Structural investigation of 2-naphthyl phenyl ether inhibitors bound to WT and Y181C reverse transcriptase highlights key features of the NNRTI binding site

Human immunodeficiency virus (HIV)-1 remains as a global health issue that is primarily treated with highly active antiretroviral therapy, a combination of drugs that target the viral life cycle. One class of these drugs are non-nucleoside reverse transcriptase inhibitors (NNRTIs) that target the viral reverse transcriptase (RT). First generation NNRTIs were troubled with poor pharmacological properties and drug resistance, incentivizing the development of improved compounds. One class of developed compounds are the 2-naphthyl phenyl ethers, showing promising efficacy against the Y181C RT mutation. Further biochemical and structural work demonstrated differences in potency against the Y181C mutation and binding mode of the compounds. This work aims to understand the relationship between the binding mode and ability to overcome drug resistance using macromolecular x-ray crystallography. Comparison of 2-naphthyl phenyl ethers bound to Y181C RT reveal that compounds that interact with the invariant W229 are more capable of retaining efficacy against the resistance mutation. Additional modifications to these compounds at the 4-position, computationally designed to compensate for the Y181C mutation, do not demonstrate improved potency. Ultimately, we highlight important considerations for the development of future HIV-1 drugs that are able to combat drug resistance.

Molecular and cellular studies evaluating a potent 2-cyanoindolizine catechol diether NNRTI targeting wildtype and Y181C mutant HIV-1 reverse transcriptase

The development of efficacious NNRTIs for HIV/AIDS therapy is commonly met with the emergence of drug resistant strains, including the Y181C variant. Using a computationally-guided approach, we synthesized the catechol diether series of NNRTIs, which display sub-nanomolar potency in cellular assays. Among the most potent were a series of 2-cyanoindolizine substituted catechol diethers, including Compound 1. We present here a thorough evaluation of this compound, including biochemical, cellular, and structural studies. The compound demonstrates low nanomolar potency against both WT and Y181C HIV-1 RT in in vitro and cellular assays. Our crystal structures of both the wildtype and mutant forms of RT in complex with Compound 1 allow the interrogation of this compound's features that allow it to maintain strong efficacy against the drug resistant mutant. Among these are compensatory shifts in the NNRTI binding pocket, persistence of multiple hydrogen bonds, and van der Waals contacts throughout the binding site. Further, the fluorine at the C6 position of the indolizine moiety makes multiple favorable interactions with both RT forms. The present study highlights the indolizine-substituted catechol diether class of NNRTIs as promising therapeutic candidates possessing optimal pharmacological properties and significant potency against multiple RT variants.

Structural and Preclinical Studies of Computationally Designed Non-Nucleoside Reverse Transcriptase Inhibitors for Treating HIV infection

The clinical benefits of HIV-1 non-nucleoside reverse transcriptase (RT) inhibitors (NNRTIs) are hindered by their unsatisfactory pharmacokinetic (PK) properties along with the rapid development of drug-resistant variants. However, the clinical efficacy of these inhibitors can be improved by developing compounds with enhanced pharmacological profiles and heightened antiviral activity. We used computational and structure-guided design to develop two next-generation NNRTI drug candidates, compounds I and II, which are members of a class of catechol diethers. We evaluated the preclinical potential of these compounds in BALB/c mice because of their high solubility (510 µg/ml for compound I and 82.9 µg/ml for compound II), low cytotoxicity, and enhanced antiviral activity against wild-type (WT) HIV-1 RT and resistant variants. Additionally, crystal structures of compounds I and II with WT RT suggested an optimal binding to the NNRTI binding pocket favoring the high anti-viral potency. A single intraperitoneal dose of compounds I and II exhibited a prolonged serum residence time of 48 hours and concentration maximum (C_max) of 4000- to 15,000-fold higher than their therapeutic/effective concentrations. These C_max values were 4- to 15-fold lower than their cytotoxic concentrations observed in MT-2 cells. Compound II showed an enhanced area under the curve (0-last) and decreased plasma clearance over compound I and efavirenz, the standard of care NNRTI. Hence, the overall (PK) profile of compound II was excellent compared with that of compound I and efavirenz. Furthermore, both compounds were very well tolerated in BALB/c mice without any detectable acute toxicity. Taken together, these data suggest that compounds I and II possess improved anti-HIV-1 potency, remarkable in vivo safety, and prolonged in vivo circulation time, suggesting strong potential for further development as new NNRTIs for the potential treatment of HIV infection.

