DNA optical sensor: a rapid method for the detection of DNA hybridization

A DNA optical sensor system is proposed based on the combination of sandwich solution hybridization, magnetic bead capture, flow injection and chemiluminescence for rapid detection of DNA hybridization. Bacterial alkaline phosphatase (phoA) gene and Hepatitis B virus (HBV) DNA were used as target DNA. A biotinylated DNA probe was used to capture the target gene onto the streptavidin-coated magnetic beads and a calf intestine alkaline phosphatase (CAP)-labelled DNA probe was used for subsequent enzymatic chemiluminescence detection. The detection cycle was less than 30 min, excluding the DNA hybridization time, which was about 100 min. Both the phoA gene and HBV DNA could be detected at picogramme or femtomole level. No response signal was obtained when target DNA did not exist in the sample. Successive sample detection could be made by removing the magnetic field and a washing step.     

Human in vivo somatic mutation measured at two loci: individuals with stably elevated background erythrocyte glycophorin A (gpa) variant frequencies exhibit normal T-lymphocyte hprt mutant frequencies

The P3 event-related potential (ERP) component was recorded from 7- to 18-year-old children of alcoholics (COAs, n = 50) and age- and sex-matched control children (n = 50) using a visual oddball paradigm, involving nontarget (76%), target (12%), and novel (12%) stimuli. Topographic maps of P3 and associated scalp current density were obtained to supplement a topographic profile analysis. COAs manifested a smaller amplitude P3 to target stimuli over the centroparietal, parietal, and occipital scalp locations than controls. Also, COAs exhibited a smaller amplitude P3 to novel stimuli over the occipital scalp than controls. There were no significant differences between COAs and controls in the P3 scalp topography, indicating that differences in intracranial source strength rather than in source configuration were responsible for the between-group amplitude differences. Also, no significant group differences were observed in the P3 peak latency or in behavioral performance. These results support the notion that the visual P3 may provide a vulnerability marker of alcoholism.     

Thioredoxin peroxidase from Onchocerca volvulus: a major hydrogen peroxide detoxifying enzyme in filarial parasites

Random screening of an Onchocerca volvulus third-stage (L3) cDNA library identified a highly abundant cDNA encoding a newly discovered antioxidant enzyme, thioredoxin peroxidase (TPx), a member of the peroxidoxin superfamily. This TPx cDNA (Ov-tpx-2) encodes a polypeptide of 199 amino acid residues with a calculated molecular weight of 21,890 Da. The Ov-tpx-2 cDNA represents roughly 2.5% of the total cDNAs from the L3 cDNA library. The gene was expressed in Escherichia coli and the protein product was shown to have antioxidant activity. Antiserum raised against Ov-TPX-2 recognized a native protein from extracts of both the L3 and adult-stages with a molecular weight of 22 kD. The localization and stage-specificity of Ov-TPX-2 protein was analyzed by immunocytochemistry and immunoelectron microscopy using monospecific antibodies. Expression was detected in late first-stage larvae during development in the vector and increased in intensity during differentiation to the infective L3-stage. The antigen was also detected in post-infective larvae and adult worms. In larvae, Ov-TPX-2 protein was predominantly localized to the hypodermis and cuticle, with additional sites in the hypodermal chords and multivesicular bodies. In adult worms, the primary sites of expression were the uterine epithelium and intestine, with additional labeling of the body wall and cuticle. Developing embryos and microfilariae in utero were bathed in Ov-TPX-2 protein discharged from epithelial cells. These results suggest that Ov-TPX-2 may protect the parasites from being damaged by host-generated oxidative stress and that Ov-TPX-2 protein provides the H2O2-detoxifying activity predicted but not previously identified in filarial parasites. Its highly upregulated expression in infective larvae may aid in parasite establishment following transmission to the definitive host.     

