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.

[Embolization of AVM of jaws]

OBJECTIVE

To report our experience to embolize the AVM of jaws by direct percutaneous puncture. in conjunction with endovascular therapy.

METHODS

3 cases of AVM of mandible and 3 cases of AVM of maxilla comprised this study group. The patients were embolized with fibered coils, PVA and NBCA. The coils were placed directly into the center of the intraosseous lesion. The procedure was under the guidance of DSA machine (PHILIPS V3000).

RESULTS

The acute arterial bleeding in 4 patients was controllable. The other two cases with oozing bleeding and a warm soft mass on the left face with a palpable pulse respectively, their symptoms and signs got improved a lot. The pericoronal oozing of blood in all patients disappeared during a 3 to 24 months follow-up and new bone formation was found in the follow-up radiography.

CONCLUSION

The embolization of the AVM of jaws by direct percutaneous puncture in conjunction with endovascular therapy is effective and safe, however the longer follow-up is expected.

Association of cocaine- and amphetamine-regulated transcript-immunoreactive elements with thyrotropin-releasing hormone-synthesizing neurons in the hypothalamic paraventricular nucleus and its role in the regulation of the hypothalamic-pituitary-thyroid axis during fasting

Because cocaine- and amphetamine-regulated transcript (CART) coexists with alpha-melanocyte stimulating hormone (alpha-MSH) in the arcuate nucleus neurons and we have recently demonstrated that alpha-MSH innervates TRH-synthesizing neurons in the hypothalamic paraventricular nucleus (PVN), we raised the possibility that CART may also be contained in fibers that innervate hypophysiotropic thyrotropin-releasing hormone (TRH) neurons and modulate TRH gene expression. Triple-labeling fluorescent in situ hybridization and immunofluorescence were performed to reveal the morphological relationships between pro-TRH mRNA-containing neurons and CART- and alpha-MSH-immunoreactive (IR) axons. CART-IR axons densely innervated the majority of pro-TRH mRNA-containing neurons in all parvocellular subdivisions of the PVN and established asymmetric synaptic specializations with pro-TRH neurons. However, whereas all alpha-MSH-IR axons in the PVN contained CART-IR, only a portion of CART-IR axons in contact with pro-TRH neurons were immunoreactive for alpha-MSH. In the medial and periventricular parvocellular subdivisions of the PVN, CART was co-contained in approximately 80% of pro-TRH neuronal perikarya, whereas colocalization with pro-TRH was found in <10% of the anterior parvocellular subdivision neurons. In addition, >80% of TRH/CART neurons in the periventricular and medial parvocellular subdivisions accumulated Fluoro-Gold after systemic administration, suggesting that CART may serve as a marker for hypophysiotropic TRH neurons. CART prevented fasting-induced suppression of pro-TRH in the PVN when administered intracerebroventricularly and increased the content of TRH in hypothalamic cell cultures. These studies establish an anatomical association between CART and pro-TRH-producing neurons in the PVN and demonstrate that CART has a stimulatory effect on hypophysiotropic TRH neurons by increasing pro-TRH gene expression and the biosynthesis of TRH.

[Embolization in arteriovenous malformations of maxillofacial region with PVA]

OBJECTIVE

To evaluate the embolization of arteriovenous malformations of the maxillofacial region with PVA.

METHODS

8 cases (male:3, female:5) of arteriovenous malformations of the maxillofacial region comprised this study group. The embolic material used was PVA (Polyvinyl Alcohol Foam) particles (250-500 microm) injected using 4.0 to 3.0 French-size catheters, catheterized selectively in the feeding pedicles of the AVM under the guidance of DSA machine (PHILIPS V3000).

RESULTS

Five patients were embolized an a single session, and three patients needed two sessions. Immediate angiographical results showed total disappearance of the AVMs in all patients. Swelling, pulsation, and bruit were disappeared after embolization. Pericoronal oozing of blood and acute arterial bleeding was controllable. Local pain, swelling,and low-grade fever usually lasted from 3 to 7 days after embolization.

CONCLUSION

The embolization of arteriovenous malformations of the maxillofacial region with PVA is effective and safe, and the longer follow-up is expected.

