Regulatory polymorphisms in the IL-10 gene promoter and HBV-related acute liver failure in the Chinese population

Recent reports indicated that high levels of interleukin 10 (IL-10) contribute to the monocytes paralysis and poor clinical outcome in acute liver failure (ALF). Polymorphisms in the promoter region of IL-10 affect IL-10 production and confer susceptibility to inflammatory diseases. The aim of this study was to determine the possible association of the three polymorphisms (A-1082G, T-819C, A-592C) in the IL-10 gene promoter with the susceptibility to hepatitis B virus (HBV)-related ALF in a Chinese population. The IL-10 gene promoter polymorphisms were genotyped in 414 unrelated healthy blood donors, 367 asymptomatic HBV carriers and 345 HBV-related ALF patients. Functional analyses were conducted to verify the biological significances of the associated genetic variations. The allele frequencies of IL-10-592C and -819C were significantly higher in HBV-related ALF patients than in blood donors and asymptomatic HBV carriers. Logistic regression analysis and stratification analysis with adjustment for age and sex indicated that the polymorphisms of A-592C and T-819C were associated with susceptibility to HBV-related ALF (P = 6.9 x 10(-7)), and the -1082A-819C-592C haplotype in the IL-10 gene promoter were associated with an increased susceptibility to ALF in HBV carriers (dominant model, P = 0.0002, odds ratio = 1.60, 95% CI 1.25-2.07). Functional analyses showed that the A-592C polymorphism is a nuclear proteins binding site, and the disease susceptible -592C allele had a higher transcription activity compared with -592A allele. This study emphasizes the importance of IL-10 in the pathophysiology of HBV-related ALF on the population level.

Tailored regimen of interferon alpha for HBeAg-positive chronic hepatitis B: a prospective controlled study

The response to interferon-alpha treatment of patients with chronic hepatitis B under the current protocol is not satisfactory. The aim of this study was to try an alternative approach to improve treatment outcome. Of 374 HBeAg-positive patients, 127 of them received 5 million units of interferon-alpha thrice weekly for 6 months and constituted the control group, while 247 in the study group received the same dosage but the duration of treatment was tailored. The study protocol provided for continuation of treatment if HBV DNA levels were continuously decreasing. The treatment ended when viral, antigenic and biochemical endpoints were reached or when HBV DNA levels were no longer decreasing. The median length of tailored treatment was 10 (range 6-24) months. The end-of-treatment response rates were 39.3% and 23.6% (P = 0.002), and after 12-month, follow-up, the sustained response rates were 40.5% and 28.3% (P = 0.013) in the study and control groups, respectively. Excluding the patients who dropped out, 228 and 115 completed a median of 40- and 44-month-long follow-up; the long-term response was thus 45.3% and 33.1% (P = 0.014) in the respective groups. Interferon-alpha treatment tailored in length demonstrated significantly increased efficacy in patients with chronic hepatitis B.

A pulsed EPR study of surfactant layer structure in composites of a synthetic layered silicate with polystyrene and polycaprolactone

Double electron electron resonance (DEER), deuterium electron spin-echo envelope modulation (ESEEM) spectroscopy and 31P electron nuclear double resonance (ENDOR) spectroscopy were applied to site-specifically spin-labeled surfactants in the organically modified layered silicate magadiite and its composites with polystyrene (PS) and polycaprolactone (PCL). The organomagadiite consist of stacks of silicate platelets with surfactant layers between these platelets. In PS composites the stacks are dispersed in the polymer matrix as a whole, while melt processing with PCL leads to intercalation of polymer chains into the galleries between the platelets. The DEER data prove that even in the case of the non-intercalated PS composites the density of surfactant molecules changes drastically during composite formation on length scales of a few nanometers. Deuterium ESEEM data demonstrate that spin labels attached both in the middle and at the end of the alkyl chain have contact with the headgroups of neighboring surfactant molecules. By analysis of the 31P ENDOR spectra, two characteristic distances are found between the spin labels and the headgroups of phosphonium surfactants. The shorter, proximal distance can be assigned to headgroups in the same surfactant layer. By comparison with the basal spacing between consecutive silicate platelets the longer, distal distance is assigned to a layer of surfactants that is not attached to the surface of the next platelet but rather located between platelets. Altogether the data support a picture of trilayers of disordered surfactant molecules with their alkyl chains oriented nearly parallel to the surface.

