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Biomedical subjects

K Wagner

Publications and source records attributed to K Wagner.

At least 307 records · Page 17Linked to original sources
PubMed1984

Preparation of low-affinity red cells with dimethylsulfoxide-mediated inositol hexaphosphate incorporation: hemoglobin and ATP recovery using a continuous-flow method.

Incorporation of IHP into red cells decreases oxygen affinity as a result of the binding of this compound to the 2,3-DPG site of hemoglobin. This investigation describes a continuous-flow method which utilizes the osmotic pulse technique to transport IHP into RBC. Using this procedure, it is possible to obtain a significant increase in P50 while maintaining in vitro cellular integrity. For example, IHP incorporation sufficient to cause an increase in the P50 of 20 mm Hg may be achieved with recovery of approximately 75% of the hemoglobin and with maintenance of ATP levels compatible with good viability. The continuous-flow method allows uniform treatment of large, unit-size volumes of red cells with a relatively small quantity of reagents. The final cell product is macrocytic/hypochromic with an increased number of stomatocytes.

Adenosine Triphosphate↗
PubMed1984

Prostaglandin E2 promotes hypotension on low-sodium hemodialysis.

The influence of low-sodium dialysate (126 mmol/l) on plasma levels of prostaglandin E2 (PGE2) and PGF2 alpha, plasma renin activity (PRA) and arterial blood pressure was investigated in 16 patients on maintenance hemodialysis. PGE2 rose more than tenfold and there was a significant increase in PGF2 alpha and PRA. Mean arterial pressure dropped by 30 mm Hg causing discomfort in several patients. By contrast, conventional hemodialysis against 140 mmol/l of sodium was followed by less pronounced changes in plasma prostaglandins, and reduction of blood pressure was moderate (13 mm Hg). It is suggested that vasodilating prostaglandins may contribute to dialysis hypotension. Their origin may not be confined to the kidneys but rather extend to the lungs and circulating blood cells. The in vitro generation of prostaglandins was demonstrated when donor blood was circulated in an extracorporeal dialysis system.

Dinoprost↗
PubMed1984

[Death following fructose and sorbitol infusions].

Hereditary Fructose Intolerance (HFI) is a rare inherited metabolic disease. Because of the wide application of infusions containing fructose and sorbitol, patients suffering from this disease are at special risk. The disease is frequently not diagnosed until adulthood and the danger associated with this delay is insufficiently recognized. This report therefore included a case history in which this is highlighted.

Adult↗
PubMed1983

Elimination kinetics of plasma exchange.

Interest in the therapeutic use of plasma exchange for various diseases is growing. The two different effects of plasma exchange are elimination and activation. The kinetics are linear for elimination by plasma exchange, but not for activation. Plasma exchange is performed intermittently and can be described by intermittent kinetics. According to intermittent kinetics, plasma exchange removes 50% to 75% of a substance in plasma within 1-2 h, corresponding to an elimination half-life of 30-40 min. Hybrid kinetics, a mixture of actually intermittent but theoretically continuous elimination by plasma exchange, can however also be applied. Hybrid kinetics are more convenient and more reliable than intermittent kinetics. This is because hybrid kinetics are based solely on the concentrations before each plasma exchange; hybrid kinetics also reflect removal from the entire body and not just from the plasma compartment. According to hybrid kinetics, the amount of a substance in the body removed within 3-4 days is 50% of the difference between the initial and the final plasma concentration, depending on the intensity of plasma exchange. The intensity may well contribute at least in part to the beneficial effect of plasma exchange in various diseases.

Antibodies↗
PubMed1983

Incorporation of inositol hexaphosphate into red blood cells mediated by dimethyl sulfoxide.

