Seasonal variations of basal metabolism and body fluid.
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A new fully automated high-performance liquid chromatography is described which detects drugs from directly injected plasma (urine, saliva) without sample pretreatment. The apparatus consists of a programmable automatic sampling unit, which is connected via two alternating working pre-columns to an analytical column ("alternating pre-column sample enrichment"). The new device is able to operate with directly injected body fluids like an auto-analyzer and is especially useful for pharmacokinetic and clinical studies, where drug concentrations have to be determined from plasma, urine or saliva.
23Na longitudinal and transverse NMR relaxation times were measured in human serum, plasma, cerebrospinal fluid (CSF), and solutions of plasma proteins. The magnetization decay curves could not be resolved into two exponentials. A procedure to extract quantitative information from the measured relaxation rates in such a case was developed. The relaxation times of 23Na in serum and plasma were analyzed in terms of the different contributions from free Na+, Na+ bound to small molecules, and Na+ bound to various protein fractions in these body fluids. While T1 is essentially that of free Na+ in a solution which is slightly more viscous than salt solution, T2 is influenced by binding to proteins with the largest contribution from serum albumin. The effect of binding to small molecules on T1 and T2 is negligible. From measurements of the relaxation times at several magnetic field strengths a rotational correlation time of Na+ bound to serum albumin of 16 +/- 6 ns was obtained. The fraction of bound Na+ in serum and plasma was roughly estimated as 0.02% of the total sodium. The relaxation times in cerebrospinal fluid are very similar to those of NaCl solution.
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The weak correlation between inflammatory activity and disease progression in patients with multiple sclerosis has shifted the emphasis from inflammatory monitoring to the investigation of the pathological processes of demyelination, axonal loss, and gliosis. New magnetic resonance imaging (MRI) techniques that have been developed to measure these processes appear very promising. This paper will briefly discuss potential body fluid markers of axonal loss, gliosis and demyelination, as the pathological substrates of brain atrophy, their function and the principles behind their future study in patients with multiple sclerosis.
Hydroxyapatite (HAp) coatings engineered for maximum surface roughness (coating type I), porosity (coating type II), and tensile adhesion strength (coating type III) were deposited by atmospheric plasma spraying (APS) onto Ti6Al4V substrates and characterized for their microstructure, phase composition, and design properties. The composition of the as-sprayed coatings changed during treatment with protein-free simulated body fluid (Hank's Balanced Salt Solution, HBSS) for up to 12 weeks by preferential dissolution of thermal decomposition products, and amorphous calcium phosphate (ACP). From solutions supersaturated with respect to calcium and phosphorus ions, a thin, very porous layer precipitated onto the leached surfaces of coating type II samples after an incubation time of 8 weeks, consisting of spherical agglomerates of a poorly crystallized bone-like Ca-deficient defect hydroxyapatite that is thought to accelerate in vivo bone apposition rates and, hence, may induce favorable osseoconductive conditions.
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Drug concentrations in biological fluids are affected by the dose, route of administration, pattern of drug use, and the dispositional kinetics (distribution, metabolism, and excretion) of the drug. As most drugs are distributed to the site of action by blood, drug concentration measurement in this body fluid provides the best information as to the potential effect on behavior such as driving impairment or on psychological high. Due to wide individual variations in the pharmacokinetics and pharmacodynamics of drugs, however, the use of plasma drug concentrations for the estimation of impairment has not been established for most drugs. As for urinalysis, drug concentrations in the urine are further complicated by other factors such as urine flow and pH. Even if a specific method is used for the quantitation of a specific drug (the active species, not the inactive metabolite), interpretation in forensic samples to predict time of drug use or impairment is not possible, except within broad time periods, because of the variations in urine drug concentration as well as the limited knowledge available about the dose or the route of administration.
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We developed an ELISA for human serum MASP-1, a C1s-like serine protease which is known to function in C4 and C2 activation. We then determined MASP-1 levels in 1063 sera from normal Japanese subjects ranging in age from 3 to 100 years, as well as in certain body fluids using this assay. Individual serum MASP-1 levels ranged from 1.48 to 12.83 microg/ml, with a normal frequency distribution pattern. The arithmetic mean +/- s.d. of MASP-1 levels in serum was 6.27 +/- 1.85 microg/ml, whereas levels of MASP-1 in cerebrospinal fluid and in urine were almost undetectable. When the mean +/- s.d. of serum MASP-1 was calculated for each age group (10 year range) and values were then compared, the age group consisting of 3-9-year-olds (7.54 +/- 1.39 microg/ml) was found to have the highest value. When MASP-1 was measured in cord blood, it was shown that levels were already as high as those of 3-9-year-olds. The serum MASP-1 level was found to be as strongly dependent on age as is the serum MBL level. MASP-1 and MBL are thought to play an active part in immunity in younger people. It was found that the serum level of MASP-1 was much higher than that of MBL, and the major portion of human serum MASP-1 appeared to exist in the circulation as a form unbound to MBL.
Magnetron co-sputtering was used to produce silicon-doped hydroxyapatite (Si-HA) as coatings intended for potential applications such as orthopedic and dental implants. It was found that the crystallinity of the as-sputtered coatings increased after annealing, resulting in a nanocrystalline apatite structure. Subsequently, the bioactivity of the coatings was evaluated in an acellular simulated body fluid (SBF). Physicochemical evaluation demonstrated that a carbonate-containing apatite layer, which is essential for bonding at the bone/implant interface, was formed on the coating surfaces after immersion in SBF between 4 and 7 days. The annealed coatings exhibited enhanced bioactivity and chemical stability under physiological conditions, as compared with the as-sputtered coatings. It is proposed that the rate at which the carbonate-containing apatite layer forms is dependent on the scale factor of the structure. A nanocrystalline structure can provide a higher number of nucleation sites for the formation of apatite crystallites, leading to a more rapid precipitation of carbonate-containing apatite layer. This work shows that Si-HA coatings offer considerable potential for applications in hard tissue replacement, owing to their ability to form a carbonate-containing apatite layer rapidly.
We describe the precision and accuracy of a liquid chromatographic method, which uses internal standards, 6-fluoroserotonin and 5-hydroxyindolecarboxylic acid, in quantitating serotonin and 5-hydroxyindoleacetic acid in human cerebrospinal fluid, plasma and urine. In addition, 5-hydroxytryptophan is measured in the cerebrospinal fluid. The limit of sensitivity of this method is 0.1 pmol/injection, the peak height/concentration ratio is linear in the concentration range of 0.1 pmol to 50 mumol/injection, and the coefficient of variation is of the order of 15% at the limit of sensitivity and below 10% at amounts above 0.5 pmol/injection. No endogenous monoamines or their metabolites interfere with the quantitation of the substances of interest in the body fluids studied.
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