Prognostic implication of residual inflammatory risk according to disease status in patients treated with percutaneous coronary intervention

Background

Compared with stable angina, acute myocardial infarction (AMI) phenotype is related with the elevated inflammatory activity. However, time-dependent change of inflammatory level and its prognostic implication has not been fully understood according to the disease entity.

Methods

We enrolled total 4,263 patients who underwent percutaneous coronary intervention (PCI) with serial measurement of high-sensitivity C-reactive protein (hsCRP) at on-admission and 1-month post-PCI. The risks of MACE (a composite of death, MI or stroke), and major bleeding were evaluated up to 4 years after procedure.

Results

Compared with the non-AMI group (n=1,887), the AMI group (n=2,376) showed the significant decrease of hs-CRP during 1 month (∇0.5 vs. ∇0.1 mg/L; P<0.001). However, 1-month hs-CRP value still was higher in the AMI group than in the non-AMI group (median: 1.0 vs. 0.9 mg/L; P=0.001). During 1-month follow-up, high vs. low inflammatory risk (upper vs. lower tertile of hs-CRP) was significantly associated with increased rate of MACE in the AMI group (HR: 7.66; 95% CI: 2.29–25.59; P<0.001), but not in the non-AMI group (HR: 0.74; 95% CI: 0.12–4.40; P=0.736). From 1-month to 4-years, patients with high inflammatory risk showed the greater rate of MACE compared to those with low inflammatory risk, in both the AMI (HR: 2.40; 95% CI: 1.73–3.45; P<0.001) and non-AMI (HR: 2.67; 95% CI: 1.80–3.94; P<0.001) groups.

Conclusion

In PCI-treated patients, patients presented with AMI showed the greater values of inflammatory activity and its prognostic implication during the early phase, but combined inflammatory risk appeared similar across the disease entity during the late phase. This result may support that clinical benefit of post-PCI anti-inflammatory treatment would be constant regardless of the disease entity during the stabilized phase.

Funding Acknowledgement

Type of funding sources: None.

Clinical significance of time-varying on-treatment platelet reactivity after percutaneous coronary intervention

Objectives

This study aimed to determine the prognostic value of serial measurement of platelet reactivity (PR) using the VerifyNow, P2Y12 reaction unit (PRU) assay following percutaneous coronary intervention (PCI) during antiplatelet therapy.

Background

On-treatment PR changes over time, but the prognostic value of serial PR measurements has not been defined.

Methods

We enrolled 3204 patients who had PCI and who were measured at PCI and 1 month. We constructed regular and time-dependent Cox proportional hazard models to compare the prognostic value between baseline and serial FU of PR on a primary endpoint of cardiovascular death, myocardial infarction (MI) or stroke over a three-year period.

Results

Time-varying PR and baseline PR were both associated with an increased risk of the primary endpoint, but the duration of association with primary endpoint differed. The prognostic value of time-varying PR (adjusted hazard ratio (HR) 1.008, 95% confidence interval (CI) 1.005–1.011, p=0.001) was rapidly decreased until 3 month and no prognostic value of time-varying PR after 3 month (adjusted HR 0.999, 95% CI 0.997–1.002, p=0.683). Baseline PR was associated with an increased risk of primary endpoint upto 1 year (adjusted HR 1.005, 95% CI 1.003–1.008, p<0.001) and no prognostic value of baseline PR after 1 year (adjusted HR 0.999, 95% CI 0.997–1.002, p=0.827) was not noted, which showed more slow reduction of the prognostic value of baseline PR.

Conclusions

Time-varying on-treatment PR reflects more real-world clinical practice. The prognostic value of PR decreased rapidly after PCI and we have to be cautious to use of single time point for the prediction of clinical event using on-treatment PR.

Funding Acknowledgement

Type of funding sources: None.

Impact of active and stable cancer on survival in patients undergoing percutaneous coronary intervention

Background

With advances in treatment of ischemic heart disease and cancer treatment, use of percutaneous coronary intervention (PCI) in cancer survivors and patients with active cancer (AC) is expanding.

Objectives

The purpose of this study was to determine the impact of cancer on survival and major cardiovascular events (MACE) in a long-term, single-center cohort of patients treated with PCI.

