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PubMed2005

Predominant constitutive CFTR conductance in small airways.

BACKGROUND: The pathological hallmarks of chronic obstructive pulmonary disease (COPD) are inflammation of the small airways (bronchiolitis) and destruction of lung parenchyma (emphysema). These forms of disease arise from chronic prolonged infections, which are usually never present in the normal lung. Despite the fact that primary hygiene and defense of the airways presumably requires a well controlled fluid environment on the surface of the bronchiolar airway, very little is known of the fluid and electrolyte transport properties of airways of less than a few mm diameter. METHODS: We introduce a novel approach to examine some of these properties in a preparation of minimally traumatized porcine bronchioles of about 1 mm diameter by microperfusing the intact bronchiole. RESULTS: In bilateral isotonic NaCl Ringer solutions, the spontaneous transepithelial potential (TEP; lumen to bath) of the bronchiole was small (mean +/- sem: -3 +/- 1 mV; n = 25), but when gluconate replaced luminal Cl-, the bionic Cl- diffusion potentials (-58 +/- 3 mV; n = 25) were as large as -90 mV. TEP diffusion potentials from 2:1 NaCl dilution showed that epithelial Cl- permeability was at least 5 times greater than Na+ permeability. The anion selectivity sequence was similar to that of CFTR. The bionic TEP became more electronegative with stimulation by luminal forskolin (5 microM)+IBMX (100 microM), ATP (100 microM), or adenosine (100 microM), but not by ionomycin. The TEP was partially inhibited by NPPB (100 microM), GlyH-101* (5-50 microM), and CFTRInh-172* (5 microM). RT-PCR gave identifying products for CFTR, alpha-, beta-, and gamma-ENaC and NKCC1. Antibodies to CFTR localized specifically to the epithelial cells lining the lumen of the small airways. CONCLUSION: These results indicate that the small airway of the pig is characterized by a constitutively active Cl- conductance that is most likely due to CFTR.

Animals↗

PubMed1997

The future of cochlear implants.

Remarkable progress has been made in recent years in the design and application of processing strategies for cochlear implants. Most notably, use of the new spectral peak (SPEAK) and continuous interleaved sampling (CIS) strategies have provided large improvements in speech reception performance compared with prior strategies (NIH Consensus Statement, 1995; Skinner et al., 1994a; Wilson et al., 1991). All major manufacturers of multichannel implant systems, including Advanced Bionics Corp., Bionic Systems, Cochlear Pty. Ltd., and Med El, now offer CIS or CIS-like strategies in their speech processors. The SPEAK strategy was developed by Cochlear Pty. Ltd and continues to be one of the options available in that company's devices. The principal purpose of this editorial is to present some of the many possibilities for further improvements in performance. To the extent that such possibilities are realized, implant systems of the future may be quite different from present systems, with different processing strategies, electrode designs, telemetry features, and fitting procedures.

Cochlear Implants↗

PubMed1997

[Comparison of 4 extraction methods of chemical constituents in medicinal tea sishen chaji].

Four extraction method for the medicinal tea Sishen Chaji, were compared with psoralen, schizandrin B and evodiamine taken as indexes. The result shows that the total contents of the three compounds decrease progressively in the following order: semi-bionic extraction, semi-bionic extraction by precipitation with alcohol, extraction with water, and extraction with water and precipitation with alcohol.

Cyclooctanes↗

PubMed1997

[Comparison of two extraction methods for maxingshigan decoction].

The semi-bionic extraction and the extraction with water, two methods for the Maxingshigan Decoction, were compared. The results show that the semi-bionic extraction is superior to the extraction with water in the yield of ephedrine, hydrocyanic acid, glycyrrhetinic acid, calcium ion and extract.

Calcium↗

PubMed2004

[Bioartificial liver support system: state of the art].

The temporary function replacement and intensive support play a pivotal role in the treatment of patients with acute or chronic end-stage organ failure. The hemodialysis and peritoneal dialysis have become routine techniques in the management of acute or chronic renal failure. But for the complexity of hepatic function, e.g. metabolism, biosynthesis and biotransformation for endogenous or exogenous substrates, the simulation or partial replacement of hepatic function is a great dream of bionic technologists. With the development of cell biology and biomedical material, the combination of biomaterial and the hepatocyte cultured ex vivo could provide a range of human liver-specific functions. The combination of biomaterial and viable cell was called hybrid or bioartificial liver support system (BALSS). It is a chimera of biomaterials and hepatocytes. The bionic technologists study the cell and its culture in vitro, which is the main component of BASLL. Many types of BALSS were translated into the early clinical stage. In this overview, we review the hepatocyte culture and the design of different bioreactors. It includes the immune obstacles in xeno-hemoperfusion and how to assess pre-clinical and clinical effectiveness.

