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PubMed1988

Use of a new plasma separation membrane for plasma donation. Technical and biological results.

Donor safety and high-quality plasma are important assumptions for a successful plasma donation. The manual technique has two major inconveniences: It is time consuming and there are risks in the transfusion because the system is not closed. Among the available technological options, filtration has great future prospects insofar as a hemocompatible and efficient membrane can be made available and at low cost. Hemascience Travenol developed the polycarbonate membrane for the first disposable. Because of a high rate of no or very low plasma flow (5-10%), the company equipped the disposable with a new membrane: the nylon membrane. This membrane was tested according to biological and technical protocols; 39 disposables were used. The anticoagulant was acid citrate dextrose formula A. The results were good: time to collect 600 g of plasma, 34 min (only two occurrences of low flow); no problem with blocking or clotting. The main biological data show no problem with molecule activation (complement factors, coagulation factors), a good recovery of Factor VIII, and no contamination of platelets (5 +/- 2 X 10(3)/ml). No side-effects in the donor were noted. These results confirm that the Hemascience Travenol system is one of the best automatic plasmapheresis systems and could be used to separate great quantities of plasma from donors.

Filtration↗
PubMed1995

Plasma trace element, plasma glutathione peroxidase, and superoxide dismutase levels in epileptic children receiving antiepileptic drug therapy.

Some antiepileptic drugs (AEDs) may alter trace element metabolism and free radical scavenging enzyme activities in humans and experimental animals. We investigated the effect of long-term AED therapy on copper (Cu), zinc (Zn), manganese (Mn), selenium (Se), magnesium (Mg), glutathione peroxidase (GSH-PX), and superoxide dismutase (SOD) in the plasma in children with epilepsy. During treatment with valproate (VPA) or carbamazepine (CBZ) monotherapy plasma Cu, Zn, Mn, Se, and Mg concentrations of patients were not statistically different from those of control subjects. The level of serum VPA weakly correlated with the increase in plasma Zn level. Recent studies suggest that membrane lipid peroxidation may be causally involved in some forms of epilepsies, and the decreased free radical scavenging enzyme activity is believed to cause the increased risk of an idiosyncratic drug reaction encountered in the management of epilepsy. Because GSH-PX and SOD are the most important members of antioxidant defense mechanisms, we quantitated the activities of these enzymes in plasma of children with epilepsy receiving VPA or CBZ. Only plasma GSH-PX activities in VPA group were higher than those of the control group, and the difference was statistically significant.

Adolescent↗
PubMed2005

The effect of platelets on fibrin gel structure formed in the presence of recombinant factor VIIa in hemophilia plasma and in plasma from a patient with Glanzmann thrombasthenia.

Fibrin gel structure has been shown to be dependent on the thrombin concentration as well as the rate of thrombin generation. Accordingly, factor VIII (FVIII)- and FIX-deficient plasma (hemophilia A and B) form loose fibrin clots with high permeability constants. By adding rFVIIa in vitro to FVIII-deficient plasma containing platelets (frozen and thawed), the fibrin gel permeability constant normalized, indicating that extra rFVIIa (1.2 microg mL(-1) or higher) induced a tight fibrin structure. Thrombin generation is highly dependent on the number of platelets, and in this study it was demonstrated that the addition of rFVIIa (5 microg mL(-1)) normalizes the fibrin gel permeability in samples containing platelets (frozen-thawed) in numbers of at least down to 20 x 10(6) mL(-1). The effect of rFVIIa was not observed when unfrozen platelets instead of frozen-thawed platelets were added. Neither was any effect on the fibrin permeability seen, in the presence of annexin V, known to block the effect of phospholipids on the platelet surface. This indicates an important role of platelet phospholipids for the effect of rFVIIa. A similar effect on the fibrin permeability of rFVIIa was observed when added to platelet-rich plasma from a patient with Glanzmann thrombasthenia. Recombinant FVIIa has been found to induce hemostasis in patients with hemophilia and inhibitors against FVIII/FIX as well as in patients with Glanzmann thrombasthenia, indicating the importance of the formation of a tight fibrin gel structure, more resistant against premature proteolysis, for maintaining hemostasis. In conclusion, the addition of rFVIIa (5 microg mL(-1)) also substantially decreased the permeability constant of fibrin gels formed in FVIII-deficient plasma in the presence of low numbers of frozen-thawed platelets (down to 20 x 10(6) mL(-1)). A similar pattern was obtained in plasma from a Glanzmann patient. No effect was found in the presence of unfrozen instead of frozen-thawed platelets. Annexin V blocked any effect of rFVIIa. A normalization of the overall fibrinolysis potential (OFP) during the same condition supports the effect of rFVIIa on the fibrin permeability in the presence of a limited number of platelets.