Recombinant human adenovirus: targeting to the human transferrin receptor improves gene transfer to brain microcapillary endothelium

Some inborn errors of metabolism due to deficiencies of soluble lysosomal enzymes cause global neurodegenerative disease. Representative examples include the infantile and late infantile forms of the ceroid lipofuscinoses (CLN1 or CLN2 deficiency, respectively) and mucopolysaccharidoses type VII (MPS VII), a deficiency of beta-glucuronidase. Treatment of the central nervous system component of these disorders will require widespread protein or enzyme replacement, either through dissemination of the protein or through dissemination of a gene encoding it. We hypothesize that transduction of brain microcapillary endothelium (BME) with recombinant viral vectors, with secretion of enzyme product basolaterally, could allow for widespread enzyme dissemination. To achieve this, viruses should be modified to target the BME. This requires (i) identification of a BME-resident target receptor, (ii) identification of motifs targeted to that molecule, (iii) the construction of modified viruses to allow for binding to the target receptor, and (iv) demonstrated transduction of receptor-expressing cells. In proof of principal experiments, we chose the human transferrin receptor (hTfR), a molecule found at high density on human BME. A nonamer phage display library was panned for motifs which could bind hTfR. Forty-three clones were sequenced, most of which contained an AKxxK/R, KxKxPK/R, or KxK motif. Ten peptides representative of the three motifs were cloned into the HI loop of adenovirus type 5 fiber. All motifs tested retained their ability to trimerize and bind transferrin receptor, and seven allowed for recombinant adenovirus production. Importantly, the fiber-modified viruses facilitated increased gene transfer (2- to 34-fold) to hTfR expressing cell lines and human brain microcapillary endothelia expressing high levels of endogenous receptor. Our data indicate that adenoviruses can be modified in the HI loop for expanded tropism to the hTfR.

Functional reconstitution of substrate transport by purified multidrug resistance protein MRP1 (ABCC1) in phospholipid vesicles

The 190-kDa multidrug resistance protein MRP1 (ABCC1) is a polytopic transmembrane protein belonging to the ATP-binding cassette transporter superfamily. In addition to conferring resistance to various antineoplastic agents, MRP1 is a transporter of conjugated organic anions, including the cysteinyl leukotriene C(4) (LTC(4)). We previously characterized the ATPase activity of reconstituted immunoaffinity-purified native MRP1 and showed it could be stimulated by its organic anion substrates (Mao, Q., Leslie, E. M., Deeley, R. G., and Cole, S. P. C. (1999) Biochim. Biophys. Acta 1461, 69-82). Here we show that purified reconstituted MRP1 is also capable of active transport of its substrates. Thus LTC(4) uptake by MRP1 proteoliposomes was osmotically sensitive and could be inhibited by two MRP1-specific monoclonal antibodies. LTC(4) uptake was also markedly reduced by the competitive inhibitor, S-decyl-glutathione, as well as by the MRP1 substrates 17 beta-estradiol 17-beta-(d-glucuronide), oxidized glutathione, and vincristine in the presence of reduced glutathione. The K(m) for ATP and LTC(4) were 357 +/- 184 microm and 366 +/- 38 nm, respectively, and 2.14 +/- 0.75 microm for 17 beta-estradiol 17-beta-(d-glucuronide). Transport of vincristine required the presence of both ATP and GSH. Conversely, GSH transport was stimulated by vincristine and verapamil. Our data represent the first reconstitution of transport competent purified native MRP1 and confirm that MRP1 is an efflux pump, which can transport conjugated organic anions and co-transport vincristine together with GSH.

Dynamics of capillary isoelectric focusing in the absence of fluid flow: high-resolution computer simulation and experimental validation with whole column optical imaging

A 150-component, dynamic electrophoresis simulator was developed and applied to the description of capillary isoelectric focusing (CIEF) of amphoteric substances in quiescent solution. The simulator is shown to be capable of producing high-resolution pH 3-10 focusing data with 140 individual carrier ampholytes (20/pH unit) and at current densities that are used in CIEF, i.e., under conditions that were hitherto unaccessible by dynamic computer simulation. Having a focusing capillary of 5-cm length, the predicted focusing dynamics for amphoteric dyes obtained at a constant voltage of 1500 V (300 V/cm) are shown to qualitatively agree with data obtained by whole-column optical imaging. The simulation data provide detailed insight into the dynamics of the focusing process for the cases with the focusing column being sandwiched between 40 mM NaOH (catholyte) and 100 mM phosphoric acid (anolyte) or having the column ends only permeable for OH- and H+ at cathode and anode, respectively. Simulation data reveal that the number of sample boundaries migrating from the two ends of the column to the focusing positions is always equal to the number of sample components. The number of detectable migrating sample boundaries, however, can be lower. Whole-column optical imaging is demonstrated to be the method of choice for following the approach to equilibrium. With that detection format, transient sample peaks can be recognized and properly identified. This would also be possible with a scanning detector moving rapidly and repeatedly along the column but cannot be accomplished by a stationary detector placed at a specified location. The data presented demonstrate that the model together with imaging monitoring can be used to optimize the CIEF separation conditions.

