[Incidence and related factors of antiviral drug resistance in HIV-infected pregnant and postpartum women in some areas of three western provinces of China from 2017 to 2019]

Objective: To analyze the incidence and related factors of drug resistance in HIV-infected pregnant and postpartum women in some areas of three western provinces of China from 2017 to 2019. Methods: From April 2017 to April 2019, face-to-face questionnaires and blood sample testing were conducted in all health care institutions providing maternal and perinatal care and midwifery-assisted services in 7 prevention of mother-to-child transmissi project areas in Xinjiang, Yunnan and Guangxi provinces/autonomous regions. Information was collected during the perinatal period and viral load, CD4+T lymphocytes and drug resistance genes were detected at the same time. The multivariate logistic regression model was used to analyze the relationship between different factors and drug resistance in HIV-infected pregnant and postpartum women. Results: A total of 655 HIV-infected pregnant and postpartum women were included in this study. The incidence of drug resistance was 3.4% (22/655), all of whom were cross-drug resistant. The rate of low, moderate and high drug resistance was 2.1% (14/655), 1.2% (8/655) and 0.8% (5/655), respectively. The drug resistance rate in the people who had previously used antiviral drugs was 1.9% (8/418), and the drug resistance rate in the people who had not used drugs was 5.9% (14/237). The NNRTI drug resistance accounted for 2.8% (18/655) and the NRTI drug resistance rate was 2.5% (16/655). The multivariate logistic regression model showed that the risk of HIV resistance was lower in pregnant women who had previously used antiviral drugs (OR=0.32, 95%CI: 0.11-0.76). Conclusion: Strengthening the management of antiviral drug use and focusing on pregnant and postpartum women who have not previously used antiviral drugs can help reduce the occurrence of drug-resistant mutations. Personalized antiviral therapy should be considered to achieve viral inhibition effects in clinical practice.

[Analysis of the catastrophic health expenditure of HIV-positive maternal households in high AIDS endemic areas in Liangshan prefecture]

Objective: To analysis the income and expenditure of HIV-positive pregnant women and the catastrophic health expenditure of their households in high AIDS endemic areas in Liangshan prefecture. Methods: From December 2018 to January 2019, a total of 250 pregnant women were recruited from 2 of 17 counties in Liangshan Prefecture, including 133 HIV-positive pregnant women and 117 HIV-negative pregnant women. The data, including basic information of pregnant women, basic information of the family, annual family income in 2017, annual family health expenditure in 2017, and maternal and child-related expenditure in 2017, were collected for analyzing the incidence of catastrophic health expenditure in the family. Results: The average annual income and average annual health expenditure of HIV-positive pregnant women households were 7 000 CNY and 2 000 CNY, while those of HIV-negative pregnant women households were 10 000 CNY and 3 000 CNY, respectively. Based on the criteria of 15%, 25% and 40%, the incidence of catastrophic health expenditure of HIV-positive pregnant households was 39.10%, 33.83% and 27.82%, with average differences of 34.84%, 31.17% and 26.65%, respectively, while that of HIV-negative pregnant women households was 38.46%, 33.33% and 23.93%, with average differences of 31.68%, 28.35% and 24.22%, respectively. Conclusion: The incidence of catastrophic health expenditure of pregnant households in high AIDS endemic areas in Liangshan prefecture is high. The incidence of HIV-positive families is slightly higher than that of HIV-negative families. We suggest that medical insurance compensation in Liangshan prefecture should be improved to reduce the impact of catastrophic health expenditure.

Suppression of αvβ6 downregulates P-glycoprotein and sensitizes multidrug-resistant breast cancer cells to anticancer drugs

Multidrug resistance (MDR) in breast cancer treatment is the major cause leading to the failure of chemotherapy. P-glycoprotein (P-gp), the product of the human MDR1 gene, plays a key role in resistance to chemotherapy and confers cross-resistance to many structurally unrelated anticancer drugs. We have previously reported that integrin αvβ6 plays a critical role in breast cancer invasion and metastasis. However, whether and how αvβ6 is associated with P-gp and regulated by potential genetic mechanisms in breast cancer remains unclear. In the present study, we further investigated the reversal effect and underlying mechanisms of MDR in breast cancer. Two small interfering RNA constructs (pSUPER-β6shRNAs) targeting two different regions of the β6 gene have been designed to inhibit αvβ6 expression by transfecting them into adriamycin-resistant MCF-7/ADR cell lines. Suppression of αvβ6 dramatically downregulated the levels of MDR1 gene mRNA and P-gp. In particular, β6shRNA-mediated silencing of αvβ6 gene increased significantly the cellular accumulation of Rhodamine 123 and markedly decreased drug efflux ability, suggesting that β6shRNAs indeed inhibit P-gp mediated drug efflux and effectively overcome drug resistance. In addition, inhibition of integrin αvβ6 suppressed the expression of ERK1/2. Interestingly, our data demonstrate that suppression of integrin αvβ6 caused significant downregulation of Bcl-2, Bcl-xL and upregulation of caspase 3, Bad, accompanied by increasing activity of cytochrome C. A possible connection between αvβ6 and P-gp in drug resistance biology is suggested. Taken together, β6shRNA could efficiently inhibit αvβ6 and MDR1 expression in vitro and these findings may offer specifically useful means to reverse MDR in breast cancer therapy.

[HIV early infant diagnosis test in HIV-exposed children in China, 2015-2017]

Objective: To understand the early infant diagnosis (EID) test rate and associated factors in HIV-exposed children in China during 2015-2017. Methods: The follow-up information cards of 12 096 HIV-exposed children for 18 months after birth during 2015-2017 were collected from the Management Information System of China's Prevention of Mother-to-Child Transmission of HIV for a retrospective analysis. The EID test characteristics of HIV exposed children and associated factors were analyzed. Results: From 2015 to 2017, the EID test rate in HIV exposed children increased from 65.6% to 83.4% in China (trend χ(2) P<0.001). The EID test rate within 8 weeks after birth increased from 61.1% to 76.8% (trend χ(2) P<0.001), but the EID positive rate decreased from 8.7% to 3.4% (trend χ(2) P<0.001). The EID positive rate in fatal HIV-exposed children was 47.7%, 36.9% and 36.3% during 2015-2017, respectively, the differences were not significant. EID test rate was associated with ethnic group, living area, survival status and the year reaching 18-month-old of the children. Conclusions: The performance of EID test has been standardized step by step in China. The positive rate of EID test decreased gradually with year. However, the EID test rates in children who were from minority ethnic groups, lived in areas with lower prevalence of HIV infection and died within 18 months after birth were relatively low.

Laser Cooling of Radium Ions

The unstable radium nucleus is appealing for probing new physics due to its high mass, octupole deformation, and energy level structure. Ion traps, with long hold times and low particle numbers, are excellent for work with radioactive species, such as radium and radium-based molecular ions, where low activity, and hence low total numbers, is desirable. We address the challenges associated with the lack of stable isotopes in a tabletop experiment with a low-activity (∼10  μCi) source where we laser-cool trapped radium ions. With a laser-cooled radium ion we measured the 7p^{2}P_{1/2}^{o} state's branching fractions to the ground state, 7s^{2}S_{1/2}, and a metastable excited state, 6d^{2}D_{3/2}, to be p=0.9104(7) and 0.0896(7), respectively. With a nearby tellurium reference line we measured the 7s^{2}S_{1/2}→7p^{2}P_{1/2}^{o} transition frequency, 640.096 63(6) THz.