Bioreactors↗

PubMed1989

Models of human memory.

The capacity to store and retrieve information is a property common to biological organisms and certain artefacts. Psychological models of human memory fall into two rival classes: a) "bionic" models which draw inspiration from the structural and functional properties of the central nervous system (computo bionic models); b) "symbolic information processing" models in which the inspiration for description and explanation of natural processes is drawn from the structural and functional properties of Von Neumann computers (computo-symbolic models).

Humans↗

PubMed1996

[Comparison of 4 extraction methods for antidotal granules of Coptis].

Four extraction methods for Antidotal Cranules of coptis were compared, with berberine, barcalin and gardenoside taken as the indexes. The result shows that the total contents of three components appear in the following order: semi-bionic extraction > semi-bionic extraction with precipitation with alcohol > extraction with water > extraction with water plus precipitation with alcohol.

Anti-Infective Agents↗

PubMed1997

Modern medicine and the "uncertain body": from corporeality to hyperreality?

This paper (re)considers the role of medical technology at three interrelated levels: first, the extent to which medical technology renders our bodies increasingly "uncertain" at the turn of the century; second, the analytical purchase which the notion of the (medical) cyborg provides regarding contemporary forms of human embodiment; and finally, at a broader level, the issues this raises in relation to a (late) modernist or postmodernist reading of contemporary medical practice. Key themes here include the plastic body, the bionic body, communal/interchangeable bodies, (genetically) engineered/ chosen bodies, and virtual bodies. The paper concludes with a critical appraisal of these themes and issues, arguing for a late modernist position on medical technology as both a positive and negative rationalising force, and a "life political agenda" in which the "all-too-human" quality of human nature is seen as inviolable.

Bionics↗

PubMed2001

BION system for distributed neural prosthetic interfaces.

We have developed the first in a planned series of neural prosthetic interfaces that allow multichannel systems to be assembled from single-channel micromodules called BIONs (BIOnic Neurons). Multiple BION implants can be injected directly into the sites requiring stimulating or sensing channels, where they receive power and digital commands by inductive coupling to an externally generated radio-frequency magnetic field. This article describes some of the novel technology required to achieve the required microminiaturization, hermeticity, power efficiency and clinical performance. The BION1 implants are now being used to electrically exercise paralyzed and weak muscles to prevent or reverse disuse atrophy. This modular, wireless approach to interfacing with the peripheral nervous system should facilitate the development of progressively more complex systems required to address a growing range of clinical applications, leading ultimately to synthesizing complete voluntary functions such as reach and grasp.

Animals↗

PubMed1977

Future of home hemodialysis.

An attempt to prophesy the future of home hemodialysis is based on anticipated near and long term technological improvements. Dialysis treatments will become shorter, due to pressure filtration, while extracting molecules in the 300 to 3000 dalton weight range through more permeable membranes. Portable and wearable dialysis systems will increase patient mobility. By the 21st century, implantable bionic kidneys and perfect host tolerance to renal allografts and xenografts will relegate home hemodialysis to history texts. A non-surgical definitive treatment for uremia is envisioned in the colonization of the human bowel with nitrogenn recycling bacteria.

Bionics↗

PubMed2003

Retinal remodeling triggered by photoreceptor degenerations.

Many photoreceptor degenerations initially affect rods, secondarily leading to cone death. It has long been assumed that the surviving neural retina is largely resistant to this sensory deafferentation. New evidence from fast retinal degenerations reveals that subtle plasticities in neuronal form and connectivity emerge early in disease. By screening mature natural, transgenic, and knockout retinal degeneration models with computational molecular phenotyping, we have found an extended late phase of negative remodeling that radically changes retinal structure. Three major transformations emerge: 1) Müller cell hypertrophy and elaboration of a distal glial seal between retina and the choroid/retinal pigmented epithelium; 2) apparent neuronal migration along glial surfaces to ectopic sites; and 3) rewiring through evolution of complex neurite fascicles, new synaptic foci in the remnant inner nuclear layer, and new connections throughout the retina. Although some neurons die, survivors express molecular signatures characteristic of normal bipolar, amacrine, and ganglion cells. Remodeling in human and rodent retinas is independent of the initial molecular targets of retinal degenerations, including defects in the retinal pigmented epithelium, rhodopsin, or downstream phototransduction elements. Although remodeling may constrain therapeutic intervals for molecular, cellular, or bionic rescue, it suggests that the neural retina may be more plastic than previously believed.

Aging↗

PubMed1988

Cell growth on metallic glasses: the interaction of amorphous metal alloys with cultured neuronal, osteoblast, endothelial, and fibroblast cells.

