AAV9:PKP2 improves heart function and survival in a Pkp2-deficient mouse model of arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a familial cardiac disease associated with ventricular arrhythmias and an increased risk of sudden cardiac death. Currently, there are no approved treatments that address the underlying genetic cause of this disease, representing a significant unmet need. Mutations in Plakophilin-2 (PKP2), encoding a desmosomal protein, account for approximately 40% of ARVC cases and result in reduced gene expression.

METHODS

Our goal is to examine the feasibility and the efficacy of adeno-associated virus 9 (AAV9)-mediated restoration of PKP2 expression in a cardiac specific knock-out mouse model of Pkp2.

RESULTS

We show that a single dose of AAV9:PKP2 gene delivery prevents disease development before the onset of cardiomyopathy and attenuates disease progression after overt cardiomyopathy. Restoration of PKP2 expression leads to a significant extension of lifespan by restoring cellular structures of desmosomes and gap junctions, preventing or halting decline in left ventricular ejection fraction, preventing or reversing dilation of the right ventricle, ameliorating ventricular arrhythmia event frequency and severity, and preventing adverse fibrotic remodeling. RNA sequencing analyses show that restoration of PKP2 expression leads to highly coordinated and durable correction of PKP2-associated transcriptional networks beyond desmosomes, revealing a broad spectrum of biological perturbances behind ARVC disease etiology.

CONCLUSIONS

We identify fundamental mechanisms of PKP2-associated ARVC beyond disruption of desmosome function. The observed PKP2 dose-function relationship indicates that cardiac-selective AAV9:PKP2 gene therapy may be a promising therapeutic approach to treat ARVC patients with PKP2 mutations.

Improved Cardiac Function in Postischemic Rats Using an Optimized Cardiac Reprogramming Cocktail Delivered in a Single Novel Adeno-Associated Virus

BACKGROUND

Cardiac reprogramming is a technique to directly convert nonmyocytes into myocardial cells using genes or small molecules. This intervention provides functional benefit to the rodent heart when delivered at the time of myocardial infarction or activated transgenically up to 4 weeks after myocardial infarction. Yet, several hurdles have prevented the advancement of cardiac reprogramming for clinical use.

METHODS

Through a combination of screening and rational design, we identified a cardiac reprogramming cocktail that can be encoded in a single adeno-associated virus. We also created a novel adeno-associated virus capsid that can transduce cardiac fibroblasts more efficiently than available parental serotypes by mutating posttranslationally modified capsid residues. Because a constitutive promoter was needed to drive high expression of these cell fate-altering reprogramming factors, we included binding sites to a cardiomyocyte-restricted microRNA within the 3' untranslated region of the expression cassette that limits expression to nonmyocytes. After optimizing this expression cassette to reprogram human cardiac fibroblasts into induced cardiomyocyte-like cells in vitro, we also tested the ability of this capsid/cassette combination to confer functional benefit in acute mouse myocardial infarction and chronic rat myocardial infarction models.

RESULTS

We demonstrated sustained, dose-dependent improvement in cardiac function when treating a rat model 2 weeks after myocardial infarction, showing that cardiac reprogramming, when delivered in a single, clinically relevant adeno-associated virus vector, can support functional improvement in the postremodeled heart. This benefit was not observed with GFP (green fluorescent protein) or a hepatocyte reprogramming cocktail and was achieved even in the presence of immunosuppression, supporting myocyte formation as the underlying mechanism.

CONCLUSIONS

Collectively, these results advance the application of cardiac reprogramming gene therapy as a viable therapeutic approach to treat chronic heart failure resulting from ischemic injury.

Abstract 543: Clinical Development of Cardiac Reprogramming Gene Therapy

Heart failure affects an estimated 38 million people worldwide and is typically caused by cardiomyocyte (CM) loss or dysfunction. Although CMs have limited ability to regenerate, a large pool of non-myocytes, including cardiac fibroblasts (CFs), exist in the postnatal heart. In vivo reprogramming of non-myocytes into functional CMs is emerging as a potential new approach to treat heart failure and substantial proof-of-concept has been achieved in this new field. However, challenges remain in terms of clinical application. First, reported human reprogramming cocktails often consist of five to seven factors that require multiple AAV vectors for delivery. Thus, a less complex cocktail that is able to fit into one AAV vector is needed for this technology to impact human health. Second, the lack of specificity in AAV tropism further complicates the safety and regulatory landscape. A means to limit the expression of reprogramming factors to target cells is critical for maximizing long-term safety. Lastly, although promising studies in small animals have already been reported, safety and efficacy results in large animal MI models are critical to justify cardiac reprogramming in human clinical trials.

We have developed a novel human cardiac reprogramming cocktail that consists of only two transcription factors and one miRNA. This new cocktail has been engineered into a single AAV cassette to efficiently reprogram human CFs into cardiomyocytes. We also substantially improved transduction of hCFs through AAV capsid engineering and eliminated CMs expression through a microRNA de-targeting method. Moreover, our novel cardiac reprogramming gene therapy improved cardiac function in both rat and swine MI models upon delivery at various time-points after MI without inducing arrhythmias. Given these promising safety and efficacy results in larger animals, we endeavor to translate direct cardiac reprogramming for clinical application.

