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PubMed2005

Management of infant brachial plexus injuries.

Management of brachial plexus injuries is geared toward normalization of limb function, primarily through optimization of nerve regeneration and mechanical increase in elbow flexion and shoulder stabilization. Changes in the skeletal muscles and the osteous structures of the upper extremity are ongoing throughout the course of treatment, mandating continual assessment and aggressive rehabilitation. In patients who present too late for microsurgical intervention, irreversible changes take place in skeletal muscles, highlighting the importance of early referral. However, secondary procedures have been shown to be beneficial in older patients and in those whose primary procedures failed. Further advances in bionics and stem cell therapy may help replace the dynamic functional deficits of obstetric brachial plexus palsy.

Birth Injuries↗
PubMed2003

Cochlear implants in children: safety as well as speech and language.

The development of cochlear implants for children at the University of Melbourne and the Bionic Ear Institute, has consisted of a routine of biological and engineering safety followed by evaluation of speech processing strategies on adults before they are undertaken on children. The initial safety studies were to ensure that insertion was atraumatic, the electrical stimulus parameters did not lead to loss of ganglion cells and that the electrode could be inserted without the risk of middle ear infection leading to meningitis. The initial second formant extraction scheme was shown to produce significant open-set speech understanding in adults and was approved by the US Food and Drug Administration (FDA) in 1985. Following this, an international study was undertaken for the FDA on children using a strategy that also included the first formant, and was approved in 1990. Additional advances in speech processing have been evaluated on adults. However, before using one with high rates of stimulation, it was tested for safety on experimental animals. Further advances have been anticipated in particular through the development of a peri-modiolar array, the Nucleus Contour. Prior to its use on adults, it was tested in the human temporal bone and found to lead to minimal trauma. It was evaluated in adults and found to lead to better current localization and lower thresholds. A study was undertaken in children using a spectral maxima scheme at high rates (advanced combination encoder (ACE)) and the Contour array as it had given best results in adults. It was approved as safe and effective for use in children in 2000. Studies were also undertaken to look at plasticity and visual dominance particularly through cognitive studies and the use of the McGurk effect. This demonstrated that deaf children with implants rely heavily on visual information and there is a great need to have unambiguous auditory stimuli to get best results.

Animals↗
PubMed2006

Direct compression as an appropriately mechanical environment in bone tissue reconstruction in vitro.

Determining how to apply an appropriately mechanical environment which can improve the quality and function of bone-like construct in vitro is a required problem to be solved for the current development of bone tissue engineering. A specific mechanical force may be a key determinant of tissue development in vitro in bone tissue engineering. From the standpoint of bionics, the mechanical environments applied on bone tissue engineering should work in three aspects: providing adequately mechanical stimuli to the cells seeded in 3-D scaffold; ensuring the efficient mass-transport of the nutrients and waste products of the cells; promoting the development of functionally extracellular matrix in 3-D scaffold. After the analysis of several differently mechanical environments comparing with that in vivo, the directly dynamical compression environment, instead of hydrostatic pressure or microgravity or direct perfusion, can recreate the in vivo mechanisms of mechanosensation, mechanotransduction and mass-transport during engineered bone-like tissue culturing process in vitro. Therefore, it is hypothesized that the directly dynamic compression will be a specific mechanical environment to bone tissue reconstruction in vitro.

Bone and Bones↗
PubMed2005

Spider's microstructure for sensing.

The spider is well known for sensing the movements of air and preys. Bionics of the spider based on this principle is being paid great attention by many researchers. Here, this paper presents some detailed organs of the spider to make an attempt to clarify the sensing mechanism of the spider from the point view of physical structure by scanning electron microscopy. And behavior characteristics concerning sensing action are observed by optical microscopy. Compared with structures, some novel features of sense movements in micro- and nano-scale size and corresponding possible models are presented. At the same time, simple structure analysis is made to explain and prove this hypothesis.

Animals↗
PubMed1989

Incorporation of ionic channels from yeast plasma membranes into black lipid membranes.

