Transgene delivery with a cationic lipid in the presence of amyloid beta (betaAP) peptide

The ability of a cationic lipid to deliver plasmid DNA (pDNA) in presence of the neurotoxic fragment of amyloid beta-peptide was evaluated. Pre-treatment of cells with betaAP (25-35) peptide resulted in a modest increase in transgene expression. When betaAP (25-35) peptide was mixed with the pDNA/liposome complex and used, the complexes lost their ability to transfect. However, the reverse sequenced betaAP (35-25) peptide demonstrated no significant differences in transgene expression in pre-treated cells, and in cells where betaAP (35-25) peptide was mixed with pDNA/liposome complexes and transfected. The amount of pDNA delivered to the cells was decreased in presence of betaAP (25-35) as measured with flow cytometry using fluorescently labeled liposomes. The decreased endocytosis may be due to their rod-like structure formation as demonstrated by electron microscopy and atomic force microscopy (AFM). These results demonstrate that betaAP (25-35) peptide may interfere with gene delivery with cationic systems.

In situ gel formulations for gene delivery: release and myotoxicity studies

The in vitro release of plasmid DNA and salmon sperm DNA from in situ gel formulations was investigated. Two in situ gel systems were studied: (a) an interpolymeric complex (IPC) of water-soluble polymers polymethacrylic acid (PMA) and polyethylene glycol (PEG) and (b) a hydroxypropylmethylcellulose-carbopol system (H:C). Two-way analysis of variance with replication demonstrated that both gel composition and medium pH influenced significantly the release of plasmid DNA from in situ gel formulations. When the release of both types of DNA was compared, higher release was observed for plasmid DNA compared to genomic salmon sperm DNA. Conformational analysis of the released plasmid DNA showed that DNA was released without degradation, but with remarkable conversion from supercoiled (SC) to open circular (OC). In addition, the tested in situ gel systems demonstrated protection from DNAse I degradation. The myotoxicity of the injectable gelling solutions was assessed by the cumulative release of creatine kinase (CK) over 120 min from the isolated rodent extensor digitorum longus (EDL) muscle. A higher level of cumulative CK was observed for IPC when compared to H:C (2:1). These results demonstrate that the in situ gelling systems can be considered as a valuable injectable controlled-delivery system for pDNA in their role to provide protection from DNAse degradation.

Pharmacokinetics of plasmid DNA in the rat

PURPOSE

The pharmacokinetics of plasmid DNA after IV bolus administration in the rat by following supercoiled (SC), open circular (OC), and linear (L) pDNA forms of the plasmid.

METHODS

SC, OC, and L pDNA were injected at 2,500, 500, 333, and 250 microg doses. The concentrations in the bloodstream of OC and L pDNA were monitored.

RESULTS

SC pDNA was detectable in the bloodstream only after a 2,500 microg dose, and had a clearance of 390(+/-50) ml/min and Vd of 81(+/-8) ml. The pharmacokinetics of OC pDNA exhibited non-linear characteristics with clearance ranging from 8.3(+/-0.8) to 1.3(+/-0.2) ml/min and a Vd of 39(+/-19) ml. L pDNA was cleared at 7.6(+/-2.3) ml/min and had a Vd of 37(+/-17) ml. AUC analysis revealed that 60(+/-10) % of the SC was converted to the OC form, and nearly complete conversion of the OC pDNA to L pDNA. Clearance of SC pDNA was decreased after liposome complexation to 87(+/-30) ml/min. However the clearance of OC and L pDNA was increased relative to naked pDNA at an equivalent dose to 37(+/-9) ml/min and 95(+/-37) ml/min respectively.

CONCLUSIONS

SC pDNA is rapidly metabolized and cleared from the circulation. OC pDNA displays non-linear pharmacokinetics. Linear pDNA exhibits first order kinetics. Liposome complexation protects the SC topoform, but the complexes are more rapidly cleared than the naked pDNA.

