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PubMed1999

Identification of two hERR2-related novel nuclear receptors utilizing bioinformatics and inverse PCR.

Identification of novel nuclear receptors based on the highly conserved DNA-binding domain (DBD) has previously depended mainly on low stringency hybridization of cDNA libraries and degenerate PCR. Establishment of the expressed sequence tag (EST) database in recent years has provided an alternative approach for the discovery of novel members of gene families. The rate-limiting step is the conversion of ESTs to full-length cDNA. This article describes the identification of two novel nuclear receptors (hERRbeta2 and hERRgamma2) related to human estrogen-receptor-related receptor 2 (hERR2) by mining the EST database and retrieving of full-length cDNA via inverse PCR on subdivided primary cDNA library pools. The deduced protein sequences of hERRbeta2 and hERRgamma2 contain 500 and 458 amino acid (aa) residues respectively. Sequence analysis revealed that hERRbeta2 and hERRgamma2 respectively share 95% and 77% overall aa sequence identity with hERR2. However, the extra C-terminal domain in hERRbeta2 and extra N-terminal domain in hERRgamma2 are not present in the closely related hERR2 or mouse ERR2 (mERR2). Extensive sequence verification revealed that hERR2 previously reported as a human gene is actually a rat gene, whereas hERRbeta2 is the true human ortholog of hERR2 and mERR2. Tissue distribution studies showed that hERRgamma2 was expressed in a broader panel of tissues at a higher level than hERRbeta2. hERRbeta2 was mapped to cytogenetic locus 14q24.3 approximately -14q31, a region containing multiple loci involved in genetic diseases, including Alzheimer and diabetes. hERRgamma2 was mapped to 1q32. Given the high sequence homology between hERRbeta2 and mERR2, the two receptors may have similar biological function in vivo.

Amino Acid Sequence↗
PubMed2006

Family participation in determination of FIM and Barthel indices.

Functional Independence Measure (FIM) is a basic indicator of severity of disability, and is used for measurement of functional independence. The aim of this paper is to present our initial experiences in the application of FIM. It needs to be noted that we have had an incomplete team in implementation of this project, and also that we have involved the patients and their families in the measurement of FIM. We selected a small sample of 23 patients, and measured their FIM and Barthel index both at the admission and discharge from the hospital. We do accept that this sample may be too small for the purposes of scientific verification. Therefore, we have included patients and their family members in the process of FIM measurement, along with the team members including a physiatrist, physiotherapist, nurse, and a help-nurse. Most of the subjects included in this project were patients with hemiplegia after a stroke (65.21 %), followed by quadriplegic patients (17.39 %), and patients with paraplegia (17.39 %). Gender structure shows 47.82 % male and 52.17 % female patients. The best progress (an increase in score from 4 to 53 points) in FIM was observed in patients with hemiplegia, and in Barthel index in patients with quadriplegia (an increase in score from 0 to 84). The differences are not statistically significant (p>0.05). The patients with hemiplegia were hospitalized in our clinic for the shortest period of time (around one month). Average rehabilitation time in our clinic for paraplegic patients was around 3 months, and for quadriplegic patients around 4 months (including early rehabilitation). We established that the patients who actively participated in FIM measurement had more control over their own medical assistance, and this participation had a supportive effect on patients. Their participation in FIM measurement needed constant encouragement. In order to make our claim that the FIM is a good supportive method as objective as possible, and in order to establish a correlation between disability and handicap, we intend to include a psychologist and apply Antonov SOC theory (coherency feeling) in our forthcoming research.

Activities of Daily Living↗
PubMed2005

Functional imaging with positron emission tomography in multiple system atrophy.