Ferrous based, corrosion resistant amorphous alloys supported the adhesion and growth of cultured chick neuronal cells, human marrow stromal cells (presumptive osteoblasts), bovine aortal endothelial cells, and hamster kidney fibroblasts. Alloys of compositions Fe60Ni10Cr10P13C7, Fe70Cr10P13C7, and Fe70Cr10P13B7 were found to be suitable. In contrast the crystalline form of these alloys was markedly less effective. Outgrowth of neurites from neuronal cells was promoted by precoating the metal surface with either laminin or neurite promotion factor. The adhesion of osteoblasts and fibroblasts suggests that corrosion resistant metal glasses should be considered as biomaterials useful for orthopedic applications. The adhesion of neuronal cells accompanied by neurite outgrowth indicates that the system might provide a functional interface between the neuromuscular system and an electromagnetic material that could be useful in bionic engineering.

Alloys↗

PubMed1992

cAMP activation of CF-affected Cl- conductance in both cell membranes of an absorptive epithelium.

Cystic fibrosis (CF) is characterized by abnormal epithelial Cl- conductance (GCl). In vitro studies that have shown that cAMP regulation is an intrinsic property of the CF-affected GCl(CF-GCl) have been carried out previously on cultured secretory cells and on nonepithelial cells. Even though GCl in absorption is defective in CF, a clear demonstration of cAMP regulation of CF-GCl in a purely absorptive tissue is lacking. We studied the cAMP regulation of CF-GCl in the microperfused intact human reabsorptive sweat duct. About 40% of the ducts responded to cAMP (responsive) while the remainder of the ducts did not. In responsive ducts, cAMP-elevating agents: beta-adrenergic agonist isoproterenol (IPR), CPT-cAMP, forskolin, theophylline or IBMX increased Gt by about 2.3-fold (n = no. of ducts = 8). Removal of media Cl-, but not amiloride pretreatment (in the lumen), abolished the cAMP response, indicating exclusive activation of GCl. cAMP activated both apical and basolateral GCl. cAMP hyperpolarized gluconate: Cl- (lumen:bath) transepithelial bionic potentials (delta Vt = -20.3 +/- 5.2 mV, mean +/- SE, n = 9) and transepithelial 3: 1 luminal NaCl dilution diffusion potentials (delta Vt = -8.8 +/- 2.9 mV, n = 5). cAMP activated basolateral GCl as indicated by increased bi-ionic (gluconate:Cl-, bath:lumen) diffusion potentials (by about 12 mV). The voltage divider ratio in symmetric NaCl solutions increased by 60%. Compared to responsive ducts, nonresponsive ducts were characterized by smaller spontaneous transepithelial potentials in symmetrical Ringer's solution (Vt = -6.9 +/- 0.8 mV, n = 24, nonresponsive vs. -19.4 +/- 1.8 mV, n = 22, responsive ducts) but larger bi-ionic potentials (-94 +/- 6 mV, n = 35, nonresponsive vs. -65 +/- 5 mV, n = 17, responsive ducts) and dilution diffusion potentials (-40 +/- 5 mV, n = 11, nonresponsive vs. -29 +/- 3 mV, n = 7, responsive ducts). These results are consistent with an inherently (prestimulus) maximal activation of GCl in nonresponsive ducts and submaximal activation of GCl in responsive ducts. We conclude that cAMP activates CF-GCl which is expressed and abnormal in both apical and basal membranes of this absorptive epithelium in CF.

Adrenergic beta-Agonists↗

PubMed2007

Enzymatic production of biosilica glass using enzymes from sponges: basic aspects and application in nanobiotechnology (material sciences and medicine).

Biomineralization, biosilicification in particular (i.e. the formation of biogenic silica, SiO2), has become an exciting source of inspiration for the development of novel bionic approaches following "nature as model". Siliceous sponges are unique among silica forming organisms in their ability to catalyze silica formation using a specific enzyme termed silicatein. In this study, we review the present state of knowledge on silicatein-mediated "biosilica" formation in marine sponges, the involvement of further molecules in silica metabolism and their potential application in nanobiotechnology and medicine.

Amino Acid Sequence↗

PubMed1989

New cardiac bioprostheses: theory, experiments, and 10 years of clinical use.