Erosion of dentine and enamel in vitro by dietary acids: the effect of temperature, acid character, concentration and exposure time

Sales of soft drinks has been increasing by 56% over the last 10 years and are estimated to keep rising at about 2-3% a year. Further, the reported incidence of tooth erosion has been increasingly documented. Whilst these factors could well be linked, many individuals with erosive diets are not presenting with erosion. This would suggest the effects of many variables, hence the aim of these investigations. Methodologies included preparing enamel and dentine samples from unerupted human third molars. Groups of five specimens were placed in citric acid over a temperature range of 5-60 degrees C for 10-min exposures; placed in citric, lactic, malic or phosphoric acid (0.05, 0.1, 0.5, and 1% (w/v)) for 10-min exposures; and placed in the same three organic hydroxy acids at 0.3% (w/v) or phosphoric acid at 0.1% (w/v) for 3 x 10-min exposures. Tissue loss was determined by profilometry. Results showed that increasing temperature, concentration and exposure time increased the erosion of dentine and enamel. This study has shown that under highly controlled conditions, erosion of dentine and enamel by dietary acids can be greatly influenced in vitro by temperature, concentration, type of acid and exposure time. These factors could be employed in order to reduce the erosivity of soft acidic drinks.

Biodegradable pH-sensitive surfactants (BPS) in liposome-mediated nucleic acid cellular uptake and distribution

The impact of biodegradable pH-sensitive surfactant (BPS)-liposomes on nucleic acid, i.e., oligonucleotide and plasmid DNA, cellular delivery was examined. Fluorescein-labeled nucleic acids complexed with 1,2-dioleoyl-3-trimethylammonium propane cationic liposomes and BPS at a charge ratio (+/-) of 10 were incubated in CV-1 cells and analyzed by flow cytometry. The fluorescence intensity of oligonucleotides but not plasmid DNA complexed with BPS-liposomes was higher than those complexed with BPS-free liposomes at early time points. However, when cells were fixed to equalize the intracellular pH since fluorescein, a pH-sensitive fluorophore, has higher fluorescence intensity in alkaline pH than acidic, no difference in intensity was observed. This indicated the incorporation of BPS in liposomes did not increase oligonucleotide cellular uptake over control liposomes, but redistributed oligonucleotides into a more basic environment, e.g., cytoplasm. An explanation consistent with the presented data is the formation of small transient membrane defects within the endosomal membrane as presented previously [Liang, E., Hughes, J.A., 1998a. Membrane fusion and rupture in liposomes: effect of biodegradable pH-sensitive surfactants. J. Membr. Biol. 166, 37-49.]. The above findings suggested that BPS may be effective agents of disrupting one of the major barriers, endosomal membrane, to enhance nucleic acid cellular transport.

Adeno-associated virus mediated gene transfer into primary rat brain neuronal and glial cultures: enhancement with the pH-sensitive surfactant dodecyl 2-(1'-imidazolyl) propionate

This study evaluated the effects of a novel, pH-sensitive surfactant, dodecyl 2-(1'-imidazolyl) propionate (DIP), on cationic lipid mediated transfection in primary rat brain neuronal and glial cultures. The cationic lipid complex DOTAP/DOPE (1, 2-dioleoyl-3-trimethylammonium propionate and dioleoyl phosphatidylethanolamine, respectively) was added over a range of concentrations (0-120 microg/ml) with DNA concentration kept constant (1.6 microg/ml). The neuron-specific enolase (NSE) and cytomegalovirus (CMV) promoters were found to drive green fluorescent protein (GFP) expression in neuron-enriched and glial cultures, respectively, using adeno-associated virus (AAV) derived constructs. NSE-driven GFP expression was not observed in glial cultures. Addition of DOTAP/DOPE increased transfection efficiency over a wide range of lipid concentrations (5-50 microg/ml) keeping DNA concentration constant (1.6 microg/ml). Addition of DIP to the lipid/DNA complex increased maximum transfection efficiencies in glial and neuronal cultures 2-3-fold. Transfection efficiencies were at their maximum with a similar total lipid concentration (50 microg/ml) in both cell-types in the presence of DIP. Neuronal cultures were more sensitive than glia to the toxic actions of DOTAP/DOPE, with or without DIP. These results indicate that AAV-mediated gene-transfer to neurons and glia can be facilitated by addition of a pH-sensitive surfactant to cationic liposome/DNA complexes and that endosomal escape could be a limiting factor in transgene expression.