[Evaluation of improved Saccomanno method in management of sputum samples of lung cancer patients]

BACKGROUND

To compare the improved Saccomanno method with conventional method not only on concentrating and detecting cytological sputum but also on preserving sputum samples for further molecular biological and flow cytometry (FCM) investigation in lung cancer patients.

METHODS

A total of 125 cases were identified as lung cancer by histological or cellular pathology, and sputum samples from these patients were collected by conventional method and improved Saccomannomethod respectively for sputum smear. Then, some sputum samples collected by improved Saccomanno method were studied by FCM and/ or PCR-SSCP-silver stain.

RESULTS

The positive smear rates were 55. 2%( 69/ 125) by improved Saccomannomethod and 28%( 35/ 125) by conventionalmethod respectively ( P < 0. 01) . Of the 125 cases, 58 by improved Saccomannomethod and 26 by conventional method were confirmed for histological types of lung cancer respecitvely, and a highly significant difference was observed between the two groups ( P < 0. 01) . The positive smear rate by improved Saccomannomethod had significant correlation with the clinical characteristics such as histology, TNM stage, and type of lung cancer . Moreover, of the samples collected by improved Saccomanno method, 41 cases were selected to detect p53 point mutation by PCR-SSCP-silver stain and 30 cases were selected to quantitate p53 and p21 protein by FCM technique successfully, the positive rates were 53. 7% ( 22/ 41) , 40%( 12/ 30) and 53. 3% ( 16/ 30) respectively.

CONCLUSIONS

The results indicate that improved Saccomannomethod has a higher value than conventionalmethod not only on concentrating and detecting cytological sputum but also on preserving sputum sample for further molecular biological study.

Automated parallel DNA sequencing on multiple channel microchips

We report automated DNA sequencing in 16-channel microchips. A microchip prefilled with sieving matrix is aligned on a heating plate affixed to a movable platform. Samples are loaded into sample reservoirs by using an eight-tip pipetting device, and the chip is docked with an array of electrodes in the focal plane of a four-color scanning detection system. Under computer control, high voltage is applied to the appropriate reservoirs in a programmed sequence that injects and separates the DNA samples. An integrated four-color confocal fluorescent detector automatically scans all 16 channels. The system routinely yields more than 450 bases in 15 min in all 16 channels. In the best case using an automated base-calling program, 543 bases have been called at an accuracy of >99%. Separations, including automated chip loading and sample injection, normally are completed in less than 18 min. The advantages of DNA sequencing on capillary electrophoresis chips include uniform signal intensity and tolerance of high DNA template concentration. To understand the fundamentals of these unique features we developed a theoretical treatment of cross-channel chip injection that we call the differential concentration effect. We present experimental evidence consistent with the predictions of the theory.

Probing the roles of the only universally conserved leucine residue (Leu122) in the oligomerization and chaperone-like activity of Mycobacterium tuberculosis small heat shock protein Hsp16.3

To understand the role of the only universally conserved hydrophobic residue among all the members of the sHsp family, this extremely well conserved Leu122 residue in Hsp16.3 was replaced by valine, alanine, asparigine, or aspartate residues. Only very small amounts of the L122D and L122N mutant Hsp16.3 proteins were expressed in the transformed E. coli; however, both the L122V and L122A were readily expressed. The L122V and L122A mutant proteins had similar oligomeric structures to the wild-type protein at room temperature. Examination of the L122A mutant protein by native pore gradient PAGE and CD spectroscopy, however, revealed a smaller oligomeric size and different secondary structure at 37 degrees C. Both L122V and L122A mutant proteins exhibited significantly lowered chaperone activities. Observations reported here suggest a very important role of this only universally conserved Leu residue in both the formation of specific oligomeric structures and the molecular chaperone activities of Hsp16.3.

