Modulation of ascorbic acid-induced DNA cleavage by polyamide: cleavage manner, kinetics and mechanism

Manipulation of DNA presents a great interest in biotechnology and therapeutics. The molecules that damage DNA selectively offer new prospects for controlled manipulation of DNA. The conjugations of DNA-code reading molecules such as polyamides to reagents that induce DNA damages provide an approach to reach this goal. In this work, a new compound which contained polyamide and ascorbic acid conjugated by flexible linker (polyamide-Vc), was successfully synthesized, characterized, and evaluated as DNA cleavage agent, compared with that by using ascorbic acid molecule. The kinetics data showed that polyamide-Vc successfully promoted the cleavage of plasmid DNA, with k(max) of 0.314 h(-1) and K(d) of 0.105 mM. The evaluation of DNA linearization elicited that the activity of cleaving double-strand in the supercoiled pUC18 plasmid DNA by polyamide-Vc was enhanced remarkably, achieving n1/n2 ratio of 13.9 at 1.2 mM for 1 h. The introduction of polyamide to Vc could also partially weaken the inhibition of hydrogen radical to double-strand cleavage process because of its good binding activity to DNA. We anticipate that this work could provide a method for improving the efficiency of double-strand cleavage, especially to oxidative cleavage agents.

The situation of sanitary systems in rural areas in the Miyun catchment, China

The Miyun Reservoir provides most of Beijing's drinking water. Despite its importance, the Miyun reservoir suffers from decreasing water quality caused by uncontrolled wastewater discharges, inadequate land use and over fertilization, which increase the pressure on soil and water resources. The major pollutants are nitrogen and phosphorus which emanate to some extent from untreated sewage. So far there is little data about the existing wastewater quantity and quality in rural settlements in northern China. This study was conducted in typical villages situated along upstream rivers in the catchment of the Miyun Reservoir. The main objective was to determine the current situation and efficiency of the wastewater treatment system in rural settlements.

Experimental study on the atlanto-axial joint and related structures with regional anatomy and medical imaging

OBJECTIVE

To evaluate the anatomy and medical imaging characteristics in a study observing the atlanto-axial joint (AAJ) and related structures.

METHODS

Eight cadaveric specimens of the AAJ segment were studied with both anatomical and imaging methods. The vertebral arteries of the AAJ segment (VA-A), the first and second cervical nerves (CN1, CN2) and synovial fold (SF) of the AAJ were observed and measured.

RESULT

After extending from the vertebral canal, the CN1 goes between the posterior arch of the atlas and VA-A, and the CN2 passes between the posterior arch of the atlas and axis, and is posterior to VA-A. Among the eight cases, six were found in the SF in the central anterior AAJ and five in lateral. The vertebral arteries of the AAJ segment go along the AAJ with four curves, of which the second and fourth are away from the bone structure of the AAJ. The distance from CN1, CN2 to VA-A and that from the second, fourth curve of VA-A to AAJ is 0.0-2.2 mm, 0.0-3.6 mm and 0.0-4.8 mm, 2.0-7.9 mm respectively. There is no significant difference between the measurements made anatomically and those by the imaging method (p > 0.05).

CONCLUSION

The anatomical method has advantages in observing the CN and SF, while the imaging method shows clearly and directly the VA-A and AAJ. Both are mutually complementary with consistent measurements. The combined use of the two provides a new way to study the complicated anatomy in this region.

Nitric oxide-releasing nanoparticle combination therapy to overcome drug resistance in platinum-resistant breast cancers

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Background: The most successful cancer chemotherapy regimens usually involve the administration of multiple cytotoxic agents simultaneously. Because different chemotherapies may have different mechanisms of action; it is difficult for cancer cells to become resistant to combination therapy. Recent investigations have discovered that nitric oxide (NO) may be involved in the reversal of cisplatin (CDDP) resistance in chemotherapy. Therefore, we sought to develop a combination regimen involving a NO-releasing prodrug (NO1) and cisplatin for the treatment of breast cancer.

Methods: The prodrug NO1 was synthesized to be localized in tumor cells and to release nitric oxide over 10 hours. The antiproliferative activity of NO1 was determined in human breast cancer cell line, MDA-MB-468LN. To evaluate the effectiveness of the CDDP/NO combination regimen, platinum-resistant MDA-MB-468LN cells were treated with either cisplatin alone ([CDDP]=0.01, 0.02 or 0.03 mM) or the CDDP/NO combination ([CDDP]=0.01, 0.02 or 0.03 mM; [NO1]=0.02 mM). The cell viability was determined 48 hours post-treatment using a live/dead trypan blue exclusion assay.

Results: The toxicity to breast cancer cells was higher than JS-K, a systemic NO agent currently in preclinical development. (NO1: IC50=26µM; JS-K: IC50=42 µM). In addition, NO1 had a long sustained release of nitric oxide, approximately one fold longer than JS-K (NO1: t1/2=6 h; JS-K: t1/2=3 h). The combination treatments resulted in 6.6-, 6.9- and 7.5-fold increase in cell death compared to cisplatin treatment alone at cisplatin concentrations of 0.01, 0.02 and 0.03 mM, respectively. A subsequent study in a murine xenograft of head and neck cancer found NO-1 conjugated to nanoparticles increased survival a mean of 10 weeks compared to controls (p<0.0001).