Effects of alginate coated on PLGA microspheres for delivery tetracycline hydrochloride to periodontal pockets

The effects of alginate coated on tetracycline (Tc) loaded poly (D, L-lactic-co-glycolic acid) (PLGA) microspheres fabricated by double emulsion solvent evaporation technique for local delivery to periodontal pocket were investigated. Alginate coated PLGA microspheres showed smoother surface but enlarged their particle sizes compared with those of uncoated ones. In addition, alginate coated microspheres enhanced Tc encapsulation efficiency (E.E.) from 11.5 +/- 0.5% of uncoated ones to 17.9 +/- 0.5%. Moreover, all of the coated PLGA microspheres even fabricated at different conditions could prolong Tc release from 9-12 days with 50% or higher in cumulative release of Tc compared with those of uncoated ones. The swelling ratios of PLGA microspheres for alginate coated or uncoated ones, one of the possible mechanisms for enhancing Tc release for the coated ones, were measured. The results showed that 20% or higher in swelling ratio for the coated microspheres at the earlier stage of hydration (e.g. < or = 24 h) could be an important factor to result in high Tc release compared to the uncoated ones. In conclusion, alginate coated Tc loaded PLGA microspheres could enhance Tc delivery to periodontal pocket by enhancing drug encapsulated efficiency, released quantities and sustained release period compared with uncoated ones.

Mechanical properties of microwave hydrothermally synthesized titanate nanowires

In this investigation titanate nanowires were synthesized by a microwave hydrothermal process and their nanomechanical characterization was carried out by a compression experiment via buckling instability using a nanomanipulator inside a scanning electron microscope. Nanowires of diameters 120-150 nm and length tens of microns can be synthesized by keeping a commercial nanoparticle inside a microwave oven at 350 W and 210 °C for 5 h. The nanowire was clamped between two cantilevered AFM tips attached to two opposing stages of the manipulator for nanomechanical characterization. The elasticity coefficients of the titanate nanowires were measured by applying a continuously increasing load and observing the buckling instability of the nanowires. The buckling behavior of a nanowire was analyzed from the series of SEM images of displacement of the cantilever attached to the nanowire due to application of load. The critical loads for different sized titanate nanowires were determined and their corresponding Young's modulus was computed with the Euler pinned-fixed end model. The Young's modulus of these microwave hydrothermal process synthesized titanate nanowires were determined to be approximately in the range 14-17 GPa. This investigation confirms the capability of the nanomanipulator via the buckling technique as a constructive device for measuring the mechanical properties of nanoscale materials.

Development of a simple and rapid immunochromatographic strip test for diarrhea-causative porcine rotavirus in swine stool

A rapid and simple immunochromatography (IC) strip test, for specific detection of porcine rotavirus (PRV) in stool specimen, was developed. Monoclonal antibodies (mAbs) to the OSU strain of PRV have been produced in mice. Among them, two hybridoma clones that generate mAb-1 and mAb-2, respectively, specific for VP6 protein of PRV, have been selected. In the IC configuration, mAb-1, one of the selected mAbs was used to the designed coat microparticles (MP), while another mAb-2 was used to fix it on the nitrocellulose membrane strip to form a result line. The control line was formed on the same membrane strip past the result line by fixing anti-mouse IgG antibody. The IC test was capable of detecting 1000 plaque-forming units of PRV/ml in less than 5min, and the binding capacity was demonstrated by specific recognition of PRV only, but not other porcine diarrhea viruses, transmissible gastroenteritis virus (TGEV) and porcine epidemic diarrhea virus (PEDV). The IC test produced positive results with all the nine PRV-positive stool specimens and negative results with five different non-PRV specimens, which were identified previously by the polymerase chain reaction (PCR) test, respectively. The results indicate an excellent concordance between the two methods, suggesting a potential application of the three combinated IC tests (PRV, TGEV and PEDV) for the on-site, rapid screening of porcine diarrhea cases.

Release of ciprofloxacin from poloxamer-graft-hyaluronic acid hydrogels in vitro

Recently, in situ gel formation has extensively been studied to enhance ocular bioavailability and duration of the drug activity. In this study, we report grafting of poloxamer onto the hyaluronic acid for application of tissue engineering oriented ophthalmic drug delivery system. Graft copolymers were prepared by coupling mono amine-terminated poloxamer (MATP) with hyaluronic acid (HA) backbone using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and N-hydroxylsuccinimide (NHS) as coupling agents. The coupling of MATP with HA was clarified by 1H NMR and FT-IR spectroscopy. The gelation temperature of graft copolymers was dependent on the content of HA and the concentration of poloxamer. From drug release studies in vitro, ciprofloxacin was sustainedly released from the poloxamer-g-hyaluronic acid hydrogel due to the in situ gel formation of the copolymer and viscous properties of HA.

Molecular cloning and characterization of Mycobacterium bovis BCG pcp gene encoding pyrrolidone carboxyl peptidase

The Mycobacterium bovis bacilli Calmette-Guerin (BCG) pcp gene that encodes the pyrrolidone carboxyl peptidase (Pcp) was cloned from a lambdagtll genomic library and sequenced. The nucleotide sequence contains a 669 bp open reading frame coding for a protein of 222 amino acid residues with a calculated molecular mass of 23,209 Da. The deduced amino acid sequence is highly homologous to the Pcps from Bacillus amyloliquefaciens, Pseudomonas fluorescens, Bacillus subtilis, Streptococcus pyogenes, and Staphylococcus aureus. A multiple sequence alignment revealed highly conserved domains. The BCG pcp gene was overexpressed in Escherichia coli. The Pcp was purified to homogeneity. The recombinant protein was further confirmed by an enzymatic assay.