Adult↗
PubMed1985

Dexamethasone suppression test and the levels of serum growth hormone, plasma vasopressin and plasma homovanillic acid in depressed in- and outpatients.

A total of 206 depressive patients (176 outpatients and 30 inpatients) underwent a dexamethasone suppression test (DST). Resting levels of serum growth hormone (GH), plasma vasopressin (AVP) and plasma homovanillic acid (HVA) were also measured in a proportion of the patients. Fifty-seven per cent of the endogenous patients showed nonsuppression of cortisol in the DST, while 92% in the nonendogenous group showed normal suppression. The diagnostic confidence of a positive test was 83%. The sensitivity and specificity of the test was slightly higher among inpatients than out-patients, and serum cortisol value at 4 p.m. was more useful than the morning value. No significant correlation was found between severity of the depression as measured by the Hamilton Rating Scale for Depression and serum cortisol. In single subjects there was, however, an obvious correlation. The levels of serum GH, plasma AVP and plasma HVA did not differ in the endogenous and nonendogenous groups, and there was no correlation between serum cortisol in the DST and the concentrations of the other hormones or HVA in plasma.

Adolescent↗
PubMed1991

Plasma kininogen concentration: the low level in cord blood plasma and age dependence in adults.

Antigenic concentration of total kininogen, kinin liberated in vitro, and the antigenic concentration of high molecular weight (HMW) kininogen was measured in 58 different samples of cord blood plasma and in plasma samples from 67 healthy blood donors. Total kininogen and kinin concentration in cord blood plasma was more than twice as low as in pooled plasma of adult persons, and the concentration of HMW-kininogen in cord blood plasma was close to one-third of normal. The concentration of total kininogen and of HMW-kininogen increased with age in adults. All these findings were highly statistically significant.

Adult↗
PubMed1995

Plasma lecithin: cholesterol acyltransferase and plasma lipolytic activity in preterm infants given total parenteral nutrition with 10% or 20% Intralipid.

The effect of 10% or 20% Intralipid on lipid clearing enzymes, plasma lipids and apoproteins was investigated during the first 5 days after birth in 37 premature infants maintained on total parenteral nutrition; 21 infants received 20% and 16 received 10% Intralipid, respectively. Lipid was infused over a 20-h period at rates of 1, 2 and 3 g/kg/day on consecutive days. Plasma lecithin: cholesterol acyltransferase (LCAT) activity was low and increased significantly (p<0.05) only during infusions of 3 g/kg/day in both groups of infants. Plasma lipolytic activity was generally not affected by the regimen or preparation (10% or 20%) of Intralipid infused, except for higher (p<0.05) levels at 3 g/kg/day of 20% compared with prelipid infusion. Plasma triglyceride concentrations wer similar after 10% or 20% Intralipid, whereas plasma total cholesterol was significantly higher during infusion of 2 and 3 g/kg/day of 10% compared with 20% Intralipid. The efficient clearing of 20% Intralipid might be related to the lower lecithin: triglyceride ration which is compatible with the low LCAT activity of premature infants.

Apolipoproteins A↗
PubMed1997

Plasma viremia in macaques infected with simian immunodeficiency virus: plasma viral load early in infection predicts survival.

A reliable method for the quantitation of plasma viremia in nonhuman primates infected with simian immunodeficiency virus (SIV) and related viruses is described. This method is based on an established quantitative-competitive PCR format and includes a truncated control for internal assay calibration. Optimization of assay conditions has significantly improved amplification specificity, and interassay variability is comparable to that of commercially available assays for human immunodeficiency virus (HIV) quantitation. This procedure was used to monitor viral loads in a group of Macaca mulatta animals that were infected with SIVsmE660 for over 2 years. Highly diverse profiles of plasma viremia were observed among animals, and high viral loads were associated with more rapid disease progression. Spearman rank correlation analyses were done for survival versus three parameters of viral load: plasma viremia, p27 core antigen, and frequency of infected peripheral blood mononuclear cells. Plasma viremia had the strongest overall correlation and was significantly (P < 0.05 to P < 0.01) associated with survival at 10 of the 13 time points examined. Plasma viremia did not correlate with survival during the primary viremia phase; however, the strength of this correlation increased with time postinfection and, remarkably, viremia levels as early as week 6 postinfection were highly predictive (P < 0.01) of relative survival. These findings are consistent with the available clinical data concerning viral load correlates early in HIV infection, and they provide further support for the view that disease outcome in lentiviral infection may be largely determined by events that occur shortly after infection.

