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At least 1,351 records · Page 75Linked to original sources
PubMed1989

Assay of factor XII in human plasma using prekallikrein or the chromogenic peptide S-2222 as substrates--significance of the functional state of plasma kallikrein.

Factor XII was assayed in acetone-treated and kaolin-activated human citrated plasma (total plasma dilution 1.0 + 0.3 v/v during activation with kaolin, 1.8 mg/ml incubate). Measurements were performed with the tetrapeptide Bz-Ile-Glu-Gly-Arg-pNa (S-2222) and with prekallikrein as substrates. The correlation of both methods to another S-2222 based method recently described was good, r = 0.90 and 0.85 for the two methods respectively. Under the assay conditions used, FXIIa was present as a S-2222 amidase that could be blocked by corn inhibitor, whereas plasma kallikrein was found to be present partly as an amidase blocked by a low concentration of soybean trypsin inhibitor, and partly in a functional state not inhibited and adding to the measured level of FXII. The presence of benzamidine 0.7 to 2.1 mM during acetone treatment increased the measured level of FXII assayed both as prekallikrein activator and as S-2222 amidase.

Buffers↗
PubMed1989

A new assay for the determination of factor XII in plasma using a chromogenic substrate and a selective inhibitor of plasma kallikrein.

A new chromogenic assay for factor XII in plasma was designed by the use of the soluble activator Kalliplastin, the substrate H-D-HHT-Gly-Arg-pNA and a synthetic inhibitor of plasma kallikrein (Pefabloc PK). The assay was carried out in one and the same cuvette and did not require factor XII-deficient plasma. There was a good correlation between F XII coagulant and amidolytic assays.

Benzamidines↗
PubMed1977

Correlation between increased bronchial responsiveness to histamine and diminished plasma cyclic adenosine monophosphate response after epinephrine in asthmatic children. Diminished plasma cyclic adenosine monophosphate response after epinephrine in moderate childhood asthma.

The respiratory threshold to histamine and the plasma cyclic adenosine monophosphate (AMP) every 5 min for 40 min after subcutaneous epinephrine were determined in 21 children with moderate bronchial asthma who were without symptoms at the time of study. There was a statistically significant correlation between a high respiratory sensitivity to histamine and a low plasma cyclic AMP response to epinephrine. The plasma cyclic AMP response was compared with that in 16 control subjects. The asthmatic patients had significantly diminished responses; the difference was greatest for the values 25 min after stimulation. This study supports the hypotheses that the bronchial hyperresponsiveness in asthma is due partly to a defective beta adrenergic system and that the defect is permanent, existing also during periods without symptoms or medication and in patients with moderate asthma.

Adolescent↗
PubMed1982

Biomedical applications of plasma polymerization and plasma treatment of polymer surfaces.

Thin polymer films obtained by plasma polymerization usually show good biocompatibility when compared to classical biomaterials such as Silastic. The thickness of these films (from several hundreds of A to several micrometers) make them suitable for the purpose of changing the surface properties of the substrate without altering its bulk properties. Both the above features together indicate the possible biomedical use of plasma polymerization as well as plasma treatment of polymer surfaces processes. The purpose of this review is to present the most significant efforts to develop such applications with the specification of particular fields where these efforts are directed.

Animals↗
PubMed1986

Role of renal nerve activity, plasma catecholamines and plasma vasopressin in cardiovascular responses to intracisternal neurotoxins in the rabbit.

We have examined the acute (0-3 h) effect of intracisternally administered 5,7-dihydroxytryptamine (DHT) and 6-hydroxydopamine (6-OHDA) on blood pressure, heart rate, renal nerve activity, plasma adrenaline, plasma noradrenaline and plasma vasopressin in conscious rabbits. The increase in blood pressure seen following 5,7-DHT treatment was associated with increases in adrenaline and vasopressin levels and renal nerve activity throughout the response. The increase in blood pressure which followed 6-OHDA administration was associated with an increase in renal nerve activity alone. These findings indicate that the rise in blood pressure elicited by these drugs involves an increase in sympathetic nerve activity. The absence of a rise in vasopressin levels during the response to 6-OHDA suggests that the rise in blood pressure seen in these animals is due entirely to a bulbospinal sympathoexcitatory pathway.

