Portal venous velocity in the follow-up of patients with biliary atresia after Kasai portoenterostomy

BACKGROUND/PURPOSE

Liver transplantation is the only therapeutic option for biliary atresia (BA) patients with failed Kasai portoenterostomy (PE). The indication for and timing of liver transplantation in these patients are important management issues. The aims of this study are to evaluate the relationship between portal venous velocity (PVV) and clinical and biochemical indicators of liver function in BA, and to examine the role of PVV in the postoperative surveillance of these patients.

METHODS

Twenty-nine children (mean age, 8 years 4 months) who had PE for BA underwent Doppler ultrasonography to evaluate PVV. Using regression analysis, these findings were correlated with biochemical indicators of liver function. The Mann-Whitney test was used to detect any significant differences in PVV between the Child-Pugh A group and combined Child-Pugh B and C group patients.

RESULTS

The mean +/- SD PVV for the Child-Pugh A group and the combined Child-Pugh B and C group was 17.1 cm/s +/- 8.9 cm/s and 10.2 cm/s +/- 3.3 cm/s, respectively, and this difference was statistically significant (P =.037).

CONCLUSIONS

Doppler ultrasonography measurement of PVV provides adjunctive information to the clinical and biochemical assessment of the liver function status in BA. Its use in the postoperative surveillance of these patients is helpful in identifying the need for and in timing of liver transplantation.

Carbohydrate fermentation and nitrogen metabolism of a finishing beef diet by ruminal microbes in continuous cultures as affected by ethoxyquin and(or) supplementation of monensin and tylosin

Long-term feedlot studies have shown positive effects (i.e., improved ADG and reduced morbidity and mortality) of dietary supplementation with ethoxyquin (AGRADO). This may be due to improving the antioxidant capacity at the ruminal, postruminal, or postabsorption levels. This study was designed to investigate the role of ethoxyquin at the rumen level. A finishing diet (12.5% CP; DM basis) was formulated to contain (on a DM basis) 77.5% flaked corn, 10% corn cobs, 10% protein/vitamin/mineral supplement, and 2.5% tallow. In a randomized complete block design experiment, the treatments were arranged as a 2 x 2 factorial. The main factors were two ethoxyquin treatments (without or with 150 ppm) and two monensin/tylosin treatments (without or with monensin and tylosin at 0.0028 and 0.0014% of dietary DM, respectively). Eight dual-flow, continuous culture fermenters were used in two experimental periods (blocks; 8 d each with 5 d for adjustment and 3 d for sample collection) to allow for four replications for each treatment. No interactions (P > 0.05) were detected for any of the measurements evaluated. Therefore, results of the main factors were summarized. Ethoxyquin supplementation improved (P < 0.05) true digestibility of OM (from 38.8 to 45.0%) but it did not alter (P > 0.05) concentrations of total VFA (averaging 131 mM) or acetate (averaging 58.8 mM). Ethoxyquin decreased (P < 0.05) propionate concentration from 51.1 to 42.4 mM and increased (P < 0.05) butyrate concentration from 18.4 to 22.9 mM. Digestion of total nonstructural carbohydrates was not altered (P > 0.05) by the treatments and averaged 86%. With the exception of increased (P < 0.05) concentration of propionate (from 42.0 to 51.5 mM) and decreased (P < 0.05) concentration of butyrate (from 25.9 to 16.3 mM), no effects (P > 0.05) were detected for monensin/tylosin. Ruminal N metabolism, including efficiency of bacterial protein synthesis (averaging 21.2 g N/kg OM truly digested), was not affected (P > 0.05) by the treatments. Results suggest positive effects of ethoxyquin on ruminal digestion of OM and unique changes in VFA production.

Identification of a new HLA-B allele, B*3705 containing a Bw6 sequence motif

HLA-B37, which is Bw4 type antigen frequently found in linkage disequilibrium with A1, Cw6 and DR10 in all ethnic groups, generally has a very low frequency all over the world. We report a new HLA-B*37 allele, B*3705, identified in two potential bone marrow donors in the Korean population. B*3705, which has the Bw6 nucleotide segment, differs from B*3701 in three nucleotide positions: 311, 317 and 319 in exon2. The serological profile of B*3705 did not exhibit the B37 specificity. The putative haplotype associated with B*3705 in the Korean population could be A*02-Cw*0602-DRB1*1001-DQA1*0101-DQB1*0501-DPB1*02011.

