Autonomy reconfigured: incorporating the role of the unconscious

The principle of respect for autonomy has served as a pillar of American bioethics. Through its application in response to physician paternalism and as the basis for informed consent, it has attained preeminent status in the discipline. New challenges in health care warrant a re-examination of the origins of our autonomy. Developmental psychology, cognitive neuroscience, and behavioral neurology all emphasize the intimate relationship between our cognitive and emotional development, and through this, our conscious and unconscious minds. Our intellectual, and particularly our moral development, are instilled in us by our moral mentors, and consequently by our community as a whole. Autonomy and community are therefore inextricably interlinked, and our emphasis on liberty, rights, and privacy without the inclusion of family, community, and social responsibility is biologically unsound. Appreciation of this reality should lead to a more balanced set of bioethical norms.     

Discrete character of the development of the photosynthetic apparatus in greening barley leaves

Biogenesis of the photosynthetic apparatus in greening etiolated leaves of barley (Hordeum vulgare L) was investigated by an approach permitting investigation of this process under conditions that minimize differences in plastid development. Distributions of barley leaves greening for 24 h as to chlorophyll content and of chloroplast grana as to number of thylakoids were shown to be of a multimodal character. The shape of time-course curves of chlorophyll accumulation in local sites of greening etiolated leaves was of a stepped or (at the end of greening) undulated character. The stepwise accumulation of chlorophyll was accompanied by wave-like changes in chlorophyll b/a ratio, intensity of low-temperature chlorophyll fluorescence and photosynthetic activity with minima at the time points of transition to accelerated chlorophyll accumulation. It is assumed that (1) development of the photosynthetic apparatus in local sites of greening etiolated leaves occurs stepwise, from one steady level to another, but not as gradually as is generally accepted, and (2) every separate step in development of the photosynthetic apparatus seems to begin with formation of photosystem cores and to end with the synthesis of light-harvesting complexes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Identification of anti-repressor elements that confer high and stable protein production in mammalian cells

The expression of transgenic proteins is often low and unstable over time, a problem that may be due to integration of the transgene in repressed chromatin. We developed a screening technology to identify genetic elements that efficiently counteract chromatin-associated repression. When these elements were used to flank a transgene, we observed a substantial increase in the number of mammalian cell colonies that expressed the transgenic protein. Expression of the shielded transgene was, in a copy number-dependent fashion, substantially higher than the expression of unprotected transgenes. Also, protein production remained stable over an extended time period. The DNA elements are small, not exceeding 2,100 base pairs (bp), and they are highly conserved between human and mouse, at both the functional and sequence levels. Our results demonstrate the existence of a class of genetic elements that can readily be applied to more efficient transgenic protein production in mammalian cells.     

Double-Layer Magnetic Nanoparticle-Embedded Silica Particles for Efficient Bio-Separation

Superparamagnetic Fe₃O₄ nanoparticles (NPs) based nanomaterials have been exploited in various biotechnology fields including biomolecule separation. However, slow accumulation of Fe₃O₄ NPs by magnets may limit broad applications of Fe₃O₄ NP-based nanomaterials. In this study, we report fabrication of Fe₃O₄ NPs double-layered silica nanoparticles (DL MNPs) with a silica core and highly packed Fe₃O₄ NPs layers. The DL MNPs had a superparamagnetic property and efficient accumulation kinetics under an external magnetic field. Moreover, the magnetic field-exposed DL MNPs show quantitative accumulation, whereas Fe₃O₄ NPs single-layered silica nanoparticles (SL MNPs) and silica-coated Fe₃O₄ NPs produced a saturated plateau under full recovery of the NPs. DL MNPs are promising nanomaterials with great potential to separate and analyze biomolecules.     

Field Evaluation of a Push-Pull System to Reduce Malaria Transmission

Malaria continues to place a disease burden on millions of people throughout the tropics, especially in sub-Saharan Africa. Although efforts to control mosquito populations and reduce human-vector contact, such as long-lasting insecticidal nets and indoor residual spraying, have led to significant decreases in malaria incidence, further progress is now threatened by the widespread development of physiological and behavioural insecticide-resistance as well as changes in the composition of vector populations. A mosquito-directed push-pull system based on the simultaneous use of attractive and repellent volatiles offers a complementary tool to existing vector-control methods. In this study, the combination of a trap baited with a five-compound attractant and a strip of net-fabric impregnated with micro-encapsulated repellent and placed in the eaves of houses, was tested in a malaria-endemic village in western Kenya. Using the repellent delta-undecalactone, mosquito house entry was reduced by more than 50%, while the traps caught high numbers of outdoor flying mosquitoes. Model simulations predict that, assuming area-wide coverage, the addition of such a push-pull system to existing prevention efforts will result in up to 20-fold reductions in the entomological inoculation rate. Reductions of such magnitude are also predicted when mosquitoes exhibit a high resistance against insecticides. We conclude that a push-pull system based on non-toxic volatiles provides an important addition to existing strategies for malaria prevention.     

