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At least 1,099 records · Page 61Linked to original sources
PubMed1984

Immunological mechanisms of reactions to macromolecular solutions.

Hypersensitivity reactions to intravenous macromolecular solutions are an exacerbation of the organism defence mechanisms with production of exaggerated and deleterious effects. The immediate adverse reactions to drugs (anaphylaxis) have clinical manifestations-due to histamine release principally: cutaneous (rash, urticaria, edema); pulmonary (bronchospasm), and cardiovascular (hypotension, collapse, cardiac arrest); their intensity may be graded in degrees I to V. These reactions may be either truly anaphylactic (immunological): hypersensitivity type I with reaginic antibodies (IgE), requiring previous exposure to the drug (true allergy); other immune responses with antigen-antibody (IgG or IgM) complexes activating classical complement pathway; or anaphylactoid; indirect histamine release by direct activation of C3 (alternate complement pathway) direct histamine release by pharmacological effect; dose related effects. The incidence of reactions to plasma substitutes vary greatly according to authors. In most cases, gelatin derivatives act by direct action on mast cells (histamine release) and indeed prevention of reaction with antihistamines is effective; antibody related reactions occasionally occur (immune complexes). With dextrans, soluble immune complexes aggregates have been described; dextrans may react to specific antibodies (possibly previously produced by bacterial polysaccharides); complement activation occur only in severe reactions. HES is comparable to dextran, antibodies have been described. Other factors may predispose to anaphylactoid reactions such as genetic factors (atopy, primary complement anomalies) underlying immune processes and stress. All macromolecular solutions carry the risk of anaphylactoid side-reactions, the mechanisms of which are not completely clarified.

Anaphylaxis↗
PubMed1978

Changes in the composition of human blood by intravenous saline infusion with and without simultaneous controlled bleeding.

The pattern of dilution and re-concentration of the blood in connection with intravenous infusion of saline-alone or in combination with bleeding-was studied in volunteers. In these we followed the immediate and delayed changes in 16 common haematological and clinical chemical variables in relation to such infusions. In one group 15 ml/kg was given in an hour. In another, 2500 ml was given during a bleeding of 870 ml. These dosage principles are elements of a recommended scheme of peroperative infusion therapy. Estimated by the haemoglobin changes the blood volume was expanded by 10% at the end of infusion alone and by 5% at the end of bleeding/infusion. This expansion, which was of short duration, was accompanied by initial reductions of 15 and 29%, respectively, in serum protein concentration. Three diagnostic enzymes were diluted less systematically. Components of low molecular weight were little affected, except serum calcium, which was 21% decreased at the end of bleeding/infusion. The larger part of the reconcentration took place in the next six hours. In this phase an entry of protein into the blood was demonstrated in both test groups. In contrast to creatininium the carbamide continued decreasing in this time interval. As demonstrated in a control group, other factors than infusion and bleeding contributed on a limited scale to the shift in plasma variables.

Blood↗
PubMed1980

[Infusion therapy and parenteral feeding in acute pancreatitis].

The acute pancreatitis can be a life-threatening disease and can demand the performance of intensive-therapeutic measures. The central position there in occupy the infusion therapy and the parenteral nutrition. On account of the increased catabolism already in the initial phase of the acute pancreatitis the supply of suitable carriers of calories in adequate quantity is necessary. The indication of glucose and the differential indication of fructose and Alvesin "Neu" are discussed. In the treatment of shock human albumin, plasma and plasma substitutes as well as blood take the precedence. Apart from the diagnostic and therapeutic value of the peritoneal lavage in the acute pancreatitis is possesses the additional effect of the dialysis in acute renal failure.

Acute Disease↗
PubMed1981

Antihypertensive effect of plasma volume expansion in pregnancy-associated hypertension.

Plasma and total extracellular fluid volume expansion was confirmed in normal pregnant women in the third trimester of pregnancy. The plasma volume contraction of pregnancy-associated hypertension (pre-eclampsia) was found to be associated with an increase in the interstitial compartment of extracellular fluid volume. The infusion of a plasma volume expander produced significant amelioration of hypertension for 48 h associated with partial reversal of the disturbance of fluid distribution. This finding confirms the central place of volume contraction in maintenance of elevated blood pressure in pregnancy-associated hypertension.