Although the current guidelines for the clinical diagnosis of multiple system atrophy (MSA) do not require structural or functional brain imaging, investigations utilizing positron emission tomography (PET) have been helpful diagnostically in differentiating between MSA and primary autonomic failure; idiopathic Parkinson's disease; and sporadic olivopontocerebellar atrophy. These investigations have demonstrated different patterns of cerebral glucose utilization and of nigrostriatal projection abnormalities among these disorders and between the cerebellar and parkinsonian forms of MSA. Most of the studies have focused upon patients with well-established disease and none have examined the utility of PET imaging in early stage patients with follow-up of clinical course and autopsy verification to ensure accuracy of diagnosis and to determine the sensitivity and specificity of PET techniques for diagnosis. Recent PET studies have revealed denervation of myocardial post-ganglionic sympathetic neurons in some MSA patients, indicating that this disorder can affect the peripheral autonomic as well as the central nervous system. Investigations utilizing ligands to quantify central nervous system dopaminergic and cholinergic terminals have begun to provide insight into the neurochemical disorders that may underlie two of the sleep disturbances common in MSA, rapid eye movement sleep behavior disorder and obstructive sleep apnea.

Animals↗
PubMedDate not supplied

[Brain death and the donation of organs. A review in the light of current Spanish legislation].

INTRODUCTION: Primary brain death (BD) is a clinical situation characterised by the total and irreversible absence of functioning in the brain as a consequence of its being destroyed, while heartbeat and breathing are maintained by artificial means. The Royal Decree 2070/1999, dated 30 December, lawfully regulates the diagnosis of BD and the activities concerning the donation of organs for transplant in Spain. METHOD: In certain patients who have suffered structural injury to the brain, serious intracranial hypertension occurs which blocks the blood flow throughout the brain, while breathing is maintained by mechanical means, together with heartbeat. The diagnosis of BD is eminently clinical and is based on the verification of three circumstances: the existence of a non reactive coma, the disappearance of brain stem reflexes and activity in its parasympathetic nuclei, and the absence of spontaneous breathing. The diagnosis can be reinforced with certain complementary tests, which in some cases are compulsory. In the paper we describe the explorations that are considered to be appropriate by current Spanish legislation. We also review the most important clinical and legal aspects of organ donation. CONCLUSIONS: BD is an iatrogenic state, known only since the development of reanimation and assisted ventilation techniques, which amounts to the death of the person. Obtaining organs for transplants is currently possible in Spain from donors in this situation, but also from those who have died from an initial cardiopulmonary arrest and from live donors.

Brain Death↗
PubMed1995

Detection, quantitation, and verification of allosteric interactions of agents with labeled and unlabeled ligands at G protein-coupled receptors: interactions of strychnine and acetylcholine at muscarinic receptors.

Novel methods of detecting and quantitating cooperative interactions between an agent and both a tritiated (muscarinic) antagonist and the endogenous agonist (acetylcholine), acting at a common (muscarinic) receptor, have been devised. In a semiquantitative protocol, binding data are transformed into affinity ratios (the ratios of the apparent affinity of the ligand in the presence of the agent to the affinity of the ligand alone), which allow estimates to be made of the potency of the agent and its cooperativity with the tritiated antagonist and with the unlabeled ligand. These parameters have been quantitated by detailed binding assays or guanosine-5'-O-(3-[35S]thio)triphosphate functional assays. The kinetic phenomena associated with the allosteric interactions have been exploited in two non-equilibrium binding assays, from which the affinity constants describing the allosteric interactions can be extracted. The different assay methods give quantitatively similar and internally consistent estimates of the parameters describing the cooperative interactions. Using these assays, strychnine has been found to act allosterically at muscarinic receptors. Strychnine has an affinity of approximately 10(5) M-1 at the unliganded m1, m2, and m4 receptors but is 5-10-fold weaker at m3 receptors. It is positively cooperative with N-methylscopolamine at m2 and m4 receptors and exhibits neutral and negative cooperativity with m1 and m3 receptors, respectively. With acetylcholine, it is negatively cooperative but the degree of cooperativity is relatively low (2-7-fold), particularly at m1 and m4 receptors. The methods and equations described should be useful in detecting and quantitating allosteric interactions of agents with the endogenous neurotransmitter at G protein-coupled receptors.

