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PubMed1995

Functional expression of human and mouse plasma phospholipid transfer protein: effect of recombinant and plasma PLTP on HDL subspecies.

The molecular cloning of mouse plasma phospholipid transfer protein (PLTP) and the eukaryotic cell expression of complementary DNA for mouse and human PLTP are described. Mouse PLTP was found to share 83% amino acid sequence identity with human PLTP. PLTP was produced in baby hamster kidney cells. Conditioned medium from BHK cells expressing PLTP possessed both phospholipid transfer activity and high density lipoprotein (HDL) conversion activity. PLTP mRNA was detected in all 16 human tissues examined by Northern blot analysis with ovary, thymus, and placenta having the highest levels. PLTP mRNA was also examined in eight mouse tissues with the highest PLTP mRNA levels found in the lung, brain, and heart. The effect of purified human plasma-derived PLTP and human recombinant PLTP (rPLTP) on the two human plasma HDL subspecies Lp(A-I) and Lp(A-I/A-II) was evaluated. Plasma PLTP or rPLTP converted the two distinct size subspecies of Lp(A-I) into a larger species, an intermediate species, and a smaller species. Lp(A-I/A-II) particles containing multiple size subspecies were significantly altered by incubation with either plasma or rPLTP with the largest but less prominent subspecies becoming the predominant one, and the smallest subspecies increasing in concentration. Thus, PLTP promoted the conversion of both Lp(A-I) and Lp(A-I/A-II) to populations of larger and smaller particles. Also, both human PLTP and mouse rPLTP were able to convert human or mouse HDL into larger and smaller particles. These observations suggest that PLTP may play a key role in extracellular phospholipid transport and modulation of HDL particles.

Amino Acid Sequence↗
PubMedDate not supplied

Concentrations of oestradiol-17 beta in plasma and milk and progesterone in plasma during the oestrus cycle and in early pregnancy in goats.

Pre-ovulatory peaks in oestradiol-17 beta concentrations were observed on days 1 or 2 and post-ovulatory peaks between days 4 and 7, both in jugular venous plasma and defatted milk, day 1 being the day of the onset of oestrus in the goats. Mean values of the magnitudes of these concentration peaks and of their timing (relative to oestrus) during the oestrus cycle did not differ significantly (P greater than 0.05) from those when the goats were mated and became pregnant. Pre-ovulatory oestradiol-17 beta peaks were invariably greater than the corresponding post-ovulatory peaks, as were peak concentrations in plasma relative to those in defatted milk collected on the same day. Mean intervals between the pre- and post-ovulatory peaks in oestradiol-17 beta concentrations were respectively 4.2 days for plasma and 4.0 days for defatted milk. Concentrations of oestradiol-17 beta in jugular venous plasma and defatted milk were strongly correlated: rank correlation coefficients for the three goats studied were 0.871, 0.668 and 0.739. It is suggested that in goats, as in cattle, ovarian follicular oestradiol-17 beta secretion approaching pre-ovulatory level is restored by 4 days after oestrus and its rapid decline after this time may be due to the inhibitory influence of the rapidly rising plasma progesterone concentration.

Animals↗
PubMed1976

Plasma protein profiling: the diagnostic evaluation of disorders in plasma protein composition by a new immunoelectrophoretic method.

A new electroimmunoprecipitation technique is presented by means of which a great variety of antigens e.g. plasma proteins can be simultaneously and quantitatively determined with a single-step electrophoretic separation. The essential features of the new technique are: (a) subdivision of the antibody gel into gel strips containing monospecific antibodies to individual plasma proteins. (b) sample application as a "sample gel" filling a trough over the width of the immunoplate. Quantitation is based on the fact that the distance an antigen can migrate within a gel containing a defined amount of specific antibody directed against the antigen is determined by the concentration of the appropriate antigen within the sample. The area where the antigen is finally completely consumed by immunoprecipitation and antibody present in excess is sharply delineated. The applicability of the method in simultaneous quantitative determination of 15 plasma proteins is demonstrated with plasma from healthy blood donors and patients with various diseases. The advantage of the new technique as compared to commonly used clinical acetate folia electrophoresis is the high degree of specificity for the determination of a great number of individual, diagnostically meaningful plasma proteins. The advantage over common quantitative two-dimensional immunoelectrophoresis is its uncomplicated way of evaluation. The potential clinical application of the new quantitative immunoelectrophoretic technique in diagnostic screening and differential diagnosis is discussed.