[Serologic surveillance indicators analysis among syphilis-infected pregnant women in East China]

Objective: To analyze serologic surveillance indicators during pregnancy among syphilis-infected women who delivered in 2013 in East China. Methods: Data were from national 'Information System of Prevention of Mother-to-child Transmission of HIV, syphilis and HBV Management' and in total 5 206 syphilis-infected pregnant women who delivered in 2013 and in East China were involved in the analysis. Information on demographic characters, laboratory tests, and treatment regimens were collected. The maternal non-treponemal testing surveillance and titer distribution were described and compare the proportions between pregnant women receiving standard testing and non-standard testing, taking baseline testing and testing before delivery or at the third trimester. Multivariate logistic regression model was analyzed using maternal titer control as dependent variable, using prior history of syphilis infection, syphilis stages, titer, gestational weeks of treatment initiation and treatment regimens as independent variables in 3 940 pregnant women with both baseline testing results and testing results before delivery or at the third trimester. Results: The ages of the 5 206 syphilis infected pregnant women were (28.1±5.8) years old. The numbers of women received penicillin treatment, other treatment regimens and no treatment were 2 967 (57.0%), 281 (5.4%), and 1 958 (37.6%), respectively. The number of women with maternal seroconversion, 4-fold or greater titer decline, or titer increase were 349 (6.7%), 251 (4.8%) and 28 (0.5%). Multivariate analysis results showed that compared with pregnant women with prior history of syphilis, the OR(95%CI) for maternal titer control was 1.49 (1.18-1.88) among those with syphilis-infection history. Compared with pregnant women initiated treatment at 28 gestational weeks or before, the OR (95%CI) for maternal titer control was 4.09 (3.19-5.24) among those who initiated treatment after 28 gestational weeks. Compared with pregnant women initiated treatment at 28 gestational weeks or before, the OR (95%CI) for maternal titer control was 4.09 (3.19-5.24) among those who initiated treatment after 28 gestational weeks or received no treatment. Compared with pregnant women received penicillin treatment, the OR (95%CI) for maternal titer control among those received non-penicillin treatment and those received no treatment were 2.35 (1.46-3.76) and 1.55 (1.13-2.12), respectively. Conclusion: In East China, the proportion of women achieved seroconversion or 4-fold or greater titer decline during pregnancy was very low. Pregnant women with no prior history of syphilis infection, early maternal initiation of treatment, and penicillin treatment were more likely to reach maternal titer control.

[Comprehensive review of factors and preventions of mother to child transmission of hepatitis B virus]

Mother-to-child transmission of hepatitis B virus (HBV) is one of major public health issues. Difference is found on effect of preventions of mother to child transmission of HBV such as Hepatitis B vaccine, Hepatitis B immunoglobulin and antiretroviral drugs. Based on the risks of hepatitis B virus on children, influencing factors and interventions of HBV mother-to-child transmission were explored to improve prevention mother-to-child transmission of hepatitis B and to search appropriate strategies reducing mother-to-child transmission of HBV.

[Mode of delivery among HIV-positive pregnant women in areas with high prevalence of HIV in China, 2007-2013]

OBJECTIVE

To describe the changing demographic profile over time of pregnant women diagnosed with HIV infection, and trends in mode of delivery and pregnancy outcome.

METHODS

An observational investigation was conducted based on a population of 1 128 HIV-positive pregnant women at eight sites in China in provinces with high prevalence of HIV among pregnant women and children between 2007 and 2013. The study area included Shangcai and Weishi counties in Henan province; Ruili and Longchuan counties and Linxiang prefecture in Yunnan province; Yining County in Xinjiang; and Lingshan county and Babu district in Guangxi province. Main outcome measures were maternal characteristics, mode of delivery, and related trends over time by Cochram-Mantel-Haenszel(CMH) χ(2)-test.

RESULTS

A total hospital delivery rate of 96.4% was reported. For each year during the period 2007-2013, hospital delivery rates were 95.1% (253/266), 94.8% (188/198), 93.7% (164/175), 98.8% (159/161), 98.6% (141/143), 97.4% (114/117), and 100.0% (68/68), respectively (χ(2)CMH=7.68, P=0.006). The neonatal survival rate increased by 0.7% incrementally from 2007 to 2013, with 98.5% (262/266), 99.0% (196/198), 99.4% (174/175), 99.4% (160/161), 100.0% (143/143), 100.0% (117/117), and 100.0% (68/68), respectively (χ(2)CMH=4.58, P=0.030). The proportions of vaginal deliveries in those years were 62.2% (166/266), 54.8% (109/198), 59.9% (105/175), 61.7% (100/161), 66.7% (96/143), 58.8% (69/117), and 66.7% (46/68), respectively (χ(2)CMH=1.19, P= 0.276). The average rate for midwives skilled in procedures such as artificial rupture of membranes and episiotomy was 37.8% (261/691), with proportions decreasing during the study period at 39.2% (65/166), 47.4% (52/109), 35.9% (38/105), 46.0% (46/100), 25.5% (25/96), 31.2% (22/69), and 28.3% (13/46), respectively (χ(2CMH)=6.76, P=0.009).

CONCLUSION

The annual rate of reported hospital delivery increased between 2007 and 2013, with a declining rate of skilled midwifery over the same period. Survival of neonates born to HIV-infected mothers in China has increased to nearly equivalent levels as those of developed countries.

Intensified nitrate and phosphorus removal in an electrolysis -integrated horizontal subsurface-flow constructed wetland

A novel electrolysis-integrated horizontal subsurface-flow constructed wetland system (E-HFCWs) was developed for intensified removal of nitrogen and phosphorus contaminated water. The dynamics of nitrogen and phosphorus removal and that of main water qualities of inflow and outflow were also evaluated. The hydraulic retention time (HRT) greatly enhanced nitrate removal when the electrolysis current intensity was stabilized at 0.07 mA/cm². When the HRT ranged from 2 h to 12 h, the removal rate of nitrate increased from 20% to 84%. Phosphorus (P) removal was also greatly enhanced-exceeding 90% when the HRT was longer than 4 h in the electrolysis-integrated HFCWs. This improved P removal is due to the in-situ formation of ferric ions by anodizing of sacrificial iron anodes, causing chemical precipitation, physical adsorption and flocculation of phosphorus. Thus, electrolysis plays an important role in nitrate and phosphorus removal. The diversity and communities of bacteria in the biofilm of substrate was established by the analysis of 16S rDNA gene sequences, and the biofilm was abundant with Comamonadaceae and Xanthomonadaceae bacteria in E-HFCWs. Test results illustrated that the electrolysis integrated with horizontal subsurface-flow constructed wetland is a feasible and effective technology for intensified nitrogen and phosphorus removal.