Acetylcholine↗
PubMed2005

Pacing with capture verification in candidates for resynchronisation therapy: a feasibility study.

BACKGROUND: Devices for cardiac resynchronisation therapy (CRT) deliver energy into 3 output channels. Such a burden can significantly reduce device longevity. Autocapture has been shown to improve pacemaker longevity and safety of right ventricular pacing in clinical studies. The aim of this study was to investigate the application of Autocapture during biventricular pacing (BIV) to decrease the energy cost of CRT. METHODS: During implantation of BIV devices, an acute study was performed to test the hypothesis that the evoked response (ER) elicited by each delivered stimulus is correctly detected and measured either on the right ventricular (RV) channel during BIV pacing with the left ventricular (LV) channel pacing first, or in the LV channel with the RV channel pacing first. A reliable measurement of ER is the critical requirement for the correct performance of Autocapture. RESULTS: ER amplitude in the right ventricle during BIV pacing was not significantly decreased compared with RV pacing in the VVI mode (16.36+/-5.27 mV vs 17.09+/-6.12 mV). ER amplitude in the left ventricle during BIV pacing was not significantly decreased compared with LV pacing in the VVI mode (12.4+/-8.95 mV vs 12.25+/-8.97 mV). Three patients in atrial fibrillation had a DDDR pacemaker with the LV lead connected to the atrial port, and received BIV pacing with Autocapture turned on in the RV channel. Autocapture performance in the long term, as assessed by the trend of RV threshold over 20+/-8 months, showed that LV depolarisation was never sensed as an ER on the RV channel. CONCLUSIONS: Our observations support the feasibility and safety of capture verification during BIV pacing on the ventricular channel paced secondly, which could increase the longevity of CRT devices, and decrease the costs of this new therapy for heart failure patients.

Algorithms↗
PubMed1990

Verification of a canine model of transient exercise induced myocardial dysfunction: antianginal effects of flestolol, an ultra short acting beta adrenoceptor antagonist.

STUDY OBJECTIVE - The aim of the study was to verify the reproducibility of a canine model of treadmill exercise induced regional myocardial dysfunction designed to mimic exertional angina pectoris in man. DESIGN - Dogs trained to run on a treadmill were chronically instrumented with a microtip manometer in the left ventricle, a hydraulic occluder around the circumflex branch of the left coronary artery, two pairs of crystals for sonomicrometry, and arterial and venous catheters. Experiments were started 10 d after surgery, when the animals were submitted to seven treadmill exercise cycles, each of 3 min, with a 7 min recovery period. Ischaemia was adjusted so as not to impair regional function at rest but to produce progressive dysfunction with increasing work load. Flestolol (1 microgram.kg-1.min-1) was infused intravenously during the third and fourth exercise cycle. SUBJECTS - Six mongrel dogs, 13.5-29.5 kg, were used. MEASUREMENTS and RESULTS - Flestolol caused a marked reduction in the exercise induced increase in left ventricular positive dP/dtmax, and minor reductions in heart rate and systolic blood pressure, resulting in a decrease in myocardial oxygen demand and an improvement in regional function in the circumflex area of the left coronary artery. The functional improvement was transient and disappeared entirely after termination of flestolol infusion. CONCLUSIONS - The results show that flestolol is beneficial in conditions of limited coronary reserve and exercise induced myocardial dysfunction. The fact that the extent of regional myocardial dysfunction was comparable before and after flestolol infusion confirms the stability and usefulness of this experimental model in the evaluation of antianginal drugs.

Adrenergic beta-Antagonists↗
PubMed1993

The role of cytokines in experimental listeriosis.