Molecular cloning and functional expression of the rfaE gene required for lipopolysaccharide biosynthesis in Salmonella typhimurium

The rfaE (WaaE) gene of Salmonella typhimurium is known to be located at 76min on the genetic map outside of the rfa gene cluster encoding core oligosaccharide biosynthesis of lipopolysaccharide(LPS). The rfaE mutant synthesizes heptose-deficient LPS; its LPS consists of only lipid A and 3-deoxy-D-manno-octulosonic acid (KDO), and the rfaE gene is believed to be involved in the formation of ADP-L-glycero-D-manno-heptose. Mutants, which make incomplete LPS, are known as rough mutants. Salmonella typhimurium deep-rough mutants affected in the heptose region of the inner core often show reduced growth rate, sensitivity to high temperature and hypersensitivity to hydrophobic antibiotics. We have cloned the rfaE gene of S. typhimurium. The chromosomal region carrying this gene was isolated by screening a genomic library of S. typhimurium using the complementation of S. typhimurium rfaE mutant. The 2.6-Kb insert in the plasmid pHEPs appears to carry a functional rfaE gene. SL1102 (rfaE543) makes heptose-deficient LPS and has a deep rough phenotype, but pHEPs complement the rfaE543 mutation to give the smooth phenotype. The sensitivity of SL1102 to bacteriophages (P22.c2, Felix-O, Br60) which use LPS as their receptor for adsorption is changed to that of wild-type strain. The permeability barrier of SL1102 to hydrophobic antibiotics (novobiocin) is restored to that of wild-type. LPS produced by SL1102 (rfaE543) carrying pHEPs makes LPS indistinguishable from that of smooth strains. The rfaE gene encoded a polypeptide of 477 amino acid residues highly homologous to the S. enterica rfaE protein (98% identity), E. coli (93% identity), Yersenia pestis (85% identity), Haemophilus influenzae (70% identity) and Helicobacter pyroli (41% identity) with a molecular weight 53 kDa.

Effects of the characteristics of chitosan on controlling drug release of chitosan coated PLLA microspheres

Chitosan has been shown to be a biomaterial with good biocompatibility, and is highly biodegradable. This study investigated the effect of post-coating PLLA microspheres with different chitosans on the initial burst and controlling the drug release of the microspheres. Without chitosan, 19.2% of encapsulated lidocaine would release from PLLA microspheres within the first hour (R1), and the time of 50% release (T50) was 25 h. After the microspheres were coated with chitosan of viscosity (eta) 384 +/- 10cp, R1 and T50 could be reduced and prolonged to 14.6% and 90 h, respectively, for all tested molecular weights (Mw) of chitosan. In the case of the same Mw of chitosan being applied, the efficacy of reducing the initial burst of drug release was higher for a lower degree of deacetylation (D.D.). With chitosan in acetic acid solution, coating the microspheres with high Mw and high viscosity could most effectively reduce the initial burst and control drug release of PLLA microspheres. For example, the microspheres coated with chitosan solution of Mw 800 kDa and eta of 1479 cp, R1 and T50 could be reduced and prolonged to 7.4% and 245 h, respectively. The study indicated that manipulating the viscosity of the chitosan solution was the most important factor in contributing to controlling the drug release of chitosan post-coated PLLA microspheres.

Growth of endothelial cells on different concentrations of Gly-Arg-Gly-Asp photochemically grafted in polyethylene glycol modified polyurethane

To improve endothelial cell adhesion and growth on the surface of polyethylene glycol modified polyurethane (PU-PEG), cell adhesive peptide Gly-Arg-Gly-Asp (GRGD) was photochemically grafted to the surface. The surface grafted GRGD-N-Succinimidyl-6-[4'-azido-2'-nitrophenylamino]hexanoate (SANPAH) on a PU-PEG surface was performed by adsorption and subsequent ultraviolet irradiation. Fourier transform infrared spectra (FTIR) and electron spectroscopy for chemical analysis (ESCA) confirmed the GRGD grafted to form a PU-PEG-GRGD surface. The composition fraction of nitrogen calculated from ESCA analysis for the PU-PEG-GRGD surface was well correlated with the concentration of GRGD to be immobilized. Human umbilical vein endothelial cells (ECs) were well adhered and growing on the PU-PEG-GRGD surface. Moreover, the viability of ECs growing on PU-PEG-GRGD surfaces, analyzed by MTT test, was also well correlated with the GRGD concentrations immobilized on the surface. With photochemical techniques, we could manipulate different contents of GRGD to form multiple regions of PU-PEG-GRGD surface that could enhance the growth of ECs on the surface, and the enhancement efficiency was well correlated with GRGD contents.

Microencapsulation of gentamicin in biodegradable PLA and/or PLA/PEG copolymer

Biodegradable carriers containing gentamicin for local treatment of bone infection were developed. This paper describes the preparation and in vitro evaluation of these biodegradable implants. Poly-L-lactic acid (PLA) and poly-L-lactic acid:polyethylene glycol (PLA/PEG) disk implants containing gentamicin sulphate were obtained by compression of microspheres prepared by a double emulsion process. The mean particle size distribution of the microspheres, based on volume, ranged from 95-270 microm. The gentamicin sulphate loading of the microspheres, after a methylene chloride-water extraction procedure, exceeded 90% of the theoretical value. In vitro dissolution studies on the microspheres and implants with drug loadings 10-40% w/w indicated that the rate of drug release from both PLA and PLA/PEG implants increased, with an increase in drug loading. The release of gentamicin from microspheres was dependent on the properties of PLA and/or PLA/PEG. The PLA/PEG copolymer was more hydrophilic than the PLA homopolymer, and with a smaller pH change in the microenvironment with polymer being degraded. In comparison, the PLA/PEG implant released antibiotic faster and had a larger inhibitory zone based on the Bauer-Kirby experiments used to test the inhibitory activity of antimicrobial devices. Experimental results showed that the biodegradable PLA/PEG gentamicin delivery system had a potential for prophylaxis of post-operative infection.