Animals↗
PubMed1977

A comparison of the erythrocyte sedimentation rate and plasma viscosity in detecting changes in plasma proteins.

The Westergren erythrocyte sedimentation rate (ESR) and plasma viscosity were compared in 114 patients and their correlations with total and differential plasma protein fractions were analysed. There is a linear correlation between these two screening tests. Higher correlation coefficients were obtained between the plasma viscosity and fibrinogen and alpha and gamma globulins than with the ESR. Albumin affected the two tests in opposite directions. The ESR was falsely increased by a fall in haemoglobulin even within two standard deviations from the mean. Both tests gave an appreciable number of incorrect values--the plasma viscosity in 21 cases and the ESR in 33. The cause for these is discussed. It is concluded that the plasma viscosity is the more sensitive and reliable measure of changes in acute phase protein reactants and more useful for monitoring clinical progress.

Alpha-Globulins↗
PubMed1988

Dissociation between plasma renin and plasma aldosterone induced by dietary glycine hydrochloride.

We evaluated the effects of selective dietary chloride loading (without sodium) on plasma renin activity (PRA) and plasma aldosterone in the sodium-deprived Sprague-Dawley rat. Three groups of animals were fed one of the following diets for 13 days: 1) low NaCl; 2) high NaCl; or 3) low sodium, high chloride, provided as glycine hydrochloride. Compared with NaCl-deprived animals, PRA and plasma aldosterone were lower (P less than 0.01) in animals fed low sodium high chloride, whereas aldosterone in animals fed glycine hydrochloride was higher (P less than 0.01) than that of NaCl-deprived animals. In contrast, plasma concentrations of corticosterone and 18-hydroxycorticosterone were not increased by selective chloride loading. Glycine chloride-fed animals were acidotic and had elevated plasma concentrations of potassium and ionized calcium. Thus stimulation of aldosterone by selective chloride loading is not related to PRA or ACTH but may be due to a direct effect of acidosis or an indirect effect of acidosis on potassium and/or calcium. Additionally, selective chloride loading appears to stimulate the conversion of 18-hydroxycorticosterone to aldosterone.

18-Hydroxycorticosterone↗
PubMed1979

Plasma epinephrine and control of plasma renin activity: possible extrarenal mechanisms.

Previous work from our laboratory has shown that physiological increments of circulating epinephrine concentration increase plasma renin activity (PRA) by an extrarenal beta-receptor mechanism. In the present experiments, epinephrine was infused intravenously at 125 ng.kg-1.min-1 for 45 min in trained, conscious dogs. PRA rose 3 to 5-fold, as previously described, and was accompanied by a transient decline of mean arterial pressure, decreased plasma potassium concentration, and increased hematocrit. Prior splenectomy to maintain hematocrit constant did not attenuate the PRA response to epinephrine. The kidneys of 4 dogs were denervated and constrictor cuff was placed around the renal artery. Renal denervation did not alter the PRA response to intravenous epinephrine infusion. A transient decline in renal perfusion pressure produced by cuff constriction only transiently increase PRA. Neither maintenance of a constant plasma potassium concentration nor oral administration of indomethacin altered the PRA response to epinephrine. We conclude that intravenous epinephrine increases PRA by a mechanism independent of the renal nerves, changes in renal perfusion pressure, hematocrit, plasma potassium concentration, and plasma prostaglandins.

Animals↗
PubMed1984

Plasma melatonin concentrations in hibernating marmots: absence of a plasma melatonin rhythm.

Plasma melatonin concentrations were measured throughout bouts of hibernation in marmots maintained in a short photoperiod (light-dark 8:16) and ambient temperature of 5 or 15 degrees C. Melatonin concentration was also measured in two animals maintained in constant darkness. As an animal entered hibernation, plasma melatonin concentrations dropped to basal levels when body temperature reached 25 degrees C, and they remained low until arousal. During deep hibernation plasma melatonin values did not vary significantly (P greater than 0.05) with respect to time of day or different ambient temperatures. With nocturnal arousal plasma melatonin levels were similar to euthermic night values. Lack of a plasma melatonin rhythm during hibernation suggests that the pineal gland is not temperature compensated during hibernation, and due to the low tissue temperature of the pineal the circadian pacemaker driving melatonin secretion is incapable of stimulating a rhythm.