Blood Proteins↗
PubMed1977

Determination of gold in plasma and plasma fractions by atomic absorption spectrometry and by neutron activation analysis.

Three techniques of gold analysis, flame and electrothermal atomic absorption spectrometry and neutron activation analysis, have been compared, using plasma and plasma fractions (derived by gel chromatography) from rheumatoid patients receiving aurothiomalate therapy and from plasma samples incubated with aurothiomalate in vitro. The three methods correlated well in the analysis of gold in whole plasma, but only neutron activation analysis was suitable for the assay of all the plasma fractions. The susceptibility of the two atomic absorption methods to interference by sodium chloride was investigated.

Gold↗
PubMed1978

Triglyceride lipase activity in postheparin plasma and plasma lipoproteins in liver disease.

Hepatic lipase activity and lipoprotein lipase activity were studied in postheparin plasma from 14 patients with various liver disorders. Plasma lecithin: cholesterol acyltransferase (LCAT) activity and lipoprotein composition and structure were also estimated. Five patients had lower hepatic lipase activity than the lowest control value, and in three of these no hepatic lipase activity was detected. Lipoprotein lipase was low in 5 patients, but in only one of them was hepatic lipase activity also low. Hepatic lipase was not significantly correlated to the concentration of plasma triglycerides, either in controls or in patients, whereas lipoprotein lipase was negatively correlated with plasma triglycerides both in controls and patients. Lipoprotein lipase and LCAT activity, but not hepatic lipase, was negatively correlated to the triglyceride content of the low density lipoproteins (density 1.019-1.063 g/ml) from the patients. No specific lipid or lipoprotein pattern was found in plasma from the patients with a low or without any hepatic lipase activity. The results suggest an important role of lipoprotein lipase and LCAT, for the increased content of triglycerides in the low density lipoproteins in patients with liver disease. The role of hepatic lipase remains unclear.

Adult↗
PubMed1992

Optimized determination of malondialdehyde in plasma lipid extracts using 1,3-diethyl-2-thiobarbituric acid: influence of detection method and relations with lipids and fatty acids in plasma from healthy adults.

We investigated the influence of different concentrations of Fe3+, phosphoric acid, butylated hydroxytoluene and glutathione on the production of the malondialdehyde-1,3-diethyl-2-thiobarbituric acid adduct in plasma lipid extracts. Following organic solvent extraction the stable product was analyzed by spectrophotometry (537 nm), fluorometry (547 nm) and high-performance liquid chromatography with fluorometric detection. Using optimized reaction conditions there was good agreement between the three methods, with slightly higher values for the spectrophotometric method. Plasma total lipid malondialdehyde reference values for 24 healthy adults amounted to 1.30 +/- 0.23 mumol/l (spectrophotometric method) and 1.11 +/- 0.31 mumol/l (fluorometric method). Plasma lipid malondialdehyde concentrations correlated significantly with plasma triglycerides (r = 0.527), total cholesterol (r = 0.612) and total fatty acids (r = 0.810) and with the total number of double bonds present in plasma fatty acids with three or more double bonds (r = 0.923).

Adult↗
PubMed1992

Differences in erythrocyte sodium transport between human plasma and artificial medium: the role and character of sodium efflux and influx stimulating plasma factors.

The main objective of this study was to further characterize the plasma factor(s) which stimulate sodium efflux from erythrocytes, which we reported previously. Dialysis of plasma against an artificial medium using membranes with varying molecular mass cut-off points revealed relative molecular mass(es) of the factor(s) of 100-1000 Da. The factor(s) could be absorbed on Dowex at pH 1.5 and Amberlite at pH 11.0, indicating 'Zwitterionic' character. They are hydrophilic and resistant to acid hydrolysis. These characteristics and direct measurements of contents made amino acids likely candidates for the efflux stimulating properties of the factor(s). Indeed, plasma amino acids added to artificial medium could abolish the sodium efflux difference between plasma and the artificial medium. The efflux stimulating effect of amino acids appeared not to be the result of sodium influx stimulation. A coincident finding was that plasma also contains dialyzable sodium influx stimulating factor(s) which are not amino acids.