Association between matrix metalloproteinase-9 rs3918242 polymorphism and development of coronary artery disease in a Chinese population

We conducted a case-control study to investigate the role of one single nucleotide polymorphism of MMP-9 rs3918242 in the development of coronary artery disease. The rs3918242 was amplified with 435-bp DNA fragments using polymerase chain reaction coupled with restriction fragment length polymorphism. When compared with control subjects, patients with coronary artery disease had higher systolic and diastolic blood pressure, as well as higher triglycerides (P < 0.05), were more likely to suffer from diabetes mellitus, and had lower total cholesterol and high-density lipopolysaccharides. Using unconditional logistic analysis, we found that individuals with CT and TT genotypes were associated with increased risk of coronary artery disease in a co-dominant model, and the ORs (95%CI) were 1.50 (1.02-2.20) and 6.89 (2.51-23.41) for CT and TT, respectively. We observed that the T allele of rs3918242 was correlated with increased risk of coronary artery disease (OR = 1.88, 95%CI = 1.39-2.55). In conclusion, we suggest that the TT and CT genotypes and T allele of MMP-9 rs3918242 polymorphism is correlated with an increased risk of coronary artery disease in a Chinese population.

Configurable NOR gate arrays from Belousov-Zhabotinsky micro-droplets

We investigate the Belousov-Zhabotinsky (BZ) reaction in an attempt to establish a basis for computation using chemical oscillators coupled via inhibition. The system consists of BZ droplets suspended in oil. Interdrop coupling is governed by the non-polar communicator of inhibition, Br2. We consider a linear arrangement of three droplets to be a NOR gate, where the center droplet is the output and the other two are inputs. Oxidation spikes in the inputs, which we define to be TRUE, cause a delay in the next spike of the output, which we read to be FALSE. Conversely, when the inputs do not spike (FALSE) there is no delay in the output (TRUE), thus producing the behavior of a NOR gate. We are able to reliably produce NOR gates with this behavior in microfluidic experiment.

Association between a functional single nucleotide polymorphism in the brain-derived neurotrophic factor gene and risk of child asthma

Brain-derived neurotrophic factor (BDNF) promotes synaptic remodeling and modulates the function of other neurotransmitters. Allergic inflammation triggers neuronal dysfunction and structural changes in the airways. Genetic polymorphisms in functional regions of the BDNF gene have a plausible role in modulating the risk of child asthma (CA). This study examined the potential association between CA and three single nucleotide polymorphisms (SNPs) in BDNF (rs2030323, rs6265, and rs16917204 in the promoter, exon 4, and 3'-untranslated regions, respectively). The study was conducted in 350 children with asthma and 356 healthy controls. The genotype and allele frequencies and difference between groups were analyzed using HaploView 4.0 and SPSS 20.0 software platforms. The analysis revealed a strong association between the rs6265 genotype distribution and CA. The frequency of the G allele was significantly higher in CA patients than in healthy controls (P = 0.0007, odds ratio = 1.323, 95% confidence interval = 1.073-1.632). Strong linkage disequilibrium was observed between rs16917204 and rs6265. A significantly higher number of G-G haplotypes were observed in CA patients than in controls (P = 0.024 after Bonferroni correction), while the G-A haplotypes were more significant in controls (P = 0.013 after Bonferroni correction). This suggested that BDNF gene polymorphisms confer susceptibility to CA, and also support the notion that BDNF dysfunction is involved in the pathophysiological process of CA.

Neuropeptide Y in black seabream Acanthopagrus schlegelii: identification, distribution and mRNA expression responses to ghrelin

The coding region of neuropeptide Y (NPY) complementary (c)DNA was cloned from the hypothalamus RNA of black seabream Acanthopagrus schlegelii, including 297 bp coding for prepro-NPY of 98 amino acids. Real-time reverse transcriptase-polymerase chain reaction was performed to determine A. schlegelii npy gene expression; NPY messenger RNA (mRNA) was expressed highly in the brain and stomach. Treatment with acylated ghrelin significantly up-regulated NPY mRNA level in the hypothalamus, suggesting that NPY may be involved in regulating food intake of A. schlegelii.

Jet or intensive care unit ventilator during simulated percutaneous transtracheal ventilation: a lung model study

BACKGROUND

Percutaneous transtracheal ventilation (PTV) via a jet ventilator (PTJV) is considered a rescue technique in difficult airway management. However, whether a conventional ventilator can generate adequate ventilation via PTV is not known. Our goal was to evaluate the tidal volume (V(T)) generated by a conventional ventilator during simulated PTV compared with PTJV in a lung model.

METHODS

A lung model simulating an adult lung was used. A catheter was inserted through the artificial trachea and connected to either a jet ventilator or a conventional ventilator. The direction of catheter insertion was perpendicular to the trachea, pointing towards the lung and away from the lung. The jet ventilator was operated at 344.7 kPa. The conventional ventilator was operated in the pressure mode at peak inspiratory pressures of 40-90 cm H(2)O.

RESULTS

The jet ventilator generated larger V(T) [817 (336) ml] when the catheter was pointing towards the lung than when pointing away from the lung or perpendicular to the trachea [121 (41) and 69 (24) ml, respectively, P<0.01]. With the conventional ventilator, changes in V(T) at different direction of catheter insertion were much less [222 (81) ml catheter pointing towards the lung, 229 (121) ml perpendicular to the trachea, and 187 (97) ml away from the lung].

CONCLUSIONS

Our result demonstrated that PTJV was effective only when the catheter was pointing towards the lung and requires high operating pressure. A conventional ventilator can generate reasonable minute ventilation through the transtracheal catheter less dependent on directions of catheter insertion and should be considered during emergent PTV.

Stimulus Novelty, and Not Neural Refractoriness, Explains the Repetition Suppression of Laser-Evoked Potentials

Brief radiant laser pulses selectively activate skin nociceptors and elicit transient brain responses (laser-evoked potentials [LEPs]). When LEPs are elicited by pairs of stimuli (S1–S2) delivered at different interstimulus intervals (ISIs), the S2-LEP is strongly reduced at short ISIs (250 ms) and progressively recovers at longer ISIs (2,000 ms). This finding has been interpreted in terms of order of arrival of nociceptive volleys and refractoriness of neural generators of LEPs. However, an alternative explanation is the modulation of another experimental factor: the novelty of the eliciting stimulus. To test this alternative hypothesis, we recorded LEPs elicited by pairs of nociceptive stimuli delivered at four ISIs (250, 500, 1,000, 2,000 ms), using two different conditions. In the constant condition, the ISI was identical across the trials of each block, whereas in the variable condition, the ISI was varied randomly across trials and single-stimulus trials were intermixed with paired trials. Therefore the time of occurrence of S2 was both less novel and more predictable in the constant than in the variable condition. In the constant condition, we observed a significant ISI-dependent suppression of the biphasic negative–positive wave (N2–P2) complex of the S2-LEP. In contrast, in the variable condition, the S2-LEP was completely unaffected by stimulus repetition. The pain ratings elicited by S2 were not different in the two conditions. These results indicate that the repetition-suppression of the S2-LEP is not due to refractoriness in nociceptive afferent pathways, but to a modulation of novelty and/or temporal predictability of the eliciting stimulus. This provides further support to the notion that stimulus saliency constitutes a crucial determinant of LEP magnitude and that a significant fraction of the brain activity time-locked to a brief and transient sensory stimulus is not directly related to the quality and the intensity of the corresponding sensation, but to bottom-up attentional processes.