Adult↗
PubMed1980

Plasma exchange (plasmapheresis).

Plasma exchange (plasmapheresis), whereby 1-4 litres of patients' plasma are exchanged for a plasma substitute, has a therapeutic appeal dating back to medieval times. This blunderbuss therapy, removing as it does inflammatory mediators such as fibrin split products and complement breakdown products, immune complexes, antibodies, drugs and antigens, has been most clearly shown to have therapeutic effect in antibody-mediated diseases such as Goodpastures syndrome and Myasthenia Gravis. In chronic rheumatic diseases, such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), claims for improvement have, in the main, been based on insufficient data. More recently, a number of small, uncontrolled trials have suggested that the vasculitis and arthritis of these two diseases is improved by plasmapheresis. Of clinical interest has been the repeated observation that whereas improvement in antibody titres (e.g. DNA antibodies) is transient, clinical improvement, and a lowering of immune complex titres often last for days or even weeks. A recent observation may explain, in part, this finding. Reticulo-endothelial (RES) function, as measured by disappearance rates of heat-damaged red blood cells, is frequently impaired in SLE and RA. Plasmapheresis appears to result in improved RES function, possibly by a 'desaturating' effect on circulating and RES-bound immune complexes.

Agammaglobulinemia↗
PubMed1980

The effect of indomethacin on renal function.

The effect of indomethacin on the renal function has been surveyed by the literature and our experimental data. The primary purpose of the present paper is to discuss the various mechanisms of the prostaglandins which participate in the overall operation of the kidney. Prostaglandin has been proposed as a "natriuretic hormone" effecting the natriuresis observed with extracellular fluid volume expansion. Dogs and rabbits were volume expanded under Nembutal anaesthesia. The massive natriuresis associated with expansion ws significantly reduced in dogs by preloading injection of indomethacin (4 mg/kg) to depress prostaglandin synthesis. The indomethacin pretreatment considerably increased the diuretic and natriuretic effect of the volume expansion in the rabbit. The data are consistent with the concept that intrarenal prostaglandins play a role in adjustment of renal vascular resistance and support the concept of a physiological role of intrarenal PG-s in regulating salt and water excretion.

Animals↗
PubMed1980

Use of human albumin in neurosurgery.

Up to day the control of brain oedema is not yet solved. The role of protein level and oncotic pressure in the maintenance of adequate plasma volume are explained. We discuss all factors worsening cerebral oedema. The haemodynamic aspects of oncotic therapy are presented. Our choice of drugs used in oncotic therapy is human albumin. The beneficial influence of human albumin on the development of cerebral oedema is accentuated.

Brain Edema↗
PubMed1980

Clinical indications for human serum albumin.

Three indications have been considered for the clinical use of human serum albumin: nutrition, binding and transport, and the volume effect due to the oncotic properties of the protein. The use of albumin as an intravenous nutrient is clearly inappropriate. The literature on its binding and transport properties is as yet clinically inconclusive, and it seems premature to enforce product specifications based on these characteristics. The effects on blood volume and hypoproteinemia are firmly established in patients with an intact capillary system. The therapeutic implications of a capillary "permeability lesion" are a subject of current debate. Such lesions occur following extensive injuries and in patients with septic pulmonary failure. Although the data are contradictory, it is largely agreed that the serum albumin level should be kept above 30 g/litre or the total serum protein above 50 g/litre.

Colloids↗
PubMed1994

Hypervolemia and cycling time trial performance.

Ten experienced cyclists rode three simulated time trials to determine whether hypervolemia was associated with improvements in cycling time trial performance. The conditions were: exercise-induced hypervolemia (ExH), dextran-induced hypervolemia (DxH), and euvolemia (Eu). ExH was induced by 3 d of submaximal cycling lasting an average of 92.9 min at an average relative intensity of 68%. DxH was induced by acute plasma volume expansion with 400 +/- 121 ml of a 6% dextran solution. Compared with Eu, ExH and DxH were associated with 9.4% and 8.7% elevations in blood volume as well as 11.1% and 12.4% elevations in plasma volume, respectively. Performance was significantly improved (P < 0.05) (i.e., target work goal reached earlier) during ExH (81.41 +/- 5.52 min) and DxH(81.36 +/- 5.06 min) than during Eu (90.87 +/- 5.27 min). Average power was significantly higher during E x H (246 +/- 13 W) and DxH (245 +/- 14 W) than during Eu (221 +/- 15 W). There were no significant differences in performance time or average power between the two hypervolemic conditions. Average sweat rates were significantly elevated during ExH (22.6 +/- 1.4 ml.min-1) and DxH (22.2 +/- 1.6 ml.min-1) than during Eu (20.4 +/- 1.7 ml.min-1). Rectal temperatures rose from approximately 37.2-39.2 degrees C during each time trial but there were no significant differences in T(re) between trials. In conclusion, hypervolemia, whether induced by short-term training or dextran-infusion, had a beneficial effect on performance and average power during simulated time trials lasting approximately 90 min. These improvements in performance were related to hypervolemia rather than other short-term training adaptations.