First Report of Race 3 of Bipolaris zeicola on Corn in China

In Meixian County of Shaanxi Province, China, during the summer of 2002, mature corn plants in a field plot showed severe leaf spot symptoms. The lesions were narrow (3.5 to 18 mm long and 0.4 to 1.5 mm wide), grayish tan, and surrounded by a light- to dark-pigmented border. Leaves wilted when lesions coalesced. From 2002 to 2005, the disease was observed in other Shaanxi Province counties, including Yangling, Wugong, Qianxian, Longxian, and Qianyang, although in most cases, symptom development was less severe than it was in Meixian. Seven isolates from four counties were obtained by isolation from host tissue on potato dextrose agar (PDA), followed by single-spore culturing and incubation on PDA at 25°C in the dark for 7 days. Conidial suspensions were prepared from a single-spored culture on PDA plates. Pathogenicity tests were performed by spraying five corn seedlings (cv. Yuyu 22) at the three- to four-leaf stage in separate 10-cm-diameter pots with 10 ml of a conidial suspension (10⁶ spores per ml) per plant. Each of three isolates was used in separate inoculations that were performed in different weeks. Controls were sprayed with sterile distilled water only. Plants were covered with plastic bags for 48 h and incubated at 23 to 25°C in a chamber. One week after inoculation, leaves on all inoculated plants developed characteristic lesions, whereas untreated controls had no symptoms. The pathogen was reisolated from diseased leaves on PDA after surface sterilization with 2% NaOCl. On PDA, proliferation of conidia usually occurred on all sides of the conidiophore. Conidiophores were cylindrical, simple, smooth, septate, and straight to flexuous. Conidia were 49 to 89 μm long and 11 to 17 μm wide, with 3 to 10 distosepta, straight or moderately curved, dark or olivaceous brown, and the cells on the ends sometimes appeared paler than those in the middle. These characteristics match those of Bipolaris zeicola (Stout) Shoemaker. On the basis of the arbitrary primers selected by Jones et al. (1), random amplified polymorphic DNA (RAPD) analysis was used for species and physiological race determination. A single DNA fragment approximately 1.2 kb, which is characteristic of B. zeicola, was amplified from all seven isolates with arbitrary primer A20 (5'CTTGGATTC3'). Analysis of PCR products obtained with arbitrary primer A03 (5'AGTCAGCCAC3') showed that all seven isolates lacked 2,700- and 2,300-base bands, and therefore, sorted into B. zeicola race 3. On the basis of pathogenicity, morphology, and RAPD band patterns of primer A20, the fungus was confirmed as B. zeicola. The shape of leaf lesions and RAPD band patterns using primer A03 showed further that the pathogen was race 3 of B. zeicola. Bai et al. (2) reported race 1 and race 2 of B. zeicola in China, but to our knowledge, this is the first report of race 3 in China. References: (1) M. J. Jones and L. D. Dunkle. Phytopathology 83:366, 1993. (2) J. K. Bai et al. Acta Phytopathol. Sin. 12:61, 1982.