Effect of pH and Zn(2+) on subcultured muscle cells from Macrobrachium nipponense

A cell culture system was devised for muscle cell of Macrobrachium nipponense in the study. The juvenile and adult shrimps were held in laboratory aquaria with penicillin 1000 IU/ml and streptomycin 1000 microg/ml for 12-24 hours. Cell cultures were established in medium 199 supplemented with 20% fetal bovine serum, 1 g/L glucose, 5.2 g/L NaCl, 1.43 g/L CaCl(2), 0.05 g/L MgCl(2), 100 IU/mL penicillin and 100 microg/ml streptomycin. Fibroblast-like cells were passaged up to three times and survived for 54 days. The results showed the optimum for subculture in vitro was in medium 199 with pH 7.6. Moreover, basal medium supplemented with Zn(2+) 60 microg/L could enhance the growth of the muscle cells. It was found that better results for cell culture would be obtained more easily with juvenile shrimps caught in spring than adults in summer or autumn; and shrimps caught within 12 hours after ecdysis could grow much better than the intermoult shrimps.

Structural analysis of the -1 ribosomal frameshift elements in giardiavirus mRNA

The RNA polymerase of giardiavirus (GLV) is synthesized as a fusion protein through a -1 ribosomal frameshift in a region where gag and pol open reading frames (ORFs) overlap. A heptamer, CCCUUUA, and a potential pseudoknot found in the overlap were predicted to be required for the frameshift. A 68-nucleotide (nt) cDNA fragment containing these elements was inserted between the GLV 5' 631-nt cDNA and the out-of-frame luciferase gene that required a -1 frameshift within the 68-nt fragment for expression. Giardia lamblia trophozoites transfected with the transcript of this construct showed a frameshift frequency at 1.7%, coinciding with the polymerase-to-capsid protein ratio in GLV. The heptamer is required for the frameshift but can be replaced with other sequences of the same motif. Mutations placing stop codons in the 0 or -1 frame, located directly before or after the heptamer, implicated the latter as the site for the -1 frameshift. Shortening or destroying the putative stem decreased the frameshift efficiency threefold; the efficiency was fully recovered by mutations to restore the stem. Deleting 18 nt from the 3' end of the 68-nt fragment, which formed the second stem in the putative pseudoknot, had no effect on the frequency of the frameshift. Chemical probing of the RNA secondary structure in the frameshift region showed that bases resistant to chemical modification were clustered in the putative stem structures, thus confirming the presence of the postulated stem-loop, while all the bases in the loop were chemically modified, thus ruling out their capability of forming a pseudoknot. These results confirmed the conclusion based on data from the mutation study that there is but a simple stem-loop downstream from the heptamer. Together, they constitute the structural elements for a -1 ribosomal frameshift in the GLV transcript.

A dual-specificity aminoacyl-tRNA synthetase in the deep-rooted eukaryote Giardia lamblia

Cysteinyl-tRNA (Cys-tRNA) is essential for protein synthesis. In most organisms the enzyme responsible for the formation of Cys-tRNA is cysteinyl-tRNA synthetase (CysRS). The only known exceptions are the euryarchaea Methanococcus jannaschii and Methanobacterium thermoautotrophicum, which do not encode a CysRS. Deviating from the accepted concept of one aminoacyl-tRNA synthetase per amino acid, these organisms employ prolyl-tRNA synthetase as the enzyme that carries out Cys-tRNA formation. To date this dual-specificity prolyl-cysteinyl-tRNA synthetase (ProCysRS) is only known to exist in archaea. Analysis of the preliminary genomic sequence of the primitive eukaryote Giardia lamblia indicated the presence of an archaeal prolyl-tRNA synthetase (ProRS). Its proS gene was cloned and the gene product overexpressed in Escherichia coli. By using G. lamblia, M. jannaschii, or E. coli tRNA as substrate, this ProRS was able to form Cys-tRNA and Pro-tRNA in vitro. Cys-AMP formation, but not Pro-AMP synthesis, was tRNA-dependent. The in vitro data were confirmed in vivo, as the cloned G. lamblia proS gene was able to complement a temperature-sensitive E. coli cysS strain. Inhibition studies of CysRS activity with proline analogs (thiaproline and 5'-O-[N-(l-prolyl)-sulfamoyl]adenosine) in a Giardia S-100 extract predicted that the organism also contains a canonical CysRS. This prediction was confirmed by cloning and analysis of the corresponding cysS gene. Like a number of archaea, Giardia contains two enzymes, ProCysRS and CysRS, for Cys-tRNA formation. In contrast, the purified Saccharomyces cerevisiae and E. coli ProRS enzymes were unable to form Cys-tRNA under these conditions. Thus, the dual specificity is restricted to the archaeal genre of ProRS. G. lamblia's archaeal-type prolyl- and alanyl-tRNA synthetases refine our understanding of the evolution and interaction of archaeal and eukaryal translation systems.

Inhibition of pyruvate-ferredoxin oxidoreductase gene expression in Giardia lamblia by a virus-mediated hammerhead ribozyme

Giardia lamblia is a primitive eukaryotic microorganism that derives its metabolic energy primarily from anaerobic glycolysis. In trophozoites, pyruvate-ferredoxin oxidoreductase (PFOR) converts pyruvate to acetyl-CoA with the transfer of a pair of electrons to ferredoxin, which can then reduce metronidazole and activate it into a potent antigiardiasis agent. It is unclear, however, whether this anaerobic disposal of electrons is essential for the energy metabolism in Giardia. In the present study, cDNAs encoding hammerhead ribozyme flanked with various lengths of antisense PFOR RNA were cloned into a viral vector pC631pac derived from the genome of giardiavirus (GLV). RNA transcripts of the plasmids showed high cleavage activities on PFOR mRNA in vitro. They were introduced into GLV-infected G. lamblia trophozoites by electroporation and stablized in the transfected cells via serial passages under puromycin selection. PFOR mRNA and enzyme activity in the transfected cells were decreased by 46-60% with the ribozyme PRzS flanked with 20 nt PFOR antisense RNA on each arm and by 69-80% with the ribozyme PRzL flanked with 600 and 1500 nt PFOR antisense RNA. PRzS without the inserted ribozyme or ribozyme flanked with alcohol dehydrogenase E antisense RNA showed no effect on PFOR mRNA and activity. The ribozyme-transfected cells demonstrated significantly enhanced resistance to metronidazole and grew equally well under anaerobic and aerobic conditions. In contrast, the wild-type cells grew slightly better anaerobically than the transfectants but did not grow at all in aerobic conditions. Thus, the reduced PFOR expression enables Giardia to grow under molecular oxygen and the presence of PFOR enhances the anaerobic growth of Giardia with an increased susceptibility towards metronidazole. In addition, this study demonstrated for the first time the feasibility of using a viral RNA vector to express a ribozyme targeted at a specific mRNA in G. lamblia to reduce the expression of a specific gene.