Recently, patch-clamping of yeast protoplasts has revealed the presence of plasma membrane K+ channels (Gustin, M. C., B. Martinac, Y. Saimi, M. R. Culberston, and C. Kung. 1986. Science (Wash. DC). 233:1195-1197). In this work we show that fusion of purified plasma membranes into planar bilayers allows the study of the yeast channels. The main cationic conductances detected were of 64 and 116 pS, however, larger and smaller conductances have been observed. The two main conductances were sensitive to the K+ channels blockers tetraethylammonium (TEA+) and Ba2+. Bionic experiments indicated that both conductances were K+ selective.

Cell Membrane↗
PubMed1992

Threonine in the selectivity filter of the acetylcholine receptor channel.

The acetylcholine receptor (AChR) is a cation selective channel whose biophysical properties as well as its molecular composition are fairly well characterized. Previous studies on the rat muscle alpha-subunit indicate that a threonine residue located near the cytoplasmic side of the M2 segment is a determinant of ion flow. We have studied the role of this threonine in ionic selectivity by measuring conductance sequences for monovalent alkali cations and bionic reversal potentials of the wild type (alpha beta gamma delta channel) and two mutant channels in which this threonine was replaced by either valine (alpha T264V) or glycine (alpha T264G). For the wild type channel we found the selectivity sequence Rb greater than Cs greater than K greater than Na. The alpha T264V mutant channel had the sequence Rb greater than K greater than Cs greater than Na. The alpha T264G mutant channel on the other hand had the same selectivity sequence as the wild type, but larger permeability ratios Px/PNa for the larger cations. Conductance concentration curves indicate that the effect of both mutations is to change both the maximum conductance as well as the apparent binding constant of the ions to the channel. A difference in Mg2+ sensitivity between wild-type and mutant channels, which is a consequence of the differences in ion binding, was also found. The present results suggest that alpha T264 form part of the selectivity filter of the AChR channel were large ions are selected according to their dehydrated size.

Amino Acid Sequence↗
PubMed1999

New technologies in medicine: biotechnology and nanotechnology.

In February 1997, researchers created Dolly, a lamb cloned from the DNA of an adult sheep. This was supposed to be impossible (or at least generations away), but suddenly it was here--a clone of a higher mammal. Whatever Dolly's ultimate significance, she conclusively demonstrated the growing power of biotechnology. Many have come to the conclusion that advances in biotechnology will fundamentally transform medicine during the coming decade. Society is in the midst of a technical revolution that will have the same relevance as the development of the printing press, the internal combustion engine, and the microprocessor. Computers have become the key tools in the accelerating progress that is occurring in the field of biotechnology. At the same time, genetic, evolutionary, and other biologic processes are providing new models for the development of computer hardware and software. Today represents the early stages of what has been called the "bionic convergence": the convergence of the biologic revolution with the information revolution, the joining of biology with electronics. Virtually everything that is important to health care practitioners and patients--diagnostic techniques, means of understanding disease causes, methods of treatment, approaches to prevention, health care facility design, medical education, and legal and ethical issues--will be changed by the revolutions currently underway in the fields of biotechnology and genetic medicine. The following monograph includes several forecasts about a range of possible opportunities that may have enormous effects on health care during the next century. These forecasts address the potential impacts of biotechnology on disease detection and diagnosis, treatment, prevention, nanotechnology, and other areas of medical significance. Every area of beneficiary care will be affected as the changes implied by these forecasts begin to develop. Beneficiary care will continue to see the emergence of a "forecast, prevent, and manage" paradigm. The emphasis will be on disease prevention, health promotion, and the creation of healthy communities. New diagnostic and treatment opportunities will be available as a consequence of breakthroughs in genetic medicine. The health care system will view health as a whole, as a person's overall sense of well-being--an entity that encompasses much more than the absence of symptoms.

Biotechnology↗
PubMed1997

Permeation and gating of alpha1 glycine-gated channels expressed at low and high density in Xenopus oocyte.