No significant differences in histology and response to interferon treatment in hepatitis B carriers of genotypes C and recombinant B

Hepatitis B virus (HBV) genotypes B and C are most prevalent in China and genotype B is found exclusively in recombination with the pre-C/C gene of genotype C. We investigated whether there is a difference in clinical relevance between the two genotypes sharing the same pre-C/C gene. Thus, we determined the genotype of HBV among consecutive HBeAg-positive patients with tailored interferon-alpha (IFN-alpha) therapy, and the demographic, baseline clinical characteristics and treatment results were compared between them. The median values of alanine transaminase (ALT) were 4.5 and 5.0 times the upper limit of normal (P = 0.419), HBV-DNA levels were 1.4 x 10(7) and 1.5 x 10(7)copies/mL (P = 0.829), mean scores of necroinflammatory histological activity 9.8 and 10.44 (P = 0.105) and fibrotic activity 2.64 and 2.86 (P = 0.227) in genotype B and C patients, respectively. The end-of-treatment response was 42.7% and 39.0% (P = 0.531) with mean tailored treatment months of 8.28 and 9.34 (P = 0.160), and the sustained response 43.4% and 37.5% (P = 0.31) at the end of a 12-month follow-up period in genotype B and C patients, respectively. These results remained similar when follow-up was extended to nearly 3 years. In conclusion, no significant differences in clinical characteristics and response to IFN-alpha between genotypes B and C were found, probably, because both types shared a common pre-C/C encoding region.

Extremely high association between appearance of HLA antibodies and failure of kidney grafts in a five-year longitudinal study

Longitudinal studies were conducted over a five-year period for HLA antibodies on 493 sera tested from 54 kidney transplant patients. HLA single antigen beads were employed to establish donor specificity of the antibodies. Only 3 of 22 patients without antibodies rejected a graft in contrast to 17 out of 32 patients with posttransplant antibodies (p = 0.003). Using a serum creatinine value of 4.0 mg/dL as the cut-off for a failed graft, 4 of 22 patients without antibodies failed compared to 21 of 32 with antibodies (p = 0.0006). Among patients with donor-specific antibodies (DSA) 13 of 15 failed (p = 0.000004). Even among patients with non-donor specific antibodies (NDSA), 8 of 17 failed (p = 0.05). Among patients who could be identified as making de novo antibodies (since they developed antibodies while not having antibodies for more than six months after transplantation), 6 of 11 failed (p = 0.03). Sequential testing for HLA antibodies shows that antibodies appear prior to a rise in serum creatinine and subsequent graft failure. The very strong association between the production of HLA antibodies after transplantation and graft failure indicates the importance of monitoring for posttransplant HLA antibodies.

Development of nondonor-specific HLA-DR antibodies in allograft recipients is associated with shared epitopes with mismatched donor DR antigens

Our previous studies showed that not only donor-specific antibodies (DSA) but also nondonor-specific antibodies (NDSA) were detected in the peripheral blood of allograft recipients. The molecular mechanism involved in the development of NDSA is examined here. HLA class II single antigen (SA) beads were used to determine the presence of HLA DR-specific antibodies in renal transplant recipients with failed allografts. Sequence-based antibody-epitope mapping was determined by the comparison of the reaction profiles of different SA recombinant cell lines containing unique epitope pattern. We found that 22 out of 65 recipients with failed grafts developed antibodies against donor HLA DR that is a mismatch with the recipient. Three of them had only DSA while 19 patients had not only DSA but also NDSA. An average of 77.3% of NDSA reacted with targets that share amino acid sequence with mismatched donor DR antigens. Either surface or nonsurface amino acid residues may constitute an antibody epitope. In conclusion, development of NDSA in allograft recipients may be associated with shared amino acids with mismatched donor antigens. SA beads technique not only helps to determine antibody specificities but also provides an ideal approach for the identification of potential HLA antibody epitopes.

Defining the pathway for Tat-mediated delivery of beta-glucuronidase in cultured cells and MPS VII mice