Methods

Patients treated with PCI between January 2010 and December 2017 were grouped as follows: controls (patients without cancer), stable cancer (SC), and AC. AC was included patients with cancer diagnosed within the past 6 months, patients who had cancer-related therapy within the past 6 months, active metastatic disease, or active recurrence of the cancer. The primary endpoints were 5-year survival and a secondary endpoint was 5-year MACE.

Results

A total of 6,743 patients (age 66±12 years, 68.4% men) treated with PCI were included: 6,404 (95.0%) controls, 245 (3.6%) SC, and 94 (1.4%) AC. Predominant malignancies were gastrointestinal (37.4%), lung (22.7%), and genitourinary cancer (14.7%). No differences were observed between patients with AC, SC and controls regarding 5-year MACE (total MACE, 33.2% vs. 28.1% vs. 17.5%, p=0.072; cardiac death, 13.6% vs. 9.1% vs. 6.7%, p=0.066; non-fatal myocardial infarction, 2.9% vs. 7.5% vs. 7.8%, p=0.820; revascularization, 17.9% vs. 17.6% vs. 11.6%, p=0.794, respectively). Patients with AC and SC had reduced 5-year survival compared with controls (62.0% vs. 81.5% vs. 89.8%, p<0.001) (Figure). AC was associated with a 1.76 (95% CI 1.22 to 2.54, p=0.002) fold increased risk of all-cause 5-year mortality in multivariable adjusted models.

Conclusions

Cumulative incidence of 5-year survival was discriminated by concurrent status of cancer following PCI. Individualized decision making is needed in the routine practice of PCI regarding concurrent cancer-specific treatment and prognosis.

Funding Acknowledgement

Type of funding sources: None.

P3637Relationship between serial measurements of NT-proBNP and cardiovascular events in patients with acute coronary syndrome

Background

Increased level of natriuretic peptides has been known as an important predictors of adverse cardiovascular (CV) outcomes in patients with acute coronary syndrome (ACS). We sought to evaluate clinical implication of N-terminal pro-brain natriuretic peptide (NT-proBNP) measured at initial and follow-up periods.

Methods

Serial NT-proBNP levels (on-admission and one-month post-PCI) were measured in ACS patients undergoing PCI (n=2,290). High NT-proBNP levels were determined according to the predefined age-specific criteria. Patients were stratified into 4 groups according to NT-proBNP levels (on-admission & one-month): (1) normal-normal group (n=1234, 53.9%); (2) high–normal group (n=257, 11.2%); (3) normal-high group (n=376, 16.4%); and (4) high-high group (n=423, 18.5%). Clinical events were defined as all-cause death and MACE (a composite of CV death, non-fatal MI, and ischemic stroke).

Results

With a median follow-up of 35.9 (IQR: 16.8, 54.5) months, all-cause death and MACE were occurred in 4.1% and 7.2%, respectively. NT-proBNP on-admission vs. at one-month did not differ significantly (median 391.6 [IQR: 143.9, 1402.3] vs. median 619.1 [IQR 240.1, 1616.1]; p=0.622), but the prevalence of high NT-proBNP was increased over time (25.3% to 34.9%; p<0.001). The rates of all-cause death and MACE significantly increased only in the high-high group compared with other groups (log-rank test, all p values <0.001, Figure). After adjustment, the high-high group remained significantly risky in terms with the occurrence of all-cause death (HR, 2.99; 95% CI, 1.65 to 5.41; p<0.001) and MACE (HR, 1.96; 95% CI, 1.28 to 3.01; p=0.002).

Figure 1

Conclusion

Serial measurements of NT-proBNP at on-admission and follow-up can help to stratify the risks of all-cause death and adverse CV events following PCI in ACS patients. About two-fifths of patients having high NT-proBNP level during hospitalization can be classified into the low-risk group for all-cause death and adverse CV events.

Acknowledgement/Funding

None

Soliton fractional charge of disordered graphene nanoribbon

We investigate the properties of the gap-edge states of half-filled interacting disordered zigzag graphene nanoribbons, and find that the midgap states can display a quantized fractional charge of 1/2. These gap-edge states can be represented by topological kinks with their site probability distribution divided between the left and right zigzag edges with different chiralities. In addition, there are numerous spin-split gap-edge states, similar to those in a Mott-Anderson insulator.