When a high density of alpha1-subunit glycine receptor (GlyR) is expressed in Xenopus oocytes, two populations of channels can be distinguished according to their apparent affinity for glycine which differs 5- to 6-fold. To compare the open pore diameter of these channels, the relative permeability of formate with respect to chloride (P(formate)/P(Cl)) was determined in bionic conditions. For the low-affinity GlyR P(formate)/P(Cl) was comparable to that reported for glycine-gated channels in cultured spinal cord and hippocampal neurons. In contrast, the high-affinity GlyR had a 56% larger P(formate)/P(Cl). In addition, the open probability of the channels was differentially sensitive to voltage. These results show that the high expression of alpha1 GlyR resulted in two populations of GlyR which differed not only in the affinity to agonists but also in permeation and gating mechanisms.

Animals↗
PubMed2002

The nature of the autonomic dysfunction in multiple system atrophy.

The concept that multiple system atrophy (MSA, Shy-Drager syndrome) is a disorder of the autonomic nervous system is several decades old. While there has been renewed interest in the movement disorder associated with MSA, two recent consensus statements confirm the centrality of the autonomic disorder to the diagnosis. Here, we reexamine the autonomic pathophysiology in MSA. Whereas MSA is often thought of as "autonomic failure", new evidence indicates substantial persistence of functioning sympathetic and parasympathetic nerves even in clinically advanced disease. These findings help explain some of the previously poorly understood features of MSA. Recognition that MSA entails persistent, constitutive autonomic tone requires a significant revision of our concepts of its diagnosis and therapy. We will review recent evidence bearing on autonomic tone in MSA and discuss their therapeutic implications, particularly in terms of the possible development of a bionic baroreflex for better control of blood pressure.

Adrenergic Fibers↗
PubMed1990

Clinical technology assessment, cost-effective adoption, and quality management by hospitals in the 1990s.

Technology assessment in the 1990s must become an integral part of a hospital's strategic priority goals, with active participation of physicians and top management. Technology assessment should involve a wide range of criteria and health care consumer expectations, so that the appropriateness, effectiveness, cost-effectiveness, and quality improvement aspects of new technologies are all considered. Mount Carmel Health's Advanced Treatment and Bionics Institute (ATBI), established in 1986, monitors significant developments in new technologies and performs technology and outcomes assessments. ATBI activities, which have facilitated adoption of 35 treatment-based projects, are integrated into the existing QA structure of Mount Carmel hospitals. Through resolution of identified problems, quality care can be promoted, while providing patients innovative medical treatments.

Academies and Institutes↗
PubMed2000

The evolution of clinical applications of biodegradable implants in arthroscopic surgery.

Arthroscopic surgery is the most recent orthopaedic discipline to embrace biodegradable implant technology. Osteochondral fractures have been shown to be amenable to arthroscopic fixation with biodegradable pins. The areas of most recent interest have been biodegradable interference screw fixation for ACL reconstruction in the knee, biodegradable suture anchors for rotator cuff repair and capsulolabral repair in the shoulder. Biodegradable implants have allowed a paradigm shift away from bionic (mechanical replacement) engineering and toward true biologic solutions to reconstructive problems in arthroscopic surgery.

Absorbable Implants↗
PubMed1997

Cochlear implantation in children under the age of two years: candidacy considerations.

Within recent years, there has been a growing trend to lower the age at implantation below 2 years in children. The motivation for this trend is to provide children with access to auditory stimulation as early as possible, thereby taking advantage of crucial periods for speech and language development. Determining implant candidacy in very young children, however, poses numerous challenges and requires the development and evaluation of assessment procedures appropriate for this population. Issues in determining audiologic candidacy and evaluating implant benefit in young children are discussed. Measures that can be used to assess auditory development in this population and the application of some of these procedures in the pediatric study of the Clarion cochlear implant (Advanced Bionics Corp., Sylmar, Calif.) are also presented.

Acoustic Stimulation↗
PubMed2000

A silastic positioner for a modiolus-hugging position of intracochlear electrodes: electrophysiologic effects.