Protein synthesis in Giardia lamblia may involve interaction between a downstream box (DB) in mRNA and an anti-DB in the 16S-like ribosomal RNA

Giardia lamblia, a parasitic protozoan, has been regarded as one of the most conserved eukaryotes evolved from the prokaryotes. One of its unique features appears to be the unusually short 5'-untranslated regions (UTR) (1-6 nucleotides (nts)) and the apparent absence of 5'-cap structures from its mRNAs. Transfection of the Giardia trophozoites with luciferase-encoding chimeric transcripts, flanked by the 5'- and 3'-ends of giardiavirus (GLV) (+)-strand RNA, indicated that the translational efficiency was enhanced by 5000-fold when the 5'-viral sequence extended 264 nts into the capsid coding region and fused with the luciferase open reading frame (ORF). A 13-nt downstream box (DB) was identified within this region which complements a 15-nt sequence between nts # 1382 and 1396 near the 3'-end of the Giardia 16S-like ribosomal RNA (the anti-DB). Deletion or scrambling of this DB in the mRNA leads to a significant loss of the translational efficiency in Giardia. A Shine-Dalgarno (SD)-like element was also identified at 9-14 nts upstream from the initiation codon in the viral (+)-strand RNA, but alteration of its sequence led to no change in translation. Using the sequence complementary to ribosomal anti-DB to probe the Giardia mRNAs available in the databases, each mRNA was found to contain a putative DB with an average length from 8 to 13 nts. It is thus possible that initiation of translation in Giardia may involve a DB in the coding region of mRNA that may bind to a putative anti-DB in the small ribosomal RNA through base pairing. This mechanism of ribosome recruitment, which finds a potential parallel in Escherichia coli, could illustrate a relatively close distance between Giardia and prokaryotes in terms of translation initiation, and may provide a model for studying the evolution of translation machinery.

Long-term protection from myocardial ischemic events in a randomized trial of brief integrin beta3 blockade with percutaneous coronary intervention. EPIC Investigator Group. Evaluation of Platelet IIb/IIIa Inhibition for Prevention of Ischemic Complication

CONTEXT

Abciximab, a monoclonal antibody fragment against the platelet receptor alphaIIb beta3 integrin, prevents platelet aggregation. A randomized, placebo-controlled study showed that abciximab improves outcomes for patients undergoing percutaneous coronary angioplasty at 30 days and at 6 months.

OBJECTIVE

To determine whether abciximab improves outcomes 3 years after coronary angioplasty.

DESIGN

Double-blind, placebo-controlled, randomized trial.

SETTING

A total of 56 academic and community hospitals in the United States.

PATIENTS

A total of 2099 high-risk patients undergoing coronary angioplasty were randomized. Sufficient time elapsed for 2.5 years of follow-up among 2001 patients and for 3 years of follow-up among 1599 patients.

INTERVENTIONS

Abciximab bolus of 0.25 mg/kg followed by infusion at 10 microg/min for 12 hours; abciximab bolus of 0.25 mg/kg followed by placebo infusion; or placebo bolus followed by placebo infusion.

MAIN OUTCOMES MEASURES

The primary outcome was the composite of death, myocardial infarction, or coronary revascularization. Secondary outcomes were death, myocardial infarction, or coronary revascularization individually. Subgroups having refractory unstable angina or evolving myocardial infarction and having different elevations of creatine kinase during initial angioplasty were analyzed.

RESULTS

At 3 years, composite end points occurred in 41.1% of those receiving abciximab bolus plus infusion; 47.4% of those receiving abciximab bolus only; and 47.2% of those receiving placebo only (for abciximab bolus plus infusion vs placebo, P=.009). Death occurred in 6.8%, 8.0%, and 8.6%, respectively (for abciximab bolus plus infusion vs placebo, P=.20); myocardial infarction in 10.7%, 12.2%, and 13.6%, respectively (for abciximab bolus plus infusion vs placebo, P=.08); and revascularization in 34.8%, 38.6%, and 40.1%, respectively (for abciximab bolus plus infusion vs placebo, P=.02). Among those with refractory unstable angina or evolving myocardial infarction, death occurred in 5.1%, 9.2%, and 12.7%, respectively (for abciximab bolus plus infusion vs placebo, P=.01). Death rates increased as periprocedural creatine kinase levels increased.

CONCLUSIONS

Abciximab bolus with infusion given at the time of coronary angioplasty improves outcomes as long as 3 years after the procedure.

[Clinical observation on effect of xiaoyu zhixue tablet on 104 patients with idiopathic multifocal bleeding and platelet aggregation defect]

OBJECTIVE

To explore the effect and pharmacological mechanism of Xiaoyu Zhixue Tablet (XZT).

METHODS

The XZT mainly composed of Chinese medicinal herbs to replenishing Qi and removing stasis was used to treat patients with idiopathic multifocal bleeding and platelet aggregation defect. Patients were divided into 2 groups. The TCM group (104 cases) treated with XZT, and the control group (84 cases) treated with vitamins C, K and P, adrenosin and (or) artificial menstruation, for at least 4 months.

RESULTS

The hemostatic effective rate was 92.3% in TCM group and 27.4% in control group (P < 0.005), the recovery rate of platelet aggregation after 6 months therapy was 69.2% and only 1.8% respectively. The difference between two groups was very significant (P < 0.005).

CONCLUSION

XZT could regulate the physiological functions of blood-vessel and platelet to realize the hemostatic action and platelet aggregation.

Stable coexpression of a drug-resistance gene and a heterologous gene in an ancient parasitic protozoan Giardia lamblia

Manipulation of gene expression in Giardia lamblia, one of the most ancient eukaryotes, may provide insights into the evolutionary transition from prokaryotes to eukaryotes. Two recent successes in transient expression of the firefly luciferase (luc) gene in G. lamblia were mediated by a 5'-untranslated region (UTR) of the Giardia glutamate dehydrogenase (gdh) gene and a giardiavirus (GLV) genomic transcript, respectively. We now report a stable coexpression of luc gene with a neomycin phosphotransferase (neo(r)) gene in G. lamblia. An in vitro transcript of the construct pC670-Neo; containing the neo(r) encoding region flanked with the 5'670 nucleotides (nt) and the 3'2022 nt portion of GLV positive strand RNA, was electroporated into G. lamblia trophozoites that were infected with GLV. G418-resistant Giardia trophozoites were cloned, and the neo(r) mRNA in these clones was found to increase with increasing G418 pressure. This drug resistance remained stable upon continuous in vitro cultivation in the absence of G418 for over 15 days. Another plasmid pNeo/GDH/Luc, was constructed by inserting luc gene downstream from the neo(r) gene and the 193 nt 5' portion of gdh gene in pC670-Neo, and its bicistronic in vitro transcript was introduced into GLV-infected G. lamblia by electroporation. The transfectants demonstrated G418-resistance and persistent luciferase activity at levels parallel to the amount of G418 used for selection, peaking at a level of several thousand-fold above the background. Taken together, these data indicate that the neo(r) gene provides an effective selection marker for transformation of Giardia trophozoites, and the bicistronic RNA transfection vector may open the way for functional analysis of other genes in Giardia.

