The importance of erythrocyte deformability.
About: This article is published in The American Journal of Medicine.The article was published on 1970-08-01. It has received 228 citations till now. The article focuses on the topics: Erythrocyte deformability.
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TL;DR: Pentoxifylline offers a well-tolerated and effective alternative to the treatment options available for patients with peripheral vascular disease and in isolated studies proved to be superior to drugs such as co-dergocrine mesylate, adenosine and pyrithioxine.
Abstract: Pentoxifylline (oxpentifylline) is an orally active haemorheological agent for the treatment of peripheral vascular disease, cerebrovascular disease and a number of other conditions involving a defective regional microcirculation. Pentoxifylline acts primarily by increasing red blood cell deformability, by reducing blood viscosity and by decreasing the potential for platelet aggregation and thrombus formation. Extensive open and placebo-controlled studies have shown that pentoxifylline 600 to 1200 mg/day for at least 6 weeks is associated with subjective and objective improvements in 60 to 100% of patients with peripheral vascular disease. The most commonly assessed clinical parameter, walking distance, is usually improved by about 100%, although much greater improvements have also been documented. Other parameters which have been clearly improved include lower limb rest pain, paraesthesia, muscle blood flow, cramps and leg ulcers. Pentoxifylline has produced consistently better results than placebo, and in those studies using comparative drugs, better results than nylidrin, adenosine and naftidrofuryl. In patients with cerebrovascular disorders, open studies with pentoxifylline, usually at a dosage of 600 to 1200 mg/day (300 to 600 mg/day in Japan), have shown marked overall clinical improvements in about 85% of patients. Symptomatic improvements in rehabilitation psychometric tests, neuromotor and speech deficits and other subjective symptoms have accompanied increased cerebral blood flow, particularly to ischaemic areas. Pentoxifylline would appear to be useful in most types of cerebrovascular disease including transient ischaemic attacks, sequelae of cerebral thrombosis and haemorrhage, and chronic ischaemic disorders. In patients with chronic cerebrovascular disease pentoxifylline 600 to 1200 mg/day conferred significant clinical benefit compared with placebo and in isolated studies proved to be superior to drugs such as co-dergocrine mesylate, adenosine and pyrithioxine. Preliminary studies indicate that pentoxifylline may also prove useful in vaso-occlusive crises of sickle cell disease, some hearing disorders, disorders of eye circulation, high altitude sickness and asthenozoospermia. Pentoxifylline is usually well tolerated when administered as the conventional controlled release formulation, gastrointestinal symptoms (about 3%) being the most common complaint, although these and other adverse effects have not occurred to a significantly greater extent than with placebo. Thus, pentoxifylline offers a well-tolerated and effective alternative to the treatment options available for patients with peripheral vascular disease.(ABSTRACT TRUNCATED AT 400 WORDS)
1,788Â citations
TL;DR: It is clearly demonstrates that fungal infections represent a common complication in cancer patients, especially in patients with leukemia.
Abstract: In an attempt to estimate the frequency of fungal infections among cancer patients, a survey of autopsy examinations was conducted in multiple institutions in Europe, Japan and Canada. Fungal infections were identified most often in leukemic patients and transplant recipients (25% each). Fifty-eight percent of fungal infections were caused by Candida spp. and 30% by Aspergillus spp. There was considerable variability in the frequency of fungal infections in different countries. Nevertheless, this study clearly demonstrates that fungal infections represent a common complication in cancer patients, especially in patients with leukemia.
527Â citations
TL;DR: The method described here is comparatively simple and has given reproducible results and is a modification of the technique evolved by Schmid-Sch6nbein and
Abstract: To pass through the microcirculation red blood cells (RBCs) need to undergo considerable deformation. The increased rigidity of older cells is probably the main cause of their selective trapping by the spleen; and indirect evidence suggests that impaired deformability may be a critical factor in causing diminished peripheral blood flow (Chien et al, 1967; Schmid-Schonbein et al, 1969; Weed, 1970). Several techniques have recently been developed to measure this property of the RBC, but so far none has achieved wide acceptance. The method described here is comparatively simple and has given reproducible results. It is a modification of the technique evolved by Schmid-Sch6nbein and
463Â citations
Cites background from "The importance of erythrocyte defor..."