We used recombinant forms of human beta-glucuronidase (GUS) purified from secretions from stably transfected CHO cells to compare the native enzyme to a GUS-Tat C-terminal fusion protein containing the 11-amino-acid HIV Tat protein transduction domain for: (1) susceptibility to endocytosis by cultured cells, (2) rate of clearance following intravenous infusion, and (3) tissue distribution and effectiveness in clearing lysosomal storage following infusion in the MPS VII mouse. We found: (1) Native GUS was more efficiently taken up by cultured human fibroblasts and its endocytosis was exclusively mediated by the M6P receptor. The GUS-Tat fusion protein showed only 30-50% as much M6P-receptor-mediated uptake, but also was taken up by adsorptive endocytosis through binding of the positively charged Tat peptide to cell surface proteoglycans. (2) GUS-Tat was less rapidly cleared from the circulation in the rat (t(1/2) = 13 min vs 7 min). (3) Delivery to most tissues of the MPS VII mouse was similar, but GUS-Tat was more efficiently delivered to kidney. Histology showed that GUS-Tat more efficiently reduced storage in renal tubules, retina, and bone. These studies demonstrate that Tat modification can extend the range of tissues corrected by infused enzyme.

Site-directed mutation on the only universally conserved residue Leu122 of small heat shock protein Hsp16.3

Hsp16.3 from Mycobacterium tuberculosis belongs to the small heat shock protein family and has chaperone-like activity in vitro. The only universally conserved hydrophobic residue Leu122 was substituted by Val and Ala, respectively. The mutations on the Leu122 of Hsp16.3 have resulted in much lower structural stability in vivo and in vitro. Both mutant proteins exhibited much weaker chaperone-like activities than the Hsp16.3 WT under heat shock conditions. Taken together, the highly hydrophobic residue L122 of Hsp16.3 was suggested to play a very important role in maintaining not only the structural stability but also the chaperone-like activity.

Electrostatic interactions play a critical role in Mycobacterium tuberculosis Hsp16.3 binding of substrate proteins

Mycobacterium tuberculosis Hsp16.3, a member of a small heat shock protein family, has chaperone-like activity in vitro and suppresses thermally or chemically induced aggregation of proteins. The nature of the interactions between Hsp16.3 and the denatured substrate proteins was investigated. A dramatic enhancement of chaperone-like activity of Hsp16.3 upon increasing temperature was accompanied by decreased ANS-detectable surface hydrophobicity. Hsp16.3 exhibited significantly enhanced chaperone-like activity after preincubation at 100 degrees C with almost unchanged surface hydrophobicity. The interaction between Hsp16.3 and dithiothreitol-treated insulin B chains was markedly weakened in the presence of NaCl but greatly enhanced by the addition of a low-polarity alcohol, accompanied by significantly increased and decreased surface hydrophobicity, respectively. A working model for Hsp16.3 binding to its substrate proteins is proposed.

The HIV Tat protein transduction domain improves the biodistribution of beta-glucuronidase expressed from recombinant viral vectors

Treatment of inherited genetic diseases of the brain remains an intractable problem. Methods to improve the distribution of enzymes that are injected or expressed from transduced cells will be required for many human brain therapies. Recent studies showed that a peptide, the protein transduction domain (PTD) from HIV Tat, could improve the distribution of cytoplasmic reporter proteins when administered systemically as fusion proteins or cross-linked chimeras. The utility of this motif for noncytoplasmic proteins has not been determined. Here, we tested how the Tat motif affected uptake and biodistribution of the lysosomal enzyme beta-glucuronidase, the protein deficient in the disease mucopolysaccharidosis VII, when expressed from viral vectors. The Tat motif allowed for mannose-6-phosphate (M6P) independent uptake in vitro and significantly increased the distribution of beta-glucuronidase secreted from transduced cells after intravenous or direct brain injection in mice of recombinant vectors. Thus, enzymes modified to contain protein transduction motifs may represent a general strategy for improving the distribution of secreted proteins following in vivo gene transfer.

Preheat treatment for Mycobacterium tuberculosis Hsp16.3: correlation between a structural phase change at 60 degrees C and a dramatic increase in chaperone-like activity

The in vitro chaperone-like activity of Mycobacterium tuberculosis small heat shock protein Hsp16.3 was found to be dramatically enhanced to the same extent after preheat treatment at or over 60 degrees C. Structural analysis using gel filtration, native pore-gradient PAGE, nondenaturing PAGE, and far-UV CD spectroscopy consistently revealed no significant difference between the native and the preheated Hsp16.3 proteins. However, near-UV CD spectroscopy clearly demonstrated that the tertiary structure of preheated Hsp16.3 is quite similar to its native conformation, with a minor but significant difference. Further analysis using differential scanning calorimetry indicated that Hsp16.3 exhibited a structural transition near 60 degrees C. All these results together indicate that Hsp16.3 suffers a phase change at approximately 60 degrees C, which seem to remove a structural energy barrier for the protein to refold to a conformational status with increased chaperone-like activity.