5,6-Dihydroxytryptamine↗
PubMed1979

Esterification of cholesterol in fish plasma: studies on the cholesterol esterifying enzyme in plasma of char (Salmo alpinus L.).

1. Plasma of sea char (Salmo alpinus L.) has the ability to esterify cholesterol in vitro. Heat inactivation of the plasma totally inhibited the esterification. 2. Arrhenius plot of the esterification of [3H]cholesterol was linear in the temperature range 5-35 degrees C. 3. Cholesterol esterification in sea char plasma could not be reversibly inhibited by sulphydryl-blocking agents. Total equilibration of the added [3H]cholesterol and the endogenous cholesterol could therefore not be obtained. 4. Comparison of esterification of endogenous and labelled cholesterol revealed that the isotopic method was valid only in qualitative measurements.

Animals↗
PubMed1991

Fully automated high-performance liquid chromatographic analysis of whole blood and plasma samples using on-line dialysis as sample preparation. Determination of oxytetracycline in bovine and salmon whole blood and plasma.

A fully automated technique for high-performance liquid chromatographic analysis of whole blood and plasma is described. Samples are automatically injected into a dialyser where proteins and blood cells are removed. The dialysates are concentrated on a small column prior to analysis. This technique is used for the determination of oxytetracycline in whole blood and plasma. After dialysis oxytetracycline and the internal standard, tetracycline, are retained on a polystyrene enrichment column and subsequently separated on a polystyrene analytical column by ion-pair chromatography. Using ultraviolet detection 50 ng/ml can be detected. Validation showed good within-day and between-day accuracy and precision. Different oxytetracycline concentrations were found in plasma and whole blood. This difference varied between the species.

Animals↗
PubMed1995

An automated liquid chromatographic plasma analysis of amino acids used in combination with positron emission tomography (PET) for determination of in vivo plasma kinetics.

Quantification of physiological processes measured with positron emission tomography (PET) requires an "input" function which can be the concentration of administered radio-tracer in plasma. Radioactive nuclides used in PET have short half lives (2-20 min) and a limited time is available for the PET investigation including analysis of the composition of the radioactive signal in plasma. Therefore, an automated method for the analysis and separation of beta-[11C]-L-5-hydroxy-tryptophan ([11C]-L-5-HTP), beta-[11C]-L-3,4-dihydroxy-phenylalanine ([11C]-L-DOPA) and L-[methyl-11C]-methionine and their respective metabolites in plasma was developed. A size exclusion exclusion column was used for isolation of the low molecular weight fraction. In the case of [11C]-L-5-HTP and [11C]-L-DOPA, the low molecular weight fraction was injected onto a liquid chromatographic system for separation of radioactive tracer from in vivo formed radio-labelled metabolites. The elution volume from the size exclusion column was 7.0, 5.0 and 3.5 ml for [11C]-L-5-HTP, [11C]-L-DOPA and L-[methyl-11C]-methionine, respectively. An interaction with the column matrix and the solutes was observed for both [11C]-L-5-HTP and [11C]-L-DOPA. The yield in the isolation step was > 98%. Separation of [11C]-L-5-HTP and [11C]-L-DOPA from their respective metabolites was performed with high-performance liquid chromatography with automated collection of fractions of the eluate corresponding to those of administered tracer and metabolites. The fractions were measured for radioactivity in a well counter.(ABSTRACT TRUNCATED AT 250 WORDS)

5-Hydroxytryptophan↗
PubMed1996

Diet and plasma lipids in women. I. Macronutrients and plasma total and low-density lipoprotein cholesterol in women: the Framingham nutrition studies.

This study examined relationships between diet and plasma total and LDL cholesterol levels in a population-based sample of 695 premenopausal and 727 postmenopausal women participating in the Framingham Offspring/Spouse Study. Regression analyses controlled for age, caloric intake, apolipoprotein E isoform type, estrogen use, and important CVD risk factors indicated that plasma total and LDL-cholesterol levels were directly associated with consumption of saturated fat and inversely associated with total calorie intake. In contrast, dietary cholesterol was not a predictor of plasma total or LDL cholesterol levels. Total cholesterol levels were also directly associated with total fat, oleic acid, and animal fat, and inversely associated with carbohydrate intake. Stepwise regressions with key nutrients indicated that saturated fat was consistently associated with total and LDL cholesterol levels in Framingham women. These analyses suggest that diet explains 2% of the variability in these lipid levels in a cross-sectional sample of women; the full model explains 22-27%.