Effects of the rate of solvent evaporation on the characteristics of drug loaded PLLA and PDLLA microspheres

We investigated the effects of the rate of solvent removal by varying ambient pressure at a fixed temperature on the morphology, particle sizes, drug encapsulation efficiency and releases pattern of lidocaine loaded poly-L-lactatide (PLLA) and poly-D,L-lactatide (PDLLA) microspheres, prepared with O/W emulsion-solvent evaporation process. Prepared in the fast rate of solvent evaporation (FRSE) process by reducing ambient pressure, smoothly morphological surface of drug loaded PLLA and PDLLA microspheres was observed. While in the normal rate of solvent evaporation (NRSE) process, roughness or pinhole surface was only found at drug loaded PLLA microspheres. Fabricated in the FRSE process, both PLLA and PDLLA microspheres showed smaller particle sizes and lower drug encapsulation efficiencies than those prepared in NRSE process. In regard to two materials, PLLA microspheres had higher drug encapsulation efficiencies than PDLLA ones for both processes. Although initial burst releases of drug were observed for both PLLA and PDLLA microspheres prepared in whatever solvent removal process, drug release for PLLA microspheres was slightly less than that for PDLLA ones in the earlier stage of drug release. However, in the subsequent stage of drug release, there was no difference between two materials. In corporation with different crystalline characteristics of PLA polymer and its derivatives, FRSE process by reducing ambient pressure could be further applied to produce different characteristics of microspheres for drug delivery.

Changes in viscosity of low shear rates and viscoelastic properties of oxidative erythrocyte suspensions

We exposed erythrocytes in soluble hemoglobin and Fe+2, in which hydroxyl radical (OH*) might be generated, and measured low shear rate viscosity and viscoelasticity of erythrocyte suspensions at Hct of 40%. The quantities of the lipid peroxidation product, malonyldialdehyde (MDA), for oxidized samples were higher than that for control (e.g., 2.20 +/- 0.46 nmol and 1.70 +/- 0.42 nmol, n = 6, p = 0.01, respectively). The viscosity values of oxidized erythrocyte suspensions for all tested shear rates were higher than those for the control samples (p < 0.05 or better, n = 6). Dynamic viscosity (eta') of oxidized erythrocyte samples was higher than that of control samples at the tested shear stress of 30 mPa whereas it was not observed in elasticity values (eta"). We tentatively concluded from the study, that oxidized erythrocytes would be more prone to form aggregates and increase viscosity of blood at low shear rates. Therefore, they might impair blood flow in the microcirculation.

A method using biodegradable polylactides/polyethylene glycol for drug release with reduced initial burst

Post-coating of biodegradable polylactides (PLA)/polyethylene glycol (PEG) microspheres with a gelatin film produced by dipping the microspheres into a gelatin solution to reduce the initial drug release burst was investigated. Biodegradable block PLA/PEG microspheres, prepared by w/o emulsion/solvent evaporation, showed that the hydrophilic segment PEG protruded to the sphere surface. However, these microspheres also showed a large burst release in the initial period. Post-coating of the PLA/PEG microspheres with a gelatin film by dipping the microspheres into a dilute gelatin solution effectively inhibited the initial burst release rate in the drug release tests. Post-coating of gelatin reduced 98% of the burst release. With thicker coatings, there were slower releasing rates, and the release rate can be simply related to the coating thickness.

PE-PEG/LEH can reduce its interactions with plasma expanders indexed through viscosity measurements

To investigate whether PE-PEG coated LEH (PE-PEG/LEH) can reduce its interaction with different plasma expanders and possibly suspended in those expanders, we measured the viscosity of PE-PEG/LEH suspended in different plasma expanders as an index for the interactions. The results showed that lower viscosity values for PE-PEG/LEH were observed compared with LEH especially in low shear rate regions (e.g., 7.72 +/- 1.46 cp vs. 14.91 +/- 1.03 cp for gamma = 2.25 sec-1, respectively). Moreover, the viscosity values for PE-PEG/LEH suspended in fibrinogen suspensions were much less than those of LEH in the same media at low shear rate regions (e.g., 7.72 +/- 1.59 cp vs. 25.78 +/- 1.59 cp, gamma = 2.25 sec-1, respectively). Similar results were observed for PE-PEG/LEH suspended in 1.83% of oxypolygelatin (Gel) suspensions and 1.5% hydrooxyethyl starch (HES) compared to LEH in the same suspension media. On contrast, PE-PEG/LEH suspended in dextran (Dex) showed that dramatically increasing the viscosity values in low shear rates compared with LEH suspended in the same media (e.g., 78.87 +/- 0.56 cp vs. 51.08 +/- 3.52 cp, gamma = 2.25 sec-1, respectively) were observed. Since only minor interactions with Gel, HES or fibrinogen suspensions were observed, we suggest that PE-PEG/LEH suspended in those media but not in Dex can possibly serve for resuscitation oxygen-carrying fluids.

An engineering model to characterize oxygen transfer rates for liposome encapsulated hemoglobin (LEH)

An engineering model was designed to evaluate oxygen transfer rates for LEH and other oxygen carriers under wall shear rates from 150 sec-1 to 450 sec-1. The results showed that increasing the shear rates (or flow rates) of oxygen carriers flowed inside of hollow fiber tubes would increase oxygen transfer rates to outside media. The values of overall oxygen transfer rate coefficients for LEH, based on 1 g/dl of hemoglobin contents, were about 2 to 2.5 times higher than those values for human blood at all of tested shear rates (e.g., 5.1 x 10(-5) cm/sec and 2.1 x 10(-5) cm/sec for LEH and blood at wall shear rates of 450 sec-1, respectively). Moreover, the results of oxygen transfer efficiency for LEH calculated by this model were consistent with the similar results reported by Usuba et al.[3] obtained by animal study. With an engineering model, we possibly estimate the effects of other factors such as viscosity on the oxygen transfer rates for LEH in microcirculation.

A biotin-avidin labeled enzyme immunoassay for the quantitation of serum TSH using protein-layered solid phase

A sensitive enzyme immunoassay for serum TSH has been developed utilizing the tight binding between biotin and avidin, and three layered protein polystyrene beads as solid phase. To increase binding capacity of TSH and sensitivity of the assay, the polystyrene beads were coated sequentially with mouse immunoglobulin as first layer, rabbit antimouse immunoglobulin as second layer and monoclonal anti-TSH as third layer. A serum sample was incubated simultaneously with a monoclonal anti-TSH immobilized polystyrene beads and a second monoclonal anti-TSH covalently attached to biotin. After washing, the antibody bound serum TSH-anti-TSH-biotin complex is reacted with horseradish peroxidase (HRP)-labeled avidin. Following a second wash, the bound HRP activity was measured colorimetrically. Reproducible results were obtained within 4 hours for serum TSH in the range between 0 microIU/ml and 50 microIU/ml with detection limit of 0.1 microIU per test.