1003. Clinical Implications of Emerging Nonvaccine-Serotype Invasive Pneumococcal Disease Among Adults in the Republic of Korea in the Era of Protein-Conjugated Pneumococcal Vaccine

Background

In the Republic of Korea (ROK), protein conjugated vaccines (PCV13 and PCV10) in replacement of PCV7 have been used in children since 2010, and then included in the childhood national immunization program (NIP) in 2014. This study investigated indirect effect of PVCs on serotypes in PCV-naïve adult invasive pneumococcal disease (IPD) and its clinical implications.

Methods

A prospective observational cohort study was conducted, through the serotype surveillance program following the NIP implementation of 23-valent pneumococcal polysaccharide vaccine (PPV23) for elderly population (≥65 years) from 2013 to 2015. Clinical data and pneumococcal isolates from adult IPD patients (≥18 years) were collected from 20 hospitals. Clinical characteristics were compared between vaccine-serotype (VT) and nonvaccine-serotype (NVT) groups.

Results

Of a total of 319 IPD patients enrolled, 189 cases (59.2%) were available for serotypes. Among them, the proportion of PCV-naïve cases was 99.5% (188/189) and 189 patients consisted of NVT (n = 64, 33.9%) and VT group (n = 125, 66.1%). Compared with the previous study in the ROK (2004–2010), the proportion of PCV13 serotypes was decreased (61.4% vs. 37.0%, P < 0.001) and PPV23 serotypes were stationary (71.5% vs. 65.6%), but NVT serotypes were increased (23.4% vs. 33.9%, P = 0.033) in our study. The most common serotype was 3 (20.8%) and 34 (23.4%) in VT and NVT group, respectively. VT group had more bacteremic pneumonia (72.0% vs. 48.4%, P = 0.002). There was no difference of the case fatality rate between NVT and VT groups (29.7% vs. 35.2%, P = 0.447). Multiple logistic regression analysis showed that chronic kidney disease (odds ratio [OR] 10.26, 95% confidence interval [CI] 1.94–54.44, P = 0.006), younger age of 18–49 years (OR 4.04, 95% CI 1.29–12.71, P = 0.017), deep-seated infection (OR 3.73, 95% CI 1.34–10.39, P = 0.012), meropenem resistance (OR 3.21, 95% CI 1.49–6.91, P = 0.003) were significantly associated with NVT-IPD cases.

Conclusion

Our study indicates that emerging and expanding NVT-IPD among adults, probably due to indirect herd effect of widespread use of pediatric PCV. Further changes of IPD serotypes might occur and IPD serotypes should be monitored for developing better pneumococcal vaccination policy.

Disclosures

All authors: No reported disclosures.

744. Effectiveness of 23-Valent Pneumococcal Polysaccharide Vaccine and Influenza Vaccine Against Pneumococcal Pneumonia Among Elderly Patients Aged 65 Years and Older in the Republic of Korea: A Case–Control Study

Background

The national immunization program (NIP) of annual influenza vaccination to the elderly population (≥65 years of age) in the Republic of Korea (ROK) has been implemented since 1987. Recently, the 23-valent pneumococcal polysaccharide vaccine (PPV23) through the NIP has been provided to the elderly population in the ROK since May 2013. The aim of this study was to assess PPV23 and influenza vaccine (IV) effectiveness in preventing pneumococcal pneumonia (PP) among elderly patients ≥65 years of age.

Methods

A case–control study using a hospital-based cohort was conducted. Cases of PP including bacteremic PP and nonbacteremic PP were collected from 14 hospitals in the pneumococcal diseases surveillance program from March 2013 to October 2015. Controls matched by age and sex in the same hospital were selected. Demographic, clinical information, and vaccination histories were collected. Previous immunization was categorized into “vaccinated” if a patient had received vaccines as follows: PPV23 (4 weeks to 5 years) and IV (2 weeks to 6 months) prior to the diagnosis of PP for case patients and prior to the hospital admission for control patients. Adjusted odds ratio (OR) was calculated, controlling for underlying medical conditions. Vaccine effectiveness was defined as (1 – OR) × 100.