Design, Conformation, and Crystallography of 2-Naphthyl Phenyl Ethers as Potent Anti-HIV Agents

Catechol diethers that incorporate a 7-cyano-2-naphthyl substituent are reported as non-nucleoside inhibitors of HIV-1 reverse transcriptase (NNRTIs). Many of the compounds have 1-10 nM potencies toward wild-type HIV-1. An interesting conformational effect allows two unique conformers for the naphthyl group in complexes with HIV-RT. X-ray crystal structures for 4a and 4f illustrate the alternatives.

Enhanced supercapacitive performances of functionalized activated carbon in novel gel polymer electrolytes with ionic liquid redox-mediated poly(vinyl alcohol)/phosphoric acid

Functionalized activated carbon supercapacitors were fabricated using [EMIM]BF₄ mediated PVA/H₃PO₄ gel polymer electrolytes. The ionic-liquid [EMIM]BF₄ addition in PVA/H₃PO₄ gel polymer electrolyte demonstrated excellent supercapacitor performances.

Potent Inhibitors Active against HIV Reverse Transcriptase with K101P, a Mutation Conferring Rilpivirine Resistance

Catechol diether compounds have nanomolar antiviral and enzymatic activity against HIV with reverse transcriptase (RT) variants containing K101P, a mutation that confers high-level resistance to FDA-approved non-nucleoside inhibitors efavirenz and rilpivirine. Kinetic data suggests that RT (K101P) variants are as catalytically fit as wild-type and thus can potentially increase in the viral population as more antiviral regimens include efavirenz or rilpivirine. Comparison of wild-type structures and a new crystal structure of RT (K101P) in complex with a leading compound confirms that the K101P mutation is not a liability for the catechol diethers while suggesting that key interactions are lost with efavirenz and rilpivirine.

Discovery and crystallography of bicyclic arylaminoazines as potent inhibitors of HIV-1 reverse transcriptase

Non-nucleoside inhibitors of HIV-1 reverse transcriptase (HIV-RT) are reported that incorporate a 7-indolizinylamino or 2-naphthylamino substituent on a pyrimidine or 1,3,5-triazine core. The most potent compounds show below 10 nanomolar activity towards wild-type HIV-1 and variants bearing Tyr181Cys and Lys103Asn/Tyr181Cys resistance mutations. The compounds also feature good aqueous solubility. Crystal structures for two complexes enhance the analysis of the structure-activity data.

Picomolar Inhibitors of HIV-1 Reverse Transcriptase: Design and Crystallography of Naphthyl Phenyl Ethers

Catechol diethers that incorporate a 6-cyano-1-naphthyl substituent have been explored as non-nucleoside inhibitors of HIV-1 reverse transcriptase (NNRTIs). Promising compounds are reported that show midpicomolar activity against the wild-type virus and sub-20 nM activity against viral variants bearing Tyr181Cys and Lys103Asn mutations in HIV-RT. An X-ray crystal structure at 2.49 Å resolution is also reported for the key compound 6e with HIV-RT.

Picomolar inhibitors of HIV reverse transcriptase featuring bicyclic replacement of a cyanovinylphenyl group

Members of the catechol diether class are highly potent non-nucleoside inhibitors of HIV-1 reverse transcriptase (NNRTIs). The most active compounds yield EC50 values below 0.5 nM in assays using human T-cells infected by wild-type HIV-1. However, these compounds such as rilpivirine, the most recently FDA-approved NNRTI, bear a cyanovinylphenyl (CVP) group. This is an uncommon substructure in drugs that gives reactivity concerns. In the present work, computer simulations were used to design bicyclic replacements for the CVP group. The predicted viability of a 2-cyanoindolizinyl alternative was confirmed experimentally and provided compounds with 0.4 nM activity against the wild-type virus. The compounds also performed well with EC50 values of 10 nM against the challenging HIV-1 variant that contains the Lys103Asn/Tyr181Cys double mutation in the RT enzyme. Indolyl and benzofuranyl analogues were also investigated; the most potent compounds in these cases have EC50 values toward wild-type HIV-1 near 10 nM and high-nanomolar activities toward the double-variant. The structural expectations from the modeling were much enhanced by obtaining an X-ray crystal structure at 2.88 Å resolution for the complex of the parent 2-cyanoindolizine 10b and HIV-1 RT. The aqueous solubilities of the most potent indolizine analogues were also measured to be ~40 μg/mL, which is similar to that for the approved drug efavirenz and ~1000-fold greater than for rilpivirine.

