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At least 1,009 records · Page 56Linked to original sources
PubMed1990

Analysis, design and development of a carbon fibre reinforced plastic knee-ankle-foot orthosis prototype for myopathic patients.

A traditional knee-ankle-foot orthosis (KAFO) for myopathic patients has been studied for the assessment of loads and fatigue resistance. Starting from this basis a thermoplastic matrix carbon fibre reinforced plastic composite (CFRP) KAFO has been developed in order to reduce the weight. A finite-element simulation programme for deformation analysis was used to compare the behaviour of conventional and CFRP orthosis. There were no breakages either of the prototype or of its parts. The CFRP orthosis allows a weight reduction of more than 40 per cent.

Ankle↗
PubMed1991

The development of a prototype patella tendon bearing prosthesis using high-density polyethylene piping (the drainpipe leg).

In Nepal, the few centres that offer a lower limb prosthetics service generally use a laminate of polyester resin with cotton stockinette in the manufacture of the hard socket and cosmesis. Until 1989 this was also the only process used at Green Pastures Hospital in Pokhara. In response to a materials shortage brought about by a local international trading dispute, however, a prototype patella tendon bearing prosthesis was developed using high-density polyethylene piping. The terrain of Nepal, local walking habits, and therefore expectations of a prosthesis, differ considerably from those in the United Kingdom; hence some unusual design requirements are needed to be taken into consideration. This paper describes the progress of the design over several months and the constraints under which the work was carried out. Feedback was sought at the meeting at which the paper was presented, and would also be valued in response to this written account of the work.

Humans↗
PubMed2005

Butorphanol: effects of a prototypical agonist-antagonist analgesic on kappa-opioid receptors.

The opioid analgesic, butorphanol (17-cyclobutylmethyl-3,14-dihydroxymorphinan) tartrate is a prototypical agonist-antagonist opioid analgesic agent whose potential for abuse has been the cause of litigation in the United States. With a published affinity for opioid receptors in vitro of 1:4:25 (mu:delta:kappa), the relative contribution of actions at each of these receptors to the in vivo actions of the drug are an issue of active investigation. A body of evidence has been developed which indicates that a substantial selective action of butorphanol on the kappa-opioid receptor mediates the development of tolerance to butorphanol and cross-tolerance to other opioid agonists; to the production of dependence upon butorphanol, particularly in the rodent; and to compensatory alterations in brain opioid receptor-effector systems. This perspective will identify the current state of understanding of the effects produced by butorphanol on brain opioid receptors, particularly on the kappa-opioid receptor subtype, and on the expression of phosphotyrosyl proteins following chronic treatment with butorphanol.

Analgesics, Opioid↗
PubMed1998

Nurse reactions to a prototype home telemedicine system.

We have studied nurse reactions to a prototype home health telemedicine system. The system used interactive video through the local cable television network. Six nurses were directly involved with telecare video-visits. There were 54 patients. The average age of the patients was 76 years (range 21-101). Thirty-six (67%) patients were female and 18 (33%) were male. The patients had an average of 4.6 different diagnoses (range 1-16). They were also on a very wide range of medications (mean 9.9, range 2-23). Nurses overwhelmingly felt the system was effective for what this particular project was trying to accomplish. They were enthusiastic about the prospects of practising nursing by telemedicine, even though they had reservations about aspects of the particular system being used. Their main complaints were about limitations of the software and limitations of the telecommunication system that linked them to the patients.

Adult↗
PubMed1984

A clinical evaluation of a prototype positron camera for longitudinal emission tomography.

