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PubMedDate not supplied

Cryoprecipitate-poor plasma fraction (cryosupernatant) in the treatment of thrombotic thrombocytopenic purpura at onset. A report of four cases.

Treatment of thrombotic thrombocytopenic purpura (TTP) with cryoprecipitate-poor plasma (cryosupernatant) as substitution liquid has brought a portion of the relapsing forms of this syndrome under control. We experimented the use of plasma exchange (PE) with CPP as plasma substitute in the initial treatment of four patients with TTP at onset, in an attempt to elicit a faster response to therapy. We observed a clinical response in the four patients treated; however, laboratory indices of complete and stable response (platelet count, serum lactate dehydrogenase level) did not normalize in concert with clinical improvement.

Adult↗
PubMed2002

Hydroxyethylstarch as a risk factor for acute renal failure: is a change of clinical practice indicated?

Hypovolaemia is extremely common among surgical and intensive care patients. The best strategy for volume replacement therapy has been the focus of debate for several years. The lack of acceptance of hydroxyethylstarch (HES) for volume replacement therapy is most likely due to reports of abnormal coagulation and to recently published studies indicating negative effects of HES on renal function. All HES solutions are not created equal - they widely differ with regard to their physicochemical characteristics (concentration, mean molecular weight (Mw), degree of substitution [DS], C2/C6-substitution ratio). These differences have important consequences for adverse effects such as alterations in the coagulation process and on kidney function. Conflicting results about the effects of different HES solutions on renal function may also be due to varying clinical protocols, selection of patients, and different criteria for volume replacement. Theoretical and documented hazards are associated with each kind of volume replacement therapy. There appears to be no reason to banish modern HES preparations with a low or medium Mw (e.g. 70, 130 or 200 kD) and a low DS (0.4 or 0.5) in patients without pre-existing kidney dysfunction. In patients with known renal dysfunction (e.g. plasma creatinine level >3 mg/dl), all HES preparations should be used cautiously and other volume replacement regimens (e.g. gelatins) should be considered since no convincing data are yet available for the latest generation of HES (Mw 130; DS 0.4).

Acute Kidney Injury↗
PubMed1995

Effects of 6% hydroxyethyl starch and 3% modified fluid gelatin on intravascular volume and coagulation during intraoperative hemodilution.

In the perioperative period, artificial colloids are most often infused in doses of 500-1000 mL intravenously. This randomized study compared the effects on intravascular volume and coagulation of approximately 2000 mL of two isooncotic artificial colloids: 6% hydroxyethyl starch (HES; MW 200,000; substitution ratio 0.40-0.55) and 3% modified fluid gelatin (GEL). We hypothesized more pronounced hypocoagulation with HES and a weaker intravascular volume effect of GEL. Forty-two patients, scheduled for primary total hip replacement, were allocated randomly to receive HES or GEL during acute normovolemic hemodilution and subsequent further intraoperative hemodilution. Blood samples were taken before and after 500 mL and 1000 mL of acute normovolemic hemodilution; intraoperatively after 20 mL/kg of artificial colloid and at the end of colloid infusion; on arrival in the recovery room; and 3 h later. We quantified: 1) coagulation variables; 2) blood loss; 3) hemodynamic stability; 4) necessary infusion volume; 5) interstitial extravasation, calculated from plasma volunteers measured using albumin marked with technetium-99m and iodine-125, respectively; 6) percentage volume effect at the end of the study as well as hematocrit, total serum protein, and colloid osmotic pressure. Intraoperative volume therapy was guided by radial systolic pressure and systolic pressure variation, mixed venous hemoglobin saturation in the pulmonary artery, and pulmonary capillary occlusion pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1996

Evaluation studies on oxypolygelatin and degraded gelatin as plasma volume expanders.