Development of anti-coxsackievirus agents targeting 3C protease

Peptidomimetic anti-viral agents against Coxsackievirus B3 (CVB3) were developed using a strategy involving the inhibition of 3C protease (CVB3 3C(pro)), a target for CVB3-mediated myocarditis or pericarditis. In an attempt to improve the inhibitory activity against CVB3, a variety of hetero-aromatic groups were incorporated into the α,β-unsaturated ester as Michael acceptor moiety, which is the position of interaction with the cysteine moiety in the P1' active site of CVB3 3C(pro). Among these hetero-aromatic groups, the quinoline analogs 9c and 9e, with IC(50) values of 250 and 130 nM as determined from an enzyme assay, significantly inhibited the CVB3-mediated cell cytotoxicity, indicating parallel anti-viral activities. A comparison of the binding modes of the potent inhibitor 9e and the relatively weak inhibitor 9n was explored in a molecular docking study, which revealed that compound 9n lacked hydrogen bonds in its interactions with Gly129, 128, and 145.

Molecular characterization of Enterococcus faecium isolated from hospitalized patients in Korea

AIMS

Multilocus sequence typing (MLST) was performed for vancomycin-resistant Enterococcus faecium (VREF) from diverse geographical areas in Korea to obtain insights into the genetic relationships with other molecular profiles. To understand the diversity of lineages, vancomycin-susceptible E. faecium (VSEF) were included.

METHODS AND RESULTS

A total of 60 E. faecium isolates were analysed by MLST and esp profile. Molecular typing of Tn1546 of 30 VREF strains was evaluated by overlapping PCR of Tn1546 and DNA sequencing. Seven sequence types (ST) were found among 30 VSEF isolates, and four STs were found among 30 VREF isolates. The types most frequently encountered were ST 78 (26 isolates) and ST 203 (16 isolates). Of the 60 E. faecium isolates, 35 isolates were positive for the esp gene. On molecular typing of Tn1546, all VREF isolates were divided into four main types. Strains with the same ST showed divergence in Tn1546 types and strains with the same Tn1546 type represented different STs.

CONCLUSIONS

An association between Tn1546 typing and MLST was not found.

SIGNIFICANCE AND IMPACT OF THE STUDY

These results suggest that the horizontal spread of Tn1546 between strains plays a major role in the dissemination of vancomycin resistance in Korea.

Functional expression of a recombinant copper/zinc superoxide dismutase of filarial nematode, Brugia malayi

A gene encoding a copper/zinc superoxide dismutase (Cu/ Zn-SOD) of a filarial nematode, Brugia malayi, has been isolated and the biochemical properties of a functionally expressed recombinant enzyme were investigated. The cloned complementary DNA contained a single open reading frame of 477 bp encoding 158 amino acids (aa), which conserved metal-binding residues as well as residues specific for Cu/Zn-SODs. Comparison of the deduced aa sequence of the enzyme with that of other helminthes species, including filarial worms, exhibited high degree of similarities (49-98%). Recombinant enzyme of 32 kDa had an isoelectric point of 6.6 and was shown to consist of 2 subunits linked by interchain disulfide bonds. Enzyme activity of the recombinant protein was inhibited by potassium cyanide and hydrogen peroxide but not by sodium azide. It showed a wide range of pH optima, i.e., 7.0-11.0 and was highly resistant to heat inactivation.

Transgene escape: what potential for crop-wild hybridization?

To date, regional surveys assessing the risk of transgene escape from GM crops have focused on records of spontaneous hybridization to infer the likelihood of crop transgene escape. However, reliable observations of spontaneous hybridization are lacking for most floras, particularly outside Europe. Here, we argue that evidence of interspecific reproductive compatibility derived from experimental crosses is an important component of risk assessment, and a useful first step especially where data from field observations are unavailable. We used this approach to assess the potential for transgene escape via hybridization for 123 widely grown temperate crops and their indigenous and naturalized relatives present in the New Zealand flora. We found that 66 crops (54%) are reproductively compatible with at least one other indigenous or naturalized species in the flora. Limited reproductive compatibility with wild relatives was evident for a further 12 crops (10%). Twenty-five crops (20%) were found to be reproductively isolated from all their wild relatives in New Zealand. For the remaining 20 crops (16%), insufficient information was available to determine levels of reproductive compatibility with wild relatives. Our approach may be useful in other regions where spontaneous crop-wild hybridization has yet to be well documented.