Reducing lipid peroxidation stress of erythrocyte membrane by alpha-tocopherol nicotinate plays an important role in improving blood rheological properties in type 2 diabetic patients with retinopathy

The effects of alpha-tocopherol nicotinate on blood viscoelasticity and viscosity and on lipid peroxidation stress in erythrocyte membranes in patients with Type 2 DM were investigated. Thirteen Type 2 diabetic subjects with retinopathy were given alpha-tocopherol nicotinate 300 mg tds, after meals, for 3 months. The treatment resulted in significant reductions of blood viscosity at different shear rates (e.g. -2.23 +/- 2.82 p<0.015, gamma = 1.5 s(-1)) and viscoelasticity (p<0.004); resistance of erythrocyte deformation (p<0.001) and lipid peroxidation stress in red cell membrane (malondialdehyde or MDA reduced by 0.17 +/- 0.13 nmol l(-1) p<0.005). Plasma viscosity, red cell rigidity, and HbA1c were unchanged. There were negative linear correlations between the indices of red cell deformability and the levels of MDA of red cell membrane both pre- and post-treatment (e.g. R = -0.79, p<0.001; R = -0.78, p<0.002, n = 13; pre- and post-, respectively). We suggest that the improvements of rheological properties of blood and red cell deformability by alpha-tocopherol nicotinate are mainly attributed to reducing lipid peroxidation stress on membrane of red blood cells. The treatment may be useful in slowing deterioration of microangiopathy in Type 2 DM.

Increment of efficiency in the identification of noble genes by colony hybridization assay. (Screening of low redundant clones from human fetal cDNA library)

For the rapid identification of noble genes in a specific tissue by computer analysis from the cDNA sequences determined by single-pass cDNA sequencing, clone redundancy was one of the major obstacles. To facilitate the efficiency in identification of noble genes, it was necessary to reduce the number of clones to be sequenced by eliminating the redundant clones for a rapid analysis. In order to increase the probability of isolating noble sequences from the cDNA clones of human fetal liver tissue origin, colony hybridization assay was adopted and redundant clones were efficiently removed. Four cDNA clones highly redundant in the human fetal liver cDNA libraries including alpha-globin, gamma-globin, serum albumin and H19 RNA sequences were selected as the probes. Two hundreds and sixty two cDNA clones were randomly selected and tested with the probes for hybridization properties. The identity of each cDNA clone giving positive or negative signals in the hybridization assay was determined by DNA homology search with the nucleic acid databases. Among the 76 clones giving positive signals, 57 clones (75%) were found to be identical to the probe sequences and could be eliminated by colony hybridization assay before neucleotide sequencing.

Differential expression of ferritin heavy chain in THP-1 cells infected with Mycobacterium bovis BCG

To identify the host genes induced or suppressed by infection of mycobacteria, the reverse transcriptase polymerase chain reaction (RT-PCR) and the differential display reverse transcriptase polymerase chain reaction (DD RT-PCR) methods were used. In this study, cDNAs complement to mRNA extracted from human peripheral monocyte derived naive THP-1 cells, THP-1 cells infected with live Mycobacterium bovis BCG, THP-1 cells treated with heat-killed BCG, and THP-1 cells incubated with IgG-coated glass-beads were compared on the sequencing gel. One (TG2-1) of the clones selected by DD RT-PCR is 446 bp long and is identical to human ferritin heavy (H) chain gene. Northern blot analysis confirmed that ferritin H chain gene has been markedly over-expressed in monocytic THP-1 cells incubated with live and dead M. bovis BCG. Differential display techniques of host genes whose expression levels were varied by infection of mycobacteria could provide information about the response of macrophages to mycobacterial infection.

Cloning and sequencing of the secY gene homolog from Mycobacterium bovis BCG

The complete nucleotide sequence of a 1,513 bp fragment of Mycobacterium bovis BCG containing the secY gene homolog and partial adk gene that encodes an adenylate kinase has been determined. The secY gene of BCG has an open reading frame of 441 amino acids with homology to the SecY protein family. Comparative analyses of the deduced amino acid sequence of additional partial ORF revealed strong similarity to the known adenylate kinases.

Cloning of the human cDNA sequence encoding the NADH:ubiquinone oxidoreductase MLRQ subunit

A cDNA clone encoding human NADH:ubiquinone oxidoreductase (complex I of mitochondrial respiratory chain) MLRQ subunit was isolated from human fetal liver cDNA library. The clone contained an open reading frame of 246 by which predicted a protein comprising 81 amino acids with a calculated molecular weight of 9,370 Da. The deduced amino acid sequence exhibited 95% homology (88% identity and 7% favored substitution) to that of bovine MLRQ subunit. Northern analysis revealed that the cDNA clone hybridized with a 0.7 kb mRNA species which was present in all tissues examined. The expression level of the 0.7 kb mRNA in heart, skeletal muscle, and brain was higher than in other organs. Human MLRQ cDNA could cross-hybridize with the genomic DNAs from various species.

Peptide-specific CTL induction in HBV-seropositive PBMC by stimulation with peptides in vitro: novel epitopes identified from chronic carriers

Cytotoxic T lymphocytes (CTL) recognize and destroy virus-infected cells, and it has been established that epitope-based peptides could induce such CTL in vivo as well as in vitro. In this study attempts were made to define the epitopes that are recognized by the CTL, and thus a series of 9- to 10-mer peptides derived from the amino acid sequences of hepatitis B virus (HBV) proteins were synthesized on the basis of the previously described HLA-A2 peptide binding motif. The binding assay of the synthetic peptides using transporter-associated with antigen processing (TAP)-deficient human cell line, T2, showed that eight out of 11 peptides tested enhanced the expression of HLA-A2 molecules on the T2 cell surface. Some of these peptides triggered activation of CTL in peripheral blood mononuclear cells of HBV-seropositive chronic carriers. The activated CTL in turn recognized and killed the T2 cells pulsed with the same peptides. This study shows that novel HLA-A2-restricted epitopes exist in the natural repertoire of immunity against HBV. These findings can be useful in developing peptide-based therapeutics against viral infections.