Hypervariable region 1 sequence stability during hepatitis C virus replication in chimpanzees

The putative envelope 2 (E2) gene of hepatitis C virus (HCV) contains a highly variable region referred to as hypervariable region 1 (HVR1). We hypothesized that this genetic variability is driven by immune selection pressure, rather than representing the accumulation of random mutations in a region with relatively little functional constraint. To test this hypothesis, we examined the E2 sequence of a human inoculum that was passaged through eight chimpanzees, which appear to have a replicative rate (opportunity for chance mutation) similar to that of humans. Acute-phase plasma samples from a human (the inoculum) and six of eight serially infected chimpanzees were studied. For each, 33 cloned cDNAs were examined by a combined heteroduplex-single-stranded conformational polymorphism assay to assess quasispecies complexity and optimize selection of clones with unique gel shift patterns (clonotypes) for sequencing. The sequence diversity of HCV was significantly lower in the chimpanzees than in the humans, and during eight serial passages there was no change in the sequence of the majority clonotype from each animal examined. Similarly, the rates of protein sequence altering (nonsynonymous) substitution were lower in the chimpanzees than in the humans. These findings demonstrate that nonsynonymous mutations indicate selection pressure rather than being an incidental result of HCV replication.

ATPase activity of purified and reconstituted multidrug resistance protein MRP1 from drug-selected H69AR cells

The ATP-binding cassette transporter protein, multidrug resistance protein MRP1, was purified from doxorubicin-selected H69AR lung tumor cells which express high levels of this protein. A purification procedure comprised of a differential two-step solubilization of MRP1 from plasma membranes with 3-(3-cholamidopropyl)dimethylammonio-1-propanesulfonate followed by immunoaffinity chromatography using the MRP1-specific monoclonal antibody QCRL-1 was developed. Approximately 300 microgram of MRP1 was obtained from 6 mg of plasma membranes at 80-90% purity, as indicated by silver staining of protein gels. After reconstitution of purified MRP1 into proteoliposomes, kinetic analyses indicated that its K(m) for ATP hydrolysis was 104+/-22 microM with maximal activity of 5-10 nmol min(-1) mg(-1) MRP1. MRP1 ATPase activity was further characterized with various inhibitors and exhibited an inhibition profile that distinguishes it from P-glycoprotein and other ATPases. The ATPase activity of reconstituted MRP1 was stimulated by the conjugated organic anion substrates leukotriene C(4) (LTC(4)) and 17beta-estradiol 17-(beta-D-glucuronide) with 50% maximal stimulation achieved at concentrations of 150 nM and 1.6 microM, respectively. MRP1 ATPase was also stimulated by glutathione disulfide but not by reduced glutathione or unconjugated chemotherapeutic agents. This purification and reconstitution procedure is the first to be described in which the ATPase activity of the reconstituted MRP1 retains kinetic characteristics with respect to ATP-dependence and substrate stimulation that are very similar to those deduced from transport studies using MRP1-enriched plasma membrane vesicles.

Effect of salt concentration on separation patterns in static capillary isoelectric focusing with imaging detection

Salts introduced into protein samples have an impact on the pH gradient in free solution in isoelectric focusing (IEF), which is reflected by the separation pattern. In this study, samples containing different concentrations of phosphate-buffered saline (PBS) were focused in capillary format and detected in a real-time mode using an imaged capillary isoelectric focusing (CIEF) system at 280 nm. It was observed that salt compressed the pH gradient with a degree of 4.3% at a PBS concentration interval of 10 mM. As a result, the same sample components, therefore, were focused at different positions inside the capillary. Using two pI markers as the internal standards, the separation patterns in the presence of salts were corrected to the salt-free matrix by simply stretching the electropherograms. The stretched electropherograms of model samples, pI markers and myoglobin, demonstrated the feasibility of this correction. This simple method is promising for identifying proteins, which may exhibit different pI values after their mutation and stability process, when salt is present in the sample.