Finite element (FE) modeling of the mandible: from geometric model to tetrahedral volumetric mesh

This paper presents our experience in using FE modeling of clinically relevant cases specifically in mandibular surgery. A semi-automatic procedure integrated with a group of Virtual Basic-based codes has been developed to clean the geometric models. Consequently, the time required for generate the tetrahedral volumetric mesh of mandible from patient-specific CT data has been reduced to less than 40 hours. Pre- and post-operation FE meshes are shown to be consistent and can be used for further modeling and analysis.

Design and synthesis of fluoroquinophenoxazines that interact with human telomeric G-quadruplexes and their biological effects

In this study we have identified a new structural motif for a ligand with G-quadruplex interaction that results in biological effects associated with G-quadruplex-interactive compounds. Fluoroquinolones have been reported to possess weak telomerase inhibitory activity in addition to their better known bacterial gyrase poisoning. Starting with a fluoroquinobenzoxazine, which has modest potency in a human topoisomerase II assay, we have designed a more potent inhibitor of telomerase that has lost its topoisomerase II poisoning activity. This fluoroquinophenoxazine (FQP) interacts with G-quadruplex structures to inhibit the progression of Taq polymerase in a G-quadruplex polymerase stop assay. In addition, we demonstrate by 1H NMR studies that this compound interacts with telomeric G-quadruplex structures by external stacking to the G-tetrad with both the unimolecular fold-over and the parallel G-quadruplex structures. A photocleavage assay confirms the FQP interaction site, which is located off center of the external tetrad but within the loop region. Molecular modeling using simulated annealing was performed on the FQP-parallel G-quadruplex complex to determine the optimum FQP orientation and key molecular interactions with the telomeric G-quadruplex structure. On the basis of the results of these studies, two additional FQP analogues were synthesized, which were designed to test the importance of these key interactions. These analogues were evaluated in the Taq polymerase stop assay for G-quadruplex interaction. The data from this study and the biological evaluation of these three FQPs, using cytotoxicity and a sea urchin embryo system, were in accord with the predicted more potent telomeric G-quadruplex interactions of the initial lead compound and one of the analogues. On the basis of these structural and biological studies, the design of more potent and selective telomeric G-quadruplex-interactive compounds can be envisaged.

Distribution of HLA-A, B alleles and polymorphisms of TAP and LMP genes in Korean patients with atopic dermatitis

BACKGROUND

Atopic dermatitis has been seen to result from multifactorial inheritance, with interaction between genetic and environmental factors. The genetic association may differ according to the ethnic backgrounds.

OBJECTIVE

The purpose of this study was to investigate the genetic factors in Korean atopic dermatitis patients by studying the human leucocyte antigen (HLA) class I association and polymorphisms of transporters associated with antigen presentation (TAP) and low-molecular-weight polypeptide (LMP) genes.

METHODS

HLA-A and B genotyping was performed in 53 atopic dermatitis patients and 184 healthy controls using the standard microlymphocytotoxicity technique. TAP1, TAP2, LMP2, and LMP7 gene polymorphisms were anaylzed using the polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP), PCR-amplification refractory mutation system (ARMS), and PCR-restriction fragment length polymorphism (RFLP).

RESULTS

Allele frequency of HLA-A24 was significantly increased in patients with atopic dermatitis compared to controls (P < 0.05). HLA-B alleles showed no differences in distribution between patients and controls. Genotype, phenotype, and allele frequencies of TAP1 gene also revealed no differences in distribution between patients and controls. Analysis of TAP2 gene polymorphisms showed increased frequencies of the TAP2*C allele and TAP2*A/TAP2*C genotype in atopic dermatitis patients compared to controls (P < 0.05). Distribution of LMP2 and LMP7 gene polymorphisms was similar for patients and controls.

CONCLUSION

This study demonstrates an association of atopic dermatitis with HLA-A24 and TAP2*C alleles in Korean patients. Discrepancy with the previous reports might be related to different patient characteristics and ethnic variations.

Evidence for a novel role of copper-zinc superoxide dismutase in zinc metabolism

The LYS7 gene in Saccharomyces cerevisiae encodes a protein (yCCS) that delivers copper to the active site of copper-zinc superoxide dismutase (CuZn-SOD, a product of the SOD1 gene). In yeast lacking Lys7 (lys7Delta), the SOD1 polypeptide is present but inactive. Mutants lacking the SOD1 polypeptide (sod1Delta) and lys7Delta yeast show very similar phenotypes, namely poor growth in air and aerobic auxotrophies for lysine and methionine. Here, we demonstrate certain phenotypic differences between these strains: 1) lys7Delta cells are slightly less sensitive to paraquat than sod1Delta cells, 2) EPR-detectable or "free" iron is dramatically elevated in sod1Delta mutants but not in lys7Delta yeast, and 3) although sod1Delta mutants show increased sensitivity to extracellular zinc, the lys7Delta strain is as resistant as wild type. To restore the SOD catalytic activity but not the zinc-binding capability of the SOD1 polypeptide, we overexpressed Mn-SOD from Bacillus stearothermophilus in the cytoplasm of sod1Delta yeast. Paraquat resistance was restored to wild-type levels, but zinc was not. Conversely, expression of a mutant CuZn-SOD that binds zinc but has no SOD activity (H46C) restored zinc resistance but not paraquat resistance. Taken together, these results strongly suggest that CuZn-SOD, in addition to its antioxidant properties, plays a role in zinc homeostasis.