Adult↗
PubMed1996

Plasma 1,5-anhydro-D-glucitol concentration and its relation to other plasma components in renal failure and renal transplant recipients.

Plasma levels of 1,5-anhydro-D-glucitol (AG) were measured in non-diabetic patients with renal failure or following renal transplant. For patients with renal failure (n = 20) from various causes, the plasma level of AG was found to be positively associated with urate and negatively with both urea and prior dialysis. The results for seven renal transplant recipients, serially assessed during the post-transplant period, verified an increase in plasma AG with time, approaching normal levels (> or = 70 mumol/l) after 60 days, and which was adversely affected by rejection episodes. The actual mean rate of plasma AG rise ranged from 0.35 to 1.29 mumol/l per day. AG levels for long term (> 1000 days) surviving renal transplant recipients (n = 16) were predominantly related to renal function as assessed by plasma creatinine.

Adult↗
PubMed1984

Changes in plasma estradiol and effects of triiodothyronine on plasma estradiol during smoltification of coho salmon, Oncorhynchus kisutch.

Plasma estradiol-17 beta levels were measured by radioimmunoassay in untreated coho salmon of both sexes or in fish fed triiodo-L-thyronine during the smoltification period. Mean plasma estradiol increased between February 25 and April 1 from 94 to 142 pg/ml, and then by May 13, it had decreased to 80 pg/ml. This hormonal cycle was followed by a second significant increase to 219 pg/ml on June 22. Plasma thyroxine level covaried with that of estradiol. Treatment with triiodothyronine had no effect on plasma estradiol or thyroxine levels. Plasma estradiol surges during the smoltification period must be considered along with other significant endocrine changes for a possible role in the developmental phenomena that characterize this period.

Animals↗
PubMed1991

Demonstration of a phospholipase A2 inhibitor in human plasma and in plasma from the European hedgehog (Erinaceus europaeus).

1. Endogenous phospholipase A2 (PLA2) inhibitors in human plasma and in plasma from the hedgehog (Erinaceus europaeus) were demonstrated. 2. The PLA2 activity increased 45-fold in human plasma when a PLA2 binding factor was removed. Furthermore, two peaks of PLA2 inhibitory activity were found after DEAE-chromatography. 3. High levels of PLA2 inhibitory activity was found in plasma from the European hedgehog, E. europaeus. 4. The molecular weight was estimated to 140,000. 5. On DEAE-chromatography two peaks were found which were chromatographically similar to the PLA2 inhibitors in human plasma.

Adult↗
PubMed1988

Plasma thiobarbituric acid reactivity: reaction conditions and the role of iron, antioxidants and lipid peroxy radicals on the quantitation of plasma lipid peroxides.

The effects of Fe3+, lipid peroxy radicals and the antioxidant butylated hydroxytoluene on the 2-thiobarbituric (TBA) acid quantitation of plasma lipid peroxides were investigated. Whole plasma and plasma fractions prepared by trichloroacetic acid (TCA) protein precipitation and lipid extraction, demonstrated markedly differing TBA reactivities in the presence or absence of added Fe3+. Examination of the spectral profiles of the TBA reacted whole plasma and TCA precipitated fractions demonstrated the presence of interfering compounds which gave rise to an artifactual increase in lipid peroxide concentrations. In contrast the TBA reacted lipid extracts had low levels of interfering compounds that could be removed by our previously described high pressure liquid chromatographic method (Wade, Jackson and van Rij (1985) Biochem. Med. 33, 291-296). Further characterization of the TBA reactivity of the lipid extract showed that Fe3+ at an optimal concentration of 0.5 mM was necessary for the quantitative decomposition of the lipid peroxides to the TBA reactive product malondialdehyde (MDA). However the presence of Fe3+ resulted in further peroxidation of any unsaturated lipids present. Butylated hydroxytoluene (BHT) at an optimal concentration of 1.4 mM inhibited Fe3+ stimulated peroxidation without affecting the formation of the MDA-TBA chromogen. Using a standardized TBA test with plasma lipid extracts and the addition of optimal concentrations of Fe3+ and BHT, we have determined the mean concentration of lipid peroxides in 30 healthy human subjects to be 102.7 +/- 20.0 ngm/ml.