Oxypolygelatin (CAS 9005-91-8, OPG) and degraded gelatin (CAS 9000-70-8, DG) have attracted the interest of many investigators as promising plasma protein substitutes. This paper deals with comparative evaluation studies on OPG and DG as regards stability and some biochemical consequences following i.v. infusions in rabbits. Accelerated aging tests showed a decrease in pH of OPG from 7.3 to 7.0. The pH of DG increased from 5.2 to 5.4 during the same period of aging. In both cases, the buffer capacity increased 3.0 to 3.5 in case of OPG and from 2.5 to 3.7 in case of DG. The relative viscosity of OPG decreased from 2.18 to 1.98 as compared to 1.79 to 1.58 in case of DG. Comparative studies on both OPG and DG postinfusion in rabbits, showed significant (p < 0.001) retention OPG in blood 24 h postinfusion, at which time, DG was practically absent. The decline in rabbit plasma protein was marked and more persistent in case of compared to DG. Plasma sodium showed a significant decline (p < 0.05) in case of OPG 1 h postinfusion, while plasma potassium showed a significant decline (p < 0.05) immediately postinfusion. In case of OPG, serum calcium showed a significant decline (p < 0.001) immediately postinfusion. This effect was marked at 1 h, 5 h and 24 h postinfusion. In case of DG, no significant changes in the levels of sodium, potassium, calcium and magnesium were observed at all time intervals postinfusion of the plasma volume expander.

Animals↗
PubMed2000

Abolishment of proton pumping and accumulation in the E1P conformational state of a plant plasma membrane H+-ATPase by substitution of a conserved aspartyl residue in transmembrane segment 6.

The plasma membrane H(+)-ATPase AHA2 of Arabidopsis thaliana, which belongs to the P-type ATPase superfamily of cation-transporting ATPases, pumps protons out of the cell. To investigate the mechanism of ion transport by P-type ATPases we have mutagenized Asp(684), a residue in transmembrane segment M6 of AHA2 that is conserved in Ca(2+)-, Na(+)/K(+)-, H(+)/K(+)-, and H(+)-ATPases and which coordinates Ca(2+) ions in the SERCA1 Ca(2+)-ATPase. We describe the expression, purification, and biochemical analysis of the Asp(684) --> Asn mutant, and provide evidence that Asp(684) in the plasma membrane H(+)-ATPase is required for any coupling between ATP hydrolysis, enzyme conformational changes, and H(+)-transport. Proton pumping by the reconstituted mutant enzyme was completely abolished, whereas ATP was still hydrolyzed. The mutant was insensitive to the inhibitor vanadate, which preferentially binds to P-type ATPases in the E(2) conformation. During catalysis the Asp(684) --> Asn enzyme accumulated a phosphorylated intermediate whose stability was sensitive to addition of ADP. We conclude that the mutant enzyme is locked in the E(1) conformation and is unable to proceed through the E(1)P-E(2)P transition.

Adenosine Triphosphatases↗
PubMed1997

Persistent pruritus after hydroxyethyl starch infusion therapy: a result of long-term storage in cutaneous nerves.

A high incidence of severe pruritus has been observed after the administration of hydroxyethyl starch (HES) on account of plasma volume substitution and improvement of the microcirculation. The aim of this study was to elucidate the possible pathomechanisms of HES-induced itching. Skin biopsies were taken from 93 patients, half of them presenting with pruritus, who received HES of various preparations and cumulative dosages. The samples were subjected to immunoelectron microscopical investigation using an antibody highly specific for HES. After infusion therapy with HES, formation of intracytoplasmic storage vacuoles in the skin could be demonstrated in all patients. A dose-dependent uptake of HES was first detectable in macrophages and, thereafter, in endothelial and epithelial cells. Consecutive control biopsies taken from single patients revealed a subsequent reduction of the vacuoles, in size and number, within 3 years, thus indicating a regular cutaneous metabolism of HES. Patients suffering from pruritus consistently showed additional deposition of HES in small peripheral nerves. HES-reactive vacuoles could be demonstrated in the Schwann cells of unmyelinated, as well as small myelinated, nerve fibres, and in endoneural and perineural cells. Neural devacuolization paralleled the clinical improvement in the symptoms. In conclusion, HES deposits in cutaneous nerves, as a consequence of a higher cumulative dosage, may account for the itching seen after HES infusion.

Adolescent↗
PubMed1981

Colloids versus crystalloids as volume substitutes: clinical relevance of the serum oncotic pressure.