A multiwire proportional-chamber positron camera, developed at the Rutherford Laboratory, has been evaluated at The Royal Marsden Hospital. The prototype camera consists of two opposing 30 X 30 cm2 chambers. Longitudinal tomograms of a positron-emitting radioactive distribution placed between the detectors are obtained via back-projection and 2D-deconvolution. Due to the limited stereoscopic angle achieved with stationary detectors, only five planes parallel to the detector faces are reconstructed. A selection of images is presented of phantoms using 68Ga and of patients using 18F, 18F fluorodeoxyglucose and Na124I, to illustrate the tomographic performance of the positron camera. A comparison between back-projected and deconvoluted images shows that the 2D-deconvolution process, which includes filtration of image noise, successfully removes the background due to scattered photons. The spatial resolution achieved depends on the half-height frequency cut-off used in the filtering process, and this parameter was chosen according to the count density in the back-projected images. A qualitative visual comparison was made between the positron images and equivalent single photon studies on the same patient. The results justify further development of this new detector, especially for use with generator-produced positron-emitting radionuclides. Three-dimensional deconvolution resulted in improved tomographic performance for phantom data, but was less successful for patient data. These problems associated with limited-angle tomography will be overcome by multi-view acquisition. This study has shown that a relatively low-cost positron imaging system can be used for routine organ imaging. Further developments in hardware and software should yield images which are superior to those from single-photon planar or tomographic studies.

Bone Marrow↗
PubMed1993

Prototype system for archiving and transmitting digitized radiographs.

A prototype system for archiving and transmitting digitized dental radiographs is described. The system uses a CCD video camera, IBM compatible personal computer with a frame-grabber and a high resolution VGA monitor. All archived images were compressed lossless by a factor of about 3. Digitized radiographs were archived together with their exposure data and assembled in an examination with a unique identifier and date of examination, together with the patient's history and reason for radiological examination. A radiological report with a list of differential diagnoses could be attached. Each examination could contain 50 digitized radiographs which could be converted to a tagged image file (TIFF) and printed halftone with a laser printer. Users of the system could receive examinations from the network-server and share the images in a local area network.

Humans↗
PubMed2006

Clinical and radiographic presentation and preparation of the prototyping model for pre-surgical planning in Apert's syndrome.

Acrocephalosyndactyly, or Apert's syndrome, described nearly a century ago, is a craniofacial dysostosis, an autosomal dominant condition characterized by severe development disturbances of the craniofacial region including bilateral coronal synostosis associated with midface hypoplasia, exophthalmia, hypertelorism, symmetric syndactyly of the hands and feet, cone-shaped calvarium, pharyngeal attenuation and malocclusion. The aim of this study was to assess clinical and computed tomography (CT) imaging patterns of a non-operated patient with Apert's syndrome, correlating the cranium, face and the skull base bone abnormalities. Three-dimensional images were generated from spiral CT scans in order to produce a prototyping model in polyamide material. Clinical examination determined that syndactyly of the hands and feet, pseudocleft in the midline palate and midface hypoplasia were present. The surgical model allowed the analysis of some abnormalities regarding to calvaria morphology, nasal bones and maxilla, improving the criteria for a case diagnosis and surgical plan.

Acrocephalosyndactylia↗
PubMed1998

Validation of transgenic mice carrying the human prototype c-Ha-ras gene as a bioassay model for rapid carcinogenicity testing.

Carcinogenicity testing is indispensable for identifying environmental carcinogens and for evaluating the safety of drugs in the process of development. Conventional 2-year rodent bioassays are one of the most resource-consuming tests in terms of animals, time, and costs. Development of rapid carcinogenicity testing systems that can assess carcinogenicity within a short period has become a social demand and is essential to improve efficacy in the identification of environmental carcinogens as well as in the development of new drugs. In this review we introduce the rapid carcinogenicity testing system using transgenic (Tg) mice carrying the human prototype c-Ha-ras gene, namely rasH2 mouse (CB6F1-TgHras2 mouse is the same mouse). The studies have been conducted to validate the rasH2 mouse as a model for the rapid carcinogenicity testing system. Our current validation studies revealed that rasH2 mice are able to detect various types of mutagenic carcinogens within 6 months. The rasH2 mice may also be able to detect various nonmutagenic carcinogens. The validation studies also revealed that rasH2 mice are generally much more susceptible to both mutagenic and nonmutagenic carcinogens than control non-Tg mice. No significant tumor induction has been observed in rasH2 mice with either mutagenic or nonmutagenic noncarcinogens. More rapid onset and higher incidence of more malignant tumors can be expected with a high probability after treatment with various carcinogens in the rasH2 mice than in control non-Tg mice. The rasH2 mouse appears to be a promising candidate as an animal model for development of a rapid carcinogenicity testing system.

Animals↗
PubMed2002

Changes in hepatic enzyme activities in transgenic mice carrying human prototype c-Ha-ras gene treated with diethylnitrosamine.