[Reconstruction of hepatitis D virus ribozymes and their ability to trans-cleave hepatitis C virus RNA]

OBJECTIVE

To study whether reconstructed hepatitis D virus (HDV) ribozymes have the ability to trans-cleave hepatitis C virus (HCV) RNA.

METHODS

We reconstructed the stem IV and substrate-binding region of HDV genomic ribozymes, thus obtained three HDV ribozymes named RzC1, RzC2 and RzC3 expected to be able to trans-cleave HCV RNA at predicted sites. The substrate containing HCV RNA 5'-noncoding region (5'-NCR) and 5'-fragment of C region (HCV RNA 5'-NCR-C) was synthesized by transcription in vitro, then radiolabelled at its 5'-end. Under certain pH and appropriate concentration of Mg(2+) with or without deionized formamide, the ribozymes and their substrate were mixed at mol ratio of 100 : 1 and reacted for two hours. Trans-cleaved products were shown by denatured polyacrylamide gel electrophoresis and autoradiography, and the percentage of trans-cleaved substrate was calculated as the activity indicator of these ribozymes.

RESULTS

RzC1 and RzC2 were able to trans-cleave HCV RNA 5'-NCR-C site specifically, and their activity could be enhanced by certain concentration of deionized formamide. RzC3 could not trans-cleave the substrate.

CONCLUSIONS

Optimized HDV genomic ribozymes can trans-cleave HCV RNA.

The structure of the multidrug resistance protein 1 (MRP1/ABCC1). crystallization and single-particle analysis

Multidrug resistance protein 1 (MRP1/ABCC1) is an ATP-binding cassette (ABC) polytopic membrane transporter of considerable clinical importance that confers multidrug resistance on tumor cells by reducing drug accumulation by active efflux. MRP1 is also an efficient transporter of conjugated organic anions. Like other ABC proteins, including the drug resistance conferring 170-kDa P-glycoprotein (ABCB1), the 190-kDa MRP1 has a core structure consisting of two membrane-spanning domains (MSDs), each followed by a nucleotide binding domain (NBD). However, unlike P-glycoprotein and most other ABC superfamily members, MRP1 contains a third MSD with five predicted transmembrane segments with an extracytosolic NH(2) terminus. Moreover, the two nucleotide-binding domains of MRP1 are considerably more divergent than those of P-glycoprotein. In the present study, the first structural details of MRP1 purified from drug-resistant lung cancer cells have been obtained by electron microscopy of negatively stained single particles and two-dimensional crystals formed after reconstitution of purified protein with lipids. The crystals display p2 symmetry with a single dimer of MRP1 in the unit cell. The overall dimensions of the MRP1 monomer are approximately 80 x 100 A. The MRP1 monomer shows some pseudo-2-fold symmetry in projection, and in some orientations of the detergent-solubilized particles, displays a stain filled depression (putative pore) appearing toward the center of the molecule, presumably to enable transport of substrates. These data represent the first structural information of this transporter to approximately 22-A resolution and provide direct structural evidence for a dimeric association of the transporter in a reconstituted lipid bilayer.