With some amplifications, Starling's concept of the serum colloid osmotic or oncotic pressure as the determinant of fluid partition between the intravascular and the interstitial compartment has been confirmed by modern physiological research. The relationship between serum oncotic pressure and interstitial edema is non-linear, i.e. edema becomes progressively greater per mm decrease of the oncotic pressure. The intravascular volume effect of crystalloids is inseparable from interstitial edema, because it depends on an expansion of the interstitium which increases the hydrostatic pressure in that compartment sufficiently to compensate for a lowered capillary oncotic pressure. With large crystalloid fluid loads, about 90% of the total edema accumulates in skeletal muscle, subcutaneous fat, and the skin. The skin is particularly susceptible to the development of edema associated with a hypoproteinemic fluid overload, presumably because its extracellular space is three times larger than the average whole-body value. The intestine also shows a marked reaction to a hypoproteinemic fluid overload. There is evidence for a pathogenetic significance of hypoproteinemic edema in the myocardium, the intestine, and the skin. To rid a patient of this type of edema, concentrated albumin is indispensable, and its effects are demonstrable in the above-mentioned tissues, whereas a diuretic alone is ineffective. The therapeutic implications of these mechanisms and findings are discussed. In the lung, fluid exchange and distribution between the intravascular and the interstitial compartment is influenced by additional factors, and opinions on the use of colloids versus crystalloids continue to differ, particularly with respect to those circumstances where capillary permeability is presumably or demonstrably abnormal. However, the weight of the evidence still favours the concept that in patients with a much greater than respiratory distress syndromes much greater than, the serum oncotic pressure should at any rate not be permitted to drop below a certain critical level. A condensed review of these complex and as yet incompletely clarified problems is presented.

Blood Physiological Phenomena↗
PubMed2001

Colloids versus crystalloids and tissue oxygen tension in patients undergoing major abdominal surgery.

UNLABELLED: The effects of intravascular volume replacement regimens on tissue oxygen tension (ptiO(2)) are not definitely known. Forty-two consecutive patients scheduled for elective major abdominal surgery were prospectively randomized to receive either 6% hydroxyethyl starch (HES) (mean molecular weight 130 kd, degree of substitution 0.4, n = 21) or lactated Ringer's solution (RL, n = 21) for intravascular volume replacement. Fluids were administered perioperatively and continued for 24 h on the intensive care unit to keep central venous pressure between 8 and 12 mm Hg. The ptiO(2) was measured continuously in the left deltoid muscle by using microsensoric implantable partial pressure of oxygen catheters after the induction of anesthesia (baseline, T0), 60 min (T1) and 120 min thereafter (T2), at the end of surgery (T3), and on the morning of the first postoperative day on the intensive care unit (T4). HES 130/0.4 2920 +/- 360 mL and 11,740 +/- 2,630 mL of RL were given to the patients within the study period. Systemic hemodynamics and oxygenation (PaO(2), PaCO(2)) did not differ significantly between the two volume groups throughout the study. From similar baseline values, ptiO(2) increased significantly in the HES-treated patients (a maximum of 59% at T4), whereas it decreased in the RL group (a maximum of -23% at T4, P < 0.05). The largest differences of ptiO(2) were measured on the morning of the first postoperative day. We conclude that intravascular volume replacement with 6% HES 130/0.4 improved tissue oxygenation during and after major surgical procedures compared with a crystalloid-based volume replacement strategy. Improved microperfusion and less endothelial swelling may be responsible for the increase in ptiO(2) in the HES 130/0.4-treated patients. IMPLICATIONS: In patients undergoing major abdominal surgery, a colloid-based (with hydroxyethyl starch [HES] 130/0.4) and a crystalloid-based (with lactated Ringer's solution [RL]) volume replacement regimen was compared regarding tissue oxygen tension (ptiO(2)) measured continuously by microsensoric implantable catheters. The ptiO(2) increased in the HES-treated (+59%) but decreased in the RL-treated (-23%) patients. Improved microcirculation may be the mechanism for the better ptiO(2) in the HES group.

Abdomen↗