Amplification, expression, and packaging of a foreign gene by giardiavirus in Giardia lamblia

Giardia lamblia is an intestinal protozoan parasite and one of the earliest eukaryotic divergents. The trophozoite multiplies via asexual binary fission and lacks all natural means of lateral gene transfer. A system is developed here for long-term expression of a foreign gene in this organism by exploiting recombinant virions derived from the giardiavirus (GLV), a double-stranded RNA virus that infects many Giardia isolates. An in vitro transcript of the cloned GLV cDNA, comprising the firefly luciferase-encoding region flanked by 5' and 3' fragments of GLV positive-strand RNA, was electroporated into GLV-infected trophozoites. Luciferase activity in electroporated cells peaked on day 2 at levels 6 orders of magnitude above background. Expression of this foreign gene remained at 80% of its peak level after 30 days in the absence of selective pressure. The chimeric RNA was replicated as double-stranded RNA and packaged into virus-like particles. The recombinant virions were partially purified from the wild-type helper virus by CsCl equilibrium density-gradient centrifugation and used to superinfect Giardia trophozoites. At multiplicities of infection of 100 or higher, these chimeric virions were able to initiate new rounds of expression of luciferase activity in the superinfected cells. Thus, the engineered virion can be successfully used to introduce and efficiently express a heterologous gene in this eukaryotic microorganism.

Vagal bronchopulmonary C-fibers and acute ventilatory response to inhaled irritants

Experiments were carried out in anesthetized Sprague-Dawley rats to determine the role of vagal bronchopulmonary C-fiber afferents in regulating the respiratory responses to inhaled irritants. Spontaneous inhalation of 2 tidal breaths of a known airway irritant (sulfur dioxide, 0.5%; ammonia, 1%; cigarette smoke, 50%) into the lower airways invariably elicited an immediate and transient inhibitory effect on breathing, characterized by apnea or bradypnea and accompanied by bradycardia, which lasted for 3-8 breaths. A delayed hyperpnea was also induced by inhalation of cigarette smoke, but not by sulfur dioxide or ammonia. After perineural capsaicin treatment of both cervical vagi to selectively block the conduction of capsaicin-sensitive C-fibers, these inhaled irritants no longer evoked any inhibitory effect on breathing; conversely, an augmented inspiration was triggered within the first 3 breaths from the onset of cigarette smoke inhalation in > 85% of the rats studied, but after a delay of several breaths following inhalation of ammonia or sulfur dioxide in only 30% of the rats. The augmented breaths were completely abolished when both cervical vagi were cooled to 6-7 degrees C. Bilateral vagotomy eliminated all the immediate responses to these irritants. These results suggest that both vagal C-fiber endings and irritant receptors in the airways are activated by these inhaled irritants, but the more dominant and consistent inhibitory effect on breathing is elicited primarily by stimulation of C-fiber afferents.

Differential inhibition of platelet aggregation induced by adenosine diphosphate or a thrombin receptor-activating peptide in patients treated with bolus chimeric 7E3 Fab: implications for inhibition of the internal pool of GPIIb/IIIa receptors

OBJECTIVES

This study sought to describe in detail the pharmacokinetics and pharmacodynamics of chimeric monoclonal 7E3 Fab (c7E3 Fab) and to compare platelet responses to adenosine diphosphate (ADP) and the 11-amino acid thrombin receptor-activating peptide (TRAP [SFLLRNPNDKY-NH2]) in patients undergoing elective coronary angioplasty.

BACKGROUND

Inhibition of platelet aggregation with monoclonal antibody c7E3 Fab directed against glycoprotein (GP) IIb/IIIa has been shown to reduce ischemic complications after angioplasty and is being considered for treatment of other acute ischemic syndromes.

METHODS

Patients undergoing elective coronary angioplasty received aspirin (325 mg orally), heparin (12,000 U intravenously) and a bolus of c7E3 Fab (0.25 mg/kg body weight). Surface GPIIb/IIIa receptor blockade and aggregation in response to 20 mumol/liter ADP, 5 micrograms/ml collagen and 7.5 and 15 mumol/liter TRAP were assessed.

RESULTS

Surface GPIIb/IIIa receptor blockade by c7E3 Fab was 80% 2 h after injection and decreased to 50% at 24 h. Platelet aggregation in response to 20 mumol/liter ADP was inhibited by 73% at 2 h, and this inhibition decreased to 27% at 24 h. Platelet aggregation in response to 7.5 mumol/liter TRAP was inhibited by 53% at 2 h and 30% at 24 h. In contrast, aggregation in response to 15 mumol/liter TRAP was inhibited only 37% at 2 h and 10% at 24 h (p < 0.001 and p = 0.006, respectively vs. 20 mumol/liter ADP). Addition of exogenous c7E3 Fab to platelet-rich plasma led to more complete inhibition of 7.5 mumol/liter TRAP-induced aggregation.

CONCLUSIONS

After c7E3 Fab treatment, inhibition of platelet aggregation depends on the agonist and can be overcome by increased thrombin activity but is restored if additional c7E3 Fab is added to block additional GPIIb/IIIa receptors. This phenomenon may be related to an internal pool of GPIIb/IIIa receptors joining the surface membrane and has implications concerning the duration of therapy with c7E3 Fab for patients with unstable angina or acute myocardial infarction.

Virus-mediated expression of firefly luciferase in the parasitic protozoan Giardia lamblia

Giardia lamblia, a prevalent human pathogen and one of the lineages that branched earliest from prokaryotes, can be infected with a double-stranded RNA virus, giardiavirus (GLV). The 6,277-bp viral genome has been previously cloned (A.L. Wang, H.-M. Yang, K.A. Shen, and C.C. Wang, Proc. Natl. Acad. Sci. USA 90:8595-8599, 1993; C.-H. Wu, C.C. Wang, H.M. Yang, and A.L. Wang, Gene, in press) and was converted to a transfection vector for G. lamblia in the present study. By flanking the firefly luciferase gene with the 5' and 3' untranslated regions (UTRs) of the GLV genome, transcript of the construct was synthesized in vitro with T7 polymerase and used to transfect G. lamblia WB trophozoites already infected with GLV (WBI). Optimal electroporation conditions used for the transfection were set at 1,000 V/cm and 500 microF, which resulted in expression of significant luciferase activity up to 120 h after electroporation. Furthermore, the mRNA and the antisense RNA of the luciferase gene were both detected by reverse transcription and PCR from 6 to 120 h postelectroporation, whereas no antisense RNA of luciferase was observed in the electroporated virus-free Giardia WB trophozoites. The mRNA of luciferase was detectable in the virus-free trophozoites by reverse transcription and PCR only up to 20 h after the electroporation, indicating that the introduced mRNA was replicated only by the viral RNA-dependent RNA polymerase inside the WBI cells. This expression of luciferase was dependent on the presence of UTRs on both ends of the viral genome transcript, including a putative packaging site that was apparently indispensable for luciferase expression. This is the first time that a viral vector in the form of mRNA URTs has been successfully used in transfecting a protozoan.