Conclusions: Nitric oxide prodrug NO-1 and nanoparticles of it have high anticancer activity in vivo and they can reverse platinum resistance in vitro. Ongoing studies are examining the safety and efficacy of CDDP/NO combination therapy in mouse xenografts of human breast cancer.

Impact of prior seasonal influenza vaccination and infection on pandemic A (H1N1) influenza virus replication in ferrets

Early epidemiologic and serologic studies have suggested pre-existing immunity to the pandemic A (H1N1) 2009 influenza virus (H1N1pdm) may be altering its morbidity and mortality in humans. To determine the role that contemporary seasonal H1N1 virus infection or trivalent inactivated vaccine (TIV) might be playing in this immunity we conducted a vaccination-challenge study in ferrets. Vaccination with TIV was unable to alter subsequent morbidity or contact transmission in ferrets following challenge with H1N1pdm. Conversely, prior infection with the contemporary seasonal H1N1 strain altered morbidity, but not transmission, of H1N1pdm despite the detection of only minimal levels of cross reactive antibodies.

Disclosure of HIV-positive serostatus to sexual partners and associated factors in southern China

In light of an increased push for disclosure of HIV-positive serostatus to sexual partners (partner disclosure, PD) in China as reflected by national and local policies, the objective of this study was to determine the proportion and evaluate associated factors of PD among people living with HIV/AIDS (PLWHA) in HIV/AIDS high-risk areas in southern China. Of the 946 HIV-positive individuals, the proportion of those who disclosed positive serostatus results to their sexual partners was 90.2% (625/693). Variables independently associated with non-disclosure included testing in Guangxi province (adjusted relative ratio [ARR] = 0.33), becoming infected with HIV via injecting drug use (IDU) transmission (ARR = 0.32), having not reported discussing disclosure with health department staff during post-test counselling (ARR = 0.41) and having a sexual relationship of ≤2 years' duration (ARR = 0.31). This study also identified a relatively larger differential between the proportion of disclosure to regular partners and the proportion of disclosure to casual partners (94.8% versus 13.0%) in comparison with other studies. Findings from this study may aid policies for future consideration.

Defects of synaptic vesicle turnover at excitatory and inhibitory synapses in Niemann-Pick C1-deficient neurons

Niemann-Pick disease type C (NPC) is a progressive neurodegenerative disorder characterized by accumulation of free cholesterol in late endosomes/lysosomes. The pathological basis for the disease is poorly understood. In the present study, electrophysiological and fluorescent dye studies were applied to examine neuron-specific functions of Niemann-Pick disease type C1 (NPC1) and to determine whether excitatory and inhibitory synapses are differentially impaired by NPC1 deficiency. Densities of spines and postsynaptic receptor clusters were not affected by NPC1 deficiency over the period examined. However, drastic defects on exocytosis were found both in glutamatergic and GABAergic synapses. The defects were caused in part by a delay in the time required for replacement of excytosed vesicles with new fusion-competent ones. Moreover, we found that the delay of synaptic vesicle turnover was longer in inhibitory synapses (>3 s) than in excitatory synapses (<0.2 s). These defects may be early indicators, and could provide a potential explanation for key features of the disease, such as dystonia and seizures.

Heritable and non-genetic factors as variables of pharmacologic phenotypes in lymphoblastoid cell lines

Publicly available genetic and expression data on lymphoblastoid cell lines (LCLs) make them a unique resource for understanding the genetic underpinnings of pharmacological outcomes and disease. LCLs have been used for pharmacogenomic discovery and validation of clinical findings associated with drug response. However, variation in cellular growth rate, baseline Epstein-Barr virus (EBV) copy number and ATP levels can all be confounders in such studies. Our objective is to better define confounding variables that affect pharmacological end points in LCLs. To this end, we evaluated the effect of these three variables on drug-induced cytotoxicity in LCLs. The drugs evaluated included daunorubicin, etoposide, carboplatin, cisplatin, cytarabine, pemetrexed, 5'-deoxyfluorouridine, vorinostat, methotrexate, 6-mercaptopurine, and 5-fluorouracil. Baseline ATP or EBV copy number were not significantly correlated with cellular growth rate or drug-induced cytotoxicity. In contrast, cellular growth rate and drug-induced cytotoxicity were significantly, directly related for all drugs except vorinostat. Importantly, cellular growth rate is under appreciable genetic influence (h²=0.30-0.39) with five suggestive linkage regions across the genome. Not surprisingly, a percentage of SNPs that significantly associate with drug-induced cytotoxicity also associate with cellular growth rate (P ≤ 0.0001). Studies using LCLs for pharmacologic outcomes should therefore consider that a portion of the genetic variation explaining drug-induced cytotoxicity is mediated via heritable effects on growth rate.

The Pirh2-keratin 8/18 interaction modulates the cellular distribution of mitochondria and UV-induced apoptosis

Intermediate filaments (IFs) provide crucial structural support in higher eukaryotic cells. Accumulating evidences show that IFs also participate in various cellular activities including stress responses, cell growth, cell death and cell migration through dynamic interactions with various non-structure proteins. Here we report the identification of Pirh2, a RING-H2-type ubiquitin E3 ligase, as a novel binding partner of the cytoplasmic IF proteins keratin 8/18 (K8/18). Phosphorylation of either Pirh2 or K8/18 affects their association. Although Pirh2 was not found to influence the stability of K8/18, it displayed an unexpected role in regulating the organization of the network of K8/18 keratin filaments. Disruption of Pirh2-K8/K18 interaction by either UV irradiation or knockdown with Pirh2 or K18 led to the aggregation of K8/18 keratin filaments. It further induced mitochondrial redistribution, and this process is likely through a microtubule-mediated pathway. The abnormal localization of mitochondria in Pirh2-knockdown cells may partially account for its increased cell sensitivity to UV-induced apoptosis, probably through enhancing the release of pro-apoptotic proteins, such as cytochrome c and Smac/DIABLO to the cytosol. Overall, our data reveal the novel role of the Pirh2-K8/18 complex in governing the distribution of mitochondria.

