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At least 415 records · Page 23Linked to original sources
PubMed2005

Bioengineering and characterization of DNA-protein assemblies floating on supported membranes.

This chapter describes the design, practical construction, and characterization of P-DNA and their applications in building a new generation of DNA chips. P-DNAs are artificial covalent assemblies involving a histidine tag head able to bind to modified phospholipids, a core protein domain derived from cytochrome b5 by genetic engineering that features specific spectroscopic and electrochemical properties useful for detection, a synthetic linker acting as a spacer, and an oligonucleotide acting as a probe. P-DNA has the property of being able to efficiently self-associate to a supported bilayer including nickel-iminodiacetate-modified phospholipids. The construction of P-DNA and its interaction with a complementary oligonucleotide sequence can be monitored in real time by surface plasmon resonance using a Biacore system or equivalent. P-DNA chips feature unique properties including tunable surface density of probes; very low nonspecific interaction with external DNA; lateral mobility, minimizing-steric interaction; optimization of hybridization efficiency; and, potentially, recognition by multiple probes of a single target and perfectly defined and homogeneous structure, permitting high density up to a compact monolayer. Potential applications of this new device are multiple, including high-sensitivity and high-selectivity chips for DNA-DNA, DNA-RNA, or DNA-protein interactions.

Amino Acid Sequence↗
PubMed2006

Bioengineering assessment of acupuncture, part 1: thermography.

In Western society, acupuncture is becoming a popular complementary method to medical treatment. However, a scientific understanding of acupuncture has not been completely developed but will absolutely be necessary for the increased acceptance of acupuncture by the Western medical community. This first part of the review article describes, in a general introduction, milestones of acupuncture research within the last 30 years and in a specific part the possibilities and limitations of infrared thermography, a noninvasive biomedical engineering method, within acupuncture research.

Acupuncture Therapy↗
PubMed2006

Bioengineering assessment of acupuncture, part 2: monitoring of microcirculation.

In the second part of the review article, monitoring of microcirculation during acupuncture is described. Laser Doppler flowmetry and laser Doppler imaging provide easy-to-use, noninvasive, real-time measurements of local tissue blood flow. Using these types of biomedical equipment, it is possible to quantify and objectify peripheral changes in microcirculation during different methods of acupuncture stimulation (manual needle acupuncture and laserneedle acupuncture).

Acupuncture Therapy↗
PubMed2006

Bioengineering assessment of acupuncture, part 3: ultrasound.

Multidirectional transcranial ultrasound monitoring can be used to prove quantifiable effects of acupuncture stimulation in the brain. This third part of the review article gives a short introduction in monitoring cerebral blood flow velocity and summarizes the scientific results in this area of research. New constructions from the Medical University of Graz that can be used for evidence-based computer-controlled acupuncture are described. With these new methods and concepts, reproducible effects of needle and laserneedle acupuncture stimulation in cerebral blood flow velocity can be objectified for the first time.

Acupuncture Therapy↗
PubMed2006

Bioengineering assessment of acupuncture, part 4: functional magnetic resonance imaging.

In the fourth part of this review article, research on the topic of acupuncture and functional magnetic resonance imaging is described. Needle as well as painless laserneedle stimulation have led to significant changes in different areas of the brain. With the help of modern biomedical engineering equipment and neuroscience, some of acupuncture's secrets have begun to be revealed. The neuro-modulating effects require further investigation in a larger population sample.

Acupuncture Therapy↗
PubMed1998

Complementary action of antioxidant enzymes in the protection of bioengineered insulin-producing RINm5F cells against the toxicity of reactive oxygen species.

To determine the importance of different antioxidative enzymes for the defense status of insulin-producing cells, the effects of stable overexpression of glutathione peroxidase (Gpx), catalase (Cat), or Cu/Zn superoxide dismutase (SOD) in insulin-producing RINm5F cells on the cytotoxicity of hydrogen peroxide (H2O2), hypoxanthine/xanthine oxidase (H/XO), and menadione have been investigated. Single overexpression of Cat or Gpx provided less protection than the combined expression of Cat plus SOD or Cat plus Gpx, while single overexpression of SOD either had no effect on the toxicity of the test compounds or increased it. RINm5F cells were also susceptible to butylalloxan, a lipophilic alloxan derivative that is selectively toxic to pancreatic beta-cells. Overexpression of enzymes, both alone and in combination, did not protect against butylalloxan-induced toxicity while SOD overexpression increased it, as evident from a half maximally effective concentration (EC50) value. The addition of Cat to the culture medium completely prevented the toxic effects of H2O2 and H/XO but had no significant effect on the toxicity of menadione or butylalloxan. Extracellular SOD had no effect on the toxicity of any of the test compounds. The results of this study show the importance of a combination of antioxidant enzymes in protecting against the toxicity of reactive oxygen species. Thus, overexpression of Cat and Gpx, alone or in combination with SOD, by use of molecular biology techniques can protect insulin-producing cells against oxidative damage. This may represent a strategy to protect pancreatic beta-cells against destruction during the development of autoimmune diabetes and emphasizes the importance of optimal antioxidative enzyme equipment for protection against free radical-mediated diseases.

Alloxan↗
PubMedDate not supplied

Bioengineers, health-care technology and bioethics.

Technology has created moral dilemmas in recent years creating an increased interest in the field of bioethics, which affects engineers in biomedicine, physicians, other health-care professionals, and society in general. For example devices like the kidney dialysis machine or Nuclear Magnetic Resonance (NMR) diagnostic scanner demonstrate state-of-the-art capabilities, yet they are very expensive. Therefore, standards of the past involving health care and allocation of resources are changing, and professionals must be aware of this change, as well as the responsibility for complete testing and review during the research and development process of medical devices. In this paper, we illustrate technological impact and stress the necessity of an understanding of ethics in order to deal effectively with product liability, conflicts of interests, and allocation of scarce resources. Hopefully, this will result in awareness and education in ethics and professional responsibilities.

Bioethical Issues↗