Modulation of ras p21 oncoprotein levels and DNA strand breakage in human cells with chemotherapeutic agents and/or deferoxamine

Oncogenes are involved with the regulation of cellular proliferation. Ras oncogenes can be activated by chemical treatment and any increased activity could be modulated by further chemical treatment. In the present study, therefore, ras p21 protein expression was examined in in vitro cultures of human lymphocytes treated with mitomycin C and in the human colon adenocarcinoma Caco-2 cell line treated with doxorubicin with and without deferoxamine. Both chemotherapeutic agents act partially through oxygen radical mechanisms. Increases in p21 protein levels were seen with mitomycin C but no clear response was seen with doxorubicin. However, deferoxamine, with and without doxorubicin, altered p21 expression. Deferoxamine is an iron chelator so these results support the hypothesis that oxygen radicals were responsible for the altered p21 protein levels. Modulating responses were confirmed by measuring DNA strand-breakage in the Comet assay after treatment with doxorubicin and deferoxamine. Alterations of ras p21 protein expression in vitro might prove a suitable system for examining modulating effects on chemical carcinogens.

Relative susceptibility of deciduous and permanent dental hard tissues to erosion by a low pH fruit drink in vitro

OBJECTIVES

The objectives of this study were two-fold: (1) to determine (by surfometry) loss of deciduous and permanent enamel and dentine following 15days' exposure to a single low pH orange drink; and (2) to determine (by surfometry) loss of deciduous and permanent enamel and dentine following exposure to the product 2 versus 4 times per day for 15days.

METHODS

This in vitro study employed the validated methodology described by West and co-workers [Journal of Dentistry, 1998;26:329-335.]

RESULTS

In all four tissues, erosion was progressive over time, though this pattern was more linear in enamel than in dentine. In general, erosion of enamel was greater in the deciduous tissue, while erosion of dentine was greater in the permanent tissue. However, these differences were rarely of statistical significance. Increasing frequency of exposure resulted in a non-proportional increase in tissue loss.

CONCLUSIONS

Differences in susceptibility of deciduous and permanent tissues to erosion by a low pH drink in vitro appear to exist, though these may not be of statistical significance. Care may be indicated in the delivery of dietary advice, since reduced frequency of exposure to a low pH drink does not appear to result in a proportional reduction in tissue loss.

Erosion of deciduous and permanent dental hard tissue in the oral environment

OBJECTIVES

The objectives of this study were two-fold: (1) to determine (by surfometry) loss of deciduous and permanent enamel and dentine following consumption of a single low pH orange drink for 15days; and (2) to determine (by surfometry) loss of deciduous and permanent enamel and dentine following consumption of the product 2 versus 4 times per day for 15days.

METHODS

Sixteen healthy volunteers participated in a single centre, single blind, 2-phase crossover study, conducted according to Good Clinical Practice, and employing the validated model described by West and co-workers (Journal of Dentistry 1998; 26:329-335).

RESULTS

In all tissues, erosion was progressive over time, the pattern being more linear in enamel than in dentine. In general, erosion of deciduous enamel was greater than that of permanent enamel, though this difference was significant only for those specimens exposed to 4 drinks per day. Conversely, erosion of dentine was generally greater in the permanent tissue, though differences rarely reached conventional levels of statistical significance. Increasing frequency of consumption resulted in increased loss of tissue, but this difference was neither proportional nor consistently statistically significant.

CONCLUSIONS

It is concluded that statistically significant differences in susceptibility of deciduous and permanent enamel to erosion appear to emerge over time and with increasing frequency of consumption. This is of importance clinically given the reduced dimensions of the deciduous dentition and the element of 'abuse' of soft drinks by the child population. Further development of soft drinks with low erosive potential is recommended.