Phospholipid metabolite 1-palmitoyl-lysophosphatidylcholine enhances human ether-a-go-go-related gene (HERG) K(+) channel function

BACKGROUND

Lysophosphatidylcholine (LPC), a naturally occurring phospholipid metabolite, accumulates in the ischemic heart and causes extracellular K(+) accumulation and action potential shortening. LPC has been incriminated as a biochemical trigger of lethal cardiac arrhythmias, but the underlying mechanisms remain poorly understood.

METHODS AND RESULTS

We studied the effect of 1-palmitoyl-LPC (Pal-LPC) on currents resulting from human ether-a-go-go-related gene (HERG) expression in human embryonic kidney (HEK) cells using whole-cell patch-clamp techniques. Bath application of Pal-LPC consistently and reversibly increased HERG current (I(HERG)). The effects of Pal-LPC were apparent as early as 3 minutes after application of the drug, reached maximum within 10 minutes, and were reversible on washout. Pal-LPC increased I(HERG) at voltages between -20 and +30 mV, with greater effects at stronger depolarization. However, Pal-LPC did not affect the voltage-dependence of I(HERG) activation. In contrast, Pal-LPC significantly shifted the inactivation curve toward more positive potentials, causing a mean 20.0+/-2.2 mV shift in half-inactivation voltage relative to control.

CONCLUSIONS

Our results indicate that apart from being a well-recognized target for drug inhibition, I(HERG) can also be enhanced by natural substances. An increase in I(HERG) by Pal-LPC may contribute to K(+) loss, abnormal electrophysiology, and arrhythmia occurrence in the ischemic heart.

Different subtypes of alpha1-adrenoceptor modulate different K+ currents via different signaling pathways in canine ventricular myocytes

Multiple subtypes (alpha1A, alpha1B, and alpha1D) of alpha1-adrenoreceptors (alpha1ARs) co-exist in the heart and mediate a variety of cellular functions. We studied alphaAR modulation of inward rectifier (IK1) and transient outward (Ito) K(+) currents in canine ventricular myocytes. Phenylephrine at 10 microM depressed only Ito without affecting IK1 and at 100 microM inhibited both Ito and IK1. The effect of phenylephrine on Ito was abolished by (+)niguldipine (10 nm) to inhibit alpha1AARs but not by chloroethyclonidine (10 microM) to inactivate alpha1BARs nor by BMY-7378 to antagonize alpha1DARs. In contrast, phenylephrine inhibition of IK1 was reversed only by BMY-7378 (1 nm). PDD (100 nm, phorbol ester activator of protein kinase C (PKC)) simulates and bisindolylmaleimide (50 nm, PKC inhibitor) weakens phenylephrine modulation of Ito but not IK1. Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) inhibitor KN-93 and inhibitor peptides abolished the effects of phenylephrine on IK1. Enhancement of PKC or CaMKII activities was seen in alpha1aAR- or alpha1dAR-transfected HEK293 cells and in myocytes pretreated with 10 or 100 microM phenylephrine, respectively. Our data suggest that different subtypes of alpha1ARs selectively modulate different cardiac K(+) currents via different signal transduction mechanisms; alpha1AARs mediate Ito regulation via PKC, and alpha1DARs mediate IK1 regulation via CaMKII.

