Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A reproducible and sensitive radioimmunoassay (RIA) was developed to measure ANF in human plasma. Immunoreactive ANF was extracted from plasma with Sep-Pak cartridges, using 0.2% ammonium acetate (pH 4) with acetonitrile. The sensitivity of the assay was 3.9 pg/ml. The coefficient of variance for inter-assay and intra-assay was 16.8% and 6.8%, respectively. In normal healthy subjects (n = 67), ANF content was 11.9 +/- 1.3 pg/ml (mean +/- SEM). Significantly-higher ANF concentrations were found in proximal coronary sinus blood, being 6 to 37 times greater than in the peripheral circulation. Comparison of the prior extraction method with direct RIA revealed a good correlation (r = 91) in samples containing higher than 100 pg/ml ANF. No correlation was observed with lower values. The elution profiles of reverse-phase HPLC of peripheral and coronary sinus plasma extracts were similar but somewhat complex, with the main immunoreactive peak corresponding to a low-molecular-weight peptide.
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PMID:Atrial natriuretic factor in human plasma. 294 52

In this simple, reliable assay for quantifying caffeine in plasma and tissues, methylxanthines are first partly purified from plasma and acid extracts of tissue by passage through solid-phase columns. The ease of this extraction method permits a relatively large number of samples to be processed daily. Quantification is by reversed-phase high-pressure liquid chromatography (mobile phase: acetic acid/acetonitrile/water, 2/6/92 by vol). Caffeine is eluted in 20 min. The reliability of this method allows its automation. This method has been adapted to measure caffeine in brain and kidney extracts and in as little as 10 microL of plasma. After 10 days of oral administration of caffeine (1 g/L, in drinking water) to six rats, the mean (+/- SEM) concentrations of caffeine in plasma, brain, and kidney were 18.6 +/- 6.0 micrograms/mL, 16.2 +/- 1.5 micrograms/g, and 18.9 +/- 2.0 micrograms/g, respectively. Correlations were linear between concentrations of caffeine in plasma and brain (r = 0.86) and between concentrations in plasma and kidney (r = 0.91). This method should be useful in studying the effects and mechanisms of actions of methylxanthines.
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PMID:A simple liquid-chromatographic method applied to determine caffeine in plasma and tissues. 318 Apr 32

An isocratic HPLC system has been developed which allows for the rapid (single run of 20 min) measurement of creatine phosphate (PCr) and adenine nucleotides (ATP, ADP and AMP) in extracts from freeze-clamped and freeze-dried myocardial tissues. The separation was achieved at room temperature by using a RP18 column and a dual variable wavelength spectrophotometer, set at 210 and 254 nm. The solvent was 30 mM potassium dihydrogen phosphate, 15 mM tetrabutylammonium hydrogen sulfate, pH 6.7, 19% (v/v) acetonitrile. A distinct separation (confirmed with the retention time of standard sample) of these high energy compounds was achieved. Standard curves were linear. In isolated rat hearts the following values were obtained (mumol/g dry wt, mean +/- SEM): ATP 21.5 +/- 1.3, ADP 4.6 +/- 0.2, AMP 1.5 +/- 1.1 and PCr 32.5 +/- 1.3; which are consistent with previously published values for high energy compounds in this tissue.
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PMID:Simultaneous determination of myocardial creatine phosphate and adenine nucleotides by reversed-phase HPLC. 350 28

Epidermal growth factor-like activity (EGF-LA) has been detected in human seminal plasma in concentrations of 5-150 ngeq/ml (36.4 +/- 2.1, mean +/- SEM), using a heterologous RRA with murine EGF. The samples were obtained from normal, subfertile and azoospermic men, aged 21-50 yr. No correlation was found between EGF concentration and age of donor, sperm count, sperm motility, or period of sexual abstinence before sample collection. High performance liquid chromatography of the seminal plasma resulted in a main peak of EGF-LA which eluted at 29% acetonitrile, compared to 33% for murine EGF. Microsomal membranes were prepared from several tissues from the human male reproductive tract and were tested for their ability to bind radioiodinated murine EGF. Specific EGF binding activity was detectable in testicular membrane preparations but was not detectable in membranes prepared from human prostate, seminal vesicle, epididymis, or spermatozoa. Endogenous EGF-LA was detectable in human testis, seminal vesicle, prostate, and epididymis.
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PMID:Identification of epidermal growth factor-like activity in human male reproductive tissues and fluids. 632 31

We describe a "high-performance" liquid-chromatographic method for measuring picogram amounts of norepinephrine and epinephrine simultaneously in human plasma. Alumina-treated samples are injected onto a strong cation-exchange column (Zipax SCX) for the separation of catecholamines, with a sodium phosphate buffer/acetonitrile mixture as mobile phase. The separated catecholamines then enter a continuous-flow system and the reagents for the trihydroxyindole reaction are added sequentially; the fluorescent products are then measured with a spectrofluorophotometer. Analytical recoveries from plasma averaged 66% for norepinephrine, 68% for epinephrine. Amount and response (peak height) were linearly related up to 1000 pg. For catecholamines in human plasma, within-run and day-to-day CV's were 0.2% and 1.0%, respectively, for norepinephrine, and 0.3% and 0.9%, respectively, for epinephrine. Average values for norepinephrine and epinephrine in apparently normal human plasma were 185 +/- 29 ng/L and 32 +/- 8 ng/L, respectively (mean +/- SEM, n = 10). This relatively rapid and highly sensitive system is suitable for routine use.
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PMID:Liquid-chromatographic determination of norepinephrine and epinephrine in human plasma. 735 64