Listeria monocytogenes is a Gram-positive, intracytoplasmatically replicating pathogen that elicits host reactions which are very similar in man and rodents. Using murine listeriosis as a highly reproducible and convenient experimental model for studying the immune response to infections with facultative intracellular bacteria, Mackaness developed the concept of T cell-mediated macrophage activation as the pivotal mechanism in host defense against this type of infectious agents. Continued research in listeriosis itself, however, provided paradoxical findings that challenged the original dogma. In particular, the finding that T cell-mediated inflammatory events, like DTH and granuloma formation, can be dissociated from protective effector mechanisms has provided a new impetus and experimental access to characterizing the molecular mediators responsible for these diverging phenomena. This review first summarizes the cellular basis for the dichotomy of immunological phenomena outlined above and will then relate recent findings on cytokine expression in infected tissues to these dual categories of the host response to infection. The authors will focus on data obtained from in vivo experiments and draw on evidence from in vitro systems only when appropriate in vivo verification is still lacking. The data presented will cover the developments made in the field of cytokine research since our previous review in 1981 (Rev. Infect. Dis. 3: 1221-1250). Detectable numbers of listeria-specific T cells become apparent on day 4 to 5 of a primary infection. Whereas the localized and sustained release of TNF and IFN-gamma mediated by CD4+ cells seems to be the focusing event triggering mononuclear cell accumulation, the coincidental eradication of bacteria critically depends on CD8+ and/or CD4-CD8-Thy1+ cells. Their effector functions, however, remain obscure, since cytokines cannot be identified that will substitute for their presence. None of the cytokines studied thus far has been demonstrated to effectively cure an established infection. In addition, the increased production of cytokines characteristic of an anamnestic response (IL-2, IL-3, IL-4, IFN-gamma and TNF) can be dramatically reduced by depleting CD4+ T cells without any effect on the animal's ability to eradicate high lethal doses of bacteria and Listeria-specific CD8+ T cells can mediate protection even in the presence of neutralizing antibodies to IFN-gamma. In conclusion, the murine model of Listeria infection provides an interesting experimental approach for the development of immunotherapeutic strategies aimed at reducing T cell-mediated immunopathology without interfering with innate resistance and T cell-mediated cure and prevention of disease.

Animals↗
PubMed1996

Verification of milled two-dimensional photon compensating filters using an electronic portal imaging device.

A computer-driven milling machine is being installed at the Mallinckrodt Institute of Radiology to fabricate photon compensating filters for conventional compensation and beam-intensity modulation. Commissioning and quality assurance procedures are being developed for the design, fabrication, and delivery systems prior to using the milled filters in the clinic. The portion of the quality assurance procedures governing the filter fabrication using a computer-driven milling machine includes, in part, a comparison of designed and fabricated filters. Test filters include geometrically regular filters, such as flat surfaces and steps. The verification of these shapes is accomplished using spatial measurements. However, to test the mill's ability to generate complex curved surfaces, filters with more complicated surfaces are generated. These filters do not lend themselves to precise verification using physical measurement of the thickness distribution. A method has been developed to verify the thickness distributions of these complex filters by irradiating the filters with high-energy x rays and comparing the scattered and transmitted fluence to the fluence calculated using the intended filter shape. The fluence measurement is made using a calibrated commercial liquid ionization chamber electronic portal imaging device. The calculated fluence is separated into transmitted primary and scattered fluences and is determined using a convolution of a distributed radiation source kernel with an exponential filter attenuation function. The attenuation coefficient is measured for the filter material (Lipowitz metal) and fit to a second-order polynomial in filter thickness and off-axis distance. The distributed source kernel is measured using a split-field technique and fit to a sum of three two-dimensional Gaussian distributions. The scattered radiation is modeled by the Klein-Nishina cross section. The algorithm is tested by comparing calculated fluences with measured fluences for a series of machined filters: an open field, flat filters of 9.6-, 15.8-, and 31.6-mm thickness, split-field filters, and a pyramid-shaped filter. In each case, the algorithm calculates the fluence to within 3% of the measured values over the entire irradiated field size to within 1.5 cm of the collimated field edges.

Algorithms↗
PubMed2006

Detection of Treponema pallidum in the vitreous by PCR.