Results

During the study period, a total of 661 cases (104 bacteremic PP cases and 557 nonbacteremic PP cases) and 661 controls were enrolled for analyses. For overall patients ≥65 years of age, there was no significant vaccine effectiveness against PP. For young elderly patients with 65–74 years, IV alone (1.2%, [95% confidence interval (CI) −95.3% to 50.0%]) and PPV23 alone (21.9%, [95% CI −39.0% to 56.1%]) were not effective. However, significant vaccine effectiveness of PPV23 plus IV against PP was noted (54.4%, [95% CI 6.9–77.7%], P = 0.031). For older elderly patients ≥75 years of age, no significant vaccine effectiveness was observed.

Conclusion

Our study indicates that PPV23 plus IV may be effective in preventing PP among young elderly patients with 65–74 years, suggesting additive benefits of influenza plus PPV23 vaccination. Further studies are required to confirm the persistent additive protective effectiveness.

Disclosures

All authors: No reported disclosures.

Topological Gap States of Rectangular Armchair Ribbon

We consider a rectangular graphene armchair ribbon with an excitation gap. The boundary of this system consists of two short zigzag edges and two long armchair edges. Within such a ribbon, topological gap states exist that are localized along the zigzag edges. The end charge of these states is an integer, which can be related to the Zak phase of the periodic armchair ribbon constructed from the rectangular armchair ribbon by connecting its zigzag edges together. In this paper, we provide an explicit analytical computation of the Zak phase of a periodic armchair ribbon, and show that its value is consistent with the integer end charges that are computed numerically. In the presence of a staggered potential, non-integer end charges are possible. We discuss its relation to the Zak phase.

Relationships between Single Nucleotide Polymorphism Markers and Meat Quality Traits of Duroc Breeding Stocks in Korea

This study was conducted to determine the relationships of five intragenic single nucleotide polymorphism (SNP) markers (protein kinase adenosine monophosphate-activated γ3 subunit [PRKAG3], fatty acid synthase [FASN], calpastatin [CAST], high mobility group AT-hook 1 [HMGA1], and melanocortin-4 receptor [MC4R]) and meat quality traits of Duroc breeding stocks in Korea. A total of 200 purebred Duroc gilts from 8 sires and 40 dams at 4 pig breeding farms from 2010 to 2011 reaching market weight (110 kg) were slaughtered and their carcasses were chilled overnight. Longissimus dorsi muscles were removed from the carcass after 24 h of slaughter and used to determine pork properties including carcass weight, backfat thickness, moisture, intramuscular fat, pH24h, shear force, redness, texture, and fatty acid composition. The PRKAG3, FASN, CAST, and MC4R gene SNPs were significantly associated with the meat quality traits (p<0.003). The meats of PRKAG3 (A 0.024/G 0.976) AA genotype had higher pH, redness and texture than those from PRKAG3 GG genotype. Meats of FASN (C 0.301/A 0.699) AA genotype had higher backfat thickness, texture, stearic acid, oleic acid and polyunsaturated fatty acid than FASN CC genotype. While the carcasses of CAST (A 0.373/G 0.627) AA genotype had thicker backfat, and lower shear force, palmitoleic acid and oleic acid content, they had higher stearic acid content than those from the CAST GG genotype. The MC4R (G 0.208/A 0.792) AA genotype were involved in increasing backfat thickness, carcass weight, moisture and saturated fatty acid content, and decreasing unsaturated fatty acid content in Duroc meat. These results indicated that the five SNP markers tested can be a help to select Duroc breed to improve carcass and meat quality properties in crossbred pigs.

Developmental expression of Pitx2c in Xenopus trigeminal and profundal placodes

Cranial placodes are thickenings of the embryonic head ectoderm that contribute to the paired sense organs and to the cephalic peripheral nervous system. Here we report the spatiotemporal expression pattern of transcription factor Pitx2c during Xenopus laevis cranial placode formation, focusing more specifically on key stages of trigeminal and profundal placode development. We also compare its expression to five genes that have been associated with development of these sensory placodes, namely Foxi1c, Islet1, NeuroD, Pax3, and Six1. We show that while initially expressed in both the trigeminal and profundal placodes, Pitx2c is later restricted to the prospective profundal ganglion, where it is co-expressed with Islet1, NeuroD and Pax3. This combination of factors defines a molecular signature for the characterization of the profundal versus trigeminal ganglia in Xenopus.