Activities of malate dehydrogenase (MDH) and aspartate aminotransferase in the malate-aspartate shuttle were significantly increased in the cytosolic fractions of livers with early neoplastic symptoms such as swelling and discoloration in transgenic mice carrying the prototype human c-Ha-ras gene, Tg-rasH2 mice, which were administered with diethylnitrosamine (DEN) as a carcinogenic chemical at a dose of 200 mg/kg body weight. Cytosolic MDH/LDH (lactate dehydrogenase) (ML) ratio increased significantly and was considered to be a useful marker to characterize the energy metabolism at early neoplastic stage in livers of the Tg-rasH2 mice.

Animals↗
PubMed2002

Tumor promoting effect of phenolphthalein on development of lung tumors induced by N-ethyl-N-nitrosourea in transgenic mice carrying human prototype c-Ha-ras gene.

In order to examine tumor modifying effects of phenolphthalein (PhP), female transgenic mice carrying human prototype c-Ha-ras gene (rasH2 mice) were given a single intraperitoneal injection of 60 mg/kg body weight of N-ethyl-N-nitrosourea (ENU), followed by the diet containing 12,000 ppm PhP for 26-week. Histopathologically, alveolar hyperplasias, adenomas and adenocarcinomas were observed in the ENU + PhP group, but only hyperplasias and adenomas were observed in the ENU alone group. The incidence and multiplicity of adenocarcinomas in the ENU + PhP group was significantly increased as compared to that in the ENU alone group. The combined multiplicity of adenomas and adenocarcinomas in this group was also significantly higher than that of the ENU alone group. In addition, the ratio of area of adenomas in the ENU + PhP group was significantly higher than that in the ENU alone group. The result of our study suggests that PhP has a clear tumor promoting effect in the lung of rasH2 mice.

Adenocarcinoma↗
PubMed2002

Prototype results of a phase-shifting interferometer capable of measuring the complex index and profile of a test surface.

Results are presented from a prototype phase-shifting interferometer capable of measuring both the real and the imaginary part of the complex index of refraction and the surface profile of a test surface. The three parameters of interest are extracted from the measured data by maximum-likelihood estimation theory. The performance of the system is quantitatively assessed with Cramer-Rao lower bounds. The results are shown to be strongly dependent on the quantization of the interferograms from the 8-bit CCD camera, the incident electric field amplitude, and the relative amplitude and phase difference of each polarized component through each arm of the interferometer.

Equipment Design↗
PubMed2004

Prototype CO2 laser-induced long-period fiber grating variable optical attenuators and optical tunable filters.

Prototype devices capable of variable attenuation at a fixed wavelength, wavelength tuning at a constant attenuation, and combinations of these spectral characteristics are demonstrated in CO2 laser-induced long-period fiber gratings (LPFGs). These devices are based on controlled flexure by means of a piezoceramic platform. CO2 laser-induced LPFG characteristics along with the fabrication and testing processes of these gratings are discussed. Devices with a optical attenuation of 13 dB and a wavelength tuning of 7 nm are reported.

Journal Article↗
PubMed2005

Development of a frequency-detuned interferometer as a prototype experiment for next-generation gravitational-wave detectors.

We report on our prototype experiment that uses a 4-m detuned resonant sideband extraction interferometer with suspended mirrors, which has almost the same configuration as the next-generation, gravitational-wave detectors. We have developed a new control scheme and have succeeded in the operation of such an interferometer with suspended mirrors for the first time ever as far as we know. We believe that this is the first such instrument that can see the radiation pressure signal enhancement, which can improve the sensitivity of next-generation gravitational-wave detectors.

Journal Article↗
PubMed2005

The ERK cascade: a prototype of MAPK signaling.

Sequential activation of protein kinases within the mitogen-activated protein kinase (MAPK) cascades is a common mechanism of signal transduction in many cellular processes. Four such cascades have been elucidated thus far, and named according to their MAPK tier component as the ERK1/2, JNK, p38MAPK, and ERK5 cascades. These cascades cooperate in transmitting various extracellular signals, and thus control cellular processes such as proliferation, differentiation, development, stress response, and apoptosis. Here we describe the classic ERK1/2 cascade, and concentrate mainly on the properties of MEK1/2 and ERK1/2, including their mode of regulation and their role in various cellular processes and in oncogenesis. This cascade may serve as a prototype of the other MAPK cascades, and the study of this cascade is likely to contribute to the understanding of mitogenic and other processes in many cell lines and tissues.