Recombinant proapoA-I(Lys107del) shows impaired lipid binding associated with reduced binding to plasma high density lipoprotein

In the present study apoA-I (Lys 107del), a naturally occurring human apoA-I variant with a deletion of Lys 107, was expressed in E. coli to examine the effect of this mutation on lipid binding, cholesterol efflux and lecithin:cholesterol acyltranferase (LCAT) activation. Dimyristoyl phosphatidylcholine (DMPC) binding studies revealed slow interaction of proapoA-I(Lys107del) with DMPC relative to normal proapoA-I. After preincubation with human plasma lipoprotein (d<1.225 g/ml) for 1 h at 37 degrees C, 125I-labeled normal proapoA-I chromatographed as a single peak with the high density lipoprotein (HDL) fraction, whereas 125I-labeled proapoA-I(Lys107del) chromatographed with both HDL and free proapoA-I (26% of the radioactivity). Circular dichroism measurements showed that the alpha-helical content of lipid-bound proapoA-I (Lys107del) was reduced to 64 versus 73% of normal proapoA-I. Non-denaturing gradient gel electrophoresis of reconstituted HDL assembled with either proapoA-I(Lys107del) or normal proapoA-I showed that the mutation led to the formation of a second population of smaller rHDL particles. DMPC/proapoA-I(Lys107del) and normal DMPC/proapoA-I complexes exhibited a similar capacity to promote cholesterol efflux from fibroblasts. ProapoA-I (Lys107del) also activated LCAT similar to wild type proapoA-I and human plasma apoA-I. We conclude that deletion of Lys 107 substantially alters the lipid binding properties of the protein, which correlated with reduced binding to plasma HDL in vitro, but did not affect the capacity of the mutant/lipid complex to promote cholesterol efflux or activate LCAT.

In vivo assessment of cardiac remodeling after myocardial infarction in rats by cine-magnetic resonance imaging

The rat infarct model offers important parallels to the process of remodeling after myocardial infarction (MI) in humans. The aim of this study was to test the feasibility of cine fast low-angle shot (FLASH) magnetic resonance imaging (MRI) for assessment of the infarcted and noninfarcted rat heart and to compare the results with established methods. In group A, MRI was done 8-16 weeks after MI on a 7-T scanner using an electrocardiogram-triggered cine-FLASH sequence. We determined left ventricular (LV) volumes and mass, wall thickness, MI size, cardiac output, and ejection fraction. Afterward, MI size was histologically determined. In group B, after MRI eight controls and eight rats 16 weeks after MI underwent conventional hemodynamic measurements for determination of cardiac output, LV volumes, and ejection fraction by electromagnetic flowmeter and pressure-volume curves. LV wet weight was determined. In group A, MRI-acquired MI size (18.5 +/- 2%) was smaller than histology (22.8 +/- 2.5%, p < 0.05) with close correlation (r = 0.97). In group B, agreement in LV mass was found between MRI and wet weight (controls, 537.6 +/- 19.6 vs. 540.3 +/- 18.4 mg; MI, 865.1 +/- 39.2 vs. 865.1 +/- 41.3 mg; for the difference p = ns, r = 0.97, p < 0.05) and in the MRI and flowmeter measurements (cardiac output, controls 73.1 +/- 2.9 vs. 75.2 +/- 2.6 ml/min; MI 82.4 +/- 5.2 vs. 81.9 +/- 3.7 ml/min; for the difference p = ns, r = 0.80, p < 0.05). End-diastolic volume by MRI differed from pressure-volume curves with good correlation (controls, 343.9 +/- 8.4 vs. 262.7 +/- 12.8 microl; MI, 737.0 +/- 70.5 vs. 671.1 +/- 64.1 microl; p < 0.05 each, r = 0.96, p < 0.05). Cine-FLASH-MRI is a valuable diagnostic tool applicable to the rat model of MI. Being noninvasive and exact, it offers new insights in the remodeling process after MI because serial measurements are possible.