Molecular dynamics simulations of peptide fragments from hen lysozyme: insight into non-native protein conformations

Molecular dynamics simulations of four peptides taken from the hen lysozyme sequence have been used to generate models for non-native protein conformations. Comparisons between the different peptides and with experimental data for denatured lysozyme and peptide fragments provides insight into the characteristics of the conformational ensembles populated in these non-native states and the dependence of their structural features on the amino acid sequence. For the denatured conformers populated local contacts dominate in determining the properties observed in the trajectories, all four peptides showing similar characteristics. These include a significant increase in the number of main-chain O(i)-NH(i+2) hydrogen bonds and hydrogen bonds involving side-chain groups, this increase compensating to a large extent for the loss of hydrogen bonds involved in helical or beta-sheet secondary structure in the native fold, and the generation of a population of collapsed states with local clusterings of hydrophobic groups. The hydrophobic clusters enable at least partial burial of many side-chains exposed by the loss of tertiary contacts on denaturation and provide models that may explain the experimentally observed protection of amides from hydrogen exchange and the existence of residual secondary structure in non-native species of lysozyme. The results suggest that this approach has an important role to play in aiding the interpretation of experimental data for conformationally disordered non-native states of proteins.     

Absence of MEN2A- or 2B-type RET mutations in primary neuroblastoma tumour tissue

A spectroscopic method for thiol analysis, based on the complexation reaction with Pd(II), is described. The proposed method is simple and sensitive and can be used for a rapid analysis of thiols in human lymphocytes.     

Femoral vascular catheterization in critically ill infants and children

The success rate and complications from femoral arterial and venous catheterization in infants and children in a university affiliate pediatric intensive care unit were determined prospectively over a 2-year period. We also performed a meta-analysis from published literature to determine the combined estimates of noninfectious and infectious complications (with 95% confidence limits) using the inverse variance-weighted method. Success rates were 94.5% and 94.4% for femoral arterial (n=110) and venous (n=89) catheterizations, respectively, and were related to operator expertise, age, and hemodynamic status. Median age was 2.4 years and 1.1 year for arterial and venous catheterizations, respectively. Immediate complications were hematoma (10.9% arterial, 16.8% venous) and minor bleeding (13.6% arterial, 13.5% venous). Decreased pulses occurred with 7.7% of arterial catheterizations, and lower limb swelling occurred in 9.5% of venous catheterizations. Vascular complications occurred only in infants and resolved within 7-14 days. Catheter-related infections occurred in 1.9% of arterial and 3.6% of venous catheterizations. The mean duration of catheterization was 5.3 days and 6.3 days with femoral arterial and venous catheterizations, respectively. Meta-analysis of published studies shows that the estimates for noninfectious complications were 5.0%, 10.1%, 1.1%, and 1.8% for femoral arterial, femoral venous, axillary arterial, and nonfemoral venous catheters, respectively. The estimates for catheter-related infection were 2.5%, 3.7%, and 3.0% for femoral arterial, femoral venous, and nonfemoral venous catheters, respectively. The meta-analytic estimates for complication rates from published literature are not significantly different from the rates observed in our study. Femoral arterial and venous catheterization in infants and children are safe with an expected high success rate and acceptably low complication rates.     

Oral contraceptives alter circadian rhythm parameters of cortisol, melatonin, blood pressure, heart rate, skin blood flow, transepidermal water loss, and skin amino acids of healthy young women

This study investigated the usage consumption pattern and chemical composition of fermented foods consumed in 191 rural households (1030 individuals) in Emene. The result showed that fermented foods were widely used and consumed by most age groups (under 2 years to adults) because of poor socioeconomic status. Fermentation period varied with type of food and was mostly carried out as a means of detoxifying certain foods. Generally, fermented foods contributed substantially to the daily caloric (46.3 to 79.9% for males and 57.5 to 78% for females); calcium (33.8 to 63.5% for males and 48.3 to 55.4% for females); iron (34.4 to 58.6% for males and 47.4 to 74.6% for females); and thiamin (23 to 58.5% for males and 37.5 to 60% for females) intakes. The contributions of fermented foods to protein (10 to 40.7%) and ascorbic acid (1.9 to 18.7%) intakes were however, low. When compared with the FAO recommendations, the daily intakes of protein, calcium, riboflavin, niacin and ascorbic acid by the subjects were low due to large consumption of starchy root crops. Poor financial status was the most limiting factor to adequate nutrient intake. Such results point out the need for nutrition education related to improved methods of preparation and food selection.