Sequences at four termini of the giardiavirus double-stranded RNA

The linear double-stranded RNA (dsRNA) genome of giardiavirus (GLV) was estimated to be 6100 nucleotides (nt) [Wang et al., Proc. Natl. Acad. Sci. USA 90 (1993) 8585-8599]. As the 5'- and 3'-untranslated regions (UTR) of viral genomes are known to contain critical information for viral replication, we reexamine the sequences at all four termini of GLV dsRNA by (i) direct RNA sequencing with RT, (ii) tailing GLV dsRNA with UTP or CTP in addition to ATP in 3' rapid amplification of cDNA ends (RACE) and (iii) adding poly(dG) to the products of primer extension in 5'-RACE. The results confirmed the reported sequence for the 5'-terminus of the GLV sense strand RNA, but uncovered an additional 177 nt at the 3'-terminus. The new study also showed conclusively that there are no protruding overhangs at either terminus of GLV dsRNA.

Maturation of giardiavirus capsid protein involves posttranslational proteolytic processing by a cysteine protease

The double-stranded RNA genome of giardiavirus (GLV) has only two large open reading frame (ORFs). The 100-kDa capsid polypeptide (p100) is encoded by ORF1, whereas the only other viral polypeptide, the 190-kDa GLV RNA-dependent RNA polymerase (p190), is synthesized as an ORF1-ORF2 fusion protein by a (-1) ribosomal frameshifting. Edman degradation revealed that p100 was N-terminally blocked except for 2 to 5% of it that showed free N terminus starting from amino acid residue 33 of ORF1. Studies using antiserum targeted against amino acid residues 6 to 27 indicated that this region (NT) is absent from viral p100 and p190, while pulse-labelling experiments showed that NT is present in nascent p100 synthesized in GLV-infected Giardia lamblia but removed subsequently. In contrast, this region was retained in the two viral proteins synthesized in vitro, and it was not removed upon prolonged incubation or inclusion of microsomal fraction in the in vitro translation reaction mixtures. These results suggest that endoplasmic reticulum is not involved in the protein processing and that the precursors of p100 and p190 are incapable of cleaving themselves or each other. This specific cleavage was reproduced when lysates from GLV-infected G. lamblia were added, but not those from uninfected cells. The cleavage activity was relatively insensitive to phenylmethylsulfonyl fluoride, but it was inhibitable by leupeptin or E-64, two known specific inhibitors of cysteine protease. The possible origin of this processing activity is discussed.

Inhibition of hepatitis B viral gene expression by antisense phosphorothioate oligodeoxynucleotides

The inhibitory effect of antisense phosphorothioate oligodeoxyribonucleotides (S-oligos) on the production of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) was studied using Hep G2 cells transfected with hepatitis B virus (HBV). Synthetic antisense oligos (15-mers) directed against the cap site of mRNA transcribed from the SP II promoter and regions of the translational initiation site of the S gene showed a sequence-specific, dose-dependent inhibitory effect on HBV gene expression between concentrations of 1.0 microM-5.0 microM. Oligos directed against the middle of the S gene had little effect on HBsAg and HBeAg expression, as did non-complementary random-sequence control. The cells remained viable throughout the experiments and no morphological abnormalities were observed with antisense S-oligos at concentrations below 20.0 microM. These results suggest a therapeutic potential for antisense oligonucleotides in the treatment of patients who are chronically infected with HBV.

Pharmacodynamics of chimeric glycoprotein IIb/IIIa integrin antiplatelet antibody Fab 7E3 in high-risk coronary angioplasty

BACKGROUND

Thrombosis has been implicated as central to the clinical complications of coronary angioplasty (PTCA). Chimeric monoclonal 7E3 Fab (c7E3 Fab) is the first of a new class of antiplatelet drugs directed at the platelet glycoprotein IIb/IIIa integrin. This study was performed to determine the pharmacodynamics of c7E3 Fab administration during PTCA and to gain an initial clinical experience with this novel agent.

METHODS AND RESULTS

The study was a multicenter, open-label, dose-escalation study conducted in two stages. Enrollment included 56 patients scheduled for elective PTCA who were estimated to be at moderate to high risk of sustaining ischemic complications. All patients were given aspirin and heparin. The study drug was given at least 10 minutes before PTCA. In stage 1, increasing bolus doses of c7E3 Fab were given to 15 patients; a bolus dose of 0.25 mg/kg was found to result in blockade of > 80% of the receptors and reduce platelet aggregation to < 20% compared with baseline, establishing this dose as that necessary to sufficiently suppress platelet activity. In stage 2, additional c7E3 Fab was administered by continuous infusion to 32 patients for progressively longer periods of time (up to 24 hours) to confirm that platelet inhibition could be maintained with prolonged drug infusion. Also, 9 patients otherwise meeting entry criteria were given placebo. There were no thrombotic events among patients receiving c7E3 Fab. Overall procedural and clinical success and complication rates as well as rates of bleeding were statistically similar among groups. However, minor bleeding was more frequent with administration of the active drug.

CONCLUSIONS

The novel antiplatelet agent c7E3 Fab can be administered during PTCA in combination with aspirin and heparin. Suppression of platelet activity is dose dependent and can be maintained for up to 24 hours. Further evaluation will be required to determine the extent of improvement in ischemic complication and restenosis rates and to provide additional insight into the safety profile of this potent monoclonal platelet antibody.

[Effect of xiaoyu pian on new platelet aggregation defect]

The Xiaoyu pian (XYP, mainly consisted of prunus persica, Carthamus tinctorius, Glycyrrhiza uralensis, etc) was used to treat patients with new platelet aggregation defect. Patients were divided into 2 groups, the TCM group (72 cases) treated with XYP and the control group (65 cases) treated with vitamin C and P and/or adrenosem for at least 3 months. The results showed that marked effective rate was 87.5% in TCM group and 35.4% in control group (chi 2 = 39.7, P < 0.01); the recovery rate of platelet was 91.8% in the former and 10.3% in the latter (chi 2 = 71.4, P < 0.01); the recurrence rate of follow-up (6 months after treatment) was 30.8% in the former and 82.1% in the latter (chi 2 = 19.2, P < 0.01). The difference between two groups was very significant. The results suggested that XYP could regulate the hemostatic action and the platelet aggregation function. It is worthwhile to use XYP as an hemostatic clinically.

Giardiavirus-resistant Giardia lamblia lacks a virus receptor on the cell membrane surface

Giardia lamblia virus (GLV) is a small nonenveloped double-stranded RNA virus that infects specifically the parasitic protozoan G. lamblia. Among the many collected strains of G. lamblia, a few turn out to be highly resistant to the virus infection. Two of these strains, Ac and JH, were subjected to electroporation with the RNA from GLV-infected G. lamblia WB strain. Subsequent studies indicated the presence of GLV double-stranded RNA and GLV protein in the electroporated and propagated cells. Virus particles, released by the transfected cells into the culture medium, were capable of infecting the virus-sensitive G. lamblia WB strain. When the WB cells were incubated with GLV at 4 degrees C and treated with the bifunctional cross-linking reagent disuccinimidyl suberate, little GLV protein was detectable inside the cells by immunofluorescent staining. However, patches of fluorescent granules were found on the membrane surface of the cells, suggesting cross-linking of the viruses with a certain membrane component(s). Similar treatment of the resistant strains Ac and JH showed no fluorescence either inside or outside of the cells. Two other closely related parasitic protozoa, Tritrichomonas foetus and Trichomonas vaginalis, cannot be infected by GLV via either viral infection or RNA transfection. The [35S]cysteine-labeled protein profiles in Triton X-114 extracts of G. lamblia WB, Ac, and JH were compared. The profile of the WB strain differs clearly from that of Ac and JH. It remains to be seen, however, whether this difference is related at all to the different susceptibilities to GLV infection.