Selective interactions of cationic porphyrins with G-quadruplex structures

G-quadruplex DNA presents a potential target for the design and development of novel anticancer drugs. Because G-quadruplex DNA exhibits structural polymorphism, different G-quadruplex typologies may be associated with different cellular processes. Therefore, to achieve therapeutic selectivity using G-quadruplexes as targets for drug design, it will be necessary to differentiate between different types of G-quadruplexes using G-quadruplex-interactive agents. In this study, we compare the interactions of three cationic porphyrins, TMPyP2, TMPyP3, and TMPyP4, with parallel and antiparallel types of G-quadruplexes using gel mobility shift experiments and a helicase assay. Gel mobility shift experiments indicate that TMPyP3 specifically promotes the formation of parallel G-quadruplex structures. A G-quadruplex helicase unwinding assay reveals that the three porphyrins vary dramatically in their abilities to prevent the unwinding of both the parallel tetrameric G-quadruplex and the antiparallel hairpin dimer G-quadruplex DNA by yeast Sgs1 helicase (Sgs1p). For the parallel G-quadruplex, TMPyP3 has the strongest inhibitory effect on Sgs1p, followed by TMPyP4, but the reverse is true for the antiparallel G-quadruplex. TMPyP2 does not appear to have any effect on the helicase-catalyzed unwinding of either type of G-quadruplex. Photocleavage experiments were carried out to investigate the binding modes of all three porphyrins with parallel G-quadruplexes. The results reveal that TMPyP3 and TMPyP4 appear to bind to parallel G-quadruplex structures through external stacking at the ends rather than through intercalation between the G-tetrads. Since intercalation between G-tetrads has been previously proposed as an alternative binding mode for TMPyP4 to G-quadruplexes, this mode of binding, versus that determined by a photocleavage assay described here (external stacking), was subjected to molecular dynamics calculations to identify the relative stabilities of the complexes and the factors that contribute to these differences. The DeltaG(o) for the external binding mode was found to be driven by DeltaH(o) with a small unfavorable TDeltaS(o) term. The DeltaG(o) for the intercalation binding model was driven by a large TDeltaS(o) term and complemented by a small DeltaH(o) term. One of the main stabilizing components of the external binding model is the energy of solvation, which favors the external model over the intercalation model by -67.94 kcal/mol. Finally, we propose that intercalative binding, although less favored than external binding, may occur, but because of the nature of the intercalative binding, it is invisible to the photocleavage assay. This study provides the first experimental insight into how selectivity might be achieved for different G-quadruplexes by using structural variants within a single group of G-quadruplex-interactive drugs.

A useful insight into 2 occlusal indexes: HLD(Md) and HLD(CalMod)

Maryland and California are among the states that have adopted the Handicapping Labiolingual Deviation (HLD) Index to determine eligibility for public funding of orthodontic treatment. As a result of several lawsuits against the state, California has developed and employed a modification of that index, called the HLD(CalMod) index. This study compared and contrasted the effects of analyzing prospective patients with the HLD(Md)-the HLD index as used in Maryland-and the HLD(CalMod) indexes. The specific aims of this study were to observe (1) the correlation between the 2 occlusal indexes in determining patients' eligibility for treatment with public funding, (2) the characteristics of patients eligible according to each index, and (3) the major contributing factors in assigning patients as eligible under each index. Initial study models of 313 patients from the orthodontic clinic at the University of Maryland were scored by both HLD(Md) and HLD(CalMod) indexes. According to the scores, the patients were divided into 2 groups-those with handicapping malocclusions and those without handicapping malocclusions. Scores from each index were analyzed by the Pearson product moment correlation. The Angle classification for each patient was also recorded with the HLD variables. The mean and the percentage of the total score for each variable were calculated. The following conclusions were obtained: (1) Of the 313 patients, 127 (41%) were approved for treatment by the HLD(Md) index, and 110 (35%) were approved for treatment by the HLD (CalMod) index.(2) The correlation between the 2 indexes (R = 0.78) was not very strong, indicating the power of the additional variables introduced in the HLD(CalMod) index. (3) The use of the HLD(CalMod) index directs more public funding toward patients with severe Class II malocclusions than does the HLD(Md) index.

Identification of HLA-A*11 variant (A*1107) in the Korean population

We report here a new HLA-A*11 allele, A*1107, identified by sequencing based typing in the Korean population. The full-length sequencing of A*1107 was conducted on cDNA. HLA-A*1107 differs from HLA-A*1101 by a single nucleotide at position 399 of codon 109 in exon3 (TTC-->TTA), leading to an amino acid change from phenylalanine to leucine. But the serological profile of HLA-A*1107 did not exhibit the altered HLA-A11.

Sequence analysis of the Spodoptera litura multicapsid nucleopolyhedrovirus genome

The complete Spodoptera litura multicapsid nucleopolyhedrovirus (SpltMNPV) genome contained 139,342 bp with a G+C content of 42.7%, and 141 putative open reading frames (ORFs) or genes of 150 nucleotides or greater that showed minimal overlap. Ninety-six ORFs had homologues in Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV), 16 had homologues in other baculoviruses, and 29 were unique to SpltMNPV. The homologues of ubiquitin and gp37 are fused in SpltMNPV. The genome lacked a homologue of the major budded virus glycoprotein gene gp64, but it contained a homologue of ORF130 of Lymantria dispar multicapsid nucleopolyhedrovirus (LdMNPV). There were two homologues of AcMNPV ORF2 (bro gene), and a DnaJ protein gene (SpltORF39) in which the N-terminus showed homologies with the J domain of DnaJ family proteins. Seventeen homologous regions (hrs) were identified, each containing 2-29 palindromic repeats, with an average length of 534 bp and base content (G+C%) of 33.0.