Modulation of multidrug resistance protein 1 (MRP1/ABCC1) transport and atpase activities by interaction with dietary flavonoids

The 190-kDa phosphoglycoprotein multidrug resistance protein 1 (MRP1) (ABCC1) confers resistance to a broad spectrum of anticancer drugs and also actively transports certain xenobiotics with reduced glutathione (GSH) (cotransport) as well as conjugated organic anions such as leukotriene C(4) (LTC(4)). In the present study, we have investigated a series of bioflavonoids for their ability to influence different aspects of MRP1 function. Most flavonoids inhibited MRP1-mediated LTC(4) transport in membrane vesicles and inhibition by several flavonoids was enhanced by GSH. Five of the flavonoids were competitive inhibitors of LTC(4) transport (K(i), 2.4-21 microM) in the following rank order of potency: kaempferol > apigenin (+ GSH) > quercetin > myricetin > naringenin (+ GSH). These flavonoids were less effective inhibitors of 17beta-estradiol 17beta-(D-glucuronide) transport. Moreover, their rank order of inhibitory potency for this substrate differed from that for LTC(4) transport inhibition but correlated with their relative lipophilicity. Several flavonoids, especially naringenin and apigenin, markedly stimulated GSH transport by MRP1, suggesting they may be cotransported with this tripeptide. Quercetin inhibited the ATPase activity of purified reconstituted MRP1 but stimulated vanadate-induced trapping of 8-azido-alpha-[(32)P]ADP by MRP1. In contrast, kaempferol and naringenin stimulated both MRP1 ATPase activity and trapping of ADP. In intact MRP1-overexpressing cells, quercetin reduced vincristine resistance from 8.9- to 2.2-fold, whereas kaempferol and naringenin had no effect. We conclude that dietary flavonoids may modulate the organic anion and GSH transport, ATPase, and/or drug resistance-conferring properties of MRP1. However, the activity profile of the flavonoids tested differed from one another, suggesting that at least some of these compounds may interact with different sites on the MRP1 molecule.

Human immunodeficiency virus seroconversion and evolution of the hepatitis C virus quasispecies

When chronic hepatitis C virus (HCV) infections are complicated by acquisition of human immunodeficiency virus (HIV), liver disease appears to accelerate and serum levels of HCV RNA may rise. We hypothesized that HIV might affect the HCV quasispecies by decreasing both complexity (if HIV-induced immunosuppression lessens pressure for selecting HCV substitutions) and the ratio of nonsynonymous (d(N)) to synonymous (d(S)) substitutions, because d(N) may be lower (if there is less selective pressure). To test this hypothesis, we studied the evolution of HCV sequences in 10 persons with chronic HCV infection who seroconverted to HIV and, over the next 3 years, had slow or rapid progression of HIV-associated disease. From each subject, four serum specimens were selected with reference to HIV seroconversion: (i) more than 2 years prior, (ii) less than 2 years prior, (iii) less than 2 years after, and (iv) more than 2 years after. The HCV quasispecies in these specimens was characterized by generating clones containing 1 kb of cDNA that spanned the E1 gene and the E2 hypervariable region 1 (HVR1), followed by analysis of clonal frequencies (via electrophoretic migration) and nucleotide sequences. We examined 1,320 cDNA clones (33 per time point) and 287 sequences (median of 7 per time point). We observed a trend toward lower d(N)/d(S) after HIV seroconversion in 7 of 10 subjects and lower d(N)/d(S) in those with rapid HIV disease progression. However, the magnitude of these differences was small. These results are consistent with the hypothesis that HIV infection alters the HCV quasispecies, but the number of subjects and observation time may be too low to characterize the full effect.

[The DSA features of AVM of jaws]

OBJECTIVE

To evaluate the vascular architecture of AVM of jaws on DSA.

METHODS

12 cases of AVM of jaws comprised this study group, and 5 cases in maxilla and 7 cases in mandible, respectively. Seldinger technique was applied to carry out carotid angiography under the guidance of DSA machine (PHILIPS V3000).

RESULTS

The DSA features of AVM of jaws included varix into the posterior area of jaws. The varix of the maxilla was supplied by the posterior superior alveolar artery and transversal facial artery when the soft tissue was involved, and the varix of the mandible was supplied by the inferior alveolar artery, maxillary and facial artery.

CONCLUSION

Angiography is considered necessary for the diagnosis and embolization of AVM of jaws, and the varix is the center of lesion.