BACKGROUND: Ocular involvement of syphilis still poses a clinical challenge due to the chameleonic behaviour of the disease. As the serodiagnosis has significant limitations, the direct detection of Treponema pallidum (TP) in the vitreous represents a desirable diagnostic tool. METHODS: Real-time polymerase chain reaction (PCR) for the detection of TP was applied in diagnostic vitrectomies of two patients with acute chorioretinitis. Qualitative verification of TP by real-time PCR and melting point analysis according to a modified protocol was ruled out. Patients underwent complete ophthalmological examination with fundus photographs, fluorescein angiography, serological examination, antibiotic treatment and follow-up. RESULTS: In two cases of acute chorioretinitis of unknown origin, real-time PCR of vitreous specimens of both patients provided evidence of TP and was 100% specific. Initial diagnosis of presumed viral retinitis was ruled out by PCR of vitreous specimen. Patients were treated with systemic antibiotics and showed prompt improvement in visual function and resolution of fundus lesions. CONCLUSIONS: With real-time PCR, detection of TP in the vitreous was possible and delivered a sensitive, quick and inexpensive answer to a disease rather difficult to assess. In cases of acute chorioretinitis, the use of PCR-based assays of vitreous specimens in the diagnostic evaluation of patients is advisable. Although syphilitic chorioretinitis is a rare disease, PCR should include search for TP, as diagnostic dilemmas prolong definitive treatment in a sight-threatening disease.

Adult↗
PubMed2004

Spatiotemporal motion boundary detection and motion boundary velocity estimation for tracking moving objects with a moving camera: a level sets PDEs approach with concurrent camera motion compensation.

The purpose of this study is to investigate a method of tracking moving objects with a moving camera. This method estimates simultaneously the motion induced by camera movement. The problem is formulated as a Bayesian motion-based partitioning problem in the spatiotemporal domain of the image quence. An energy functional is derived from the Bayesian formulation. The Euler-Lagrange descent equations determine imultaneously an estimate of the image motion field induced by camera motion and an estimate of the spatiotemporal motion undary surface. The Euler-Lagrange equation corresponding to the surface is expressed as a level-set partial differential equation for topology independence and numerically stable implementation. The method can be initialized simply and can track multiple objects with nonsimultaneous motions. Velocities on motion boundaries can be estimated from geometrical properties of the motion boundary. Several examples of experimental verification are given using synthetic and real-image sequences.

Algorithms↗
PubMed2002

Pharmacological applications of magnetic resonance imaging.

Magnetic resonance imaging (MRI) techniques are capable of spatial and temporal resolution and within subject repeatability that far exceed other currently available methods of noninvasively investigating brain functioning. While functional MRI (fMRI) techniques have traditionally been used to investigate sensory, motor, and cognitive functions, they are also very attractive for investigating the effects of pharmacological agents in the brain. However, because pharmacological agents may interfere with the very mechanisms that give rise to the fMRI signal, careful attention to experimental design and data analysis issues must be exercised. Specifically, introducing a drug into the system could potentially alter the coupling of neural activity with regional cerebral blood flow and/or the extraction of oxygen from blood, or may cause local or global cardiovascular changes unrelated to neural activity. These concerns notwithstanding, careful attention to experimental detail and verification procedures promises to make pharmacological MRI a valuable tool for understanding the actions of drugs on the brain at many levels. The physiological and biophysical bases of blood oxygen level-dependent, arterial spin labeling, cerebral blood flow, cerebral blood volume, and spectroscopy acquisition methods are presented to illustrate where confounds may arise when a drug is added to the system. Selected studies combining administration of pharmacological agents with MRI techniques are critically reviewed to illustrate both the challenges inherent in these applications and some possible solutions. Included are studies of acute direct effects of drugs, effects of drugs on task-related activation, chronic effects of drugs, effects of drugs on cerebral metabolism, and variable effects of drugs in different populations.

Animals↗
PubMed2005

Intraoperative functional MRI: implementation and preliminary experience.