Structural and functional properties of apolipoprotein A-I mutants

Apolipoprotein (apo) A-I is composed of 243 amino acid residues that fold into amphipathic helixes, and plays a central role in the high density lipoprotein (HDL) metabolism. Familial apoA-I deficiency is a rare metabolic disorder of which three cases have been characterized at a molecular level in western Japan. However, in subjects with apoA-I deficiency, coronary artery disease was not always present. One apo A-I deficiency was compound heterozygous apoA-I mutant for a TATA box mutation and a structural nonsense mutation. To date, screening analysis in our laboratory has identified nine genetically-determined structural mutations of apo A-I. We have also characterized these apo A-I mutations, including apoA-I (Glu235del) Nichinan. Few structural mutations were associated with altered HDL cholesterol levels.

Different distribution of HLA class II alleles according to response to corticosteroid therapy in sudden sensorineural hearing loss

OBJECTIVE

To investigate the association of HLA class II alleles with the susceptibility to sudden sensorineural hearing loss and with the results of corticosteroid treatment in the Korean population.

DESIGN

HLA-DRB1, -DQA1, -DQB1, and -DPB1 genotyping by the sequence-specific oligonucleotide probes method in 41 patients with sudden sensorineural hearing loss and in 206 healthy control subjects. Initial hearing levels at the onset of hearing loss and final hearing levels after treatment were evaluated for the association with HLA class II alleles.

SETTING

Tertiary care referral center, ambulatory and hospitalized care.

SUBJECTS

Forty-one patients (24 men and 17 women; mean age, 49.2 years) were compared with 206 controls. Patients were divided into 2 groups according to their response to corticosteroid therapy (good response vs nonresponse).

RESULTS

The frequencies of HLA-DRB1, -DQA1, -DQB1, and -DPB1 alleles were not significantly different between patients and controls (P>.05). When an association between the results of corticosteroid treatment and the frequency of HLA alleles was evaluated, the frequencies of HLA-DRB1*14 (relative risk [RR] = 3.5, P<.02), -DQA1*03 (RR = 4.2, P<.02), and -DQA1*05 (RR = 3.1, P<.03) were significantly increased, but HLA-DQA1*01 (RR = 0.2, P<.004) and -DQB1*06 (RR = 0.2, P<.009) were decreased in the group nonresponsive to corticosteroid therapy, compared with the controls. The distribution of HLA-DQA1*01 (P<.04), -DQB1*06 (P<.02), and -DQA1*03 (P<.003) was significantly different between the responsive and the nonresponsive groups. HLA-DQA1 allelic combination analysis showed that the frequencies of DQA1*03 and *05 had a high RR value in patients with sudden sensorineural hearing loss (RR = 4.1, P<.003) and in patients in the nonresponsive group (RR = 8.9, P<.001), compared with the controls.

CONCLUSION

The presence of HLA class II alleles may be a useful genetic marker in forecasting a prognosis in Korean patients with sudden sensorineural hearing loss.

The interaction of azide with polyphenol oxidase II from tobacco

Spectroscopy studies of absorption and circular dichroism of native PPO II and azide PPO II complex demonstrate two new absorptions at 375 nm and 500 nm after azide's binding with PPO II, which are assigned as the terminal azide to copper charge transfer transitions II(o)nb-to-copper and II(v)nb-to-copper charge transfer transitions respectively. FT-IR spectra also demonstrate that the azide binds in terminal geometry with one of type-3 coppers. The interaction between azide and PPO II is discussed. One terminal azide's binding with one type-3 copper improves the activity of PPO II and the other three azides' further binding in terminal geometry with the type-3 coppers decreases the activity. We theorize that steric hindrance of azides makes oxygen difficult to bind in the active site.

