gene containing two copies of a glucocorticoid response element was constructed and transiently transfected into FTO2B rat hepatoma cells. A dose-dependent induction of the reporter gene was observed in response to G-Rg1, and the inductive effect was blocked by treatment with the antiglucocorticoid RU486. In addition, both G-Rg1- and dexamethasone (Dex)-induced transcription was synergistically enhanced by the treatment of dibutyryl cAMP (Bt2-cAMP). G-Rg1 treatment also led to the down-regulation of intracellular GR content, which was similar to the effect of Dex. By showing that G-Rg1 down-regulates GR and induces GR-mediated transcription synergistically with cAMP, we conclude that G-Rg1 is a functional GR ligand in FTO2B cells.

Transcription factor YY1 represses cell-free replication from human papillomavirus origins

We have established cell-free replication for the human papillomavirus type 18 (HPV-18) origin of replication (ori)-containing DNA by using purified HPV-18 E1 and E2 gene products expressed as fusion proteins in Escherichia coli. The transcription factor YY1 has been shown to regulate RNA transcription by binding to a sequence overlapping the putative E1 protein binding site in the HPV-18 ori. We show that exogenously added YY1 fusion protein inhibited HPV-18 ori replication. Cotransfection of YY1 expression vectors also inhibited transient replication in 293 cells. However, inhibition did not appear to be mediated by binding to its cognate site in the ori as YY1 also inhibited the replication of the HPV-11 ori, which does not have a known or suspected YY1 binding site. Moreover, inhibition was not alleviated by the inclusion of YY1 binding oligonucleotides in the replication reaction mixtures. Rather, we demonstrated a direct interaction between purified fusion E2 protein and fusion YY1 protein by the pull-down assay and a partial restoration of replication activity by an elevated E2 protein concentration. These results suggest that YY1 can inhibit HPV ori replication by interfering with E2 protein functions.

pH-sensitive release of indomethacin using lactan-acetate microspheres

Hydrophobic lactan acetate was prepared from hydrophilic lactan gum by chemical modification and it was used for a pH-sensitive drug delivery system. Lactan acetate microspheres were prepared by the solvent evaporation method. The size of the microspheres prepared from lactan acetate was below 5 microns. The drug loading efficiencies of microspheres were approximately 70 and 80% at the initial amount of drug 40 and 80 mg, respectively. The microsphere showed pH-sensitive swelling behavior. The swelling capacity of microspheres at pH 7.4 was much greater than that at pH 1.2. The pH of the medium significantly influenced the in vitro release rate; the rate at pH 7.2 was approximately 10 times faster than that at pH 1.2. A pH-sensitive drug release pattern was due to the escape of drug from the microsphere that disintegrated after swelling.

Isolated bilateral abducens nerve palsy due to carotid cavernous dural arteriovenous fistula

Carotid cavernous dural arteriovenous fistula (DAVF) usually presents with conjunctival injection, proptosis, loss of visual acuity and ophthalmoplegia. There have been some carotid cavernous DAVF case reports presenting with isolated oculomotor, abducens and trochlear nerve palsy. We experienced a patient presenting with bilateral abducens nerve palsy and no other ocular signs who was diagnosed as carotid cavernous DAVF after conventional angiography. According to this case, carotid cavernous DAVF should be considered in the differential diagnosis of isolated bilateral abducens nerve palsy, in which case conventional angiography may be helpful in diagnosis.

Pituitary adenylate cyclase-activating peptide stimulates rat pancreatic secretion via secretin and cholecystokinin releases

BACKGROUND & AIMS

Pituitary adenylate cyclase-activating polypeptide (PACAP) stimulates protein and/or amylase secretion from isolated rat pancreatic acini. The effect of PACAP on pancreatic secretion in vivo and its mechanism of action were studied.

METHODS

Rats were prepared with pancreatic duct cannulation, pyloric ligation, and bile diversion into duodenum, and 2.5, 5, and 10 nmol/kg PACAP-27 was administered intravenously while pancreatic juice was collected for 30 minutes. In other groups of rats, the effect of 10 nmol/kg PACAP-27 was studied under the influence of either atropine; loxiglumide, an antisecretin serum; a combination of both loxiglumide and the antiserum; or a PACAP antagonist (PACAP 6-38). Plasma secretin and cholecystokinin concentrations were measured by radioimmunoassay.