Adult↗
PubMed1996

Diet and plasma lipids in women. II. Macronutrients and plasma triglycerides, high-density lipoprotein, and the ratio of total to high-density lipoprotein cholesterol in women: the Framingham nutrition studies.

This study examined relationships between macronutrients and plasma triglycerides, HDL, and the total-to-HDL cholesterol ratio (T/H ratio) in a population-based sample of 695 premenopausal and 727 postmenopausal women participating in the Framingham Offspring/Spouse Study. Multivariate regression analyses revealed that plasma triglycerides were inversely related to protein, fiber, and polyunsaturated fat and directly related to saturated fat and oleic acid. Alcohol intake was directly related to HDL cholesterol and inversely related to the T/H ratio in all subgroups of women, except for postmenopausal women with the 3/2 or 2/2 apolipoprotein E phenotype. Similarly, a direct relationship between dietary fat and HDL cholesterol was limited to this single subgroup of postmenopausal women. Since dietary fat and alcohol do not appear to have consistent effects on plasma lipids in all groups of women, it is important to consider the genetic contribution to diet/lipid relationships in epidemiological studies and when evaluating lipid-lowering interventions.

Adult↗
PubMed2004

Changes in drug plasma concentrations of an extensively bound and highly extracted drug, propofol, in response to altered plasma binding.

OBJECTIVE: Cardiopulmonary bypass is known to result in a reduction in the plasma binding of drugs. The resulting effect on the hepatic clearance of drugs with low extraction is well understood. However, the situation with those that are highly extracted is less clear. Studies were, therefore, undertaken with one such drug, propofol, for which plasma binding was changed during cardiac surgery with cardiopulmonary bypass. METHODS: After induction of anesthesia with midazolam in 19 patients, propofol was infused continuously at a rate of 4 mg. kg(-1). h(-1) during surgery. Propofol's concentration was measured by HPLC in blood samples collected from the radial artery and hepatic vein during surgery at predetermined intervals. The drug's unbound fraction in arterial plasma was estimated via equilibrium dialysis. RESULTS: The total concentration of propofol in blood was unchanged during surgery except shortly after the initiation of cardiopulmonary bypass. By contrast, the fraction of unbound propofol in blood increased by 2-fold during cardiopulmonary bypass and then decreased after the completion of cardiopulmonary bypass. The hepatic extraction ratio of propofol was greater than 0.8 and remained constant throughout surgery. The ratio of propofol concentration in erythrocytes to that in blood increased by 1.6-fold during cardiopulmonary bypass. CONCLUSIONS: During cardiopulmonary bypass, a significant increase in the concentration of unbound propofol occurred without alteration in the total propofol concentration in blood. The effect of the changes of propofol's protein binding on its kinetics was consistent with the predictions based on the well-stirred model of hepatic elimination for an intravenously infused high-clearance drug. Our finding on propofol pharmacokinetics may be the first example demonstrating the theoretic prediction of the well-stirred model.

Adult↗
PubMed2005

Almonds in the diet simultaneously improve plasma alpha-tocopherol concentrations and reduce plasma lipids.

The objective of this study was to assess the dose-response effect of almond intake on plasma and red blood cell tocopherol concentrations in healthy adults enrolled in a randomized, crossover feeding trial. Participants were 16 healthy men and women, aged 41+/-13 years. After a 2-week run-in period, participants were fed three diets for 4 weeks each: a control diet, a low-almond diet, and a high-almond diet, in which almonds contributed 0%, 10%, and 20% of total energy, respectively. Changes in blood tocopherol levels were assayed by high pressure liquid chromatography. Incorporating almonds into the diet helped meet the revised Recommended Dietary Allowance of 15 mg/day alpha-tocopherol and increased lipid-adjusted plasma and red blood cell alpha-tocopherol concentrations. A significant dose-response effect was observed between percent energy in the diet from almonds and plasma ratio of alpha-tocopherol to total cholesterol.

Adult↗
PubMed2004

Development and validation of a chiral liquid chromatographic method, based on Chiralpak to quantify enantiomers of (+/-)-DRF 2725 in rat plasma: lack of inversion of ragaglitazar (S(-)-DRF 2725) to its antipode in plasma.