An essential role of the JAK-STAT pathway in ischemic preconditioning

The goal of this study was to determine the role of the Janus tyrosine kinase (JAK)-signal transducers and activators of transcription (STAT) pathway in the late phase of ischemic preconditioning (PC). A total of 230 mice were used. At 5 min after ischemic PC (induced with six cycles of 4-min coronary occlusion/4-min reperfusion), immunoprecipitation with anti-phosphotyrosine (anti-pTyr) antibodies followed by immunoblotting with anti-JAK antibodies revealed increased tyrosine phosphorylation of JAK1 (+257 +/- 53%) and JAK2 (+238 +/- 35%), indicating rapid activation of these two kinases. Similar results were obtained by immunoblotting with anti-pTyr-JAK1 and anti-pTyr-JAK2 antibodies. Western analysis with anti-pTyr-STAT antibodies demonstrated a marked increase in nuclear pTyr-STAT1 (+301 +/- 61%) and pTyr-STAT3 (+253 +/- 60%) 30 min after ischemic PC, which was associated with redistribution of STAT1 and STAT3 from the cytosolic to the nuclear fraction and with an increase in STAT1 and STAT3 gamma-IFN activation site DNA-binding activity (+606 +/- 64%), indicating activation of STAT1 and STAT3. No nuclear translocation or tyrosine phosphorylation of STAT2, STAT4, STAT5A, STAT5B, or STAT6 was observed. Pretreatment with the JAK inhibitor AG-490 20 min before the six occlusion/reperfusion cycles blocked the enhanced tyrosine phosphorylation of JAK1 and JAK2 and the increased tyrosine phosphorylation, nuclear translocation, and enhanced DNA-binding activity of STAT1 and STAT3. The same dose of AG-490 abrogated the protection against myocardial infarction and the concomitant up-regulation of inducible NO synthase (iNOS) protein and activity observed 24 h after ischemic PC. Taken together, these results demonstrate that ischemic PC induces isoform-selective activation of JAK1, JAK2, STAT1, and STAT3, and that ablation of this response impedes the up-regulation of iNOS and the concurrent acquisition of ischemic tolerance. This study demonstrates that the JAK-STAT pathway plays an essential role in the development of late PC. The results reveal a signaling mechanism that underlies the transcriptional up-regulation of the cardiac iNOS gene and the adaptation of the heart to ischemic stress.

Analysis of trace amino acid neurotransmitters in hypothalamus of rats after exhausting exercise using microdialysis

A simple but effective coupling of microdialysis and capillary electrophoresis with laser induced fluorescence detection technique was applied to analysis of amino acid neurotransmitters in the hypothalamus of rats after acute exhausting exercise. The separation of amino acids was achieved using an uncoated fused-silica capillary (57 cm x 75 microm I.D.) with a buffer of 10 mM disodium tetraborate at pH 10 and an applied voltage of 12.5 kV. The detection limit was 10(-10) M for each amino acid. It is sufficiently sensitive and rapid for the determination of amino acids in a 5-microl Microdialysate. In comparison to pre-exercise, a significant increase in the levels of six hypothalamic amino acids (arginine, glycine, lysine, glutamic acid, alanine, gamma-amino-n-butyric acid) was found after exercise. These results demonstrate that the increase of metabolic amino acids in the hypothalamus of rats can be induced by exhausting exercise and suggests that amino acid neurotransmitters may play functional roles in the central effects of exercise.

Oxidative preconditioning and apoptosis in L-cells. Roles of protein kinase B and mitogen-activated protein kinases

Oxidative stress can cause significant cell death by apoptosis. We performed studies in L-cells to explore whether prior exposure to oxidative stress ("oxidative preconditioning") can protect the cell against the apoptotic consequences of subsequent oxidative insults and to establish the mediators in the preconditioning signaling cascade. Cells were preconditioned with three 5-min exposures to H(2)O(2), followed by 10-h recovery and subsequent exposure to 600 microm H(2)O(2) for 10 h. A single 10-h exposure to H(2)O(2) induced substantial apoptotic cell death (approximately 90%), as determined by enzyme-linked immunosorbent assay, TUNEL (terminal deoxyribonucleotide transferase-mediated dUTP nick end labeling), and Annexin V methods, but apoptosis was largely prevented in preconditioned cells. The degree of cytoprotection depended on the strength of preconditioning or H(2)O(2) concentration (20 approximately 600 microm). Transient increases in mitogen-activated protein kinase (MAPK), p38, and JNK/SAPK activities and sustained protein kinase B (Akt) activation, accompanied by drastically reduced caspase 3 activity, were seen after preconditioning. The expression levels of these kinases were unaltered. Inhibitors of p38 (SB203580) and phosphoinositide 3-kinase (PI3K, LY294002) pathways abolished the protection provided by preconditioning. We conclude that oxidative preconditioning protects cells against apoptosis and that this effect involves MAPK and PI3K/Akt pathways. This system may be important in regulating apoptotic cell death in development and disease states.

Serum cystatin C is an independent predictor of total homocysteine levels in stable Korean renal transplant recipients with normal serum creatinine

OBJECTIVES

To examine the determinants of fasting plasma total homocysteine (tHcy) levels such as cystatin C, serum creatinine (SCr), estimated glomerular filtration rate (GFR) from Cockroft-Gault equation, albumin, plasma folate, vitamin B12, and pyridoxal-5'-phosphate (PLP) among Korean renal transplant recipients (RTR) with normal SCr levels (< or =1.4 mg/dL).

DESIGN

Cross-sectional study.