Association of HLA genes with ankylosing spondylitis in Han population of eastern China

Ankylosing spondylitis (AS) is a chronic inflammatory disorder with a multifactorial genetic basis. HLA-B27 was reported with the greatest susceptibility to AS but did not act alone. The aim of this study was to search for other gene(s) associated with AS independently of HLA-B27 using 13 microsatellite markers spanning 1.5 Mb from locus TAP1 to HLA-Cw and a single-nucleotide polymorphism marker within NFkappaBIL1 gene promoter. Genotyping for microsatellites was performed in 175 AS patients of eastern Chinese and 219 ethnically matched healthy controls using polymerase chain reaction with fluorescence-labelled primers, whereas the SNP marker was genotyped by direct DNA sequencing. Allele as well as haplotype frequencies were compared between cases and controls, and a linkage disequilibrium analysis was performed to estimate the LD relationship between the candidate regions. The frequencies of alleles D6S2811*128, STR_MICA*A5.1 and D6S2672*109, as well as haplotypes D6S2811*128-D6S2927*213-D6S2810*340, D6S2927* 221-D6S2810*350-MICA*A5.1, and D6S2810*350-MICA*A5.1-D6S2800* 136 were significantly increased in B27-positive AS patients when compared with B27-positive controls. The results indicated that there may be other gene(s) within the HLA region, especially around locus HLA-B or HLA-Cw, with susceptibility to AS independently of HLA-B27.

Living environment and schooling of children with HIV-infected parents in southwest China

A cross-sectional household survey was conducted in Longchuan County, China, to study the lives of children with HIV-infected parents. Registered HIV-infected drug users and their households were approached and information about the living environment of children < or =15 years of age was collected. Of the 266 households interviewed, there were 213 children < or =15 years old. Forty percent of the children had lost at least one parent. Most of the children resided in a household with low economic status and a high dependency ratio. One-half of the children experienced discordant family relations, family anxiety and shame. Compared to orphans, non-orphans and their families were less likely to receive social support from the community. Orphans and older children were less likely to attend school and more likely to be truant if enrolled in school. Findings in the current study suggest that many children whose parents are infected with HIV or have died from HIV are living in stressful environments with minimal support from the community. Efforts should be taken to provide support and supervision to these children.

Transmission disequilibrium test provides evidence of association between promoter polymorphisms in 22q11 gene DGCR14 and schizophrenia

Recent research has suggested that the DiGeorge syndrome critical region gene 14 (DGCR14) exhibits activity differences of more than 1.5 fold between the haplotypes of the variants in the promoter region. DGCR14 is located at 22q11.21, an acknowledged region for susceptibility to schizophrenia. To test the hypothesis that DGCR14 may be involved in the etiology of the disease, we carried out a family-based association study between the reported functional markers and schizophrenia in 235 Chinese Han trios. We found significant evidence of preferential transmission of the promoter variants of DGCR14 across all the trios (Best p-value = 0.00038, Global p-value = 0.0008). The positive results have suggested that DGCR14 is likely to play an important role in the etiology of schizophrenia in the Chinese Han population.

Failure to find association between TRAR4 and schizophrenia in the Chinese Han population

The TRAR4 gene locates in SCZD5 (MIM 603175), which a number of studies have linked with schizophrenia. One recent study suggested that three TRAR4 variants (M1: rs4305745, P=0.0014; M2: rs6903874, P=0.0026; M3: rs6937506, P=0.0052) in the 3'-UTR were associated with schizophrenia. To replicate these findings, we conducted a family-based association study within a sample of 235 Chinese Han trios. However, we didn't find significant evidence of preferential transmission of the three variants across all the trios (all P values>0.2). Thus, we conclude that TRAR4 is not a major or independent determinant in the occurrence of schizophrenia in the Chinese Han population.

Multi-zone modeling of probable SARS virus transmission by airflow between flats in Block E, Amoy Gardens

More than 300 residents of a private high-rise housing estate were infected with severe acute respiratory syndrome within a short period during the 2003 epidemic in Hong Kong. The outbreak occurred after the identified index patient visited a flat on a middle floor in Block E of the Amoy Gardens estate on two nights. Approximately 45% of the subsequently infected people resided in Block E, while the other 55% of infected cases mainly resided in six other blocks close to Block E. The distribution of the infected flats in Block E conformed to a non-uniform spatial pattern. Probable environmental causes for airborne transmission associated with the air movements between flats in Block E are identified. The well-established multi-zone airflow modeling method was used to analyze the virus-laden bio-aerosol dispersion between flats through door and window leakage areas in Block E under six different scenarios. The distribution of infection risk in Block E matched with the virus concentrations in flats predicted with the use of multi-zone modeling. Our study shows the importance of ventilation design in high-rise residential apartments.