RESULTS

(1) PACAP dose-dependently increased pancreatic secretion of fluid, bicarbonate, and protein; (2) the increase in pancreatic secretion paralleled that of plasma secretin and cholecystokinin; (3) a combination of loxiglumide and antisecretin serum eliminated the PACAP-stimulated pancreatic secretion, whereas loxiglumide or antisecretin serum alone partially but significantly blocked pancreatic secretion; (4) atropine failed to influence PACAP-induced pancreatic secretion; and (5) PACAP antagonist profoundly suppressed the PACAP action.

CONCLUSIONS

PACAP-27 dose-dependently stimulates pancreatic secretion of fluid, bicarbonate, and protein in rats. This effect is mediated by release of both secretin and cholecystokinin and is independent of cholinergic tone.

Intestinal tuberculosis: clinicopathologic analysis and diagnosis by endoscopic biopsy

OBJECTIVES

Tuberculosis is still an important cause of granulomatous colitis in developing countries. If we can diagnose tuberculosis using endoscopic biopsy material, clinicians can avoid invasive diagnostic procedures and needless operations. For this purpose, we evaluated clinical manifestations, pathological findings, and diagnostic methods in endoscopically biopsied intestinal tuberculosis patients.

METHODS

From January 1991 to December 1996, 42 patients with intestinal tuberculosis were endoscopically examined and tissue culture, immunohistochemical stain, Ziehl-Neelsen stain, and polymerase chain reaction in fresh and fixed tissue were applied. The pathological findings were analyzed and compared with the results of the other diagnostic methods.

RESULTS

In tuberculosis patients, transverse ulcers with surrounding hypertrophic mucosa and multiple erosions were usual colonoscopic findings. The granulomas were found in 74% of the cases. The positivity ranged from 30-45%. There were no significant differences in the positivity among those diagnostic methods (p > 0.05). The positivity of Ziehl-Neelsen stain in fixed tissue was higher in the group having granulomas and it was reversed in PCR (p < 0.05). The increasing number of biopsy particles raised the positivity of Ziehl-Neelsen stain and PCR in fixed tissue (p < 0.05).

CONCLUSIONS

Transverse ulcers were the most characteristic colonoscopic finding and granulomas were frequent pathological findings in intestinal tuberculosis. Higher positivity and reliable results were found in tissue culture, Ziehl-Neelsen stain, and polymerase chain reaction. To increase the diagnostic rate, the endoscopist should take enough tissue and deep biopsy material from ulcer bases and diseased mucosae.

Glycogen storage disease type IV: a case report

Glycogen storage disease type IV (GSD-IV) is a rare autosomal recessive disease caused by deficient glycogen branching enzyme (GBE). We report a 15-month-old female patient with GSD-IV who exhibited an abdominal distension and failure to thrive for 9 months. The patient showed hepatosplenomegaly with massive ascites. The laboratory findings showed abnormal liver functions including prolongation of prothrombin time and partial thromboplastin time. The light microscopic and electron microscopic findings of the liver biopsy specimen were consistent with GSD-IV. Measurement of glycogen quantity in the red blood cells showed increased storage of glycogen in the patient and interestingly, in her mother. The GBE activity of the patient's red blood cells was undetectable. The patient's ascites, general condition, and laboratory findings have been improved with supportive treatment with diuretics and a low dose of prednisolone.

Preparation of chitosan self-aggregates as a gene delivery system

Hydrophobically modified chitosan containing 5.1 deoxycholic acid groups per 100 anhydroglucose units was synthesized by an EDC-mediated coupling reaction. Formation and characteristics of self-aggregates of hydrophobically modified chitosan were studied by fluorescence spectroscopy and dynamic light scattering method. The critical aggregation concentration (cac) of the self-aggregate was determined by measuring the fluorescence intensity of pyrene as a fluorescent probe. The cac value in PBS solution (pH 7.2) was 1.7x10(-2) mg/ml. Mean diameter of self-aggregates in PBS solution (pH 7.2) was 162 +/- 18 nm with an unimodal size distribution. Charge complex formation between self-aggregates and plasmid DNA was confirmed by electrophoresis on an agarose gel. Migration of DNA on an agarose gel was completely retarded above a charge ratio ( +/-) of 4/1 at pH 7.2. The free DNA dissociated from the complexes was observed by electrophoresis above pH 8.0 at a fixed charge ratio of 4/1. An efficient of COS-1 cells was achieved by self-aggregates/DNA complexes.