Inositol hexaphosphate (IHP) binds to deoxyhemoglobin and markedly decreases the affinity of hemoglobin for oxygen. We introduce here a method for incorporating this polyphosphate into erythrocytes, thus preparing very low affinity cells for use in respiration research. The method uses dimethyl sulfoxide (DMSO) to facilitate entry of IHP. The cells are exposed to a high concentration of DMSO which is rapidly diluted with IHP solution. During this dilution the cells become leaky and IHP enters. The influence of several variables at each step of the process has been investigated and the data support a transient osmotic gradient mechanism for IHP incorporation.

Dimethyl Sulfoxide↗
PubMed1982

Demonstration of cerebrospinal fluid oligoclonal banding in neurologic diseases by agarose gel electrophoresis and immunofixation.

Demonstration of an oligoclonal immunoglobulin pattern in cerebrospinal fluid by a commercial agarose gel electrophoresis system and immunofixation were evaluated in the service clinical laboratory of a university hospital. In 303 patients, 45 with clinically definite multiple sclerosis and 209 with other neurologic diseases, the sensitivity of oligoclonal banding for multiple sclerosis was 71%, and the specificity, 83%. Oligoclonal banding was frequent in inflammatory disease, tumor/pseudotumor or vascular diseases of the central nervous system (35%, 36% and 26%, respectively) and less frequent in degenerative central nervous system disease and peripheral neuropathy (5.2% and 15%). No patient with non-neurologic disease had oligoclonal banding. The addition of an immunochemical step (immunofixation) did not increase sensitivity and only minimally increased specificity. It did permit distinction in selected cases between immunoglobulin and other molecules with identical electrophoretic mobility.

Brain Neoplasms↗
PubMed1982

Influence of prostaglandins A1, E1, E2, and F2 alpha on renal blood flow and plasma renin activity. Investigations in chronically instrumented conscious dogs.

The effects of different prostaglandins (PG) on serial determination of renal blood flow (RBF), mean arterial blood pressure (MABP), renal vascular resistance (RVR) and renin release were investigated in the conscious, chronically instrumented dog. 2 months after right-sided nephrectomy, female beagle dogs (n = 6) were implanted with an electromagnetic flow probe and an inflatable pneumatic cuff around the left renal artery, and a catheter was inserted into the aorta above the renal artery. In repeated experiments, different prostaglandins (PGA1, E1, E2 and F2 alpha) were infused above the renal artery at increasing doses (infusion time 15 min, doses 0.03--1.0 micrograms min-1 kg-1). Lower and medium doses induced an increase of RBF, which returned to or were slightly below control levels with higher doses. PGA1 appeared to be the most potent vasodilator with a significant hypotensive activity and the greatest augmentation of RBF. Simultaneously, renin release was most pronounced by PGA1.

Animals↗
PubMed1981

Inhibition of anti-inflammatory drugs of prostaglandin production in cultured macrophages.

1. A sensitive, simple, reproducible, and economical assay for structure-activity investigations of non-steroidal anti-inflammatory drugs (NSAID) is lacking. This has prompted us to investigate the advantages and limitations of defining for that purpose the potency of NSAID's as inhibitors of tumour promoter-induced prostaglandin (PG) release from mouse peritoneal macrophages in culture. 2. These cells release mainly PGE2 and PGI2 (measured as its stable hydrolysis product 6-keto-PGF1 alpha) upon stimulation with the tumour promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). 3. The PG release was dose-dependently inhibited by a variety of NSAID's. Their inhibitory potency was dependent on the culture conditions employed. The widely used acidic NSAID's were more potent when assayed under serum free culture conditions at low pH. 4. Dose response curves for acidic NSAID tested under serum free conditions allowed for the definition of IC50 values being reproducible within their 95% confidence limits. 5. The IC50 values obtained for different standard acidic NSAID's varied within 4 orders of magnitude. They corresponded favourably to their clinical potency and their potency in a variety of standard tests for anti-inflammatory drugs. 6. IC50 values of five congeners of indomethacin differed up to 2 orders of magnitude in agreement with in vivo observations indicating the applicability of this assay for structure-activity investigations.

Animals↗