Butylated Hydroxytoluene↗
PubMed1988

Weight loss in massive obesity: reciprocal changes in plasma HDL cholesterol and HDL binding to human adipocyte plasma membranes.

Human obesity is frequently associated with elevated plasma triglyceride and cholesterol concentrations and reduced high density lipoprotein (HDL) cholesterol, abnormalities that commonly revert to normal levels with weight loss. This study was undertaken to examine possible mechanism(s) associated with the changes in plasma HDL cholesterol concentrations in massively obese patients after weight loss. Ten massively obese patients (two men and eight women, age = 37.8 +/- 2.4 years) were studied before, during, and after 1 year of weight loss and weight maintenance following gastric stapling. Total cholesterol and low density lipoprotein cholesterol were within the normal range for sex and age before weight loss and did not change significantly during or after weight reduction. In the females, HDL cholesterol concentrations increased from 0.96 +/- 0.06 mmol/L to 1.23 +/- 0.3 mmol/L (mean +/- SEM, n = 8, P less than .05) with weight reduction. In the two men, plasma HDL cholesterol concentrations were, respectively, 1.22 and 0.65 mmol/L before and 1.23 and 0.98 mmol/L after weight loss. Specific binding of 125I-HDL2 and 125I-HDL3 to purified plasma membranes was determined using abdominal and omental fat depot before and after weight loss in six of the ten obese patients. An average reduction of 30% to 40% in 125I-HDL2 and 125I-HDL3 binding capacity to these membranes occurred after weight loss. Furthermore, a positive correlation (r = .65, n = 10, P less than .05) was observed between plasma HDL cholesterol and triglyceride concentrations before weight loss but not after weight loss (r = .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1995

Relationships of plasma and hepatic variables with rates of plasma low-density lipoprotein apolipoprotein B metabolism in baboons fed low- and high-fat diets.

These studies were conducted to determine relationships of plasma low-density lipoprotein (LDL) cholesterol concentrations and hepatic mRNA levels for apolipoprotein (apo) B, LDL receptor, and hepatic hydroxymethyl glutaryl coenzyme A (HMG CoA) synthase with plasma LDL apo B production and catabolic rates in baboons maintained on a low-cholesterol, low-fat chow diet and on a high-cholesterol, high-fat (HCHF) diet. Twelve baboons with LDL cholesterol levels ranging from low to high on the HCHF diet but with similar high-density lipoprotein (HDL) cholesterol levels were selected from a colony of selectively bred pedigreed baboons. LDL apo B turnover and hepatic mRNA concentrations for apo B, LDL receptor, and HMG CoA synthase were measured on a chow diet and again on a HCHF diet fed for 14 weeks. LDL apo B fractional catabolic rates decreased and production rates increased on the HCHF diet. Hepatic mRNA concentrations for apo B were not affected by the HCHF diet. Hepatic LDL receptor and HMG CoA synthase mRNA concentrations decreased on the HCHF diet as compared with the chow diet. LDL apo B fractional catabolic rate was negatively correlated with plasma cholesterol, LDL cholesterol, LDL apo B, and LDL apo B production and positively correlated with hepatic LDL receptor and HMG CoA synthase mRNA concentrations and with plasma LDL triglyceride to cholesterol ratio on the chow diet but not on the HCHF diet. LDL apo B production was positively correlated with plasma cholesterol, LDL cholesterol, and LDL apo B on the HCHF diet and negatively correlated with LDL triglyceride to cholesterol ratio on both chow and HCHF diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Diurnal variation of plasma and saliva oestrogen, progesterone, cortisol and plasma dehydroepiandrosterone sulphate in late pregnancy.