Viscosity measurements for LEH suspended in different plasma expanders

To investigate the possibility of hemodilution with oxygen carrying fluid, we measured the viscosity effects of LEH which was suspended in different weight percentage of plasma expanders for different shear rates. All of LEH/Plasma expander suspensions show shear thinning flow behavior, and the viscosity of those suspensions increase with increased the weight percentage of each expander in suspensions for a fixed shear rate. Compared the viscosity data to those of human blood at 40% of hematocrit, LEH/albumin suspensions contained with 4% to 8% of albumin are the most suitable, whereas LEH/dextran (Dex) suspensions contained with 6% Dex70c is the least favorable suspension media for LEH. In point of viscosity effects, hemodilution with LEH/albumin or LEH/0.9% oxypolygelatin (Gel) may be valuable for further testing their efficacy in animal model.

Complete sequence of the UPP gene encoding uracil phosphoribosyltransferase from Mycobacterium bovis BCG

The nucleotide sequence of a 799 bp fragment of Mycobacterium bovis BCG containing the putative upp gene that encodes a uracil phosphoribosyltransferase (UPRTase [EC 2.4.2.9]) has been determined. The upp gene of BCG has an open reading frame (ORF) of 621 bp (207 amino acids) starting with GTG (position 112) and ending with TGA (position 733), and its molecular mass was calculated to be 21,864 Da. Comparative analyses of the deduced amino acid sequence of BCG UPRTase with the UPRTase of six bacterial genera revealed that 24% (50/211) of the residues are perfectly conserved and 32% (67/211) of the residues are well conserved.

Molecular cloning of the leuB genes from Mycobacterium bovis BCG and Mycobacterium tuberculosis

A gene responsible for the biosynthesis of leucine has been cloned by the complementation of the Escherichia coli leuB6 auxotroph mutant after transformation with the Mycobacterium bovis BCG genomic DNA library, which was constructed by ligating the partially digested BCG DNA with Sau3A1 into the pUC19 digested with BamHI. Sequencing of the leuB gene of BCG revealed an ORF (open reading frame) of 1.011 bp encoding isopropylmalate dehydrogenase with a calculated molecular weight of 42 kDa. The leuB gene of Mycobacterium tuberculosis isolated from Korean tuberculosis patient is shown to be identical to that of BCG except one bp.

Knowledge and attitudes about smoking in medical students before and after a tobacco seminar

A 3-hour seminar on tobacco was introduced to second year (pre-clinical) medical students in Hong Kong in 1994. The differences in knowledge and attitudes were measured by a self-administered and anonymous questionnaire with 14 items before the seminar (n = 145), and again 2 weeks after the seminar (n = 151). The students also completed an evaluation form at the end of the seminar. Before the seminar, the students were most deficient in their knowledge on the exact magnitude of the risks from smoking and on the risks from smoking relative to the risks from air pollution and asbestos. After the seminar, their knowledge increased significantly (P < 0.005). As for attitudes, in the pre-test 35% strongly agreed that tobacco advertising should be completely banned, and 50% did so in the post-test (P = 0.02). The corresponding figures for banning of all forms of tobacco promotion were 26% and 43% (P < 0.005). In the pre-test, one in four students strongly disagreed that doctor's advice to their patients to stop smoking is totally ineffective, with this proportion increasing to 70% in the post-test (P < 0.005). The majority of the students stated that the seminar was useful. The preclinical medical curriculum should, at the very least, include a tobacco seminar. Our survey shows that it is effective in improving students' knowledge and attitudes on tobacco control.

Sequence analysis of the 5'-flanking region of the gene encoding human N-acetylglucosaminyltransferase III

We have isolated and characterized the immediate (1651 bP) 5'-flanking region of the gene (GnT-III) encoding N-acetylglucosaminyltransferase III (GnT-III) from a human placental genomic library. Analysis of promoter elements shows a similarity to the 5'-flanking region of murine 1,4-galactosyltransferase. The sequence lacks obvious TATA elements and CCAAT boxes; however, putative regulatory sites, including 2 potential cAMP-response regulatory elements (CRE), 11 insulin-response element consensus sequences (IRE), 7 potential AP-2 binding sites, 2 SP1 consensus sequences (GC boxes) and 2 sequences similar to the half-palindromic glucocorticoid-responsive element (GRE), are present.

Use of progesterone-3(O-carboxymethyl oxime)-horseradish peroxidase in a sensitive microtitre-plate EIA and its application to a visual membrane EIA of progesterone

A simple method of visual membrane enzyme-immunoassay (EIA) for the detection of progesterone is described. When two types of progesterone-horseradish peroxidase (HRP) tracers were challenged for binding, in the presence of progesterone, to the monoclonal anti-progesterone antibody, 15A, coated on the microtitre plate, the HRP conjugated at the C-3 position (A-ring) of progesterone competed more effectively with progesterone to the binding site of the monoclonal antibody (mAb) than HRP conjugated at the C-11 position of the C-ring. By using this combination of mAb, 15A, and progesterone-3(O-carboxymethyloxime)-HRP (P-3CMO-HRP), we developed a visual membrane EIA system in which free progesterone in the sample could be quantified by the degree of color development. In this system, free progesterone competed with P-3CMO-HRP for binding sites of mAb immobilized on the nitrocellulose membrane. The stable grey color was formed on the surface of membrane for progesterone-negative and no color for progesterone-positive sample using 3,3'-diaminobenzidine (DAB) with Co2+ as an insoluble substrate solution. To examine whether tetramethylbenzidine (TMB) can substitute for DAB in membrane EIA, an experiment was conducted where TMB was used as an insoluble substrate.