Effects of Aster scaber Seed Oil Containing trans-Δ3 Fatty Acids on Lipid Profiles of Hamsters and Rats

The effects of Aster scaber seed oil (ASO) on lipid profiles were studied in rats and hamsters. ASO contained considerable amounts of Δ3t-16:1 (11.4%), Δ3t, 9c-18:2 (4.6%), and Δ3t, 9c, 12c-18:3 (11.3%). Young rats and hamsters were fed diets containing ASO, soybean oil (SBO), or olive oil (OLO) as fat sources for 4 weeks in separate experiments with or without cholesterol. In the rat study, there were no significant differences in the concentrations of serum total cholesterol, high-density lipoprotein (HDL)-cholesterol, and triacylglycerol among the groups. The serum but not liver malondialdehyde (MDA) level was significantly lower in the ASO-fed group than it was in the other groups. The biochemical and growth parameters revealed no significant biological damages in the ASO-fed animals. In the hamster study, dietary cholesterol-dependent effects were evident in the serum lipids profiles, whereas the fat-induced effect was only observed in the ratio of serum low-density lipoprotein (LDL)-/HDL-cholesterol. Furthermore, fat- and cholesterol-induced effects were evident in the ratio of serum LDL-/HDL-cholesterol. Significant interactions between dietary fat and cholesterol were observed as evident from the concentration of serum cholesterol and triacylglycerol, as well as the activity of serum cholesterol ester transfer protein. These results suggest that dietary ASO containing trans-Δ3 fatty acids appeared to improve the serum LDL-/HDL-cholesterol ratio more than the SBO did, especially when hamsters were simultaneously fed cholesterol-supplemented diet.

Stability of Anomalous States of a Local Potential in Graphene

Graphene Landau levels have discrete energies consisting zero energy chiral states and non-zero energy states with mixed chirality. Each Landau level splits into discrete energies when a localized potential is present. A simple scaling analysis suggests that a localized potential can act as a strong perturbation, and that it can be even more singular in graphene than in ordinary two-dimensional systems of massful electrons. Parabolic, Coulomb, and Gaussian potentials in graphene may have anomalous boundstates whose probability density has a sharp peak inside the potential and a broad peak of size magnetic length l outside the potential. The n = 0 Landau level with zero energy has only one anomalous state while the n = ±1 Landau levels with non-zero energy have two (integer quantum number n is related to the quantized Landau level energies). These anomalous states can provide a new magnetospectroscopic feature in impurity cyclotron resonances of graphene. In the present work we investigate quantitatively the conditions under which the anomalous states can exist. These results may provide a guide in searching for anomalous states experimentally.

Follistatin-like 3 is a mediator of exercise-driven bone formation and strengthening

Exercise is vital for maintaining bone strength and architecture. Follistatin-like 3 (FSTL3), a member of follistatin family, is a mechanosensitive protein upregulated in response to exercise and is involved in regulating musculoskeletal health. Here, we investigated the potential role of FSTL3 in exercise-driven bone remodeling. Exercise-dependent regulation of bone structure and functions was compared in mice with global Fstl3 gene deletion (Fstl3-/-) and their age-matched Fstl3+/+ littermates. Mice were exercised by low-intensity treadmill walking. The mechanical properties and mineralization were determined by μCT, three-point bending test and sequential incorporation of calcein and alizarin complexone. ELISA, Western-blot analysis and qRT-PCR were used to analyze the regulation of FSTL3 and associated molecules in the serum specimens and tissues. Daily exercise significantly increased circulating FSTL3 levels in mice, rats and humans. Compared to age-matched littermates, Fstl3-/- mice exhibited significantly lower fracture tolerance, having greater stiffness, but lower strain at fracture and yield energy. Furthermore, increased levels of circulating FSTL3 in young mice paralleled greater strain at fracture compared to the lower levels of FSTL3 in older mice. More significantly, Fstl3-/- mice exhibited loss of mechanosensitivity and irresponsiveness to exercise-dependent bone formation as compared to their Fstl3+/+ littermates. In addition, FSTL3 gene deletion resulted in loss of exercise-dependent sclerostin regulation in osteocytes and osteoblasts, as compared to Fstl3+/+ osteocytes and osteoblasts, in vivo and in vitro. The data identify FSTL3 as a critical mediator of exercise-dependent bone formation and strengthening and point to its potential role in bone health and in musculoskeletal diseases.