A selective, accurate and reproducible high-performance liquid chromatographic (HPLC) method for the separation of individual enantiomers of DRF 2725 [R(+)-DRF 2725 and S(-)-DRF 2725 or ragaglitazar] was obtained on a chiral HPLC column (Chiralpak). During method optimization, the separation of enantiomers of DRF 2725 was investigated to determine whether mobile phase composition, flow-rate and column temperature could be varied to yield the base line separation of the enantiomers. Following liquid-liquid extraction, separation of enantiomers of DRF 2725 and internal standard (I.S., desmethyl diazepam) was achieved using an amylose based chiral column (Chiralpak AD) with the mobile phase, n-hexane-propanol-ethanol-trifluoro acetic acid (TFA) in the ratio of 89.5:4:6:0.5 (v/v). Baseline separation of DRF 2725 enantiomers and I.S., free from endogenous interferences, was achieved in less than 25 min. The eluate was monitored using an UV detector set at 240 nm. Ratio of peak area of each enantiomer to I.S. was used for quantification of plasma samples. Nominal retention times of R(+)-DRF 2725, S(-)-DRF 2725 and I.S. were 15.8, 17.7 and 22.4 min, respectively. The standard curves for DRF 2725 enantiomers were linear (R(2) > 0.999) in the concentration range 0.3-50 microg/ml for each enantiomer. Absolute recovery, when compared to neat standards, was 70-85% for DRF 2725 enantiomers and 96% for I.S. from rat plasma. The lower limit of quantification (LLOQ) for each enantiomers of DRF 2725 was 0.3 microg/ml. The inter-day precisions were in the range of 1.71-4.60% and 3.77-5.91% for R(+)-DRF 2725, S(-)-DRF 2725, respectively. The intra-day precisions were in the range of 1.06-11.5% and 0.58-12.7% for R(+)-DRF 2725, S(-)-DRF 2725, respectively. Accuracy in the measurement of quality control (QC) samples was in the range 83.4-113% and 83.3-113% for R(+)-DRF 2725, S(-)-DRF 2725, respectively. Both enantiomers and I.S. were stable in the battery of stability studies viz., bench-top (up to 6 h), auto-sampler (up to 12 h) and freeze/thaw cycles (n = 3). Stability of DRF 2725 enantiomers was established for 15 days at -20 degrees C. The application of the assay to a pharmacokinetic study of ragaglitazar [S(-)-DRF 2725] in rats is described. It was unequivocally demonstrated that ragaglitazar does not undergo chiral inversion to its antipode in vivo in rat plasma.

Animals↗
PubMed2004

Liquid chromatographic determination of the plasma concentrations of cefotaxime and desacetylcefotaxime in plasma of critically ill patients.

A method for the simultaneous determination of cefotaxime (CTX) and desacetylcefotaxime (DES) in plasma was developed, using acetonitrile protein precipitation and high-performance liquid chromatography (HPLC) with UV-detection at 285 nm. Desacetylcefotaxime was also analysed after conversion in highly acidic medium to its lactone form (DES-lactone). The chromatographic separation was performed on a C18 Aqua column. The lower limit of quantitation was 1 microg/ml for CTX and 0.5 microg/ml for DES and DES-lactone, using 25 microl of plasma samples. The linearity of the calibration curves was satisfactory as indicated by correlation coefficients of > or =0.990. The within-day and between-day precisions were <12% (n = 18) for the two products and the accuracy was between 88 and 101%. The developed HPLC method was applied for CTX and DES determination in plasma samples of critically ill patients after continuous intravenous infusion of CTX.

Anti-Bacterial Agents↗
PubMed2005

Raw and boiled garlic enhances plasma antioxidant activity and improves plasma lipid metabolism in cholesterol-fed rats.