Animals↗
PubMed2003

Thrombin generation measurement in factor VII-depleted plasmas compared to inherited factor VII-deficient plasmas.

Activated factor VII (FVIIa)/tissue factor enzyme complex is the initiator of the coagulation cascade in vivo. FVIIa is of particular interest because it has been found to induce haemostasis in various bleeding disorders. In order to evaluate the FVII threshold that is required to initiate the clotting cascade, we measured thrombin generation in FVII-depleted plasmas spiked with increasing amounts of normal pooled plasma and in inherited FVII-deficient plasmas. According to the literature, only trace amounts of FVII are sufficient to initiate blood coagulation in vitro. By contrast, results on inherited FVII-deficient plasmas showed a wide variety of the amounts of thrombin generated in plasmas with the same FVII coagulant activity levels. This suggests that the threshold of FVII required to initiate haemostasis in vivo depends on one or more, hitherto unknown, plasmatic or cellular factors.

Blood Coagulation Tests↗
PubMed1976

Responses of plasma "estradiol" and plasma LH to ovariectomy, ovariectomy plus adrenalectomy, and estrogen injection at various ages.

Plasma LH and "estradiol" were measured by radioimmunoassay in female rats 5, 10, 15, 20, 25, 30, 40, and 80 days of age, and the changes in these hormone levels 24 h after ovariectomy, ovariectomy plus adrenalectomy, and estrogen injection were determined. Plasma "estradiol" was high at 5 days of age; it increased further to a peak at 15 days of age, and declined thereafter to the low levels seen in adult rats. At each age, plasma "estradiol" declined about 50% 24 h after ovariectomy, whereas it fell to undetectable levels 24 h after ovariectomy plus adrenalectomy at 20 and 80 days of age. Plasma LH did not increase 24 h following ovariectomy at 5 days of age, but it did at all ages thereafter. The peak increase occurred 24 h after ovariectomy at 15 days of age, and the increment was progressively smaller at older ages. Ovariectomy plus adrenalectomy did not cause a significantly greater increase in plasma LH than ovariectomy alone. Injection of estradiol caused a decrease in plasms LH at all ages except in the animals ovariectomized at 5 days of age. The greatest decrease was seen in animals ovariectomized at 15 days of age, with a progressively smaller negative feedback response as age increased. In addition to providing systematic data on changes in the negative feedback effect of estradiol at various ages, the results indicate that, especially in immature animals, there is a circulating substance which cross-reacts with antibodies to estradiol but which does not appear to be a biologically-active estrogen. It does not come from the ovaries and disappears from the circulation if the adrenals as well as the ovaries are removed.

Adrenal Glands↗
PubMed1983

LH-RH and dopamine levels in hypophysial stalk plasma and their relationship to plasma gonadotrophins and prolactin levels in male rats bearing a prolactin- and adrenocorticotrophin-secreting pituitary tumor.

The present study was concerned with the effects of a transplantable pituitary tumor secreting prolactin (PRL) and adrenocorticotrophin (ACTH) on the levels of LH and FSH in peripheral plasma and on the hypothalamic release of LH-RH and dopamine in the male rat. Male rats of the same age not inoculated with the tumor served as controls. Hypophysial stalk blood was collected from urethane-anesthetized rats 4-5 weeks after tumor inoculation to measure their LH-RH and dopamine content. A peripheral blood sample was withdrawn from the animals just before sectioning the hypophysial stalk to measure their content of LH, FSH and PRL. It was found that in the tumor-bearing rats the levels of PRL increased 17-fold, whereas plasma levels of LH and FSH decreased by 45 and 70% respectively, when compared with the control rats. In the tumor-bearing rats, the secretion rate of dopamine in hypophysial stalk plasma increased from 1.4 to 4.1 ng/h, whereas the secretion rate of LH-RH decreased from 122 to 61 pg/h. However, when at the time of tumor inoculation adrenalectomy was performed, the tumor did not decrease plasma levels of LH and FSH and the secretion of LH-RH into hypophysial stalk blood any longer. The effect of the tumor on hypothalamic dopamine secretion was, however, still present in the adrenalectomized rats. It is concluded that the effect of the PRL- and ACTH-secreting pituitary tumor on plasma levels of LH and FSH requires the presence of the adrenal gland and that this effect is mediated through an inhibition of the hypothalamic release of LH-RH. Furthermore, this tumor increases the hypothalamic release of dopamine independent of the presence of the adrenal gland.