Monoclonal antibodies that inhibit the transport function of the 190-kDa multidrug resistance protein, MRP. Localization of their epitopes to the nucleotide-binding domains of the protein

Multidrug resistance in tumor cells is often accompanied by overexpression of multidrug resistance protein (MRP), a 190-kDa transmembrane protein that belongs to the ATP-binding cassette superfamily of transport proteins. MRP mediates ATP-dependent transport of a variety of conjugated organic anions and can also transport several unmodified xenobiotics in a glutathione-dependent manner. To facilitate structure-function studies of MRP, we have generated a panel of MRP-specific monoclonal antibodies (mAbs). Four of these mAbs, QCRL-2, -3, -4, and -6, bind intracellular conformation-dependent epitopes, and we have shown that they can inhibit the transport of several MRP substrates. Binding competition and immunoprecipitation assays indicated that mAbs QCRL-4 and -6 probably recognize the same detergent-sensitive epitope in MRP, whereas mAbs QCRL-2, -3, and -4 each bind distinct, non-overlapping epitopes. Fab fragments inhibit transport as effectively as the intact mAbs, suggesting that inhibition results from direct interactions of the mAbs with MRP. Immunodot blot and immunoprecipitation analyses revealed that the minimal regions of MRP sufficient for full reactivity of mAbs QCRL-2 and -3 are amino acids 617-858 and 617-932, respectively, which encompass the NH2-proximal nucleotide-binding domain (NBD). In contrast, the epitope bound by mAb QCRL-4 localized to amino acids 1294-1531, a region that contains the COOH-proximal NBD. However, none of the mAbs inhibited photolabeling of intact MRP with 8-azido-[alpha-32P]ATP. This suggests that rather than preventing nucleotide binding, the mAbs inhibit transport by interfering with substrate binding or by trapping MRP in a conformation that does not allow transport to occur. Our results also demonstrate for the first time that the NBDs of MRP can be expressed as soluble polypeptides that retain a native conformation.

[Inhibitory effect of replication and expression of HDV by antisense oligodeoxynucleotides in H1 delta 9 cell]

OBJECTIVE

To study inhibitory effect of an antisense oligodeoxynucleotide (ASODN) and its phosphorothioate (S-ASODN) on replication and expression of HDV in H1 delta 9 cell.

METHODS

In previous studies, it was proved that the ASODNs which are complementary to genomic HDV ribozyme self-cleavage site and stem I regions can inhibit availably genomic HDV ribozyme activity. In the present study, a 15-mer ASODN and S-ASODS which are complementary to this region (nucleotide 684-698) were added to medium of cultured H1 delta 9 cell. HDAg and HDV cDNA were detected by ELISA and Dot blot hybridization.

RESULTS

Twenty-fourth hour after 6 mumol/L ASODN and S-ASODN were added, both the secreting amount of HDAg in the supernatant and HDV RNA were inhibited. The inhibiting rates were 76.14% and 84.50% respectively. When the concentration of S-ASODN was 2, 4, 6 mumol/L, the inhibiting rate showed the feature of dosage dependence. Inhibitory effect of ASODN and S-ASODN were similar in the same dosage.

CONCLUSION

The results suggest that ASODN and S-ASODN can availably inhibit replication and expression of HDV in H1 delta 9 cell.

Capillary isoelectric focusing with whole column imaging detection for analysis of proteins and peptides

Whole column imaging detection has been developed for capillary isoelectric focusing (CIEF) of proteins and peptides. In this imaged C1EF technique, a solution of sample and ampholytes was introduced into a short (4-5 cm), internally coated capillary stabilized by a cartridge. After applying high DC voltage, the isoelectric focusing process takes place and the focused zones are monitored in a real-time mode using the imaging detectors developed. Three types of imaging detectors have been developed including refractive index gradient, laser-induced fluorescence (LIF), and absorption. Of these, absorption imaging detection is the most practical at the present time due to its quantitative ability and universal characteristics. Whole column imaging detection eliminates the mobilization step required for single point detection after the focusing process. Therefore, it provides a fast analysis speed (3-5 min for each sample), and avoids the disadvantages associated with the mobilization process, such as distortion of pH gradient and loss in resolution. In this paper, we review the methodology of imaged CIEF as well as progress in instrumental development, IEF performed on a microchip, and the application to protein and peptide analysis.

[Chemical constituents of Epimedium acuminatum Franch. (II)]

OBJECTIVE

To study the components of roots of Epimedium acuminatum.

METHOD

Column chromatography was employed for the isolation. The isolated compounds were elucidated by UV, IR, FAB-MS, 1HNMR and 13CNMR analysis.

RESULT

Four constituents were obtained and elucidated as epimedoside A(V), diphylloside B(VI), epimedin C(VII) and ikarisoside C(VIII).

CONCLUSION

Four constituents are all flavonol glycosides, of which VI, VII and VIII were separated from this plant for the first time.