Compressive creep characteristics of extruded ultrahigh-molecular-weight polyethylene

The static compressive creep behavior of ultrahigh-molecular-weight polyethylene (UHMWPE) was studied under physiologic conditions. Specimens were machined from the center and periphery of extruded GUR 4150HP rod stock and were subjected to constant pressures of 2, 4, or 8 MPa for intervals as long as 10(4) min. The creep strain (creep divided by initial thickness) was compared to the pressure and duration of loading by using analysis of variance and linear regression analysis. The amount of creep strain increased rapidly in the early period of testing and was followed by a reduced rate of creep, which reached a steady state after approximately 4000 min. The amount and rate of creep strain increased linearly with pressure. Surprisingly, the rate of creep strain varied with the radial position in the rod stock: specimens obtained from the periphery had 8-19% larger creep strain rates than did specimens obtained from the center (p = 0.1 to p < 0.001). These results advance the characterization of creep's contribution to the in vivo penetration of the metallic component into the UHMWPE component, thereby facilitating the measurement of true in vivo wear. These data also help explain the azimuthally nonuniform deformation observed in retrieved acetabular cups.

Jacalin interacts with Asn-linked glycopeptides containing multi-antennary oligosaccharide structure with terminal alpha-linked galactose

The carbohydrate binding properties of jacalin lectin were examined using RAF9 cell-derived D-[6-3H]glucosamine-radiolabeled total glycopeptides containing N-linked and O-linked oligosaccharides. The binding of N-linked glycopeptides to jacalin was abolished by treatment of alpha-galactosidase whereas O-linked glycopeptides were still bound lectin after this treatment. The removal of O-linked oligosaccharides by mild alkaline/borohydride treatment completely eliminated the lectin binding of alpha-galactosidase treated glycopeptides. These results demonstrate that jacalin interacts with cellular glycopeptides containing N-linked oligosaccharides with terminal alpha-galactose residues as well as glycopeptides containing O-linked oligosaccharides.

Suppression of xenobiotic-metabolizing enzyme expression in rats by acriflavine, a protein kinase C inhibitor. Effects on epoxide hydrolase, glutathione S-transferases, and cytochromes p450

The effects of acriflavine (ACF), a protein kinase C inhibitor, on the expression of hepatic microsomal epoxide hydrolase (mEH), glutathione S-transferases (GSTs), and cytochrome P450 (P450) were assessed in rat hepatic tissue. Northern blot analysis revealed that treatment of rats with thiazole, allyl disulfide (ADS), oltipraz, or clotrimazole at a single dose of 100 mg/kg resulted in 7-18-fold increases in mEH mRNA levels at 24 hr, whereas concomitant ACF treatment (20 mg/kg, im) caused 50-95% inhibition of the chemical-induced increases in hepatic mEH mRNA levels. rGSTA2, rGSTA3, and rGSTM1 mRNA levels were also significantly suppressed at 24 hr in response to a single dose of ACF (20 mg/kg, im). Animals treated with both ACF and ADS showed complete blockage of mEH and GST gene expression as early as 12 hr after treatment. ADS-inducible increases in mEH and rGSTA2 mRNA levels were suppressed at 24 hr after treatment with ACF, in a dose-related manner, with 50% inhibitory dose (ID50) values of 2.0-2.3 mg/kg, whereas glyceraldehyde-3-phosphate dehydrogenase mRNA levels were not altered. Immunoblot analysis revealed that ACF (15 mg/kg/day, im, for 3 days) inhibited induction of mEH or rGSTA2 protein by ADS (100 mg/kg/day, po, for 3 days). The levels of hepatic P450 2B1/2, P450 2C11, and P450 3A1/2 were decreased in rats treated with ACF (15 mg/kg/day, im, for 3 days), whereas P450 1A2 and P450 2E1 expression was not affected. Treatment of rats with ACF in combination with gadolinium chloride, which inhibits mEH and GST expression through calcium channel blocking, shifted the dose-inhibitory response curves for ACF to the left, with 7-15-fold decreases in the ID50 values, indicating that the active site for ACF for suppression of mEH and GST mRNA levels differs from that for gadolinium chloride. Proflavine and safranine O, which are structurally related to ACF, also caused suppression of ADS-induced increases in mRNA levels, in a dose-dependent manner, with ID50 values of 4-9 mg/kg. These results demonstrate that ACF and its related compounds effectively suppress the expression of a battery of hepatic xenobiotic-metabolizing enzymes, including mEH, GSTs, and certain P450 forms.