The biological valve "BAKS" has the following specific features: (1) it is practically devoid of immunogenicity due to fermentative-chemical treatment; (2) it is completely treated with glutaraldehyde through gradual soaking in solutions of increasing concentration; (3) the biological part is fashioned taking into account the biomechanics of the aortic root; (4) the polypropylene stent is functional due to the use of the principles of bionics in valve construction; and (5) practically no thromboemboli occur, because of the special morphologic organization of the cuff and the distant location of the bioprosthesis leaflets from the stent edge. In the Department of Heart Surgery of the National Research Center of Surgery, "BAKS" valves have been used in 237 patients undergoing isolated mitral valve replacement for rheumatic heart disease. Of these 35% were younger than 35 years, 93.7% belonged to New York Heart Association functional class IV, and 24% had had a previous heart operation. The 10-year survival rate without hospital mortality was 68.94% +/- 4.86%. Total follow-up was 11,232 patient-months (range; 6 to 118 months; mean, 57 months; 97% complete). Main causes of death and reoperation were (per patient-year) infectious endocarditis, 3.2%; spontaneous bioprosthesis degeneration, 0.96%; mechanical dysfunction resulting from damage in the manufacturing of the prosthesis, 0.74%; left atrial thrombosis and/or thromboemboli, 0.5%; sudden death, 0.2%; cardiac insufficiency, 0.3%; and other, 0.4%.

Bioprosthesis↗

PubMed1994

Signal transmission from motor axons to group Ia muscle spindle afferents: frequency responses and second-order non-linearities.

Spinal recurrent inhibition via Renshaw cells and proprioceptive feedback via skeletal muscle and muscle spindle afferents have been hypothesized to constitute a compound feedback system [Windhorst (1989) Afferent Control of Posture and Locomotion; Windhorst (1993) Robots and Biological Systems--Towards a New Bionics]. To assess their detailed functions, it is necessary to know their dynamic characteristics. Previously we have extensively described the properties of signal transmission from motor axons to Renshaw cells using random motor axon stimulation and data analysis methods based thereupon. Using the same methods, we here compare these properties, in the cat, with those between motor axons and group Ia muscle spindle afferents in terms of frequency responses and nonlinear features. The frequency responses depend on the mean rate (carrier rate) of activation of motor axons and on the strength of coupling between motor units and spindles. In general, they are those of a second-order low-pass system with a cut-off at fairly low frequencies. This contrasts with the dynamics of motor axon-Renshaw cell couplings which are those of a much broader band-pass with its peak in the range of c. 2-15 Hz [Christakos (1987) Neuroscience 23, 613-623]. The second-order non-linearities in motor unit-muscle spindle signal lines are much more diverse than those in motor axon-Renshaw cell couplings. Although the average strength of response declines with mean stimulus rate in both subsystems, there is no systematic relationship between the amount of non-linearity and the average response in the former, whilst there is in the latter. The qualitative appearance of motor unit-muscle spindle non-linearities was complicated as was the average response to motor unit twitches. Thus, whilst Renshaw cells appear to dynamically reflect motor output rather faithfully, muscle spindles seem to signal local muscle fibre length changes and their dynamics. This would be consistent with the hypothesis that the two feedback pathways monitor different state variables determining the production of muscle force: neural input and length and its changes. Specifically, the dynamic properties of both subsystems may combine favourably to decrease the risk of instability (tremor) in the motoneuron-muscle spindle loop.

Animals↗

PubMed1992

Total eye transplantation for the blind: a challenge for the future.

Blindness is a human and social problem of incalculable weight. In the future, artificial 'bionic' prostheses and retinal grafts could achieve a long-sought cure. Several lines of evidence led to the speculation that a total eye transplantation for the cure of retinal blindness may become feasible in the near future. It is proposed that a brain dead patient's eye, whose retinal viability has been demonstrated with an electroretinogram recording, be transplanted into the blind's voided orbital socket, through a frontoorbitotemporal craniotomy and orbitozygomatic osteotomy. Regenerating optic nerve axons are channeled in a specially constructed guide to the homolateral corpus genicolatum laterale, while the retinal ganglion cells are adequately protected during the regrowth period. Aspects of this paradigm are reviewed and discussed.

Animals↗

PubMed2006

Olfactory cell-based biosensor: a first step towards a neurochip of bioelectronic nose.

Human olfactory system can distinguish thousands of odors. In order to realize the biomimetic design of electronic nose on the principle of mammalian olfactory system, this article reports an olfactory cell-based biosensor as a real bionic technique for odorants detection. Effective cultures of olfactory receptor neurons and olfactory bulb cells have been achieved on the semiconductor chip. Using light-addressable potentiometric sensor (LAPS) as sensing chip to monitor extracellular potential of the neurons, the response under stimulations of the odorants or neurotransmitters, such as acetic acid and glutamic acid, was tested. The results demonstrate that this kind of hybrid system of LAPS and olfactory neurons, which is sensitive to odorous changes, has great potential and is promising to be used as a novel neurochip of bioelectronic nose for detecting odors.

Animals↗