We developed and validated a RIA for measuring serum activin A. The least detectable value of this assay was 0.1 micrograms/L, and the antibody used cross-reacted slightly with bovine inhibin (3.2%) and porcine activin AB (10.0%) but not with porcine activin B (< 0.5%). Serum activin A was extracted with acetonitrile and trifluoroacetic acid to get rid of the interaction with possible binding proteins in serum. As a result of this extraction procedure, the dose-response curve of serum extract was parallel to the standard curve and a single immunoreactive (ir-) peak was demonstrated on gel chromatographic analysis with constant recovery rates over 80%. Serum ir-activin A level in healthy adults was 1.27 +/- 0.03 micrograms/L (mean +/- SEM, n = 180); being 1.38 +/- 0.05 micrograms/L (n = 90) in male, and 1.16 +/- 0.05 micrograms/L (n = 90) in female subjects, with a tendency to increase with age. Serum ir-activin A level during pregnancy showed a marked increase with the advance of gestation; 1.65 +/- 0.41 micrograms/L (n = 7) in the early, 4.50 +/- 1.13 micrograms/L (n = 21) in the middle, and 16.32 +/- 2.25 micrograms/L (n = 26) in the late trimester, with a rapid decline after delivery. On the other hand, serum ir-activin A level was elevated in patients with hyperthyroidism (1.91 +/- 0.37 micrograms/L, n = 31), liver cirrhosis (2.03 +/- 0.71 micrograms/L, n = 10), chronic renal failure (3.41 +/- 0.34 micrograms/L, n = 41), and advanced solid cancer (2.24 +/- 0.52 micrograms/L, n = 67). These findings indicate that serum ir-activin A level varies with physiological conditions such as aging and pregnancy, and that it may reflect the altered production and metabolism of activin A in certain diseased conditions.
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PMID:Serum immunoreactive activin A levels in normal subjects and patients with various diseases. 896 39

A high-performance liquid chromatography (HPLC) method was developed for the simultaneous analysis of trimethoprim (TMP), sulphamethoxazole (SMX), and acetylsulphamethoxazole (AcSMX) in small amounts of blood. The method involved precipitation with 50 microL trichloracetic acid (1M) to 125 microL plasma or serum sample. 60 microL supernatant was added to 60 microL mobile phase, modified with 50microL 1 M sodium hydroxide/mL. The mobile phase consisted of 20% acetonitrile and 80% phosphate buffer adjusted to pH 6.15. Using 125 microL of the sample, limits of quantitation were 0.1 microg/mL for TMP, 1.0 microg/mL for SMX, and 1.0 microg/mL for AcSMX. The precision of the method was 2% to 11% over the range of concentrations tested, 0.5-30 microg/mL for TMP, 5-300 microg/mL for SMX, and 2.5-150 microg/mL for AcSMX, respectively. No interference with other commonly used drugs was observed. The method is rapid, simple, specific, and sensitive enough for pharmacokinetic studies. The small amount of blood required makes it suitable for pediatric patients. The method was used to analyze samples from Tanzanian children aged 6-59 months participating in a cotrimoxazole (TMP/SMX)/chloroquine randomized trial for the treatment of uncomplicated malaria. Venous blood samples from 68 children were collected 2 hours after the first dose of TMP/SMX (4 mg/kg TMP/20 mg/kg SMX at two divided doses for 5 days) and again at treatment day 4. Individual variations in plasma concentrations of TMP, SMX, and AcSMX were considerable. The mean and SEM plasma concentrations (g/mL) of TMP, SMX, and AcSMX 2 hours after the first treatment dose were 2.0 +/- 1.0 (range 0.5-6), 53 +/- 22 (range 24-146), and 13.5 +/- 12 (range 0-65), respectively. On the fourth day the attained plasma concentrations were not significantly different from samples collected after the first dose.
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PMID:A reversed-phase high-performance liquid chromatography method for the determination of cotrimoxazole (trimethoprim/ sulphamethoxazole) in children treated for malaria. 1060 20