The glucose transporter of Escherichia coli with circularly permuted domains is active in vivo and in vitro

The bacterial phosphotransferase system (PTS) consists of two energy-coupling soluble proteins (enzyme I and HPr) and a large number of inner membrane transporters (enzymes II) that mediate concomitant phosphorylation and translocation of sugars and hexitols. The transporters consist of three functional units (IIA, IIB, IIC), which occur either as protein subunits or domains of a multidomain polypeptide. The membrane-spanning IIC domain contains the substrate binding site; IIA and IIB are phosphorylation domains that transfer phosphate from HPr to the transported sugar. The transporter complexes of the PTS are good examples for variation of design by modular assembly of domains and subunits. The domain order is IIC-IIB in the membrane subunit of the Escherichia coli glucose transporter (IICBGlc) and IIB-IIC in Salmonella typhimurium sucrose transporter (IIBCScr). The phosphorylation domain of IICBGlc was translocated from the carboxyl-terminal to the amino-terminal end of the IIC domain, and the activity of the circularly permuted form was optimized by variation of the length and the composition of the interdomain linker. IIBapCGlc with an alanine-proline-rich interdomain linker has 70% of the control specific activity after purification and reconstitution into proteoliposomes. These results indicate that the amino-terminal end of IICBGlc must be on the cytoplasmic side of the inner membrane, that membrane insertion of the IIC domain is insensitive to the modification of its amino-terminal end, and that a domain swap as it could occur by a single DNA translocation event can rapidly lead to a functional protein. However, IIB could not be substituted for by glucokinase. Fusion proteins between the IIC domain and glucokinase do not transport and phosphorylate glucose in an ATP-dependent mechanism, although the IIC moiety displays transport activity upon complementation with soluble subclonal IIB, and the glucokinase moiety retains ATP-dependent nonvectorial kinase activity. This indicates that IIC and IIB are two cooperative units and not only sequentially acting upon a common substrate, and that translocation of glucose must be conformationally coupled to the phosphorylation/dephosphorylation cycle of IIB.

Recent developments in capillary isoelectric focusing with whole-column imaging detection

Capillary isoelectric focusing (CIEF) is a high resolution technique for protein separation. The on-column single point detector requires a mobilization step which lengthens the analysis time and causes an uneven resolution along the separation column. The real time and whole column imaging detection has been developed for performing CIEF without mobilization. Three types of imaging detection systems have been developed: optical absorption, refractive index gradient, and laser induced fluorescence. This technique provides a fast analysis speed (about 6 min) and a good resolution of 0.03 pH unit level. Using the absorption imaging detector, ampholyte-free IEF in tapered capillary is being demonstrated, which eliminates the interference of the expensive carrier ampholytes for protein detection in UV region. Recent advancements in this imaged CIEF technique as well as its applications are reviewed.

[Chemical constituents of the root of Epimedium acumiantum Franch]

Four known flavonol glycosides, ikarisoside A(I), 2"-O-rhamnosyl-icariside II (II), 2"-O-rhamnosyl-ikarisoside A(III) and ikarisoside B(IV) were isolated from the ethyl acetate extract of the root of Epimedium acuminatum. Their structures were elucidated by spectroscopic and chemical methods. II, III and IV were isolated from this plant for the first time.

[Phenomenon of intrinsic rhythm of luteinizing hormone release from isolated anterior pituitary gland of female rat]

The intrinsic nature of rthymic release of luteinizing hormone (LH) of isolated human and rat anterior pituitary gland reported independently by Macro Gambacciani and Xie in 1987 can be more directly demonstrated by a computer programme of Time Series-HSY Hidden Periodic Analytic Approach for continuous monitoring the LH output of the perfusate from a perfusion system with in vitro anterior pituitary of SD female rat. The results are as follows: (1) Under various reproductive conditions the average frequency (min/cycle) and amplitude (ng/ml) of the intrinsic rhythm of LH release were quite different: In proestrous group the frequency and amplitude were the highest, being intermediate in the ovariectomized group and lowest in the lactation group. (2) The intrinsic rhythm of LH release could be changed by either peptide or steroid hormones. In proestrous group with 30 min of gonadotropin-releasing hormone (GnRH), stimulation would reduce both frequency and amplitude. In case of lactation, the frequency was unchanged, but amplitude lowered, while in the ovariectomized rat pituitary, the 30 min GnRH stimulation decreased the frequency of release only. The intrinsic rhythm of the LH release could also be influenced by steriod hormones (Ru486 and Anordrin). With 120 min before removal of the anterior pituitary gland the rats receiving i.m. injection of Ru486 (2 mg/kg bw) or Anordrin (2 mg/kg), the results showed that Ru486 decreased frequency, while Anordrin decreased only the frequency to a less extent, both without amplitude affected. (3) Verapamil and EGTA added to the perfusion system did not abolish but only decreased the rhythmic phenomenon by using proestrous pitutary. This suggests that participation of Ca2+ may take place in the intrinsic release of LH. The above results indicated that the intrinsic rhythm of LH release of isolated anterior pituitary gland is different from various reproductive hormonal conditions and capable of being modified by exogenous hormones. The physiological function of the intrinsic rhythm of LH release of anterior pituitary gland remains to be elucidated.