Methods used for reconstruction in aggressive bone tumours: an early experience

Improvements in the overall treatment of patients with aggressive, large tumours involving the bone have made it possible to preserve and salvage limbs instead of amputating them. Each patient is unique in his clinical presentation and social circumstance. The different reconstructive options available allow us to choose the most appropriate method suited to the particular patient and with minimal delay, even when resources are limited. The patient and the relatives actively participate in the choice. The early experience of the different techniques for reconstructing these bone defects at our hospital are presented in this paper.

Identification of a novel insertion sequence in vanB2-containing Enterococcus faecium

AIMS

The characterization of a novel insertion sequence (IS) in vanB2-containing Enterococcus faecium was conducted.

METHODS AND RESULTS

Direct PCR amplification of ORFC region of Tn5382 from DNA extracted from vanB2-containing E. faecium, and sequence analysis were performed. A novel IS was identified. It is 1418 bp in length and contains one putative open reading frame that is similar to transposase. There exists inverted terminal repeats of 12 bp, but direct repeats are not present. According to high similarity to putative transposases of IS3 members, such as, IS150, IS861, IS1077 and IS911, we designated it ISEnfa3.

SIGNIFICANCE AND IMPACT OF STUDY

Since ISEnfa3 was detected in all vanB2-containing strains examined so far, it could be used as a tool for epidemiological study.

Covariation in leaf and root traits for native and non-native grasses along an altitudinal gradient in New Zealand

Across 30 grassland sites in New Zealand that ranged from native alpine grasslands to low elevation improved pastures, there were consistent patterns of leaf and root traits and significant differences between native and non-native grasses. Plants of high altitude sites have low N concentrations in both their leaves and roots, have thick leaves and roots, yet no differences in tissue density or photosynthetic water use efficiency when compared to plants of low altitude sites. Both the leaves and roots of the low altitude plants were enriched in (15)N relative to the plants of higher altitude, indicating that the low-N set of traits is associated with a more closed N cycle at high altitude. A second independent set of correlations shows that plants of wetter habitats have lower photosynthetic water use efficiency (more negative partial differential (13)C) and lower leaf and root tissue density than the plants of drier sites. For both leaves and roots, plants of native species consistently had traits associated with lower resource availability: lower N concentrations, denser tissues, more negative partial differential (15)N, and more positive partial differential (13)C than non-native species. If root %N is correlated with root longevity as has been shown in other systems, root longevity may be able to be predicted from simple measurements of leaf %N, though a hysteresis in the relationship between leaf and root N concentrations may make prediction of high longevity roots difficult.

Regulation of apoptosis by vitamin C. Specific protection of the apoptotic machinery against exposure to chlorinated oxidants

We have investigated the ability of intracellular vitamin C to protect human umbilical vein endothelial cells from exposure to hypochlorous acid (HOCl) and a range of derived chloramines. Ascorbate provided minimal protection against the cytotoxicity induced by these oxidants, as measured by propidium iodide uptake. In contrast, there was a marked effect on apoptosis, monitored by caspase-3 activation and phosphatidylserine exposure. Extended incubation of the cells with glycine chloramine or histamine chloramine completely blocked apoptosis initiated in the cells by serum withdrawal. This effect was significantly abrogated by ascorbate. Inhibition of apoptosis required the oxidant to be present for an extended period after serum withdrawal and occurred prior to caspase-3 activation. General protection of thiols by ascorbate was not responsible for the protection of apoptosis, because intracellular oxidation by HOCl or chloramines was not prevented in supplemented cells. The results suggest a new role for vitamin C in the regulation of apoptosis. We propose that, by protection of an oxidant-sensitive step in the initiation phase, ascorbate allows apoptosis to proceed in endothelial cells under sustained oxidative stress.

Clinical Analysis of Phyllodes Tumor of the Breast

PURPOSE

Phyllodes tumors are fibroepithelial mammary lesions that tend to behave in a benign fashion but may undergo sarcomatous transformation. They account for 0.3 to 0.5 percent of all breast tumors. Their behavior is not well understood by many clinicians.

MATERIALS AND METHODS

We retrospectively reviewed the clinical, radiologic, and pathologic finding and treatment modality of 31 patients of phyllodes tumor diagnosed at the Breast Clinic, Gachon Medical School Gil Medical Center between July 1992 and July 2000.

RESULTS

Pathologically, 6 patients (19.3%) had malignant tumor and 25 patients (80.7%) had benign lesions. All were women with average age of 36 years. The patients with malignant tumors tended to be older and had larger tumors and shorter duration. For preoperative diagnosis, we used mammography, sonography, and MIBI Scintimammography, fine needle aspiration cytology and biopsy. All these diagnostic methods suggested the diagnosis of phyllodes tumors in only 8 cases (26%). All patients received surgical treatment: excision in 21 cases, wide excision in 3 cases, simple mastectomy in 5 cases, and simple mastectomy with axillary lymph node dissection 2 cases. One patient with malignant tumor, two patients with borderline tumor and three patients with benign tumor experienced recurrence (19.3%).