Kinetic study for the optimization of ginsenoside Rg3 production by heat treatment of ginsenoside Rb1

BACKGROUND

Ginsenoside Rg3 is a promising anticancer agent. It is usually produced by heat treatment of ginseng, in which ginsenoside Rb1 is the major ginsenoside. A kinetic study was conducted to optimize ginsenoside Rg3 production by the heat treatment of ginsenoside Rb1.

METHODS

Ginsenoside Rb1 was heated using an isothermal machine at 80°C and 100°C and analyzed using HPLC. The kinetic parameters were calculated from the experimental results. The activation energy was estimated and used to simulate the process. The optimized parameters of ginsenoside Rg3 production are suggested based on the simulation.

RESULTS

The rate constants were 0.013 h(-1) and 0.073 h(-1) for the degradation of ginsenosides Rb1 and Rg3 at 80°C, respectively. The corresponding rate constants at 100°C were 0.045 h(-1) and 0.155 h(-1). The estimated activation energies of degradation of ginsenosides Rb1 and Rg3 were 69.2 kJ/mol and 40.9 kJ/mol, respectively. The rate constants at different temperatures were evaluated using the estimated activation energies, and the kinetic profiles of ginsenosides Rb1 and Rg3 at each temperature were simulated based on the proposed kinetic model of consecutive reaction. The optimum strategies for producing ginsenoside Rg3 from ginsenoside Rb1 are suggested based on the simulation. With increased temperature, a high concentration of ginsenoside Rg3 is formed rapidly. However, the concentration decreases quickly after the reaching the maximal concentration value.

CONCLUSION

The optimum temperature for producing ginsenoside Rg3 should be the highest temperature technically feasible below 180°C, in consideration of the cooling time. The optimum reaction time for heat treatment is 30 min.

Presenilin enhancer-2 (PSENEN), a component of the gamma-secretase complex, is involved in adipocyte differentiation

This study was conducted to identify genes expressed during adipocyte differentiation of bovine intramuscular fibroblast-like cells using differential display reverse-transcriptase polymerase chain reaction. The presenilin enhancer-2 (PSENEN) gene was found to be down-regulated during adipocyte differentiation of bovine intramuscular fibroblast-like cells. The ectopic expression of bovine PSENEN in 3T3-L1 reduced adipogenesis and the inhibition of endogenous PSENEN by siRNA induced adipogenesis on d 4 of adipocyte differentiation of 3T3-L1 cells. Interestingly, the expression of gamma-secretase complex gene-related Notch signaling was decreased at d 2 and d 4 during adipocyte differentiation. In addition, expression of the Notch-signaling genes (Notch-1, Hes-1, Pref-1, adipsin) was regulated during adipocyte differentiation by regulation of PSENEN expression. These results suggest that PSENEN plays an important role in adipocyte differentiation and that Notch signaling is involved in adipogenesis.

Non-resonant and resonant x-ray scattering studies on multiferroic TbMn2O5

Comprehensive x-ray scattering studies, including resonant scattering at Mn L, Tb L, and M edges, were performed on single crystals of TbMn2O5 for crystallographic data to elucidate the nature of its commensurate and incommensurate phases. The scattering results provide direct evidence of symmetry lowering to the ferroelectric phase driven by magnetically induced lattice modulations and show the presence of multiple magnetic orders. The competing orders under spin-frustrated geometry are believed to cause discommensuration and result in the commensurate-to-incommensurate phase transition around 24 K. It is proposed that the low temperature incommensurate phase consists of commensurate domains separated by antiphase domain walls which change both signs of spontaneous polarizations and x-ray scattering amplitudes for forbidden reflections.