PRACTICAL IMPLICATIONS

The present study on the Amoy Gardens outbreak presented a scenario in which crowded living spaces might lead to infection disasters. There is a need to improve the current sanitary drainage design and maintenance standards to avoid any leakage of foul gas into the indoor environments. Our study revealed the need for a review of indoor air quality and ventilation design in buildings including offices, homes and hotels. The study has implications to public health in, for example, the control of other airborne respiratory infectious diseases such as influenza, and in bio-terror safety in buildings.

Linkage disequilibrium maps constructed with common SNPs are useful for first-pass disease association screens

To develop an efficient strategy for mapping genetic factors associated with common diseases, we constructed linkage disequilibrium (LD) maps of human chromosomes 5, 7, 17, and X. These maps consist of common single nucleotide polymorphisms at an average intermarker distance of 100 kb. The genotype data from these markers in a panel of American samples of European descent were analyzed to produce blocks of markers in strong pair-wise LD. Power calculations were used to guide block definitions and predicted that high-level LD maps would be useful in initial genome scans for susceptibility alleles in case-control association studies of complex diseases. As anticipated, LD blocks on the X chromosome were larger and covered more of the chromosome than those found on the autosomes.

Strain selection of Metarrhizium anisopliae by image analysis of colony morphology for consistency of steroid biotransformation

Quantitative description of colony morphological images of the fungus Metarrhizium anisopliae was done by means of computer image analysis based on fractal analysis. Compared with simple fractal analysis, the differences in the morphological features of colonies were expressed more accurately by multifractal analysis. The use of multifractal analysis markedly improved the reliability of colony image analysis, which could be extended to morphological characterization for colony recognition and classification. First, the multifractal spectrum was calculated from each morphological image and 14 features were defined on the spectrum to describe the spectral line profile. Second, three features, alpha-right, alpha-width, and f-start, were selected from the 14 features in two-dimensional feature vector spaces and a feature augmented vector (alpha-right, alpha-width, and f-start, 1)(T) was generated and used for classifier design. Third, a statistical least mean square error (LMSE) algorithm was applied to design a piecewise-linear classifier, which consists of two linear classifiers, d(1)(x) and d(2)(x). Representative colony samples were used as training and test sample sets, which were previously classified into a high-activity class and another class by a training person. After passing the training phase, the piecewise-linear classifier could be used for automated classification of unknown colony samples. A correct recognition rate of 96% was achieved in this manner. Compared with conventional strain selection methods, this new method has the advantage of less subjectivity, reduced labor and time, and improved ability to deal with a large number of colonies.

Universal SNP genotyping assay with fluorescence polarization detection

The degree of fluorescence polarization (FP) of a fluorescent molecule is a reflection of its molecular weight (Mr). FP is therefore a useful detection methodfor homogeneous assays in which the starting reagents and products differ significantly in Mr. We have previously shown that FP is a good detection method for the single-base extension and the 5'-nuclease assays. In this report, we describe a universal, optimized single-base extension assay for genotyping single nucleotide polymorphisms (SNPs). This assay, which we named the template-directed dye-terminator incorporation assay with fluorescence polarization detection (FP-TDI), uses four spectrally distinct dye terminators to achieve universal assay conditions. Even without optimization, approximately 70% of all SNP markers tested yielded robust assays. The addition of an E. coli ssDNA-binding protein just before the FP reading significantly increased FP values of the products and brought the success rate of FP-TDI assays up to 90%. Increasing the amount of dye terminators and reducing the number of thermal cycles in the single-base extension step of the assay increased the separation of the FP values benveen the products corresponding to different genotypes and improved the success rate of the assay to 100%. In this study the genomic DNA samples of 90 individuals were typed for a total of 38 FP-TDI assays (using both the sense and antisense TDI primers for 19 SNP markers). With the previously described modifications, the FP-TDI assay gave unambiguous genotyping data for all the samples tested in the 38 FP-TDI assays. When the genotypes determined by the FP-TDI and 5'-nuclease assays were compared, they were in 100% concordance for all experiments (a total of 3420 genotypes). The four-dye-terminator master mixture described here can be used for assaying any SNP marker and greatly simplifies the SNP genotyping assay design.

Anodic coupling reactions: probing the stereochemistry of tetrahydrofuran formation. A short, convenient synthesis of linalool oxide

[reaction: see text]. Intramolecular coupling reactions between enol ether radical cations and oxygen nucleophiles are primarily governed by stereoelectronics. By taking advantage of this observation, a tetrahydrofuran building block for use in constructing (+)-linalool oxide and rotundisine has been synthesized in four steps from a commercially available starting material. The synthesis of (+)-linalool oxide has been completed.

Genotyping single-nucleotide polymorphisms by the invader assay with dual-color fluorescence polarization detection

BACKGROUND

The PCR-Invader assay is a robust, homogeneous assay that has been shown to be highly sensitive and specific in genotyping single-nucleotide polymorphism (SNP) markers. In this study, we introduce two changes to improve the assay: (a) we streamline the PCR-Invader method by assaying both alleles for each SNP in one reaction; and (b) we reduce the cost of the method by adopting fluorescence polarization (FP) as the detection method.

METHODS

PCR product was incubated with Invader oligonucleotide and two primary probes at 93 degrees C for 5 min. Signal probes corresponding to the cleaved flaps of the primary probes [labeled with fluorescein and 6-carboxytetramethylrhodamine (TAMRA) dye] and Cleavase VIII enzyme (a flap endonuclease) were then added to the mixture. This reaction mixture was incubated at 63 degrees C for 5 min. FP measurements were made with a fluorescence plate reader.