Diclazuril (4-chlorophenyl [2,6-dichloro-4-(4,5-dihydro-3H-3,5-dioxo-1,2,4-triazin-2-yl)pheny l] acetonitrile), is a benzeneacetonitrile antiprotozoal agent (Janssen Research Compound R 64433) marketed as Clinacox . Diclazuril may have clinical application in the treatment of Equine Protozoal Myeloencephalitis (EPM). To evaluate its bioavailability and preliminary pharmacokinetics in the horse we developed a sensitive quantitative high-pressure liquid chromatography (HPLC) method for diclazuril in equine biological fluids. MS/MS analysis of diclazuril in our HPLC solvent yielded mass spectral data consistent with the presence of diclazuril. After a single oral dose of diclazuril at 2.5 g/450 kg (as 500 g Clinacox), plasma samples from four horses showed good plasma concentrations of diclazuril which peaked at 1.077 +/- 0.174 microg/mL (mean +/- SEM) with an apparent plasma half-life of about 43 h. When this dose of Clinacox was administered daily for 21 days to two horses, mean steady state plasma concentrations of 7-9 microg/mL were attained. Steady-state levels in the CSF ranged between 100 and 250 ng/mL. There was no detectable parent diclazuril in the urine samples of dosed horses by HPLC or by routine postrace thin layer chromatography (TLC). These results show that diclazuril is absorbed after oral administration and attains steady-state concentrations in plasma and CSF. The steady state concentrations attained in CSF are more than sufficient to interfere with Sarcocystis neurona, whose proliferation is reportedly 95% inhibited by concentrations of diclazuril as low as 1 ng/mL. These results are therefore entirely consistent with and support the reported clinical efficacy of diclazuril in the treatment of clinical cases of EPM.
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PMID:Diclazuril in the horse: its identification and detection and preliminary pharmacokinetics. 1065 66

This paper describes a new iodine-125 radioimmunoassay of 9alpha ,11beta-PGF2, and its use for the determination of urinary 9alpha,11beta-prostaglandin F2 after a selective one-step solid-phase extraction. The newly reported immunoassay is based on the use of 125I-tyrosyl methyl ester derivative of 9alpha,11beta-PGF2 and specific polyclonal antibody raised in rabbits. The assay detected as lowas 0.85 pg/tube 9alpha,11beta-PGF2, and the antibodyshowed lessthan 0.01 cross-reaction with PGF-ring metabolites (e.g., 8-iso-PGF2alpha, PGF2alpha 2,3-dinor-6-keto-PGF1alpha, and 5 more PGF-ring compounds). Both the intra-assay, and inter-assay CVs were lessthan 20% for internal controls containing low, medium and high concentrations of 9alpha,11beta-PGF2. Immuno-HPLC analysis showed a very low ratio of specific immunoreactivity in both non-extracted urine (6.5%), and in urine extracted on C18-silicacartridge (14.8%). By contrast, approximately 80% specific immunoreactivity could be achieved by using C2-silicaas the sorbent, acetonitrile: water (15:85, v/v) as wash solvent, and ethyl acetate as eluent of 9alpha,11beta-PGF2. This extraction procedure enabled a reasonably high extraction efficiency of 80.4 +/- 0.855 (mean +/- SEM, n=82), as determined by 3H-9alpha,11beta-PGF2. The new SPE/RIA method was applied for the determination of urinary 9alpha,11beta-PGF2 values in 50 healthy human volunteers. For the concentration and for the excretion rate 37.52 +/- 4.61 pg/ml (mean +/- SEM), and 3.50 + 0.35 ng/mmol creatinine (mean +/- SEM), respectively, was measured. The specificity of the SPE/RIA method was supported by the observed 69% decrease in 9alpha, 11beta-PGF2 excretion rate after acetylsalicylic acid treatment. The effect of nicotinic acid, a PGD2-stimulatory agent, was monitored by the urinary excretion of 9alpha ,11beta-PGF2 in 6 patients, by using the new SPE/RIA method. In patients responding with flushing symptoms nicotinic acid induced an increase of the urinary excretion of 9alpha,11beta-PGF2 in the range between 11% and 187%. In summary, the combination of the newly developed specific [125I] radioimmunoassay with solid-phase extraction on C2-silica cartridges enables the specific, sensitive, and reliable determination of 9alpha,11beta-PGF2 in human urine without the need for further laborious chromatographic purification before radioimmunoassay.
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PMID:Determination of 9alpha, 11beta prostaglandin F2 in human urine. combination of solid-phase extraction and radioimmunoassay. 1199 20

Angiotensin II (ANG II) was identified immunocytochemically and biochemically in biopsy samples of human nasal tissue. Staining for ANG II was predominantly found in structures similar to a string of pearls with consecutive short varicose areas, which is characteristic for neuronal tissue. The localization of ANG II in neurons was confirmed by positive staining of adjacent tissue sections with a specific antibody to neurofilament or doublestaining with both antibodies in one section. Likewise, ANG II-like material was also determined radioimmunologically in nasal tissue extracts. The concentrations of ANG II varied form 1.28 to 332.78 fmol/g wet tissue weight with an average concentration of 79.61+/-44.09 fmol ANG II/g wet tissue weight (mean+/-SEM, n=7). The ANG II-immunoreactive material was further characterized biochemically by HPLC on a reversed phase C(18) column in an acetonitrile and methanol gradient as Ile(5)-ANG II and ANG II metabolites such as Ile(4)-ANG III, Ile(3)-ANG II(3-8)hexapeptide and Ile(2)-ANG II(4-8)pentapeptide.
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PMID:Immunocytochemical and biochemical identification of angiotensin II in human nasal tissue. 1213 61


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