For a non-invasive identification of eloquent brain areas in neurosurgical procedures up to now only preoperative functional brain mapping techniques are available. These are based, e.g., on preoperative functional magnetic resonance imaging (fMRI) investigations in awake patients. The aim of this study was to investigate the feasibility to perform fMRI during neurosurgical procedures in anesthetized patients. For that purpose, a passive stimulation paradigm with peripheral nerve stimulation was applied. A 1.5-T MR scanner placed in a radiofrequency-shielded operating room with an adapted operating table was used for intraoperative fMRI. The fMRI data were analyzed during acquisition by an online statistical evaluation package installed on the MR scanner console. In addition, phase reversal of somatosensory evoked potentials was used for verification of intraoperative fMRI. In four anesthetized patients with lesions in the vicinity of the central region a total of 11 fMRI measurements were successfully acquired and analyzed online. Activation was found in the somatosensory cortex, which could be confirmed by intraoperative phase reversal for each measurement. Furthermore, statistical parametric mapping (SPM) was employed for an extensive offline data analysis. We did not observe any neurological deterioration or complications due to the stimulation technique. Intraoperative fMRI is technically feasible allowing a real-time identification of eloquent brain areas despite brain shift.

Adult↗
PubMed1998

Low-level laser therapy in ankle sprains: a randomized clinical trial.

OBJECTIVE: To test the efficacy of low-level laser therapy on lateral ankle sprains as an addition to a standardized treatment regimen, a trial was conducted in which high-dose laser (5J/cm2), low-dose laser (0.5J/cm2), and placebo laser therapy (0J/cm2) at skin level were compared. DESIGN: Randomized, double-blind, controlled clinical trial with a follow-up of 1 year. Patients, therapists, assessors, and analysts were blinded to the assigned treatment. SETTING: An ambulatory care setting. PATIENTS: After informed consent and verification of exclusion criteria, 217 patients with acute lateral ankle sprains were randomized to three groups from September 1, 1993, through December 31, 1995. INTERVENTIONS: Twelve treatments of 904nm laser therapy in 4 weeks as an adjunct to a standardized treatment regimen of 4 weeks of brace therapy combined with standardized home exercises and advice. The laser therapy device used was a 904nm Ga-As laser, with 25-watt peak power and 5,000 or 500Hz frequency, a pulse duration of 200nsec, and an irradiated area of 1cm2. PRIMARY OUTCOME MEASURES: Pain and function as reported by the patient. RESULTS: Intention-to-treat analysis of the short-term results showed no statistically significant difference on the primary outcome measure, pain (p = .41), although the placebo group showed slightly less pain. Function was significantly better in the placebo group at 10 days (p = .01) and 14 days (p = .03) after randomization. The placebo group also performed significantly better on days of sick leave (p = .02) and at some points for hindrance in activities in daily life and pressure pain, as well as subjective recovery (p = .05). Intention-to-treat analysis showed that total days of absenteeism from work and sports were remarkably lower in the placebo group than in the laser groups, ranging from 3.7 to 5.3 and 6 to 8 days, respectively. The total number of relapses at 1 year in the low-dose laser group (n = 22) was significantly higher (p = .04) than in the other two groups (high laser, n = 13; placebo, n = 13). Subgroup analysis to correct for possible confounders did not alter these findings. CONCLUSIONS: Neither high- nor low-dose laser therapy is effective in the treatment of lateral ankle sprains.

Adult↗
PubMed1994

PEACH: A simulation model of reproductive and vegetative growth in peach trees.

The hypothesis that carbohydrate partitioning is driven by competition among individual plant organs, based on each organ's growth potential, was used to develop a simulation model of the carbon supply and demand for reproductive and vegetative growth in peach trees. In the model, photosynthetic carbon assimilation is simulated using daily minimum and maximum temperature and solar radiation as inputs. Carbohydrate is first partitioned to maintenance respiration, then to leaves, fruits, stems and branches, then to the trunk. Root activity is supported by residual carbohydrate after aboveground growth. Verification of the model was carried out with field data from trees that were thinned at different times. In general, the model predictions corresponded to field data for fruit and vegetative growth. The model predicted that resource availability limited fruit and stem growth during two periods of fruit growth, periods that had been identified in earlier experimental studies as resource-limited growth periods. The model also predicted that there were two periods of high carbohydrate availability for root activity. The fit between model predictions and field data supports the initial hypothesis that plants function as collections of semiautonomous, interacting organs that compete for resources based on their growth potentials.