Pre-exposure of cells to cationic lipids enhances transgene delivery and expression in a tissue culture cell line

Several factors influence non-viral transfection in tissue culture models including nature of the cationic lipid, plasmid construction, and DNA lipid complex, among others. The cell line itself is another confounding variable. Each subcellular population may respond independently to the transgene or specific delivery vector with regards to toxicity or transgene expression. In this study, the SKnSH (human neuroblastoma) and COS-1 (African green kidney) cells were exposed to three different treatments A, B, and C. Treatment A refers to cells obtained from American Type Culture Collection (ATCC) and cultivated as recommended, treatment B to cells that were grown in presence of cationic lipids for two weeks, and treatment C to cells that were grown in presence of cationic lipids for two weeks followed by normal media for two weeks to determine if lipid mediated effects were reversible. Treatment B resulted in a three-fold increase in transgene expression of a reporter gene as compared to the other treatments. This increase in transgene expression appeared not to be related to alterations in toxicity. Interestingly, the fluid phase endocytic uptake of fluorescently labeled oligonucleotides was increased in treatment B. However, there was no significant difference in the cellular-associated signal when fluorescently labeled plasmid-DNA was evaluated. In COS-1 cells, no difference in transfection was observed with treatment B illustrating that cell lines respond independently. In conclusion, pre-exposure of SKnSH cells to cationic liposomes (treatment B) resulted in higher transgene production.

The effect of lyophilization on plasmid DNA activity

The effect of lyophilization of plasmid DNA's ability to express an encoded protein was studied. Plasmid DNA, pRL-CMV expressing Renilla luciferase, was purified and stored in Tris-ethylenedi-aminetetraacetic acid (EDTA) buffer. Aliquots of the plasmid were lyophilized using analytical equipment, both alone and in the presence of carbohydrate. Samples were rehydrated and subject to functional and structural analyses. Analytical techniques included transfection efficiency in COS-1 cells, agarose gel electrophoresis, dimethylethylenediamine (DMED) assay for abasic sites, circular dichroism measurement, and UV spectroscopy. The lyophilization of pRL-CMV plasmid DNA resulted in a statistically significant loss of transfection efficiency (p < 0.05). Mono- and disaccharides could completely restore transfection efficiency. Agarose gel electrophoresis and the DMED assay demonstrated no change in gross plasmid structure or increase in abasic sites during lyophilization, respectively. Changes in DNA form, as measured by a change in ellipsisity, were observed on lyophilization. However, these changes were transient and were not shown to be responsible for loss of transfection efficiency. A hyperchromic effect was observed at 260 nm after lyophilization and could be reversed by the presence of carbohydrates. Lyophilization causes a decrease in plasmid DNA activity as measured by an in vitro transfection assay. Carbohydrates can ameliorate this decreased activity, which may be due to structural changes seen during the lyophilization process.

Effects of pH and concentration of citric, malic and lactic acids on enamel, in vitro

OBJECTIVE

Dental erosion associated with soft drink consumption probably results from the contained dietary acids in the formulations. The pH value of any formulation is an important variable in acid erosion but not necessarily the only important factor. The aim of this study was to measure enamel erosion by citric, malic and lactic acids at pH values and acid concentrations representative of a range found in soft drink formulations and to determine the effect of adding calcium to citric acid.

METHODS

Flat ground enamel samples were prepared from unerupted human third molar teeth. Groups of five specimens were placed in citric, malic and lactic acid solutions of different pH and acid concentration for three by 10 min exposures at 35 degrees C. Enamel loss was measured by profilometry. Enamel specimens were also exposed to citric acid solutions containing calcium at different pH values and at the same pH with different concentrations of calcium.

RESULTS

Numerical data and contour plots for each acid showed a similar pattern for increasing erosion with decreasing pH and increasing acid concentration and vice versa for decreasing erosion. Increasing the concentration of calcium in a fixed pH citric acid solution resulted in decreased erosion. This effect was most marked at higher pH.

CONCLUSIONS

This study has shown that under highly controlled conditions the erosion of enamel by solutions of dietary acids is influenced by the interplay of pH, acid concentration and presence of calcium. These variables and in particular the concentration of calcium could be manipulated to produce soft drinks with reduced erosivity to enamel.