Animals↗
PubMed2003

Fenretinide: a prototype cancer prevention drug.

Fenretinide (N-4-hydroxyphenylretinamide [4-HPR]) is a synthetic retinoid that has been examined in in vitro assays, preclinical animal models and clinical trials as a cancer chemopreventive agent. Its pharmacology, toxicity and mechanisms of action initially suggested an increased therapeutic index relative to native retinoids for the control of tumours of the breast, prostate, bladder, colon, cervix and head and neck. Although fenretinide at the doses and schedules used in several pivotal Phase II and III clinical trials has not been proven to be efficacious in reducing the incidence of cancer or in retarding the development of preneoplastic lesions, encouraging observations regarding unanticipated preventative activity, such as for ovarian cancer control, have arisen from these studies. Research in cancer therapy and the elucidation of molecular pathways activated by fenretinide have also yielded clues about how this agent might be better used in a prevention setting. Current trials are underway to re-examine both dose and schedule of fenretinide administration as well as the target tissues of interest. Investigations of potential synergism between fenretinide and other candidate chemopreventative molecules with complementary mechanisms of action may support future assessments of this prototype cancer prevention drug or its newer analogues.

Animals↗
PubMed2003

BH3 domains as BCL-2 inhibitors: prototype cancer therapeutics.

It is likely that most, if not all, cancer cells possess a mechanism for opposing programmed cell death, or apoptosis. One mechanism often used by cancer cells to escape apoptosis is the overexpression of B cell leukaemia/lymphoma-2 protein (BCL-2) or related antiapoptotic proteins. Inhibiting BCL-2, therefore, is an anticancer strategy worthy of attention. BCL-2 homology 3 (BH3) domains are alpha-helical segments found in BCL-2 family member proteins. In pro-apoptotic members, the BH3 domain is necessary for pro-apoptotic function. It has been shown that short peptides derived from the BH3 region possess intrinsic pro-death activity. Furthermore, certain peptides of this group exert their pro-death function by specifically binding BCL-2 and opposing BCL-2's antideath function. Therefore, BH3 domains are prototype BCL-2 inhibitors. Mimetics of BH3 domains, whether derived from peptides or small molecules, have promise as cancer therapeutics.

Animals↗
PubMed2005

Design and evaluation of a prototype rear obstacle detection and driver warning system.

This study, concerned with the development of driver interface criteria for a rear obstacle detection system, assessed the appropriateness of alternative warning timing algorithms and evaluated various interface approaches for presenting warning information to drivers. Interface testing used a minivan and a passenger sedan equipped with a prototype rear obstacle detection system. Two different warning timing algorithms and four different interface conditions were examined. The appropriateness of the warning timing algorithms was tested using an alerted backing procedure wherein drivers backed to known obstacles and braked in response to the warning. A surprise event scenario was also included in order to examine driver reaction to the warning under unexpected conditions. Alerted backing results suggest that although both timing algorithms led to few target strikes, one algorithm led to more acceptable ratings, fewer target strikes and close calls, and less urgent braking. None of the interface warning conditions reliably induced avoidance braking under the surprise event condition. Actual or potential applications of this work include the appropriate design of effective backing warning systems.

Accidents, Traffic↗
PubMed2000

A prototype matching approach to diagnosing personality disorders: toward DSM-V.

The current diagnostic system for personality disorders (PD) has a number of problems that may require a thorough revision for DSM-V. This article (a) outlines problems with the current taxonomy that suggest the need for a different approach to PD diagnosis that preserves the strengths of the current system while addressing some inherent weaknesses; (b) discusses key issues that must be addressed in moving toward DSM-V, such as revising the distinction between Axis I and Axis II and combining categorical and dimensional diagnosis; and (c) describes a prototype matching approach to diagnosis, which we believe has the potential to be both psychometrically sound and faithful to the clinical data.

Humans↗