RESULTS

Eighty-eight individuals were genotyped across a panel of 10 SNPs, using PCR product as template, for a total of 880 genotypes. An average "no call" rate of 3.2% was observed after first round of experiments. PCR products were remade in those samples that failed to produce any genotype in the first round, and all gave clear-cut genotypes. When the genotypes determined by the PCR-Invader assay and template-directed dye-terminator incorporation assay with FP were compared, they were in 100% concordance for all SNP markers and experiments.

CONCLUSIONS

The improvements introduced in this study make PCR-Invader assay simpler and more cost-effective, and therefore more suitable for high-throughput genotyping.

[The effect of lactate-buffered peritoneal dialysis fluid in human peritoneal mesothelial cells function]

OBJECTIVE

To investigate the effect of lactate-buffered peritoneal dialysis fluid (L-PDF) on human peritoneal mesothelial cells (HPMC) function.

METHODS

Mesothelial cells from human omentum were isolated and cultured in vitro. Proliferation of HPMC was detected by MTT assay. The quantity of interleukin-8 (IL-8) and fibronectin (FN) in culture supernatants was determined by ELISA. Reverse transcription and polymerase chain reaction amplification were used to detect the expression of IL-8 mRNA in HPMC. Total cellular protein in these supernatants was estimated by using Lowry method.

RESULTS

L-PDF inhibited proliferation of HPMC in a time-dependent manner. The levels of IL-8 and FN in the supernatants were remarkably high, and expression of IL-8 mRNA was up-regulated in HPMC exposure to L-PDF. During a subsequent recovery period of 48 hours in culture medium containing lipopolysaccharide (LPS, 10 mg/L), enterotoxin of staphylococcus aureus (10 mg/L) or TNFalpha(10 x 10(6) U/L), the levels of FN in the supernatants increased (P < 0.05). The levels of IL-8 also increased in HPMC stimulated with TNFalpha(P < 0.01).

CONCLUSION

L-PDF inhibited proliferation of HPMC and increased levels of IL-8 and FN in the HPMC.

Single-nucleotide polymorphisms in the public domain: how useful are they?

There is a concerted effort by a number of public and private groups to identify a large set of human single-nucleotide polymorphisms (SNPs). As of March 2001, 2.84 million SNPs have been deposited in the public database, dbSNP, at the National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov/SNP/). The 2.84 million SNPs can be grouped into 1.65 million non-redundant SNPs. As part of the International SNP Map Working Group, we recently published a high-density SNP map of the human genome consisting of 1.42 million SNPs (ref. 3). In addition, numerous SNPs are maintained in proprietary databases. Our survey of more than 1,200 SNPs indicates that more than 80% of TSC and Washington University candidate SNPs are polymorphic and that approximately 50% of the candidate SNPs from these two sources are common SNPs (with minor allele frequency of > or =20%) in any given population.

Hepatitis B virus S gene mutants in infants infected despite immunoprophylaxis

OBJECTIVE

To assess the correlation between hepatitis B virus (HBV) surface gene mutant infection and hepatitis B (HB) vaccination failure.

METHODS

Using sera from 106 infants who were born to HBV carrier mothers and failed in HB immunoprophylaxis, HBV S gene was amplified by PCR, transferred to nylon membranes for Southern blots, and then hybridized with oligonucleotide probes. Eleven of non-hybridizing samples were used for DNA sequencing.

RESULTS

93.4% (99/106) of the samples were HBV DNA positive, and 30.3% (30/99) failed to hybridize with at least one of the four probes. DNA sequencing confirmed that 10 of the 11 samples had an S gene mutation with amino acid (aa) change. The identified mutants included nucleotide (nt) 546T-->A (aa131N-->T), nt531T-->C (aa1261-->T), nt491A-->C (aa113T-->P), nt491T-->A (aa113S-->T), nt533C-->A (aa127P-->T), nt581T-->A (aa143S-->T), nt636A-->T (aa161Y-->F), and nt679A-->C (aa175L-->F). The sequence in one mother-infant pair was completely the same, with mutations at aa131 and aa161.

CONCLUSIONS

The prevalence of HBV surface mutants is about 30% in the children failing in HB vaccination. HBV mutants can infect infants by maternal-infant transmission.

[The complication of multiple system organs failure in pregnancy: a clinical analysis of 13 cases]

OBJECTIVE

To find out the features and causes of the complications of multiple system organs failure (MSOF) in pregnancy and increase the level of its prevention and treatment.

METHODS

A retrospective study was carried out on 13 cases with the complication of MSOF in pregnancy admitted between Feb 1992-Jun 1999.

RESULTS

There were two or more organs or systems function failure in the pregnancy. Four cases induced by infection, 5 cases induced by heart diseases, 3 cases induced by pregnancy induced hypertension, 1 case induced by amniotic fluid embolism. 12 of 13 were cured. 1 was died. Among them one infant was died.

CONCLUSIONS

During the treatment of pregnancy with multiple system organs failure, it is important to control the causes and inducements. It is forcible to terminate pregnancy in time and choose a best style of delivery. It is better to keep watch on saving multiple system organs function.