Infection of the macrophage cell line NR8383 with Mycobacterium tuberculosis (H37Ra) leads to an increase in oligodeoxynucleotide accumulation

Mycobacterium tuberculosis infection continues to be a daunting clinical challenge. Although it may well be one of the most studied bacteria in history, several aspects of its pathology remain a mystery. The resurgence of drug-resistant M. tuberculosis strains and with its unusual pathology have promoted a renewed basic and clinical research interest in developing new therapies to combat this pathogen. The primary localization site for M. tuberculosis is within alveolar macrophages. Drug delivery strategies and novel therapeutic agents designed to target alveolar macrophages may lead to efficient destruction of M. tuberculosis. Oligodeoxynucleotides (ODN) are short segments of nucleic acids that can interfere with transcription and translation processes. In this report, a monocyte-macrophage cell line was characterized in regard to ODN transport in the presence or absence of M. tuberculosis infection. The cells accumulated ODN in a time-dependent and concentration-dependent manner, regardless of the presence of serum. After 4 hours of incubation with M. tuberculosis (multiplicity of infection [MOI] 10:1), infected NR8383 cells demonstrated 1.5-7-fold increase in fluorescein isothiocyanate (FITC)-labeled phosphorothioate ODN accumulation as measured by flow cytometry. The increase in uptake was associated only with fluorescent-labeled ODN and not labeled markers of fluid phase endocytosis (e.g., tetramethylrhodamine isothiocyanate [TRITC], FITC-labeled dextran). NR8383 cells activated by phytohemagglutinin (PHA) did not demonstrate a significant increase in the uptake of either FITC-labeled dextran or FITC-labeled ODN. These studies demonstrate that NR8383 cells that have been infected with M. tuberculosis can specifically accumulate ODN, and this route of accumulation may lead to a means of drug targeting to mycobacteria-containing cells.

Quantifiable analysis of human immunoglobulin heavy chain class-switch recombination to all isotypes

Somatic recombinational events, including the immunoglobulin heavy chain class-switch, are a normal feature of B-cell maturation. To enable comprehensive and sensitive class-switch analysis in ex vivo human B cells, we have developed multiple digestion-circularization PCR (DC-PCR) techniques for quantifiable detection of switching to all immunoglobulin isotypes. This technology was validated by extensive sequencing of PCR products, tests with control non-lymphoid cells and B-cell lines of known isotypic specificities, and by demonstrating DC-PCR selectivity in a model system. With tonsillar B-cell DNA, switching to gamma 3, gamma 1, alpha1, gamma 2, gamma 4 and alpha2 isotypes was reproducibly detectable among different individuals. Levels of epsilon switching were relatively low and usually required higher total amounts of template DNAs for detection. Quantitation of alpha1 class switching in a panel of human tonsillar whole B cells was performed by the internal-competitor approach, and showed a pattern consistent with previous studies on IgA+ tonsillar cells. We demonstrate that these assays can rapidly show germline status or specific switch rearrangements in B lymphoid cell lines.

Enhanced transgene expression in rat brain cell cultures with a disulfide-containing cationic lipid

The transfection efficiency of a disulfide-containing cationic lipid, 1',2' dioleoyl-sn-glycero-3'-succinyl-2-hydroxyethyl disulfide ornithine conjugate (DOGSDSO) and its non-disulfide analog (DOGSHDO) were compared in neuronal, astroglial and microglial cultures from newborn rat cerebral cortex. We hypothesized that the relatively high intracellular concentrations of reductive substances in the cytoplasm may help to cleave the reversible disulfide bond in DOGSDSO, thus increasing free DNA and decreasing toxicity due to rapid degradation of the lipid. We have demonstrated through mass spectrometric analysis that a reductive compound, e.g. dithiothreitol (DTT) could degrade the disulfide lipid. DOGSDSO was more efficient at transfecting each type of brain cell than were the non-disulfide DOGSHDO and DOTAP (1,2-dioleoyl-3-trimethyl-ammonium-propane) liposomes. These results demonstrate that disulfide-containing cationic liposomes facilitate gene transfection in cultured rat brain cells.