Purification of functional human P-glycoprotein expressed in Saccharomyces cerevisiae

A system for expression and facile purification of the human P-glycoprotein (Pgp) from the yeast Saccharomyces cerevisiae is described. The wild-type human mdr1 cDNA was cloned into a high copy number yeast expression vector under the control of the constitutive promoter of the yeast plasma membrane H+-ATPase. Western blots of membranes from the stable transformants confirmed that the Pgp is expressed in yeast cells in amounts approximately 0.4% of the total yeast membrane protein. Density gradient sedimentation analysis of the yeast membranes indicated that the expressed Pgp is localized in the plasma membrane. Yeast cells transformed with the Pgp expression plasmid acquire increased resistance to valinomycin, suggesting that the expressed Pgp is properly folded and functional. The expressed Pgp can be solubilized from the yeast membranes with lysophosphatidylcholine, and when tagged with ten histidines at its C-terminus, can be readily purified to about 90% homogeneity by Ni2+ affinity chromatography. About 50 microg of the Pgp can be purified from 20 mg of crude yeast membranes. The purified human Pgp exhibits a verapamil-stimulated ATPase activity and the maximal activity is 2.5 +/- 0.5 micromol/min per mg of Pgp, suggesting that the purified Pgp from yeast is highly functional. The Pgp expressed in yeast has the same electrophoretic mobility (ca. 130 kDa) as the Pgp produced in Sf9 insect cells and is unaffected by N-glycosidase treatment, suggesting that it is not glycosylated. Because of the relative ease of growing yeast in massive quantities this expression system appears to be excellent for producing this membrane transporter at levels sufficient for further biochemical and biophysical studies, and for site-directed mutagenesis studies as well.

[An image analysis of the morphological changes of LH cells during LH release peak induced by LHRH in male rats]

The relationship between the peak of LH release induced by exogenous LHRH and morphological change of LH cells in male rats was investigated by ABC Affinity histochemistry and qualitatively characterized by Medical Image Processing System-I. The serum LH concentration was determined by RIA. During the period of basal secretion of LH (3.76 +/- 0.39 ng/ml), the LH cells might be assigned at a storage state. Most of such cells (56.7%) are round and large, and their cross sectional areas are larger then 340 micron 2, usually containing large vacuoles, while the smaller cells of X-sectional area less then 190 micron 2 counted only 2% of the total population. Thirty minutes after injection of LHRH the serum LH level increased significantly (6.46 +/- 1.6 ng/ml, P < 0.01), there appeared a lot of small angular cells, the average cross sectional areas of LH cells decreased significantly (P < 0.0001). When LHRH was injected at sixty minutes, the LH level reached a peak (18.78 +/- 0.79 ng/ml), the number of the large cells decreased to only 4%, while the small cells increased to 66%, vacuoles were almost disapperanced and a large part of cells (52.6%) became irregular. Thereafter, the LH serum gradually subsided to its original basal level with attendant resumption of the morphology of the LH cells at storage state. It appears that the morphological changes, such as size, shape, vacuoles and so on, of the LH cells may serve as an important index for showing the effect of LHRH on LH secretion.