[Cloning and expression of caiDE genes in E. coli BL21(DE3)]

The caiDE genes for carnitine racemase and its relative factor were cloned into pUC18 from the chromosomal DNA of E. coli MC4100 by shot-gun approach and have been verified by sequence analysis. The target plasmid was named as pJX393 and subcloned to form a transcription plasmid pDSW2. After its transformation into BL21(DE3) strain and induction by IPTG, the recombinant strain containing pDSW2 expressed two apparent protein bands on SDS-PAGE, whose molecular weight were 30 kD and 24 kD individually.

[Effect of puerarin on heart function and serum oxidized-LDL in the patients with chronic cardiac failure]

OBJECTIVE

To observe the effect of puerarin on heart function and serum oxidized-LDL(ox-LDL) in patients with chronic cardiac failure.

METHODS

Seventy-eight patients with chronic cardiac failure were randomly divided into two groups, regular group (R) and regular + puerarin group (P). All patients in two groups received conventional treatment with inotropic agents, diuretic, and vasodilator, etc. The patients in the P group took puerarin 400 mg.d-1 for 10 days.

RESULTS

After treatment, the clinical heart function of the patients in the two groups was improved, but there was no significant difference between them; the left ventricular ejection fraction (EF) of patients in the P group was higher than that in the R group(P < 0.05); and serum ox-LDL level was significantly decreased in the P group patients, but that was no change in the R group patients(P < 0.05).

CONCLUSION

Puerarin may improve the clinical heart function, increase the left ventricular ejection, meanwhile, it may decrease the level of ox-LDL.

[Chronic pulmonary heart diseases treated by fraxiparin]

OBJECTIVE

The effects of fraxiparine with hypodermic on the treatment of patients with chronic pulmonary heart diseases(CPHD) at acute phase were studied.

METHODS

Twenty patients were hypodermically injected with 0.4 ml fraxiparine per day for 7 days as a course. Fibrin fibrinogen degradation products (FDP and D-dimer), antithrombin III (AT-III), PaO2 and PaCO2 were detected before and after the treatment.

RESULTS

In the therapy group, FDP and D-dimer decreased after the treatment, AT-III increased. All indexes didn't alter in the control group.

CONCLUSION

Fraxiparine is effective on patients with CPHD at acute phase.

[The natural history of HIV infection among IDUs in Ruili, Yunnan province, China]

OBJECTIVE

To study the natural history of HIV infections among intravenous drug users.

METHODS

Six hundred and twenty five HIV infected people in Ruili, Yunnan province were observed. Retrospective data was analysed combined with a cross - sectional survey.

RESULTS

The number of death was 190 among 625 HIV - positive people. The cumulative death rate among HIV infected persons was 76.9 per 1,000 person - year, and the AIDS related death rate was 19.8 per 1,000 person - year. The median survival period of HIV infected persons was 9 years, and the median incubation period was about 8 years.

CONCLUSION

Of HIV infected people in Ruili, the median survival and incubation period were shorter compared with those in the United States and Western Europe.

Glutamate and GABA activate different receptors and Cl(-) conductances in crab peptide-secretory neurons

Responses to rapid application of glutamic acid (Glu) and gamma-aminobutyric acid (GABA), 0.01-3 mM, were recorded by whole-cell patch clamp of cultured crab (Cardisoma carnifex) X-organ neurons. Responses peaked within 200 ms. Both Glu and GABA currents had reversal potentials that followed the Nernst Cl(-) potential when [Cl(-)](i) was varied. A Boltzmann fit to the normalized, averaged dose-response curve for Glu indicated an EC(50) of 0.15 mM and a Hill coefficient of 1.05. Rapid (t(1/2) approximately 1 s) desensitization occurred during Glu but not GABA application that required >2 min for recovery. Desensitization was unaffected by concanavalin A or cyclothiazide. N-methyl-D-aspartate, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, quisqualate, and kainate (to 1 mM) were ineffective, nor were Glu responses influenced by glycine (1 microM) or Mg(2+) (0-26 mM). Glu effects were imitated by ibotenic acid (0.1 mM). The following support the conclusion that Glu and GABA act on different receptors: 1) responses sum; 2) desensitization to Glu or ibotenic acid did not diminish GABA responses; 3) the Cl(-)-channel blockers picrotoxin and niflumic acid (0.5 mM) inhibited Glu responses by approximately 90 and 80% but GABA responses by approximately 50 and 20%; and 4) polyvinylpyrrolydone-25 (2 mM in normal crab saline) eliminated Glu responses but left GABA responses unaltered. Thus crab secretory neurons have separate receptors responsive to Glu and to GABA, both probably ionotropic, and mediating Cl(-) conductance increases. In its responses and pharmacology, this crustacean Glu receptor resembles Cl(-)-permeable Glu receptors previously described in invertebrates and differs from cation-permeable Glu receptors of vertebrates and invertebrates.