Adrenocorticotropic Hormone↗
PubMed1975

Diurnal variations of food consumption, plasma glucose and plasma insulin concentrations in lean and obese hyperglycaemic mice.

Diurnal variations in food consumption and plasma concentrations of glucose and insulin were determined at 3-hourly intervals in obese hyperglycaemic mice (C57BL/6J ob/ob) and lean mice (C57BL/6J+/+). In lean mice, food consumption and plasma insulin concentrations increased during the light period and were reduced during the dark period, whereas plasma glucose concentrations were maximal at the beginning of the light period and declined to a minimum during the early dark period. In ob/ob mice, the plasma glucose concentration declined temporarily at the beginning of both the light and the dark period and became elevated towards the ends of these periods, but there were no significant diurnal variations of food consumption or plasma insulin concentrations. These observations indicate differences in the diurnal regulation of glucose homeostasis in lean and ob/ob mice.

Animals↗
PubMed1988

Diurnal pattern of plasma and cerebrospinal-fluid vasopressin levels in hydrocephalic patients: absence of a circadian rhythm and of a correlation between plasma and cerebrospinal-fluid variations.

The arginine vasopressin (AVP) concentrations were determined in plasma and in cerebrospinal fluid (CSF) during a 24-hour period in 7 male patients suffering from hydrocephalus of differing etiologies. Blood and ventricular CSF samples were simultaneously collected every 2 h during the day (08.00-22.00) and every hour during the night (24.00-07.00). In both plasma and CSF, the AVP levels did not show significant time-related circadian variations. No significant correlation was found between the plasma and CSF AVP values during the 24-hour period. The data obtained indicate the absence of the plasma and CSF AVP circadian rhythm in hydrocephalic patients and suggest that in these patients, and possibly in healthy humans, physiological stimuli which are able to induce variations in the plasma AVP concentration during daily life do not alter the CSF AVP content.

Arginine Vasopressin↗
PubMed1977

Distribution of label in maternal plasma, placenta, fetal plasma and tissues after injection of 14C-palmitate into the circulation of 21- and 28-day-pregnant rabbits.

Tissue and plasma samples were obtained from fetuses removed 1--20 min after injection of 14C-palmitate into the doe at day 21 or day 28 of gestation. Specific activity of maternal plasma free fatty acids (FFA) was higher, but that of fetal plasma FFA lower in 21- than 28-day-pregnant rabbits. In 21-day fetuses, total radioactivity in the liver never exceeded that in the placenta; in 28-day fetuses, the liver radioactivity exceeded that in the placenta after 3 min. Total radioactivity in the fetal brown adipose tissue (BAT) never exceeded that in the placental. Most of the placental radioactivity was initially in the FFA, but at later time intervals the majority of the label was in the phospholipids. The fetal liver and BAT rapidly esterified label into triglycerides. It is concluded that transport of FFA across the placenta is greater at 28 days than at 21 days gestation. The evidence suggests that a pool of placental FFA, which equilibrates rapidly with the maternal plasma FFA, is a possible source of fetal plasma FFA. The rapidity and quantity of label appearing in the fetal liver suggest that fatty acids may first be processed by the liver before transport to extrahepatic tissues.

Adipose Tissue↗
PubMed1979

Protease deficiency in plasma of patients with cystic fibrosis. Reduced reaction of 4-methylumbelliferylguanidinobenzoate with plasma of patients with cystic fibrosis.

Protease activity in plasma is assayed using 4-methylumbelliferylguanidinobenzoate. The assay is modified by carrying out the reaction in the presence and absence of benzamidine, a competitive inhibitor of trypsin-like proteases. The parameters of the assay are described in detail. Using this assay, our earlier demonstration of a deficiency of protease activity in plasma of patients with cystic fibrosis is confirmed. The activity, corrected for the nonspecific hydrolysis of 4-methylumbelliferylguanidinobenzoate by benzamidine, is expressed as nanomoles of 4-methylumbelliferone released per milliliter plasma. Under standard conditions, the activity in plasma activated with chloroform-ellagic acid was 127.2 +/- 23.1 in 7 controls, 70.4 +/- 11.7 in 11 obligate heterozygotes, and 48.7 +/- 16.6 in 12 patients with cystic fibrosis. Identical results were obtained when unactivated plasma was used. These data demonstrate that the judicious use of specific inhibitors such as benzamidine might be useful in assaying low levels of protease activity in crude systems.

Benzamidines↗