Different conformations and site selectivity of HO-2-Co(III)-bleomycin A2 and Co (III)-bleomycin A2 bound to DNA oligomers

Conformational properties of HO2(-)-Co(III)-bleomycin A2 (Form I) and Co(III)-bleomycin (Form II) bound to DNA oligomers offering either principal cleavage site for the drug, d(GGAAGCTTCC)2 or d(AAACGTIT)2, have been studied by NMR methods. Form I binds in slow exchange to these oligomers. It retains most of its solution nuclear Overhauser effects (NOEs) upon binding to either oligomer. Pyrimidinyl methyl protons from the metal domain of the drug make an NOE connection with a G5 2-amino proton on DNA. The bithiazole intercalates between base pairs involving either C6 and T7 or T6 and T7 of the two DNA molecules, according to NOE connections between the bithiazole protons and protons from these bases and changes in the positions of their chemical shifts. Form II also retains most of its solution NOEs upon association with the first oligomer. However, in contrast to Form I it binds to DNA in fast exchange on the NMR time scale over the temperature range of 5-35 degrees C and does not break the degeneracy of the DNA proton chemical shifts. No intermolecular NOEs between Form II and the 10-mer have been detected. Likewise, the major perturbation in chemical shift of the histidine H2 and guanine G5 protons seen in Form I-DNA adducts is absent in Form II-DNA. The association constant of Form II with d(GGAAGCTTCC)2 in 20 mM HEPES buffer at pH 7.4 and 25 degrees C is 1.7 x 10(5) M(-1), and 1.0 mol of Form II bind per mol of 10-mer.

Research into analgesia by inhaling analgesic

This article deals with analgesia by inhaling analgesic. According to Chinese medical theories, TCM analgesics were chosen from the literature and folk prescriptions screened and proved by analgesic tests on animals. A reasonable prescription was made up and the drug inhaled. Its analgesic effect was superior to that of dolantin injection (3 mg/kg body weight, intraperitoneal injection). Clinical trials showed its analgesic effect in 3-10 minutes and it lasted for more than 2 hours in over 70% of the cases for a total effective rate of 94.6%. The drug is absorbed quickly and acts directly on the nerve center. Its use is not addictive.

[Inhibition of genomic HDV ribozyme activity by antisense oligodeoxynucleotides]

OBJECTIVE

To study inhibitory effect of antisense oligodeoxynucleotides (asODNs) on genomic HDV ribozyme activity.

METHODS

Plasmid pHDVrz277 used to transcribe a 112 nucleotides (nt) genomic HDV ribozyme constructed earlier in our laboratory. It had genomic and antigenomic HDV ribozyme sequences from 665-941nt. The inhibitory effect of five asODNs on genomic HDV ribozyme activity was studied to select the potential effective sequences in vitro.

RESULTS

The results showed that asODN, being complementary to 683-703nt (stem I and self-cleavage site), completely blocked the activity of a 112nt genomic HDV ribozyme transcription in vitro. The inhibition rate of asODNs against 756-770nt (SSrB) and 721-735nt (SSrA) were 69.36% and 48.64% respectively. However, two asODNs covered the 736-750nt (stem IV) and 704-720nt (SSrC) showed almost no inhibitory effect on genomic HDV ribozyme. Fine sequence specificity testing at region 683-703nt revealed that asODN as small as 13 nt flanking the self-cleavage site (683-695nt) retained a high inhibition rate (> 90%).

CONCLUSION

The results suggested that stem I and SSrB may play an important role in genomic HDV ribozyme and asODNs can block genomic HDV ribozyme activity almost completely.

A string of enzymes, purification and characterization of a fusion protein comprising the four subunits of the glucose phosphotransferase system of Escherichia coli

A multidomain protein comprising the four subunits of the glucose phosphotransferase system of Escherichia coli was constructed by fusion of the transmembrane subunit IICBGlc and the three cytoplasmic proteins, IIAGlc, HPr, and enzyme I. The subunits were linked in the above order with Ala-Pro-rich linkers; the fusion protein was overexpressed in E. coli and purified by Ni2+ chelate affinity chromatography. Approximately 3 mg of the fusion protein could be purified from 1 liter of culture. The phosphotransferase activity of the purified fusion protein was 3-4 times higher than that of an equimolar mixture of the isolated subunits. The mannose transporter, which also requires enzyme I and HPr, was not an effective competitor in the overall phosphoryltransfer reaction when the fusion protein was used, whereas it was a competitor when an equimolar mixture of the separate subunits was employed. Transphosphorylation activity of the fusion protein was almost indistinguishable from the wild-type IICBglc. Addition of extra IICBGlc subunit could significantly stimulate the phosphotransferase activity of the fusion protein, addition of extra IIAGlc subunit and enzyme I, in contrast, was slightly inhibitory, and HPr had almost no effect. An optimal detergent-lipid ratio is required for maximum activity of the fusion protein. Our results suggest that Ala-Pro-rich linker sequences may be of general use for the construction of catalytically active fusion proteins with novel properties.