Glutamate induces rapid upregulation of astrocyte glutamate transport and cell-surface expression of GLAST

Glutamate transporters clear glutamate from the extracellular space by high-affinity binding and uptake. Factors that regulate glutamate transporter expression and activity can thereby influence excitatory neurotransmission. Transporter function in GABAergic and other systems has been shown to be regulated by transporter substrates. Here, glutamate regulation of glutamate transport was studied using primary murine astrocyte cultures that express the GLAST (EAAT1) and GLT-1 (EAAT2) transporter subtypes. Glutamate was found to stimulate glutamate transport capacity (V(max)) in a dose- and time-dependent manner. The maximal increase was 100%, with an ED(50) of 40 microM glutamate and with onset beginning approximately 15 min after onset of glutamate exposure. The uptake stimulation was reproduced by D-aspartate, which is also a transporter substrate, but not by nontransported glutamate receptor agonists. Moreover, glutamate incubation did not stimulate transport when performed in a sodium-free medium, suggesting that the stimulatory effect of glutamate is triggered by increased transporter activity rather than receptor activation. Treatment with the actin-disrupting agents cytochalasin B or cytochalasin D prevented the glutamate-induced increase in glutamate uptake. Biotinylation labeling of membrane surface proteins showed that glutamate incubation produced an increase in GLAST expression at the astrocyte cell surface. These results suggest that cell-surface expression of GLAST can be rapidly regulated by glutamate through a process triggered by GLAST activity and involving the actin cytoskeleton. This feedback loop provides a mechanism by which changes in extracellular glutamate concentrations could rapidly modulate astrocyte glutamate transport capacity.

[Molecular characterization of glucose-6-phosphate dehydrogenase variants in four ethnic groups in Yunnan province of China]

OBJECTIVE

In order to understand the molecular evolution, race origin and the relationship between the G6PD gene structure and clinical symptoms, the authors identified the molecular characterization of glucose-6-phosphate dehydrogenase and determined the G6PD gene frequency in four ethnic groups in Yunnan province of China.

METHODS

The point mutations of G6PD were detected by Mismatch-PCR/RE, SSCP,ARMS,DNA sequence and so on. G6PD gene frequency was determined by Hardy-Weinberg Law.

RESULTS

G6PD G1388A, G1376T,A95G mutations were determined in Bai and Dai people for the first time and G1388A also in Harni people by DNA sequence. G6PD C1024T were detected in Dai population by Mismatch-PCR/RE. The gene frequency of G6PD in Bai population in Dali city is 0.0113, and the incidence is 1.19% which are different from those in Dai population.

CONCLUSION

G6PD G1388A,G1376T, A95G and C1024T are the mutations in national minorities as well as in the Han people. The results suggest that different national minorities of China may have the same ancestor. The incidence of G6PD deficiency and the G6PD gene frequency in Bai population are different from those in Dai population. The distribution of G6PD deficiency in Yunnan is associated with the distribution of malaria epidemic in that province.

Selective inhibition of transient K+ current by La3+ in crab peptide-secretory neurons

Although divalent cations and lanthides are well-known inhibitors of voltage-dependent Ca2+ currents (ICa), their ability to selectively inhibit a voltage-gated K+ current is less widely documented. We report that La3+ inhibits the transient K+ current (IA) of crab (Cardisoma carnifex) neurosecretory cells at ED50 approximately 5 microM, similar to that blocking ICa, without effecting the delayed rectifier K+ current (IK). Neurons were dissociated from the major crustacean neuroendocrine system, the X-organ-sinus gland, plated in defined medium, and recorded by whole cell patch clamp after 1-2 days in culture. The bath saline included 0.5 microM TTX and 0.5 mM CdCl2 to eliminate inward currents. Responses to depolarizing steps from a holding potential of -40 mV represented primarily IK. They were unchanged by La3+ up to 500 microM. Currents from -80 mV in the presence of 20 mM TEA were shown to represent primarily IA. La3+ (with TEA) reduced IA and maximum conductance (GA) by approximately 10% for 1 microM and another 10% each in 10 and 100 microM La3+. Normalized GA-V curves were well fit with a single Boltzmann function, with V1/2 +4 mV and slope 15 mV in control; V1/2 was successively approximately 15 mV depolarized and slope increased approximately 2 mV for each of these La3+ concentrations. Cd2+ (1 mM), Zn2+ (200 microM), and Pb2+ (100 microM) or removal of saline Mg2+ (26 mM) had little or no effect on IA. Steady-state inactivation showed similar right shifts (from V1/2 -39 mV) and slope increases (from 2.5 mV) in 10 and 100 microM La3+. Time to peak IA was slowed in 10 and 100 microM La3+, whereas curves of normalized time constants of initial decay from peak IA versus Vc were right-shifted successively approximately 15 mV for the three La3+ concentrations. The observations were fitted by a Woodhull-type model postulating a La3+-selective site that lies 0.26-0.34 of the distance across the membrane electric field, and both block of K+ movement and interaction with voltage-gating mechanisms; block can be relieved by depolarization and/or outward current. The observation of selective inhibition of IA by micromolar La3+ raises concerns about its use in studies of ICa to evaluate contamination by outward current.

[The peripheral blood levels of TNF alpha and PLA2 activities in dialysis and non-dialysis patients with uremia]

The levels of tumor necrosis factor a (TNF alpha) and phospholipase A2 (PLA2) in peripheral blood were determined by means of the ELISA and improved micromethod in 31 patients with urmia and 12 normal healthy persons. The results showed: 1. In non-dialysis group and during a single dialysis session, a significant increase in the levels of TNF alpha was observed. 2. In non-dialysis and peritoneal dialysis patients, serum levels of PLA2 were significantly increased compared to normal subjects. The results suggest that acute complications induced by hemodialysis are related to increasing levels of TNF alpha, souble PLA2 in cleared by hemodialysis.