CONCLUSION

None of the clinical or radiologic characteristics was useful in predicting for phyllodes tumor. Phyllodes tumors were difficult to make proper preoperative diagnoses and to differ malignant tumor from a benign one. This led to a simple excision and resulted in high local recurrence. We suggest that the initial or subsequent wide excision is an appropriate surgery to decrease the recurrence.

High-rate continuous production of lactic acid by Lactobacillus rhamnosus in a two-stage membrane cell-recycle bioreactor

It is important to produce L(+)-lactic acid at the lowest cost possible for lactic acid to become a candidate monomer material for promising biodegradable polylactic acid. In an effort to develop a high-rate bioreactor that provides high productivity along with a high concentration of lactic acid, the performance of membrane cell-recycle bioreactor (MCRB) was investigated via experimental studies and simulation optimization. Due to greatly increased cell density, high lactic acid productivity, 21.6 g L(-1) h(-1), was obtained in the reactor. The lactic acid concentration, however, could not be increased higher than 83 g/L. When an additional continuous stirred tank reactor (CSTR) was attached next to the MCRB a higher lactic acid concentration of 87 g/L was produced at significant productivity expense. When the two MCRBs were connected in series, 92 g/L lactic acid could be produced with a productivity of 57 g L(-1) h(-1), the highest productivity among the reports of L(+)-lactic acid that obtained lactic acid concentration higher than 85 g/L using glucose substrate. Additionally, the investigation of lactic acid fermentation kinetics resulted in a successful model that represents the characteristics of lactic acid fermentation by Lactobacillus rhamnosus. The model was found to be applicable to most of the existing data with MCRBs and was in good agreement with Levenspiel's product-inhibition model, and the Luedeking-Piret equation for product-formation kinetics appeared to be effective in representing the fermentation kinetics. There was a distinctive difference in the production potential of cells (cell-density-related parameter in Luedeking-Piret equation) as lactic acid concentration increases over 55 g/L, and this finding led to a more precise estimation of bioreactor performance.

Possible horizontal transfer of the vanB2 gene among genetically diverse strains of vancomycin-resistant Enterococcus faecium in a Korean hospital

A total of 25 isolates of vanB-containing Enterococcus faecium were recovered from patients in a single Korean hospital over a 20-month period. There were two distinct vanB2 patterns among the 11 pulsed-field gel electrophoresis types; 17 contained the prototype vanB2 and 8 contained a novel vanB2 with a 177-bp deletion in vanY(B). Both vanB2 genes were transmissible in vitro at a mean frequency of 1.1 x 10(-8) transconjugants/donor. These results suggest the horizontal spread of vanB2 is occurring among genetically diverse strains of E. faecium in Korean hospitals.

Succinic acid production with reduced by-product formation in the fermentation of Anaerobiospirillum succiniciproducens using glycerol as a carbon source

Succinic acid was produced by fermentation of Anaerobiospirillum succiniciproducens using glycerol as a carbon source. When cells were anaerobically cultured in a medium containing 6.5 g/L glycerol, a high succinic acid yield (133%) was obtained while avoiding the formation of by-product acetic acid. The gram ratio of succinic acid to acetic acid was 25.8:1, which is 6.5 times higher than that obtained using glucose (ca. 4:1) as a carbon source. Therefore, succinic acid can be produced with much less by-product formation by using glycerol as a carbon source, which will facilitate its purification. When glucose and glycerol were cofermented with the increasing ratio of glucose to glycerol, the gram ratio of succinic acid to acetic acid and succinic acid yield decreased, suggesting that glucose enhanced acetic acid formation irrespective of the presence of glycerol. Glycerol consumption by A. succiniciproducens required unidentified nutritional components present in yeast extract. By intermittently feeding yeast extract along with glycerol, a high succinic acid yield (160%) could be obtained while still avoiding acetic acid formation. This resulted in the highest ratio of succinic acid to acetic acid (31.7:1).