[Gene variation in the pre-C region of hepatitis B virus]

We examined the serum HBV DNA of the chronic hepatitis B patients with positive c-system by using polymerase chain reaction (PCR). Twenty samples of HBeAg(+)/anti-HBe(-) positive PCR products and 20 samples of HBeAg(-)/anti-HBe(+) positive PCR products were selected. These products were dot-hybridized by synthetic HBV pre-C region geno oligonucleotide probes M0 (non mutated), M1 (one) point-mutated), M2 (two point-mutated). The results thus obtained showed that for 85% (17/20) of the chronic hepatitis patients with HBeAg(-)/anti-HBe(+), point mutation occurred at the 1,896th nucleotide, resulting in the stop codon, and half (10/20) of the patients suffered two points mutation. The direct determination of the sequence of some mutation PCR products selected proved the existence of point mutation. The result indicated that the natural conversion of hepatitis patients' HBeAg(+) to anti-HBe(+) may have resulted from the genovariation in the pre-c region of HBVDNA rather than from the decreased of virus replication.

[Inhibition of hepatitis B viral gene expression by antisense phosphrothioate oligonucleotides]

Hep G2 cells transfected with HBV genomes were used to study the inhibitory effect of antisense phosphrothiate oligodeoxynucleotides on HBsAg and HBeAg production. The synthetic antisense 15-s-oligomers against the cap site of mRNA transcribed from the SPII promoter and regions of the translational initiation site of the S gene showed a dose-dependent and sequence-specific inhibitory effect on HBV gene expression between concentrations of 1.0-5.0 mumol/L. But the oligomers directed on the middle site of the S gene exerted little effect on HBsAg and HBeAg expression as well as the non-complementary random sequence control. The cells remained viable throughout the experiments and no morphological abnormalities and cytotoxicity were observed with antisense S-oligomers at concentrations below 20.0 mumol/L. These results suggest a therapeutic potential for antisense oligonucleotides in the treatment of patients who are chronically infected with HBV.

Nicotine is responsible for airway irritation evoked by cigarette smoke inhalation in men

To determine whether nicotine is involved in evoking the irritant effects of cigarette smoke in airways, we studied the responses to inhalation of a single puff (30 ml) of three types of smoke (high nicotine, low nicotine, and gas phase) in healthy male nonsmokers. After the upper airways were locally anesthetized, the subjects, breathing through a mouthpiece, were instructed to signal the detection and the intensity of airway irritation with a push-button device. Inhalation of high-nicotine smoke consistently triggered an intense airway irritation in the lower neck and upper chest region; the total number of push-button signals generated in the first 5 s was 6.61 +/- 0.87 (mean +/- SE, n = 12), with a detection latency of 0.93 +/- 0.11 s. By contrast, inhalation of low-nicotine and gas phase smoke either was not detected or caused only very mild irritation (0.89 +/- 0.4 and 0.36 +/- 0.22, respectively). In addition, the intensity of smoke-induced airway irritation was markedly reduced after premedication with aerosolized hexamethonium, a nicotinic receptor antagonist (P < 0.01, n = 8). Furthermore, inhalation of nicotine aerosol also immediately evoked intense airway irritation and coughs (n = 5). Thus we conclude that the airway irritation evoked by inhaling cigarette smoke results from an activation of sensory endings located in the central airways and nicotine is the primary agent responsible for this action.

Giardiavirus double-stranded RNA genome encodes a capsid polypeptide and a gag-pol-like fusion protein by a translation frameshift

Giardiavirus is a small, nonenveloped virus comprising a monopartite double-stranded RNA genome, a major protein of 100 kDa, and a less abundant polypeptide of 190 kDa. It can be isolated from the culture supernatant of Giardia lamblia, a parasitic flagellate in human and other mammals, and efficiently infects other virus-free G. lamblia. A single-stranded copy of the viral RNA can be electroporated into uninfected G. lamblia cells to complete the viral replication cycle. Giardiavirus genomic cDNA of 6100 nt was constructed and its sequence revealed the presence of two large open reading frames that are separated by a -1 frameshift and share an overlap of 220 nt. The 3' open reading frame contains all consensus RNA-dependent RNA polymerase sequence motifs. A heptamer-pseudoknot structure similar to those found at ribosomal slippage sites in retroviruses and yeast killer virus was identified within this overlap. Immunostudies using antisera against synthesized peptides from four regions in the two open reading frames indicated that the 100- and 190-kDa viral proteins share a common domain in the amino-terminal region. But the 190-kDa protein makes a -1 switch of its reading frame beyond the presumed slippage heptamer and is therefore a -1 frameshift fusion protein similar to the gag-pol fusion protein found in retroviruses.

Asian/non-Asian transcultural tricyclic antidepressant psychopharmacology: a review

1. Transcultural psychopharmacology is a discipline that seeks to determine the relative importance of society, culture, environment, genetics, and biophysiology on the prescribing and metabolism of, and response to psychotherapeutic medications. 2. Studies and surveys comparing psychotropic medication use in Asian and non-Asian populations suggest that differences may exist in drug dosage requirements, plasma drug concentrations corresponding to therapeutic and toxic effects, and the incidence and severity of adverse drug reactions. 3. This paper reviews and critiques the published controlled studies on Asian/non-Asian transcultural tricyclic antidepressant psychopharmacology, provides guidelines for the use of psychotropic medications in Asian populations, and offers suggestions for future transcultural studies. 4. Anecdotal reports suggest that differences exist between Asian and non-Asian populations in the pharmacokinetics of tricyclic antidepressants. Controlled studies have not consistently supported this view. 5. Studies with larger sample sizes and more rigorous controls are needed to determine if such differences do, in fact, exist.

Bronchoconstriction and delayed rapid shallow breathing induced by cigarette smoke inhalation in anesthetized rats

Bronchomotor and ventilatory responses to inhalation of cigarette smoke (50% concentration, 6 ml) were studied in anesthetized and vagotomized Sprague-Dawley rats. Low-nicotine cigarette smoke did not cause any detectable delayed response, whereas high-nicotine cigarette smoke induced rapid, shallow breathing, and a marked increase in airway resistance (RL). The increase in f reached a peak (delta f = 43 +/- 8%) at the 5th breath after the onset of smoke inhalation, preceding both the decrease in VT (delta VT = -27 +/- 4%) and the increase in RL (delta RL = 89 +/- 19%); the latter 2 reached their peaks at approximately the 10th breath, displaying a similar temporal pattern of responses between them. The bronchomotor response to high-nicotine cigarette smoke was slightly attenuated but not prevented by prior administration of isoproterenol (0.2 mg/kg, intravenously [iv]), nor was the smoke-induced rapid, shallow breathing. In contrast, prior administration of mecamylamine (0.9 mg/kg, iv) completely abolished both the bronchomotor and ventilatory responses to smoke inhalation, indicating that nicotine is the primary causative agent responsible for these changes.