Cytogenetic damage and ras p21 oncoprotein levels from patients with chronic obstructive pulmonary disease (COPD), untreated lung cancer and healthy controls

The purpose of the present communication was to determine in patients with chronic obstructive pulmonary disease (COPD), untreated lung cancer and healthy controls if there was a possible association between the disease state and biomarkers of cytogenetic damage and ras p21 oncoprotein levels, and if various exogenous confounding factors such as smoking habit and endogenous ones (sex, cancer in the immediate family) could affect these biomarkers. The individuals in all groups were as well-matched as possible for age to determine if this could be eliminated as a confounder. Peripheral blood and plasma were collected from 20 COPD patients, 31 cancer patients and 20 healthy controls. Chromosomal aberrations (CA), sister chromatid exchanges (SCE) and high frequency SCE cells (HFC) were examined from the blood and ras p21 oncoproteins from the plasma. These parameters were used as biomarkers of genotoxic anomalies. All the biomarkers were examined for their relationship to the confounding factors. Results were analysed by a t-test, analysis of variance (ANOVA) and stepwise multivariate regression analysis. There was an increase in CA, although not statistically so, in COPD and cancer patients by comparison with healthy controls, but there was a statistically significant increase in SCE, HFC and ras p21 oncoproteins. There was also a statistically significant difference between respiratory volume parameters in COPD patients and controls. Respiratory parameters were not measured in cancer patients. Ras p21 oncoproteins were also statistically significantly increased in the COPD and cancer patients, suggesting that the disease state alone might be sufficient to increase the oncoproteins, or that some of the COPD patients were in the process of developing cancer or perhaps some would die from COPD before cancer developed. Smoking was shown to have a marked effect on all parameters investigated. Ex-smokers showed less effects. Since age was very well controlled, there was little effect due to age. There was an effect due to sex, but cancer in the immediate family had little effect on any of the parameters.

Synthesis of a single-tailed cationic lipid and investigation of its transfection

Single-tailed cationic lipids were originally reported to have low transfection efficiency and high toxicity in plasmid delivery. We hypothesized that particular single-tailed cationic lipids may also function in plasmid transfection. To test this hypothesis, we synthesized a new cationic lipid-oleoyl ornithinate (OLON). To decrease cytotoxicity, we then introduced a potential biodegradable ester bond in the tail of lipid yielding 6-lauroxyhexyl ornithinate (LHON). The data demonstrated that the cytotoxicity of LHON was lower than that of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) or OLON. To investigate the transfection activity of the new lipids and determine the cellular uptake of DNA/liposome complexes, we compared the transfection of liposomes produced from double-tailed 1',2'-dioleyl-sn-glycero-3'-succinyl-1, 6-hexanediol ornithine conjugate (DOGSHDO) with an ornithine headgroup, single-tailed OLON with an ornithine head group, double-tailed DOTAP with quaternary amine group, and single-tailed cetyltrimethylammonium bromide (CTAB) with a quaternary amine group. At the optimal ratios as defined in transfection experiments, OLON/DOPE had more than 10 times the transgene expression than other liposomes even though the DNA uptake was not necessarily greater. In the experiments comparing the release of DNA from DNA/liposome complexes by anionic substances, a greater fraction of DNA was released from DNA/OLON/DOPE complexes than that from DNA/DOTAP/DOPE complexes.

Factors that impact nurses' use of electronic mail (e-mail)

As electronic applications are used increasingly in healthcare, nurses are being challenged to adopt them. Electronic mail (e-mail) is an electronic tool with general as well as healthcare uses. E-mail use may be an opportunity to learn a tool that requires skills similar to those used in other applications. This study aimed to identify barriers and facilitators that impact nurses' use of e-mail in the workplace. Data for this study were gathered using focus group methodology. Content analysis identified and labeled factors into seven major categories. Specific factors identified were generally consistent with those previously described in the literature as affecting use of computers in general. However, there were several additional factors identified that were not reported in other previous studies: lack of face-to-face communication, individual writing skills, recency of any educational experience, volume of mail received, password integrity, and technical support. Findings from this study provide information for any individual involved in introducing or updating an e-mail system in a healthcare environment.