SETTING

Nephrology and Transplant Service, Catholic University Kangnam St. Mary's Hospital, Seoul, Korea.

PARTICIPANTS

Fifty-one chronic stable Korean RTR with normal SCr levels (< or =1.4 mg/dL) 6 months or more following transplantation.

MEASURES

Medical record review, anthropometric measurements, and overnight (10 to 14 hours) fasting blood samples for measurement of plasma tHcy, folate, vitamin B12, PLP, SCr, albumin, and cystatin C.

RESULTS

General linear regression model including age, gender, vitamin status, and measurements of renal function showed that cystatin C and folate were independent predictors of tHcy levels. The partial regression coefficient for folate was -0.444 (P <.01) and for cystatin C, it was +0.334 (P <.05). SCr, estimated GFR, vitamin B12, PLP, age, and gender were not independent predictors of tHcy levels in this model.

CONCLUSION

Both cystatin C and folate status were major independent determinants of fasting tHcy levels in the subgroup of Korean RTR with normal SCr.

[Establishment of suc2 signal sequence trap system]

The secretion of proteins depends on the signal peptide located to the N-terminal of the protein precursor. We established a genetic system in yeast to screen cDNA library for the signal peptide encoding sequences. To do it, we mutated genomic suc2 gene (encoding yeast invertase) of EGY48 by one-step gene disruption method, and got yeast cell lines without invertase expression (EGY48-delta suc). To get vector for library screening, we inserted suc2 gene encoding mature peptide of invertase downstream to yeast promoter P-ADH1, and multiple cloning sites for insertion of library is between suc2 and P-ADH1. EGY48-delta suc transformed with the vector can grow on the medium with glucose as carbon source, but not on the medium with raffinose. Signal peptide of suc2 and alpha chain of human interleukin-2 was fused in frame to suc2 gene, then the two resulting vectors were transformed into EGY48-delta suc, all the transformants can grow in the medium with either raffinose or glucose as carbon source. Hence, the system established here can discern cDNA encoding signal peptide from the one not encoding signal peptide.

Expression of multiple subtypes of muscarinic receptors and cellular distribution in the human heart

Five isoforms of the muscarinic acetylcholine receptor (mAChR) have been identified by molecular cloning and designated m(1)-m(5), of which four correspond to the functional subtypes M(1), M(2), M(3), and M(4) in primary tissues. The presence of M(5) receptors in tissues remains uncertain. The present study was designed to explore the diversity and cellular distribution of various mAChR subtypes in human hearts. Competition binding of [N-methyl-(3)H]-scopolamine methyl chloride with various mAChR antagonists yielded data consistent with the presence of multiple subtypes (M(1)/M(2)/M(3)/M(5)) of mAChRs in both human atrial (HA) and ventricular (HV) tissues. Expression of mRNAs encoding all five subtypes was readily detected by reverse transcription-polymerase chain reaction in both HA and HV samples. Immunoblotting with subtype-specific antibodies confirmed the presence of M(1), M(2), M(3), and M(5), but not M(4), proteins in membrane preparations from both HA and HV. The protein levels of M(1) and M(2) were comparable between HA and HV. Although the density of M(3) appeared approximately 10-fold higher in HV than HA, that of M(5) was approximately 5 times lower in HV than in HA. Positive immunostaining of single ventricular myocytes by M(1), M(2), M(3), and M(5) antibodies, respectively, was consistently detected. Under confocal microscopy, M(5) showed characteristic localization to the intercalated discs, whereas other subtypes were more evenly distributed throughout the surface membrane. Our results provide the first molecular evidence for the presence of multiple subtypes of mAChR, including endogenous M(5) receptors, in human hearts and suggest that different subtypes have different tissue distributions and cellular localization.

[Cloning, sequence analysis of deacetoxycephalosporin C synthetase/hydroxylase gene cefEF]

Chromosomal DNA preparations were made form the fungi C. acremonium and A. chrysogenum respectively by a method using 1-Chloro methyl benzene solution. Then the cefEF gene of deacetoxycephalosporin C synthetase/hydroxylase was amplified by polymerase chain reaction. The cefEF gene could only be amplified from the chromosomal DNA of A. chrysogenum. This fragment about 1.0 kb was cloned into pGME-T vector and then sequenced. The sequence indicates that the cloned cefEF gene contains 999 nucleotides encoding for 333 amino acids and there are three bases and two amino acids different from those that have been reported. Both of the two amino acids are not in active site. The result also indicates that the reported C. acremonium or A. chrysogenum generating deacetoxycephalosporin C synthetase/hydroxylase corresponds with A. chrysogenum but not C. acremonium in China.