UNLABELLED: In the present study the effect of garlic, in a form more similar to how most people eat garlic, on lipid and antioxidant metabolism in rats was investigated. The antioxidant activity was determined by the efficacy to scavenge 2, 2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) derived radicals in garlic samples. The highest results were estimated in aqueous fraction in comparison with other extracts divided on the basis of polarity. Wistar male rats were randomly divided into 10 diet groups, each with seven animals. The groups were named: Control, RG (raw garlic), BG (boiled garlic for 20 min), AERG (aqueous extract of raw garlic), AEBG (aqueous extract of boiled garlic), Ch (Cholesterol), Ch/RG, Ch/BG, Ch/AERG and Ch/AEBG. All experimental diets were supplemented with 25 mg of lyophilized garlic/kg body weight obtained from raw, boiled and their aqueous extracts over a period of 30 days. Serum lipid (total cholesterol, LDL-cholesterol and triglycerides) concentrations were higher in all groups fed cholesterol (Ch); however, the increase was significant only in Ch group, without garlic supplementation. In groups of rats fed diets with cholesterol, garlic samples significantly hindered the rise of TC and LDL-C (P < 0.05). A significant increase (P < 0.05) in the plasma antioxidant activity was registered in experimental groups of rats fed cholesterol-free diets supplemented with garlic; oppositely, a significant decrease was only in group of rats given food containing cholesterol without garlic. The protein spectra has shown that during short boiling some proteins change their functional properties such as solubility and mobility, resulting in a number of protein bands in SDS-electrophoresis. CONCLUSIONS: Raw and boiled garlic improved plasma lipid metabolism and plasma antioxidant activity in an experiment on rats. Thus, dietary hypolipidemic garlic was effective in reducing the oxidant stress, which was indicated by an increase of antioxidant activity and a decrease of lipids in the rats' blood. It was found that garlic boiled for 20 min has the same bioactivity as raw garlic in its antioxidant and protein spectra. Therefore it should be added at this time to foods. The selenium and copper content of raw garlic is not altered by boiling. The protein electrophoretic pattern of raw garlic is altered by boiling.

Animals↗
PubMed2004

Hepatitis C-related posttransplant plasma cell proliferative disorder with hepatitis C virus in neoplastic plasma cells: a new posttransplant disease entity?

Plasma cell proliferative disorder (PCPD) developed in two patients with actively replicating hepatitis C virus (HCV) in neoplastic plasma cells after orthotopic liver transplantation for HCV-related end-stage liver disease. PCPD was confined to the transplanted liver and was associated with monoclonal proteins in blood. Bone marrow biopsy did not show any evidence of PCPD. Epstein-Barr virus was not detected by in situ hybridization in either case. In situ hybridization for HCV RNA with sense and antisense probes in liver biopsy specimens showed signals in neoplastic plasma cells as well as in hepatocytes. We suggest that our patients had posttransplant PCPD resulting from HCV. It may represent a new posttransplant disease entity different from previously described posttransplant lymphoproliferative disorder. The findings raise intriguing questions about the role of HCV in PCPDs in patients with chronic HCV infection.

Antigens, CD↗
PubMed1975

A method for the separation of plasma amino acids by ion-exchange chromatography combined with a semi-automatic computation of plasma amino acid concentrations.

A method is described for combining the separation of plasma amino acids on a single column amino acid analyzer with semi-automatic computation of the plasma amino acid concentrations. The system used for the quantitation of the amino acids consists of an integrator with a teletype printer fitted with a puncher, and a table calculator with a punch reader and a converter. By using this system, the total time required for the calculation of the molar plasma concentration of 30 amino acids from one analytical run is less than 10 min.

Amino Acids↗
PubMed1987

Analysis of platinum species originating from cis-diamminedichloroplatinum(II) (cisplatin) in human and rat plasma by high-performance liquid chromatography with on-line inductively coupled plasma atomic emission spectrometric detection.

The applicability of reversed-phase ion-pair chromatography with on-line inductively coupled plasma atomic emission spectrometric detection was investigated for the analysis of cisplatin, its hydrolysis products and two methionine-platinum complexes in aqueous solutions. The detector response for cisplatin was linear over three orders of magnitude. The detection limit was found to be 3.5 ng, corresponding to a concentration detection limit of 35 ng/ml. The ion-pair system developed was applied to the analysis of (bio)transformation products originating from cisplatin in human and rat plasma in vitro and in vivo. In vitro, a number of platinum-containing species are formed, two of which show the same retention as the mono- and diaqua hydrolysis products of cisplatin. Preliminary results for in vivo experiments indicate cisplatin to be the predominant species in rat plasma.

Acetonitriles↗