Enhancing phage display of antibody fragments using gIII-amber suppression

The effect of utilizing Ex12 helper phage, a mutant M13K07 helper having two amber codons at the gIII (gIII-amber), in combination with Escherichia coli host strains belonging to the supE genotype on improving the phage display of antibody fragments was investigated. Because of an inefficient read-through of the UAG codons, Ex12 helper phage produced approximately 10% of the intracellular wt pIII in the supE host cells compared to M13K07. The phage progenies rescued from the supE XL-1 Blue MRF' strain carrying the recombinant phagemid, pCMTG-SP112, by Ex12 helper phage displayed both antibody-DeltapIII fusion and wt pIII at a ratio of 1:1.5, and achieved a 50-fold greater display of the antibody-DeltapIII compared to those obtained by a conventional phage rescue using M13K07. Additionally observed were a 100-fold increase in antigen-binding functionality and a drastic improvement on antigen-specific panning efficiency by the phage progenies. Our approach permits the display of at least one antibody fragment as well as more than one copy of wt pIII on the surface of recombinant phages, and this would make the phagemid-based phage display technology more practical and reliable.

Coherent manipulation of electronic States in a double quantum dot

We investigate coherent time evolution of charge states (pseudospin qubit) in a semiconductor double quantum dot. This fully tunable qubit is manipulated with a high-speed voltage pulse that controls the energy and decoherence of the system. Coherent oscillations of the qubit are observed for several combinations of many-body ground and excited states of the quantum dots. Possible decoherence mechanisms in the present device are also discussed.

Continuous culture of immobilized streptomyces cells for kasugamycin production

Continuous cultures of immobilized Streptomyces kasugaensis, a kasugamycin producer, were carried out on Celite beads. When using a prototype separator for immobilized-cell separation and recycling, the continuous operation could not be sustained for an extended period as a result of an excessive loss of immobilized cells caused by the poor performance of the separator. Accordingly, the immobilized-cell separator was revised to provide better immobilized-cell settling and thus recycling into the reactor. In a subsequent culture using the revised separator, a stable operation was maintained for over 820 h with a high kasugamycin productivity. The kasugamycin productivity ranged from 9.8 to 16.1 mg/L/h, which was about 14- to 23-fold higher than that in a batch suspended-cell culture. When the original feeding medium concentration was doubled at the end of the continuous culture, the productivity became severely impaired for several reasons, which will be discussed. An excessive formation of free cells and loss of immobilized cells through the separator were also observed.

Screening of hexavalent chromium biosorbent from marine algae

A highly chromate-selective biosorbent with high adsorption capacity was found by examining the chromate adsorption capacities of 48 species of red, brown, or green marine algae sampled from the east coast of Korea. As a result of screening, a red marine alga showed excellent adsorption characteristics. It was identified as Pachymeniopsis sp. The timing of the sampling of Pachymeniopsis sp. did not affect the adsorption capacity of the alga but the optimum period for mass collection was April-May. The alga also showed high selectivity for chromate and its adsorption capacity for other heavy metal ions such as cadmium and manganese was relatively low. An investigation of the adsorption isotherm of Pachymeniopsis sp. as a dried powder for chromate adsorption at 25 degrees C showed Langmuir-type dependence. The maximum chromate adsorption capacity of the selected alga was about 225 mg/g. The desorption of adsorbed chromate from Pachymeniopsis sp. was done by treating samples with 1 N NaOH. It was confirmed that ion exchange type adsorption was observed with anion exchangers but not with cation exchangers. Therefore it is believed that the chromate adsorption is based on the anionic exchange of Pachymeniopsis sp.

Ammonia removal using hepatoma cells in mammalian cell cultures

It was examined whether hepatocyte cell lines can be used for ammonia removal in mammalian cell cultures. It was found that there exists a critical ammonium concentration level for each hepatocyte cell to remove ammonia. Among the cells tested in this work, primary hepatocytes showed the strongest ammonia removal capability if ammonium concentration is higher than the critical level. However, primary hepatocytes lost the liver function gradually and finally died after 2-3 weeks. Because of this limitation, primary hepatocytes were not appropriate to be used for ammonia removal in long-term cultures. Hep G2 cells, which are immortal, also showed a strong ammonia removal activity. The ammonia removal activity of Hep G2 cells depended on the concentration of ammonium in the medium, as in the case of primary hepatocytes. However, urea could not be detected in the course of ammonia removal by Hep G2 cells. Instead of urea, Hep G2 cells secreted glutamine into the culture medium. The capacity for ammonia removal was higher in the absence than in the presence of glutamine. Thus we checked the activity of glutamine synthetase in the Hep G2 cells. The level of glutamine synthetase activity increased with the addition of ammonium chloride. This result accounts for the ammonium concentration dependency of Hep G2 cells in ammonia removal and glutamine synthesis. Furthermore Hep G2 cells could grow well in the absence of glutamine, which was necessarily required in mammalian cell cultures. These results prove that glutamine formation serves as the primary mechanism of detoxifying ammonia in hepatocyte cell lines as expected. In addition, it was demonstrated that ammonium level could be reduced 38% and that erythropoietin production increased 2-fold in the mixed culture of Hep G2 and recombinant CHO cells.