Batch and continuous cultivation of Anaerobiospirillum succiniciproducens for the production of succinic acid from whey

Batch and continuous cultivation of Anaerobiospirillum succiniciproducens were systematically studied for the production of succinic acid from whey. Addition of 2.5 g l(-1) yeast extract and 2.5 g l(-1) polypeptone per 10 g l(-1) whey was most effective for succinic acid production from both treated and nontreated whey. When 20 g l(-1) nontreated whey and 7 g l(-1) glucose were used as cosubstrates, the yield and productivity of succinic acid reached at the end of fermentation were 95% and 0.46 g (1 h)(-1), respectively. These values were higher than those obtained using nontreated whey alone [93% and 0.24 g (1 h)(-1) for 20 g l(-1) whey]. Continuous fermentation of A. succiniciproducens at an optimal dilution rate resulted in the production of succinic acid with high productivity [1.35 g (1 h)(-1)], high conversion yield (93%), and higher ratio of succinic acid to acetic acid (5.1:1) from nontreated whey.

Signaling pathways to the assembly of an interferon-beta enhanceosome. Chemical genetic studies with a small molecule

Small molecules that modulate specific protein functions are valuable tools for dissecting complex signaling pathways. Here, we identified a small molecule that induces the assembly of the interferon-beta (IFN-beta) enhanceosome by stimulating all the enhancer-binding activator proteins: ATF2/c-JUN, IRF3, and p50/p65 of NF-kappaB. This compound stimulates mitogen-activated protein kinase kinase kinase 1 (MEKK1), which is a member of a family of proteins involved in stress-mediated signaling pathways. Consistent with this, MEKK1 activates IRF3 in addition to ATF2/c-JUN and NF-kappaB for the assembly of the IFN-beta enhanceosome. MEKK1 activates IRF3 through the c-JUN amino-terminal kinase (JNK) pathway but not the p38 and IkappaB kinase (IKK) pathway. Taken together with previous observations, these results implicate that, for the assembly of an IFN-beta enhanceosome, MEKK1 can induce IRF3 and ATF2/c-JUN through the JNK pathway, whereas it can induce NF-kappaB through the IKK pathway. Thus, specific MEKK family proteins may be able to integrate some of multiple signal transduction pathways leading to the specific activation of the IFN-beta enhanceosome.

Continuous ethanol production from concentrated wood hydrolysates in an internal membrane-filtration bioreactor

Continuous culture for the production of ethanol from wood hydrolysate was carried out in an internal membrane-filtration bioreactor. The hydrolysate medium was sterilized at a relatively low temperature of 60 degrees C with the intention of reducing the formation of inhibitory compounds during the sterilization. The maximum ethanol concentration and productivity obtained in this study were 76.9 g/L and 16.9 g/L-h, respectively, which were much higher than those (57.2-67 g/L and 0.3-1.0 g/L-h) obtained in batch cultures using hydrolysate media sterilized at 60 degrees C. The productivity was also found to be much higher than that (6.7 g/L-h) obtained in a continuous cell retention culture using a wood hydrolysate sterilized at 121 degrees C. These results show that the internal membrane-filtration bioreactor in combination with low-temperature sterilization could be very effective for ethanol production from wood hydrolysate.

Chemotherapeutic DNA-damaging drugs activate interferon regulatory factor-7 by the mitogen-activated protein kinase kinase-4-cJun NH2-terminal kinase pathway

Chemotherapeutic drugs and energy-rich radiation cause DNA damage, inducing signaling pathways for apoptotic cell death or cell growth arrest. The tumor suppressor gene p53 plays the critical role in the regulation of these DNA damage responses. Human tumor cells can become resistant to chemotherapy through functional inactivation of p53. Thus, it is important to identify p53-independent DNA damage signaling pathways. Here, treatment of cells with chemotherapeutic drugs or UV irradiation potentiated the transcriptional activity of IFN regulatory factor-7 (IRF7), inducing its phosphorylation and its nuclear translocation. Furthermore, IRF7 was activated by the c-Jun NH2-terminal kinase (JNK) in response to DNA-damaging agents. Activation of JNK by mitogen-activated protein kinase kinase-4 stimulated the transcriptional activity of IRF7 and induced its translocation into the nucleus. Thus, activation of IRF7 through the JNK signaling pathway may play a role in the transcriptional regulation of genes in response to DNA-damaging agents.

Clinical and molecular biological analysis of a nosocomial outbreak of vancomycin-resistant enterococci in a neonatal intensive care unit

Vancomycin-resistant enterococci (VRE) have emerged as important nosocomial pathogens since 1988. We report here an outbreak of VRE between April 1997 and May 1997 in our neonatal intensive care unit (NICU). All isolates from four patients were identified as Enterococcus faecium positive and were resistant to vancomycin and teicoplanin. All of the patients with VRE were isolated for at least 5 d after admission to the unit and the positive cultures lasted between 13 and 31 d. There were no cases of sepsis or mortality in the patients with VRE. Two cases had previously received vancomycin therapy. All isolates were shown to have the vanA gene and had the same band pattern on repetitive PCR. After the four episodes, all equipment used to care for the patients were decontaminated and the staff engaged in therapy used disposable gloves and gowns. There were no more episodes. However, the NICU is no longer a safety area with regards to vancomycin-resistant enterococcal infection.