Adaptation, Physiological↗
PubMedDate not supplied

The effect of 6% hydroxyethyl starch and desmopressin infusion on von Willebrand factor: ristocetin cofactor activity.

Hydroxyethyl starch is commonly used as a plasma volume expander in the surgical patient. Although it is generally considered a safe plasma substitution, some reports of an acquired von Willebrand's disease-like syndrome have been documented. To examine this further, von Willebrand factor: ristocetin cofactor activity (RCoF) was measured in two groups of patients perioperatively, following hydroxyethyl starch infusion and at 30, 60, and 240 minutes following either deamino-8-D-arginine vasopressin (DDAVP) (group I, n = 12) or saline (group II, n = 11). Following hydroxyethyl starch infusion, ristocetin cofactor activity decreased to 58 percent (group I) and 55 percent (group II) of their respective baseline values. After infusion of DDAVP, mean ristocetin cofactor activity in group I increased significantly to 95 percent at 30 minutes and 100 percent of baseline at 60 minutes. Mean ristocetin cofactor activity levels in group II, however, remained decreased, 69 percent and 57 percent of baseline at the same time points. There was no statistical difference between groups before or immediately after hydroxyethyl starch administration or at 240 minutes post-DDAVP or saline infusion. It is our conclusion that DDAVP is a safe therapy for the mild coagulapathy infrequently associated with hydroxyethyl starch administration.

Blood Coagulation Disorders↗
PubMed1995

Opposite effects of red blood cell aggregation on resistance to blood flow.

We summarized the results of two series of independent experiments recently published by our group which studied the consequences of changes in red blood cell (RBC) aggregation on resistance to blood flow in vivo. The first series compared in vivo apparent viscosity in isolated hearts perfused by either normo-aggregating or non-aggregating RBC suspension. We showed that a moderate degree of RBC aggregation induces a significant decrease in apparent relative viscosity of a suspension of RBC when compared to a non-aggregating RBC suspension. The second series studied the effects of normo vs. hyperaggregation in muscle microvascular network. We showed that hyperaggregation of RBC is responsible for a decrease in arteriolar blood flow velocity and for a decrease in density of perfused capillaries. This latter induces an additional increase in the resistance to blood flow and may also have important deleterious consequences for tissue oxygenation. From these two series of experiments, we concluded that RBC aggregation can have two opposite effects on in vivo viscosity and tissue perfusion. A moderate level of RBC aggregation reduces in vivo viscosity whereas a high level of aggregation increases this viscosity and the resistance to blood flow. We believe that the normo-aggregating state is approximately an equilibrium point between these two tendencies. Consequently, RBC hyperaggregation induced either by acute pathological states, or by use of hyperaggregating plasma substitutes or by biological disturbances which increase RBC aggregation, such as high fibrinogen may have important deleterious consequences for tissue perfusion and tissue oxygenation.

Animals↗
PubMedDate not supplied

[Experimental study of therapeutic efficacy of plasmapheresis in acute radiation injury].

In experiments with dogs exposed to 2.9 Gy (LD80/45) it was found that plasmapheresis treatment 4-6 h after irradiation reduce the severity of the radiation sickness clinical manifestations and post-radiation toxemia thus increasing the rate of animal survival up to 60%. Sham plasmapheresis included all the manipulations of plasmapheretic treatment except plasma substitution and had no detoxication effect and did not affect the irradiated animals survival. This is evidence for leading role of detoxication in the mechanisms of the therapeutic action of plasmapheresis in acute irradiation.

Acute Disease↗