[Solid-phase microextraction of dichlorvos from white spirits]

DDVP was isolated from white spirits using Solid-Phase Microextraction (SPME) technique, and determined by wide-bore capillary gas chromatography (GC) coupling a flame ionization detector. This method had an excellent linearity among 0.5-12 mg/L. Correlation coefficient and minimum detectable concentration were 0.9983 and 0.05 mg/L respectively. This method enables the extraction, the enrichment and the injection to integrate into a single step, and it was free-solvent in whole process. SPME is an advanced technique for the extraction and analysis of the samples.

International clinical trials of HIV vaccines: II. phase I trial of an HIV-1 synthetic peptide vaccine evaluating an accelerated immunization schedule in Yunnan, China

A Phase 1, double-blind, placebo controlled trial was conducted in Longchuan County, China, to evaluate the safety and immunogenicity of a prototype HIV-1 synthetic peptide vaccine in a target population at risk for HIV infection, and to establish the infrastructure for future large-scale HIV vaccine efficacy trials. Subjects were randomly assigned to receive 100 microg or 500 microg of vaccine or alum placebo, and were given three injections at an accelerated 0, 1, and 2 month schedule. The vaccine was well tolerated with no significant local or systemic reactions observed in any subjects. Fifty-five percent (100 microg dose) and 64% (500 microg dose) of subjects who received the vaccine produced binding antibody to the immunogen as determined by ELISA. However, HIV-1 (MN) neutralizing antibody was detected in only 23% (3/13) of subjects with detectable HIV-1 specific binding antibody. It was concluded that this prototype HIV-1 synthetic peptide vaccine was well tolerated, safe and immunogenic, and that a 0, 1, 2 month schedule was not as effective in stimulating HIV-1 specific neutralizing antibodies compared with previous trials utilizing a 0, 1, 6 month schedule. Finally, this trial demonstrated that well-designed HIV vaccine trials can be performed at this clinical trials site in Yunnan, China, and that this site should be considered for conducting larger safety, immunogenicity and efficacy trials of candidate HIV vaccines.

Characteristics of risk-taking behaviors, HIV and AIDS knowledge, and risk perception among young males in southwest China

A cross-sectional survey was undertaken to describe risk-taking behaviors and to assess the knowledge and risk perception of HIV and AIDS among young males aged 18 to 29 years in 82 villages in Longchuan, Yunnan, China, in 1994. Information on demographic, behavioral, and drug-using factors, and knowledge of HIV transmission and prevention, and risk perception was collected using an interviewer-administered anonymous questionnaire. A total of 1,548 individuals were interviewed and 433 drug users, including 52 nonsharing injectors and 140 sharing injectors, were identified. Over half the individuals scored 0 on HIV knowledge, but knowledge was greater among nonsharing drug injectors. Most drug injectors had initiated drug injection after 1990. The reported incidence continues to increase in all three major ethnic groups. Sharing of equipment was common (73%) among injectors. Drug users were four times more likely to have had premarital or extramarital sex, but condoms were used by only 2.5%. Thus, factors promoting spreading of HIV are common in this area. We recommend that a community-based intervention program, targeting both young men and women, be implemented and evaluated in Longchuan as soon as possible.

[Simultaneous analysis of theophylline, phenobarbital, amobarbital and carbamazepine in serum by high performance liquid chromatography]

Theophylline, phenobarbital, amobarbital and carbamazepine are the chief therapeutic drugs in clinical practice. Because of the differences among inter-individuals in the metabolic clearance of these drugs and their toxicity at certain levels of concentration in serum, the dosage should be regulated to maintain a therapeutic blood drugs level. To achieve this a rapid and accurate assay method for drugs in blood is necessary. This paper reports that a reversed phase high performance liquid chromatographic (HPLC) method had been established for the simultaneous separation and quantitative determination of the four drugs in serum. The separation was performed on RP-C18 column using methanol:water (1:1) as mobile phase and 4-aminoantipyrime as internal standard. The eluted substances were detected at 210nm.

A preliminary study on interruption of HBV transmission in uterus

OBJECTIVE

The infection of Hepatitis B virus (HBV) in the uterus may occur in neonates born to HBV carrier mothers. The rates of intrauterine transmission in these neonates were 10%-16%, Recent studies on the methods of combined passive and active immunizations indicate an efficacy approaching 70%-90%, but intrauterine infection of HBV is the major cause of failure of vaccination to combat hepatitis B in neonates born to HBV carrier mothers. We studied the interruptive effect of HBV specific immunoglobulin (HBIG) before delivery in the prevention of intrauterine transmission of HBV.

METHODS

Of 3632 pregnant women, two hundred and four were HBV carriers; they were randomly divided into an HBIG group and a control group. Each subject in the HBIG group received 200 IU of HBIG intramuscularly at 3, 2 and 1 month before delivery. The subjects in the control group did not receive any specific treatment. Blood tests were conducted for all the subjects and their neonates after birth. Blood specimens were tested for HBsAg and HBeAg by enzyme immunoassay (Abbott Kits).

RESULTS

The results showed that the rates of intrauterine transmission in the two groups were 5.7% and 14.7% respectively (X2 = 4.58 P < 0.05). No significant differences were observed for the positive rates of HBsAg and HBeAg between the two groups after delivery, but titer of HBsAg was reduced significantly in the HBIG group (t = 4.82, P < 0.01).

CONCLUSIONS

Our study suggests that HBV infection in the uterus may be interrupted using multiple HBIG intramuscularly before delivery without any side effects.