Screening of hexavalent chromium biosorbent for marine algae

A high-chromate-selective biosorbent with high adsorption capacity was sought by examining the chromate adsorption capacities of 48 species of red, brown, or green marine algae sampled from the east coast of Korea. Screening showed a red marine alga to have the most excellent adsorption characteristics among them, and it was identified as Pachymeniopsis sp. The period at which Pachymeniopsis sp. was sampled did not affect the adsorption capacity of the alga, but the optimum period for mass collection was April to May. The alga also showed high selectivity for chromate since its adsorption capacity for other heavy metal ions such as cadmium and manganese ions was relatively low. An investigation of the adsorption isotherm of dried powder of Pachymeniopsis sp. for chromate adsorption at 25 degrees C showed a Langmuir-type dependence. The maximum chromate adsorption capacity of the selected alga was about 225 mg/g. Desorption of the adsorbed chromate from Pachymeniopsis sp. was done by treating the sample with 1 N NaOH. It was confirmed that ion exchange type adsorption was observed with an anion exchanger but not with a cation exchanger. It is therefore believed that the chromate adsorption is based on anionic exchange of Pachymeniopsis sp.

Atrial fibrillation in patients with permanent VVI pacemakers: risk factors for atrial fibrillation

OBJECTIVES

Atrial fibrillation (AF) does not only deteriorate the cardiac function and increases the thromboembolic risk but also triggers rapid and irregular ventricular rhythm in patients with atrial synchronous pacing. However, the risk factors for the development of AF in patients with pacemakers are not clearly determined yet. The present study was designed to determine the risk factors for AF in patients with VVI pacemakers.

METHODS

This study included 80 patients (41 sick sinus syndrome, 39 AV block) who were followed for more than 6 months or developed AF regardless of the duration of follow-up after implantation of VVI pacemakers. Patients were divided into two groups according to whether or not AF developed during follow-up (mean: 25.7 +/- 2.5 months): group A developed AF and group B did not. The underlying arrhythmias, cardiovascular risk factors, left atrial size, characteristics of P wave were compared between the two groups.

RESULTS

The mean age of the patients was 58.9 +/- 11.4 years and 28 (35%) were male. AF developed in 13 (16.3%) of 80 patients with VVI pacemakers. Sick sinus syndrome (SSS) as an underlying arrhythmia was significantly more frequent in group A than group B (84.6% vs. 44.8%, p < 0.01). P wave width was greater in group A (127.6 +/- 24.8 ms) than in group B (110.7 +/- 17 ms) (p < 0.05). There was, however, no significant difference in cardiovascular risk factors, left atrial size, P wave axis and amplitude between the two groups.

CONCLUSION

These results suggest that sinus node dysfunction and intra-atrial conduction delay may be the risk factors for AF in patients with VVI pacemakers. Further studies are needed to determine how sick sinus syndrome and intra-atrial conduction delay increase the risk for AF in patients with VVI pacemakers.

The design of original antimalarial drugs. An example of phospholipid metabolism

The aim of our program was to find an original chemotherapeutical treatment (and eventually a preventive treatment) of malaria, an illness largely predominant in developing countries, by interfering on an essential metabolism developed by Plasmodium during its erythrocytic phase. Apart from what has been learnt about metabolism and the pharmacological target, a crucial step has been taken during this contract by passing from micromolar in vitro active concentrations (during 1986-1990) to nanomolar ones (during 1990). These compounds should naturally short-circuit resistance phenomena already established against drugs in current use, as has already been verified on polypharmacoresistant strains or isolates of P. falciparum. The administration of a therapeutic dose of our molecules would now appear to be possible in all cases.