Ethanol Production Using Concentrated Oak Wood Hydrolysates and Methods to Detoxify

Ethanol production from concentrated oak wood hydrolysate was carried out to obtain a high ethanol concentration and a high ethanol yield. The effect of added inhibitory compounds, which are typically produced in the pretreatment step of steam-explosion on ethanol fermentation, was also examined. p-Hydroxybenzoic aldehyde, a lignin-degradation product, was the most inhibitory compound tested in this study. Compounds with additional methyl groups had reduced toxicity and the aromatic acids were less toxic than the corresponding aldehydes. The lignin-degradation products were more inhibitory than the sugar-derived products, such as furfural and 5-hydroxymethylfurfural (HMF). Adaptation of yeast cells to the wood hydrolysate and detoxification methods, such as using charcoal and overlime, had some beneficial effects on ethanol production using the concentrated wood hydrolysate. After treatment with charcoal and low-temperature sterilization, the yeast cells could utilize the concentrated wood hydrolysate with 170 as well as 140 g/L glucose, and produce 69.9 and 74.2 g/L ethanol, respectively, with a yield of 0.46-0.48 g ethanol/g glucose. In contrast, the cells could not completely utilize untreated wood hydrolysate with 100 g/L glucose. Low-temperature sterilization, with or without charcoal treatment, was very effective for ethanol production when highly concentrated wood hydrolysates were used. Low-temperature sterilization has advantages over traditional detoxification methods, such as using overlime, ion exchange, and charcoal, because of the reduction in the total cost of ethanol production.

Quadruplex amplification of polymorphic STR loci in a Korean population

Multiplex PCR amplification has been useful for gene mapping with polymorphic short tandem repeat (STR) loci. We have tested the four loci D20S470, D13S325, HumFOLP23 and D10S2325 for the simultaneous typing of more than 100 unrelated Koreans. This analysis allows a single base pair resolution and rapid typing with silver staining. The allele and genotype distributions are in accordance with Hardy - Weinberg expectations. These STR loci have proven useful for forensic analysis and paternity tests in which the variable number of tandem repeat (VNTR) loci have some limitations.

Effects of intravenous immunoglobulin on plasma interleukin-10 levels in Kawasaki disease

Kawasaki disease is an acute febrile disease in children and many inflammatory cytokines are known to be involved in its pathogenesis. Interleukin-10 (IL-10) is an anti-inflammatory cytokine and previous reports have shown blood IL-10 levels were elevated during the acute phase of Kawasaki disease. In this study, we endeavoured to clarify the effects of i.v.IG on plasma IL-10 levels and to verify by RT-PCR, using specific primers, whether viral IL-10 or human IL-10 was responsible for high plasma IL-10. T-cells and B-cells were separated using magnetic beads, and IL-10 mRNA expressions were tested in both cell types. The mean plasma IL-10 levels were significantly decreased from 125.037 +/- 111.161 pg/ml, before i.v.IG treatment, to 32.437 +/- 54.716 pg/ml, after i.v.IG treatment, in subjects with Kawasaki disease. The levels of patients before i.v.IG treatment were significantly higher than those of the acute febrile patients (mean 26.956 +/- 13.316 pg/ml) and the normal controls (mean 16.042 +/- 5.088 pg/ml). RT-PCR was performed using specific primers to distinguish whether viral IL-10 (BCRF-1) or human IL-10 was produced in Kawasaki disease. Viral IL-10 (BCRF-1) mRNA expression was not detected in any groups and only human IL-10 mRNA transcripts were detected in PBMCs of Kawasaki patients as well as in those of acute febrile patients and normal controls. Human IL-10 mRNA transcripts were detected in both CD3+ T-cells and CD19+ B-cells. Elevated IL-10 levels during the acute phase of Kawasaki disease decreased immediately after i.v.IG administration, coincidentally with rapid improvement of inflammatory symptoms. Elevated plasma IL-10 in Kawasaki disease was transcripted from the human IL-10 gene and IL-10 mRNA expressions were detected in both T- and B-cells. Therefore, this study suggests that plasma IL-10 levels may be useful in the early identification and discrimination of the acute phase of Kawasaki disease from other febrile diseases. However, i.v.IG effects on IL-10 production still needs further investigation.