A rheological equation to express the relations among hemoglobin contents, hematocrits, and viscosity of hemosome

The relations among hemoglobin contents, hematocrit and viscosity of hemosome at a fixed shear rate have been studied. These relations can be well fitted by a rheological equation with internal viscosity of hemosome, (Tk)h, as a parameter. Where, (Tk)h are correlated (r = 0.996) with logarithm of hemoglobin content of hemosome by an equation: (Tk)h = 0.315 ln (hemoglobin contents of hemosome) + 0.435. The correlation can serve as an alternative way to predict hemoglobin content of hemosome instead of Benesch's method. The results of this study serve as a reference to determine an optimal conditions for in vivo tests of hemosome.

Rheological parameter alternations in blood may impair oxygen transported to the retina in type II diabetes (NIDDM)

Rheological properties of blood, retinal capillary blood flow velocity and oxygen transport efficiency (TE) were measured and calculated from 21 type II diabetic patients (NIDDM) and 19 normal subjects. The results showed that the diabetes group had increased plasma viscosity and blood viscosities (P < 0.05 or better) at all tested shear rates. For both shear rates (gamma) of 225 sec-1 and 450 sec-1, the diabetes group displayed increased internal viscosity of red cells (Tk) (P < 0.002 and P < 0.001, respectively) but lower values of TE (P < 0.001, both). A lower value of retinal capillary blood flow velocity (P < 0.005) was also noted. Upon further analysis of possible relations between Hct values and Tk of red cells, it was found that Hct values were linearly correlated with Tk for both shear rates of the diabetes group (gamma = 225 sec-1 and gamma = 450 sec-1; R = -0.63 and -0.65, n = 21 and 19, respectively, both P < 0.005); control group (gamma = 225 sec-1 and gamma = 450 sec-1; R = -0.84 and -0.82, respectively, n = 19, both P < 0.001) and all subjects (gamma = 225 sec-1 and gamma = 450 sec-1; R = -0.70 and -0.72, n = 40 and 38, respectively, both P < 0.001). The impaired rheological properties of blood and internal viscosity of red cells may result in both reduced capillary blood flow velocities and less oxygen transported to tissues. This may possibly contribute to the deterioration of retinopathy or microangiopathy in diabetic patients.

A model for analyzing the formation of thrombin in vessels

A pseudo steady-state model is proposed to analyze the effects of a vessel-length, blood-flow velocities, and the concentration levels of Va/Xa/phospholipid complex on the formation of thrombin in an arterial vessel. The outlet concentrations of thrombin are calculated in either physiological or pathological coagulation process. Among those factors, blood-flow velocity is the most important factor which affects the amount of thrombin formation. The model and its results might be used as a reference for those who clinically manage coagulation problems of patients with severe sepsis.

Influence of the conjugation site on the specificity of monoclonal antibodies to progesterone and on the performance of direct enzyme immunoassay

Monoclonal antibodies against progesterone conjugated to carrier protein through substituent on the A-ring (C3 position ) or the C-ring (C11 position) of progesterone were used in the enzyme immunoassay. Antibody specificities were determined by testing the ability of 11 represensitive steroids to displace labelled progesterone in a competitive enzyme immuno-assay (EIA) and a radioimmunoassay (RIA). Immunization with progesterone conjugated to BSA through substituent on the A-ring (C3) resulted in the formation of monoclonal antibody (mAb) which fairly specific for progesterone. While immunization with progesterone at the 11-position (C11) resulted in the mAbs which were very specific for progesterone. The best EIA system was developed by using mAb against progesterone-11 alpha -hemisuccinyl BSA and tracer of progesterone-3(O-carboxymethyl oxmine)-horseradish peroxidase. Our approach is to confirm the overall orientation of the steroid in the binding site. Immunobiochemical analysis of mAb suggested that the D-ring is substantially more buried in the binding pocket than the A-ring. Our assay was designed to use the reagent inactivating cholesterol binding globulin in serum so that the extraction of the hormone into organic solvent was unnecessary. Therefore, our assay system can detect directly and rapidly the progesterone level in serum within one hour.

Production and characterization of monoclonal antibody that simultaneously recognizes methamphetamine and its major metabolite

A series of monoclonal antibodies (mAbs) that react with methamphetamine-bovine serum albumin (MA-BSA) were established by intrasplenic immunization method. Among established 36 clones, two typical mAbs, designated NK-1 and NK-2, were described. The inhibition assay of enzyme-linked immunosorbent assay (ELISA) analysis using methamphetamine analogs indicated that NK-1 showed considerable reactivity not only MA-BSA but also methamphetamine and its major metabolite, para-hydroxymethamphetamine (p-hydroxymethamphetamine). The cross-reactivity between NK-1 and the methamphetamine analogs with modified alkyl side chain, indicates that methyl groups of R5 and R7 in the methamphetamine molecules are important for the maximum affinity. The length of alkyl side chain on methamphetamine significantly affected the binding affinity of NK-1. The results may suggest that NK-1 will recognize not only methamphetamine but also the bridge part of the methamphetamine that binds the methamphetamine molecules to a carrier protein.