Prevalence of the Helicobacter pylori babA2 gene and correlation with the degree of gastritis in infected Slovenian children

The aims of our study were to determine the prevalence of the babA2 gene within Helicobacter pylori strains circulating in the Slovenian pediatric population, to further clarify its significance in causing inflammation of gastric mucosa in children and to verify whether cagA, vacA, iceA and babA genes work independently or synergistically in causing gastritis. A total of 163 H. pylori isolates obtained from the same number of children were tested for the presence of cagA, vacA and iceA genes using previously established methods, while the babA2 gene was determined using novel polymerase chain reaction assay targeting a 139-bp fragment of the central region of babA2. The babA2 gene was detected in 47.9 % of H. pylori samples. The presence of the babA2 gene was strongly associated with cagA, vacA s1 and vacA m1 genotype. The babA2 status correlated positively with bacterial density score, activity of inflammation and chronic inflammation of gastric mucosa. No significant correlation was found between the babA2 status and the presence of atrophy or intestinal metaplasia. In addition, the activity of gastric inflammation and density score were significantly associated with the coexpression of the cagA, vacA s1, vacA m1 and babA2 genes. The study, which included the largest number of pediatric H. pylori samples to date, confirmed that babA2 gene plays an important role in the pathogenesis of H. pylori gastritis in children. Furthermore, our results suggest that babA2, cagA and vacA s1 and m1 gene products may work synergistically in worsening the inflammation of gastric mucosa.     

Oxygen consumption is maintained in fetal sheep during prolonged hypoxaemia.

Experiments were conducted in 12 chronically-catheterized pregnant sheep to examine the effect of prolonged hypoxaemia secondary to the restriction of uterine blood flow on fetal oxygen consumption. Surgery was performed at 115 days gestation to place a teflon vascular occluder around the maternal common internal iliac artery and for insertion of vascular catheters. Following a 5-day recovery period, uterine blood flow was reduced in 6 animals for 24 hours and in 6 animals, the occluder was not adjusted. Fetal arterial PO2 decreased from 19.9 +/- 2.0 mmHg to 12.8 +/- 2.0 mmHg and 11.0 +/- 2.0 mmHg at 1 and 24 hours respectively in the experimental group and did not change the control group. Fetal pH decreased from 7.34 +/- 0.01 to 7.25 +/- 0.03 and 7.29 +/- 0.02 at 1 and 24 hours of hypoxaemia respectively. Fetal arterial lactate concentrations remained elevated throughout the experimental period with maximum concentrations of 6.6 +/- 2.1 mmol/l being present at 4 hours compared to 1.3 +/- 0.2 mmol/l during the control period. Umbilical blood flow increased from 186 +/- 19 ml/min/kg to 251 +/- 39 ml/min/kg at 1 h of hypoxaemia and returned to 191 +/- 21 ml/min/kg at 24 h. In association with the progressive fall in oxygen delivery to the fetus, oxygen extraction increased from 0.33 +/- 0.04 to 0.43 +/- 0.04 and 0.54 +/- 0.05 at 1 and 24 hours, respectively. Overall oxygen consumption by the fetus remained unchanged from control values.(ABSTRACT TRUNCATED AT 250 WORDS)     

Specificity of HCPTP variants toward EphA2 tyrosines by quantitative selected reaction monitoring

EphA2 receptor tyrosine kinase and the human cytoplasmic protein tyrosine phosphatase (HCPTP) are overexpressed in a number of epithelial cancers. Overexpressed EphA2 in these cancers shows a significant decrease in phosphotyrosine content which results in suppression of receptor signaling and endocytosis and an increase in metastatic potential. The decreased phosphotyrosine content of EphA2 has been associated with decreased contact with its ligand, ephrin A1 and dephosphorylation by HCPTP. Potential specificity of the two HCPTP variants for tyrosines on EphA2 has not been investigated. We have used a mass spectrometry assay to measure relative rates of dephosphorylation for the two HCPTP variants at phosphotyrosine sites associated with control of the EphA2 kinase activity or interaction with downstream targets. Our results suggest that although both variants dephosphorylate the EphA2 receptor, the rate and specificity of dephosphorylation for specific tyrosines are different for HCPTP-A and HCPTP-B. The SAM domain tyrosine Y960 which has been implicated in downstream PI3K signaling is dephosphorylated exclusively by HCPTP-B. The activation loop tyrosine (Y772) which directly controls kinase activity is dephosphorylated about six times faster by HCPTP-A. In contrast, the juxtamembrane tyrosines (Y575, Y588 and Y594) which are implicated in both control of kinase activity and downstream signaling are dephosphorylated by both variants with similar rates. This difference in preference for dephosphorylation sites on EphA2 not only illuminates the different roles of the two variants of the phosphatase in EphA2 signaling, but also explains why both HCPTP variants are highly conserved in most mammals.     

Assessment of the antiviral properties of recombinant porcine SP-D against various influenza A viruses in vitro

The emergence of influenza viruses resistant to existing classes of antiviral drugs raises concern and there is a need for novel antiviral agents that could be used therapeutically or prophylacticaly. Surfactant protein D (SP-D) belongs to the family of C-type lectins which are important effector molecules of the innate immune system with activity against bacteria and viruses, including influenza viruses. In the present study we evaluated the potential of recombinant porcine SP-D as an antiviral agent against influenza A viruses (IAVs) in vitro. To determine the range of antiviral activity, thirty IAVs of the subtypes H1N1, H3N2 and H5N1 that originated from birds, pigs and humans were selected and tested for their sensitivity to recombinant SP-D. Using these viruses it was shown by hemagglutination inhibition assay, that recombinant porcine SP-D was more potent than recombinant human SP-D and that especially higher order oligomeric forms of SP-D had the strongest antiviral activity. Porcine SP-D was active against a broad range of IAV strains and neutralized a variety of H1N1 and H3N2 IAVs, including 2009 pandemic H1N1 viruses. Using tissue sections of ferret and human trachea, we demonstrated that recombinant porcine SP-D prevented attachment of human seasonal H1N1 and H3N2 virus to receptors on epithelial cells of the upper respiratory tract. It was concluded that recombinant porcine SP-D holds promise as a novel antiviral agent against influenza and further development and evaluation in vivo seems warranted.