Genetic variations at four tetrameric tandem repeat loci in Korean population

Allele and genotype frequencies for four tetrameric short tandem repeat (STR) loci, HumFES/FPS, HumFOLP23, HumGABRB15, and HumCYAR04, have been determined by polymerase chain reaction (PCR) amplification and subsequent polyacrylamide gel electrophoresis from approximately 200 genetically unrelated Koreans. This method allows a single base pair resolution and rapid typing with silver staining. The allele and genotype distributions satisfy Hardy-Weinberg expectation. Also, these STR loci have proven to be useful for forensic analyses and paternity tests in which the variable number of tandem repeat (VNTR) loci have some limitations.

A case of disseminated coccidioidomycosis--autopsy report

Disseminated coccidioidomycosis is a systemic fungal infection that is occurring more commonly and causes high mortality in patients with compromised host defense or debilitated. It is endemic in certain areas of North, Central, and South America. Increasingly, cases are being recognized outside the endemic area, due to travelers who have visited an endemic area. We experienced a case of disseminated coccidioidomycosis, as a reactivation of infection acquired earlier in a patient, who was a former resident of an endemic area.

Bacteremia with nontyphi Salmonella and therapeutic implication

OBJECTIVES

The recent decades witnessed the increased incidence of bacteremia with nontyphi Salmonella, especially in patients with underlying diseases. To evaluate clinically the patients with bacteremia by nontyphi Salmonella, we investigated the clinical records of the patients.

METHODS

Retrospective study was performed on 30 cases of bacteremia with nontyphi Salmonella admitted to Soon Chun Hyang University Hospital from 1987 to 1993, and we analyzed with regard to age distribution, underlying diseases, clinical presentation and fatality.

RESULTS

Children below 2 years of age were seven patients and patients over 55 years of age were 8 patients. The male to female ratio was 3:2. Only five cases were nosocomially acquired. More than two-thirds (21 patients) had no discernible other illness at the time of their bacteremia. A quarter of the patients presented without gastrointestinal manifestation. There were four deaths in the 30 patients with nontyphi Salmonella septicemia (13.3%).

CONCLUSIONS

We investigated the clinical characteristics of 30 cases of non-typhi Salmonella bacteremia, which has a relatively high incidence nowadays while, to the contrary, Salmonella typhi trends toward being on the decrease in Korea.

Design features and surgical use of a cannulated extrusion needle

A cannulated extrusion needle was designed as a modification of the standard 20-gauge extrusion by including an inner 24-gauge flexible cannula that can be extended up to 18 mm beyond the metal tip. Indications for use of the instrument are reviewed along with selected case histories demonstrating its use. The instrument is used primarily for internal subretinal fluid drainage in eyes with complex retinal detachments caused by proliferative vitreoretinopathy. The flexible cannula is guided into the subretinal space through an open peripheral retinal break and the subretinal fluid is evacuated during a simultaneous fluid/air exchange. The positive pressure of the automated air pump creates a pressure gradient sufficient to achieve passive egress of subretinal fluid through the cannula. Active suction is avoided because of the risk of posterior retinal incarceration into the cannula tip. In addition, the cannula can be used to remove hemorrhage, gas, or silicone oil in the subretinal space.

Applications of a cannulated extrusion needle during vitreoretinal microsurgery

A specially designed cannulated extrusion needle facilitates the internal drainage of subretinal fluid during vitreoretinal microsurgery. Case histories demonstrate the use of this instrument in the management of complex retinal detachments including eyes with preretinal and subretinal hemorrhage, proliferative vitreoretinopathy with open peripheral retinal breaks, retinal detachment with giant retinal tear, and combined traction-rhegmatogenous detachments due to diabetic retinopathy. This method of internal drainage appears to have specific advantages over standard techniques by allowing the removal of subretinal hemorrhage, the utilization of pre-existing peripheral breaks for internal drainage, and the complete reattachment of shallow posterior pole retinal detachments to allow laser endophotocoagulation.

Psychological evaluation of the child with a suspected central auditory dysfunction

I have attempted to summarize the role of the psychologist and psychological evaluation in assessing a child with a suspected central auditory dysfunction. The reasons why a child may be referred for a psychological evaluation along with some of the exhibiting behaviors were discussed. The role of the psychological evaluation was examined. The indications for psychological evaluation in central auditory dysfunction were presented and alternative types of education were discussed.