A biofunctional assay to study pRL-CMV plasmid DNA formulation stability

The ability of a plasmid DNA formulation to code for a functional protein was assayed as a marker for plasmid DNA stability using a cotransfection method to measure transcription efficiency. This method shows increased sensitivity and reproducibility over single plasmid transfection methods. Method validation, by measuring DNA degradation rates, demonstrates that buffer choice may be of some importance in the pharmaceutical formulation of plasmid DNA. Degradation rates dependant on citrate buffer concentration were observed. This cotransfection method has proven superior to standard agarose gel electrophoresis in quantifying subtle pRL-CMV plasmid DNA damage and could be used to help predict stability of a final plasmid DNA dosage form.

Examination of ras oncoproteins in human plasma from healthy controls and workers exposed to petroleum emissions, including benzene-related compounds

Ras oncoproteins in blood plasma from workers exposed to petroleum emissions and unexposed controls were examined from Polish and Estonian samples. Twenty-four workers and 35 unexposed controls were examined from Poland and 97 exposed and 40 unexposed controls from Estonia. Of the Estonian workers, 50 were exposed to benzene in a benzene production plant and 47 to polyaromatic hydrocarbons and benzene in a cokery. Blood plasma proteins were separated by gel electrophoresis, transferred to a nitrocellulose membrane by Western blotting and detected by chemiluminescence using a monoclonal antibody as the primary antibody. There were no statistically significant differences between the exposed and the control groups in either the Polish or the Estonian samples.

Use of dithiodiglycolic acid as a tether for cationic lipids decreases the cytotoxicity and increases transgene expression of plasmid DNA in vitro

Two major barriers that limit cationic lipids in gene delivery are low transfection efficiency and toxicity. In the present studies, we used dithiodiglycolic acid as a new tether for the polar and hydrophobic domains of a cationic lipid, cholesteryl hemidithiodiglycolyl tris(aminoethyl)amine (CHDTAEA). We compared the transfection activity and toxicity of CHDTAEA with its nondisulfide analogue and cholesteryl N-(dimethylaminoethyl) carbamate (DC-Chol). The liposomes of CHDTAEA had more than 2 orders of magnitude greater transfection activity than DC-Chol in CHO cells and 7 times greater transfection activity in SKnSH cells. CHDTAEA also demonstrated much less toxicity than the other two lipids. Dithiodiglycolic acid may act as an excellent linker in the application of cationic lipid syntheses.

Building a balanced scorecard for a burn center

The Balanced Scorecard provides a model that can be adapted to the management of any burn center, burn service or burn program. This model enables an organization to translate its mission and vision into specific strategic objectives across the four perspective: (1) the financial perspective; (2) the customer service perspective; (3) the internal business perspective; and (4) the growth and learning perspective. Once the appropriate objectives are identified, the Balanced Scorecard guides the organization to develop reasonable performance measures and establishes targets, initiatives and alternatives to meet programmatic goals and pursue longer-term visionary improvements. We used the burn center at the University of Colorado Health Sciences Center to test whether the Balanced Scorecard methodology was appropriate for the core business plan of a healthcare strategic business unit (i.e. a burn center).

Oligonucleotide delivery: a cellular prospective

The use of oligonucleotides (ONs) for gene therapy of certain diseases has been discussed since the late 1970s. ONs are single stranded chains of nucleic acids that can hybridize with target nucleic acid sequences to inhibit specific proteins, and therefore allow selective treatment of various diseases. The use of ONs is limited due to their instability in biological tissues and difficulty in delivery to the intracellular compartments of the cell. Chemical analog approaches have been used to address the instability issue and delivery systems have been developed to increase cellular uptake of ONs. It is generally thought that ONs with or without a delivery system are transported into cells by endocytosis, and then accumulate within endosomes where they are significantly inactivated. The rate and extent of movement of ON from endosomes appears to be important in determining ON effects. Consequently, developing accessory compounds or delivery methods that enhance endosome to cytoplasm transfer may be vital to ON therapy. This review focuses on investigating mechanisms of various delivery approaches at the cellular/intracellular level that have demonstrated utility in increasing ON activity or cellular accumulation. The future prospects of ON delivery are also addressed.