Solid-phase immunoassay using a flow cytometer: quantitative and qualitative determination of protein antigens and a hapten

A fluoroimmunoassay employing a flow cytometer as the fluorescence-detecting device is described. Three kinds of antigens, murine immunoglobulin (Ig), human chorionic gonadotropin (hCG) and progesterone were chosen as examples of the assay using fluorescein-labeled antibodies. Cyanogen bromide-activated agarose beads were used as solid-phase supporters. The flow cytometric immunoassay was applied to both qualitative and quantitative analyses; determination of murine Ig isotypes, quantitative determination of Ig, hCG and a hapten, progesterone. This assay produced very reproducible and less-fluctuating data since thousands of particles in the assay were collected and processed to produce a single value for fluorescence intensities. Furthermore, the working range of the assay in terms of antigen concentration was much broader than that of enzyme immunoassay. Therefore, we believe that microparticles like agarose beads could be useful solid-phase supporters in immunoassay, and the flow cytometer could provide a reliable alternative to the fluorescence-detecting device in immunoassay.

Structural role of amino acids 99-110 in recombinant human erythropoietin

Erythropoietin is the prime regulator of red blood cell production. Previous studies demonstrated that antipeptide antibodies to amino acids 99-119 and 111-129 bind to two non-overlapping domains and inhibit the hormone's action (Sytkowski, A.J. & Donahue, K. A. (1987) J. Biol. Chem. 262, 1161-1165). Oligonucleotide-directed mutagenesis now shows that amino acids 99-110 (domain 1) but not 119-129 (domain 2) are important to erythropoietin's structure and function. Mutagenesis of wild-type human erythropoietin cDNA was used to produce a series of mutant proteins with sequential deletion of three adjacent amino acids and insertion of the sequence Glu-Phe across the two domains. Transient expression in COS-7 cells revealed 2.0-kb transcripts encoded by all of the cDNAs. Domain 2 mutants exhibited specific biological activities similar to that of the wild type. In contrast, domain 1 mutants were not secreted. In vitro transcription and translation of the domain 1, domain 2 and wild-type cDNAs resulted in the isolation of 23.5-kDa and 32-kDa proteins in the absence or presence of pancreatic microsomes, respectively, consistent with efficient translation of all of the mutants and equivalent post-translational processing of each protein. The data suggest that mutation within domain 1 results in the intracellular biosynthesis of erythropoietins with altered structure, rendering them subject to rapid degradation. The bioassay of erythropoietins synthesized entirely in vitro demonstrated that domain 1 mutants were inactive, whereas both wild type and domain 2 mutant hormones exhibited biologic activity. The results are consistent with a critical role for amino acids 99-110 in the structure of human erythropoietin.

Simple enzyme immunoassay for the simultaneous measurement of whole choriogonadotropin molecules and free beta-subunits in sera of women with abnormal pregnancies or tumors of the reproductive system

A multiple enzyme immunoassay (multi-EIA) was developed to quantify whole-molecule human choriogonadotropin (w-hCG) and free hCG beta-subunits (hCG-beta) simultaneously. A clone of a specific monoclonal antibody was coupled to solid phase; two other clones of different monoclonal antibodies were conjugated to horseradish peroxidase (HRP; EC 1.11.1.7) and alkaline phosphatase (AP; EC 3.1.3.1), respectively. These two enzyme conjugates were mixed together to measure w-hCG or hCG-beta, depending on the selection of the enzyme substrate. To measure w-hCG and hCG-beta simultaneously, both enzyme substrates were used with the blended enzyme conjugates. The assay is simple and reproducible, and can be completed within 2 h with high specificity and sensitivity. We measured w-hCG and hCG-beta in the sera of women with abnormal pregnancies and in patients with tumors of the reproductive system, and observed different hCG-beta/w-hCG ratios in patients with various types of trophoblastic tumors.

Simple enzyme immunoassay for the simultaneous measurement of whole choriogonadotropin molecules and free beta-subunits in sera of women with abnormal pregnancies or tumors of the reproductive system

A multiple enzyme immunoassay (multi-EIA) was developed to quantify whole-molecule human choriogonadotropin (w-hCG) and free hCG beta-subunits (hCG-beta) simultaneously. A clone of a specific monoclonal antibody was coupled to solid phase; two other clones of different monoclonal antibodies were conjugated to horseradish peroxidase (HRP; EC 1.11.1.7) and alkaline phosphatase (AP; EC 3.1.3.1), respectively. These two enzyme conjugates were mixed together to measure w-hCG or hCG-beta, depending on the selection of the enzyme substrate. To measure w-hCG and hCG-beta simultaneously, both enzyme substrates were used with the blended enzyme conjugates. The assay is simple and reproducible, and can be completed within 2 h with high specificity and sensitivity. We measured w-hCG and hCG-beta in the sera of women with abnormal pregnancies and in patients with tumors of the reproductive system, and observed different hCG-beta/w-hCG ratios in patients with various types of trophoblastic tumors.

Survival factors in a canine septic shock model

Physiological indicators of tissue perfusion in a canine septic shock model have been examined. An early death (ED) group and a combined late death and survivor group (LDS) were defined and the corresponding data compared. It was found that the LDS group had less reductions in mean systemic arterial pressure (P less than 0.05), transcutaneous oxygen pressure (P less than 0.05), and red blood cell deformability (P less than 0.001); a smaller increase in hematocrit (P less than 0.05); and a lower concentration of white blood cells (P less than 0.05), relative to the ED group, at 6 hr after an infusion of Escherichia coli organisms. These results suggest that dogs in the LDS group have better tissue perfusion than those in the early death ED group. Post-treatment of dogs with pentoxifylline did not improve survival time or enhance flow factors.

Effect of lactate dehydrogenase isoenzymes on the coupled enzymatic assay for alanine aminotransferase activity

We show an example of the importance of specifying the form of isoenzyme and source of indicator enzymes to be used in coupled enzymatic assays. When we compared H-4 (pig heart) and M-4 (rabbit muscle) isoenzymes of lactate dehydrogenase for their suitability as indicator enzymes in the assay for alanine aminotransferase activity, we found that about fourfold as much M-4 as H-4 was required in terms of lactate dehydrogenase activity to reflect accurately equivalent amounts of alanine aminotransferase activity. Moreover, the substrate specificities of the two isoenzymes differed quantitatively.