The diurnal variation of plasma oestrone (E1), oestradiol (E2), oestriol (E3), progesterone (P), cortisol (F) and dehydroepiandrosterone sulphate (DHAS) and saliva E1, E2, E3, P and F was investigated in matched plasma, and saliva samples were obtained hourly from 08.00 to 24.00 h and at 04.00, 07.00 and 08.00 h from nine pregnant women (3 at 30, 3 at 34 and 3 at 38 weeks gestation). A diurnal variation in plasma and saliva cortisol levels was found in all subjects and in plasma DHAS in 8 out of 9 subjects. No consistent diurnal variation was found at any gestation in any of the other hormones in plasma or saliva. There was a significant correlation between saliva E3 and P levels at 30 weeks gestation but no other consistent correlations between hormone levels were found at any gestation.

Circadian Rhythm↗
PubMed1986

Mechanism of the plasma cholesterol lowering effect of tazasubrate in rats: accelerated plasma cholesterol transport with increased liver lipoprotein receptor activity.

Tazasubrate (30 mg/kg/day) a new lipid lowering agent, chemically unrelated to fibrates, reduces plasma cholesterol in rats within 2-3 days to 50% of controls. During the early rapid decrease of plasma cholesterol, increased liver cholesterol concentrations are observed. These return to normal, once the new steady state of plasma cholesterol (at 50% of controls) has been reached. Radiotracer studies with 3H-cholesterol labelled plasma very low density lipoproteins are consistent with an accelerated plasma cholesterol turnover. Analysis of the binding to liver membranes of 125I labelled cholesterol rich very low density lipoproteins (beta-VLDL) shows a marked increase in the total binding (Bmax rising from 106 ng/mg of protein 378 ng/mg), without significant alterations in the receptor affinity.

Animals↗
PubMed1995

Inter-individual variation of selenium in maternal plasma, cord plasma and placenta.

Selenium (Se) in high doses has been known to cause injury to the fetus and newborn. The major difficulty in assessing the effects of selenium on human reproduction stems from the need for a suitable means of estimating maternal and fetal exposure. The present investigation, therefore, examines the respective reliability of maternal plasma, cord plasma and placenta as epidemiological indicators as well as inter-individual variation of this trace element. An unselected population of 128 pregnancies was studied. Obstetrical characteristics were noted. Selenium concentrations were determined for maternal plasma, cord plasma, and placental tissue by fluorometric analysis. Maternal plasma selenium concentrations (Se-Bm) were significantly greater than fetal concentrations (Se-Bc). Placental selenium (Se-Pl) levels were four times that of fetal levels. Variability of Se-Bc is best explained by placental concentrations. Maternal weight and ethnic origin are significantly correlated with Se-Bc. Female newborn have higher selenium levels than male newborn. The present study demonstrates the significance of the placenta as an indicator of fetal selenium exposure.

Adult↗
PubMed1984

Purification and some properties of a protein obtained from normal human plasma which inhibits the platelet aggregation induced by thrombotic thrombocytopenic purpura plasma.

Plasma from patients with thrombotic thrombocytopenic purpura (TTP) caused the aggregation of washed human platelets, which was inhibited by preincubation with normal plasma. Using salt fractionation, ion exchange chromatography, and preparative agarose gel electrophoresis, we purified a protein from normal plasma which inhibited the platelet aggregation caused by TTP plasma. On SDS polyacrylamide gel, the purified inhibitor gave a single band with a M.W. of 150,000. The antiserum against the purified protein neutralized the activity of the inhibitor and formed an identical precipitin line against normal and TTP plasma.

Blood Coagulation Factors↗
PubMed1987

Regulation of factor VIIa activity in plasma: evidence that antithrombin III is the sole plasma protease inhibitor of human factor VIIa.

The inhibition of human factor VIIa by antithrombin III and normal human plasma was studied in the presence and absence of heparin. In the absence of heparin, no apparent inhibition of factor VIIa was observed in either system. In the presence of heparin, factor VIIa activity was inhibited 50% by purified antithrombin III and plasma in 90 min and 75 min, respectively. No inhibition of factor VIIa was observed in heparinized plasma previously depleted of antithrombin III by immunoaffinity adsorption. Incubation of factor VIIa with antithrombin III-heparin or heparinized plasma resulted in the formation of a covalent complex with an apparent molecular weight of 100 kilodaltons. These data indicate that antithrombin III appears to be the sole plasma protease inhibitor of human factor VIIa, and the expression of its inhibitory activity against factor VIIa is absolutely dependent upon the presence of exogenous heparin.

Antithrombin III↗