HYPOTHESIS: It was postulated that an electrode array that achieved a close modiolar proximity would result in reduced threshold levels and amplitude slopes, as measured with electrically evoked auditory brainstem responses (EABRs). BACKGROUND: Quality and quantity of auditory information transmitted by a cochlear implant to patients with sensorineural hearing loss depend on spatial and temporal resolution achieved by the electrical intracochlear stimulation. METHODS: To improve spatial resolution, a new electrode system was developed by Advanced Bionics Corp., with the intention of obtaining greater modiolar proximity. The implant version specified for animal experiments consists of a straight electrode array of seven embedded platinum discs and a so-called Silastic-positioner. The Silastic positioner is shaped to follow the dimensions of the scala tympani with a concave (triangular) inner side, which fits the form of the electrode array. The aim of the study was to evaluate the influence of a modiolus-hugging electrode position in contrast to a conventional electrode position on EABR in short-term animal experiments. Short-term electrophysiologic studies were performed on six adult cats. After local intracochlear application of neomycin solution (50 mg/mL), electrodes were inserted into the scala tympani. Electrically evoked auditory brainstem response threshold levels and EABR amplitude slopes were systematically investigated with and without the positioner. RESULTS: Electrically evoked auditory brainstem response measurements revealed a distinct apicobasal threshold shift, with increasing thresholds toward the basal end of the electrode. After insertion of the positioner, this shift diminished or was inverted and EABR thresholds and amplitude slopes were reduced significantly. CONCLUSIONS: Threshold and amplitude slope data emphasize the functional benefit of the positioner system, especially for the stimulation of electrodes in the more basal channels.

Animals↗
PubMed1999

Cochlear implants: response to therapeutic irradiation.

PURPOSE: To determine the response of cochlear implants ("bionic ears") to therapeutic irradiation. METHODS AND MATERIALS: A patient with a cochlear implant was referred for palliative cranial irradiation. As there were no published or manufacturer's data available regarding the response to radiation, implants were tested for functional changes following irradiation. Cochlear implants were supplied by Cochlear Ltd. Two units each of models CI22M, CI22M (with the second generation integrated circuit) and CI24M were irradiated with 4 MV X-rays, and an unirradiated unit of each model was used as a control. The implants were irradiated initially with 25 daily fractions to 50 Gy. To determine the response at higher doses, 10 Gy fractions were delivered to the same implants to 100 Gy, followed by a final fraction of 50 Gy (total dose 150 Gy). The implants were tested after each 10 Gy, up to 1100 Gy, and at 150 Gy. Several indicators of functionality were assessed, including RF (radio frequency) link range, and stimulator output current. The radiation shielding effect of the implants was also assessed. RESULTS: Within the dose range < or = 50 Gy, the stimulator output current of the CI22M units was the only parameter to change. At higher doses (to 150 Gy), changes in current output continued, and gradual loss of RF link range occurred in the CI22M units. The CI24M units showed changes in output current to 100 Gy, and large changes at 150 Gy. Dose attenuation by the implants was measured at 6% for ipsilateral single field 4 MV X-rays. CONCLUSION: Our results suggest that patients with these cochlear implants can receive cranial irradiation with a low risk of implant failure. Changes in stimulator output current can be compensated simply by reprogramming the speech map after the course of radiation treatment.

Adenocarcinoma↗
PubMed2006

Proteobionics: biomimetics in proteomics.

Proteomics was established 10 years ago by the analysis of microbial genomes via their protein complement or proteome. Bionics is an ancient art, which converts structures optimized by nature into advanced technical products. Previously, we analyzed survival modalities in nanobacteria and converted the interplay between survival-oriented protein functions and nanoscale mineral shells into models for advanced drug delivery. Exploiting protein functions observed in nature to design biomedical products and therapies could be named proteobionics. Here, we present examples for this new branch of nanoproteomics.

Animals↗
PubMed2026

Decoding mechanoregulation in immunological synapses using biomimetic artificial cells.