Journal Article↗
PubMed2001

High surface density immobilization of oligonucleotide on silicon.

Oligonucleotide (11-mer) molecules are immobilized on silicon in high surface population using either a permanent thioether bond or a chemo-selectively reversible disulfide bond to the surface thiol functionality. Substrate hydroxy groups are first silanized with an 11 carbon trichlorosilane containing a terminal, protected thiol moiety. Oligonucleotide modified with a tether possessing a terminal thiol group is further derivatized with a water-soluble, halobenzylic bifunctional reagent, which allows the complete conjugate to be attached to the surface through a permanent thioether bond. Alternatively, the oligonucleotide-tether complex can be combined with a pyridyldisulfide compound, which, in turn, facilitates the formation of a reversible disulfide bond with surface thiol. The amount of immobilized oligonucleotide was determined by radiochemical labeling with 32P. Additional verification of surface amounts was obtained from X-ray photoelectron spectroscopic analysis of substrates. The results of the immobilization protocols are compared with the oligonucleotide surface population achieved through the conventional silanizing agent, mercaptopropyltrimethoxysilane. Finally, a preliminary confirmation of duplex formation of a TTU-attached 25-mer with its complementary strand is outlined.

Journal Article↗
PubMed2003

[Physical simulation of human body metabolism in sealed module on the ground].

OBJECTIVE: To provide a test platform for experimental verification of environmental control and life support system (ECLSS) of manned spacecraft on the ground. METHOD: According to characters of ECLSS ground simulation test, simulation of human body metabolism was divided into different units, and a ground metabolic simulator was designed. RESULT: The ground metabolic simulator accurately simulated human body metabolic oxygen consumption, carbon dioxide production, water and heat productions in the sealed module. CONCLUSION: The physical method for simulating human body metabolism is feasible and has the advantages of high precision and easiness of control. It can be used for verifying and appraising the function of ECLSS.

Carbon Dioxide↗
PubMed2002

Verification of the chemical composition and specifications of haemodialysis membranes by NMR and GPC-FTIR-coupled spectroscopy.

The chemical composition of a dialysis membrane is decisive towards determining its physical and biochemical properties--two fundamental determinants of the success of therapy offered to patients suffering from chronic renal failure. From the vast variety of synthetic polymers available, only a few are suitable for the manufacture of dialysis membranes that have to conform to the diverse demands of modern haemodialysis and related therapies. Recently, a membrane labelled as polyamide (Polyamide S) has caused some confusion to end-users in that the product specification for the membrane is given as 'polyarylethersulfone' or simply as Polyamide S membrane. As the chemical and physical properties of these two polymer types are distinctly different, it is unclear whether the functional characteristics of Polyamide S are to be attributed to polyamide, polyarylethersulfone, or, to both polymers. We therefore undertook investigations to ascertain the exact chemical nature of the Polyamide S membrane using a series of chemical analytical tools and an appropriate polyamide reference. The analytical techniques were conventional gel permeation chromatography (GPC), GPC-FTIR coupled spectroscopy using dimethyl acetamide and hexafluoroisopropanol as solvents and nuclear magnetic resonance spectroscopy. Glass transition temperature measurements and quantitative elemental analysis were also carried out. None of the analytical techniques used showed any traces of polyamide in Polyamide S; no aliphatic or aromatic polyamide chemical entities were detected in any of the samples tested. The Polyamide S dialysis membrane thus comprises, solely, of polyarylethersulfone, which is also known as polyethersulfone.

Biocompatible Materials↗