Mechanical force-driven signaling has emerged as a key regulator of cell-cell interactions (CCIs), which can enhance immune cell function. However, current biochemical approaches for studying CCIs offer minimal direct control over cellular bulk phenotypes, while synthetic biomaterial systems fail to mimic the dynamic complexity of cells. Here we introduce kpiCells, a biomaterial-based platform that uses a biomimetic membrane-endoplasmic architecture to enable finely tuned phenocopying of cellular states via modular mechanical, chemical and topographical inputs. We demonstrate that kpiCells can engage in physiological CCIs and reproduce critical subcellular features. In T cell systems, kpiCells enable integrated interrogation of afferent mechanosensing pathways and efferent force-exertion pathways, and support measurement of piconewton-scale forces at individual T cell antigen receptors as well as single cell-cell force fingerprints that define activation thresholds. This work establishes kpiCells as a bionic model that enables synthetic material design with the level of functional complexity approaching living cell systems.

Artificial Cells↗
PubMed2004

An investigation of telephone use among cochlear implant recipients.

The purpose of this study was to examine telephone use among cochlear implant recipients. A questionnaire was constructed and mailed to 803 adults who received a Clarion cochlear implant system manufactured by Advanced Bionics Corporation. Questionnaire recipients were implanted at least 12 months prior to receiving the questionnaire (i.e., they were implanted in 1998 or 1999). Approximately 60% (n = 478) responded, of whom 70% (n = 336) were considered "telephone users" (i.e., they answered the telephone and/or initiated calls). Telephone users were significantly younger and had significantly more daily hours of cochlear implant use than nonusers. Not surprisingly, there were differences between groups with respect to method of communication (i.e., more users employed oral communication, while more nonusers employed both oral and manual communication) and ability to understand words without lipreading (i.e., more users were able to understand). Thirty-seven percent of the telephone users were male, and 63% were female. The average age was 51.8 years (SD = 15.5). Ninety-five percent of users initiated calls to family and friends, 65% made appointments by phone, and approximately 50% asked for information about a product or service and conducted business over the phone. Over 95% of users could identify a dial tone, a busy signal, and voices. The average telephone use per week was 5.4 hr. Approximately 85% indicated that they were able to interact with strangers on the telephone within 5 months of receiving the sound processor. Approximately 30% communicated via a cellular phone for personal use. The findings of this survey suggest an increase in cochlear implant users' telephone use relative to a decade earlier. Advances in cochlear implant and telephone technologies are 2 of several factors that may contribute to the changes observed.

Adult↗
PubMed1996

[The Clarion cochlear implant--technical principles, initial clinical experiences and results].

BACKGROUND: Certain design characteristics of the Clarion device (Advanced Bionics Corp.) make it significantly different from other cochlear implant systems. It has a preformed electrode array to be placed closer to the modiolus, thus providing a more efficient coupling of the electrical signal to the auditory nerve; a telemetric function which permits the evaluation of the implant electronics; and two different speech processing strategies. The strategies are continuous interleaved sampling (CIS) and compressed analog (CA); both can be programmed into the same speech processor and alternatively selected by the patients, as they desire. The surgical procedure is only slightly different from the procedure familiar from the Nucleus system with the exception of a significantly larger cochleostomy. PATIENTS: The results of a series of speech tests designed to evaluate benefit in terms of speech understanding were administered to the first ten Clarion patients and compared to the results of a similar group of patients using the Nucleus system and the M Peak method. From a data-base of more than 300 Nucleus users, it was possible to select ten subjects who had near-equivalent data for onset of deafness, duration of deafness, and age at implantation (so-called matched pairs). In the majority of cases, etiology and course of deafness (progressive or sudden) could also be matched. RESULTS: It was found that the Clarion patients had higher test scores than the Nucleus patients after two weeks, three months, and six months after implantation. This positive experience with the Clarion device encouraged us to continue implanting this system in patients. As of September 1995, 106 patients (including 35 children between the ages of two and fourteen) are currently enrolled in the study. CONCLUSIONS: A final assessment of results with the Clarion implant is not possible because of the short follow-up. In any case, it appears that the patients with this implant system achieve faster open-set speech understanding and that it is accomplished with less effort in programming and shorter rehabilitation time.

Adolescent↗