...The increased rigidity of older cells is probably the main cause of their selective trapping by the spleen; and indirect evidence suggests that impaired deformability may be a critical factor in causing diminished peripheral blood flow (Chien et al, 1967; Schmid-Schonbein et al, 1969; Weed, 1970)....
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TL;DR: Pentoxifylline given orally in doses up to 1200 mg/day was significantly more effective than placebo in increasing both the initial and absolute claudication distances in patients with COAD.
396Â citations
TL;DR: Application of this approach to a variety of pathologic blood samples showed that various hematologic disorders can be characterized by the shape of this profile and the position of specific features of the profile along the osmolality axis.
372Â citations
References
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1,417Â citations
TL;DR: The oxygen affinity of hemoglobin is decreased in the presence of 2,3-diphosphoglycerate over a wide pH range, and at high concentrations of phosphate buffer, diphosphglycerate has practically no effect on the log p1 2 and n values.
911Â citations
TL;DR: It is proposed that the changes seen in the physical properties of ATP-depleted erythrocytes represent ATP-calcium-dependent sol-gel changes occurring at the interface between the membrane and the cell interior, and that thesol-gel balance determines membrane deformability.
Abstract: A B S T R A C T The contribution of the metabolic state of human erythrocytes to maintenance of cellular deformability was studied during and after in vitro incubation in serum for periods up to 28 hr. An initial loss of membrane deformability became apparent between 4 and 6 hr when cellular adenosine triphosphate (ATP) levels were approximately 70% of initial values. Membrane deformability then remained stable between 6 and 10 hr. After 10 hr, when cellular ATP had decreased to < 15% of initial values, progressive parallel changes occurred in red cell calcium which increased 400% by 24 hr and in the viscosity of red cell suspensions which had risen 500-750% at 24 hr. A further progressive decrease in membrane deformability also occurred and was reflected by a 1000% increase in negative pressure required to deform the membrane. Red cell filterability decreased to zero as the disc-sphere shape transformation ensued. These changes were accompanied by an increase in ghost residual hemoglobin and nonhemoglobin protein. Regeneration of ATP in depleted cells by incubation with adenosine produced significant reversal of these changes, even in the presence of ouabain. Introduction of calcium into reconstituted ghosts prepared from fresh red cells mimicked the depleted state, and introduction of ATP, ethylenediamine tetraacetate (EDTA), and magnesium into depleted cells mimicked the adenosine effects in intact depleted cells. ATP added externally to 24-hr depleted cells was without effect. Simultaneous
800Â citations
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TL;DR: Rheology 863 Experimental Methods, Rheological Tests or Simplified Testing, and Effect of Additives on Blood Rheology.
Abstract: Rheology 863 Experimental Methods. 865 Artifacts and Blood Rheology. 868 Pure water. 868 Physiological saline, Ringer solution. 868 Saline solutions of fractionated plasma proteins. 869 Plasma andserum. 869 Formed elements and physiological saline or equivalent. 870 Whole blood and suspensions of red cells in plasma. 871 Rheology of Normal Human Blood. 874 Basicdata 874 Hematocrit. 876 Fibrinogen. 876 Temperature. 877 Abnormal Human Blood. 877 Polycythemia, anemia. 877 Afibrinogenemia, hyperfibrinogenemia. 878 Diabetes mellitus. 879 Hyperlipemias 879 Plasma protein abnormalities other than fibrinogen. 879 Blood after extracorporeal circulation. 880 Effect of Additives on Blood Rheology. 881 Anticoagulants 88 1 Saline solution. 88 1 Plasma expanders, substitute plasma. 881 Mammalian Blood Other Than Human. 883 Indirect Rheological Tests or Simplified Testing. 884 Physiological Significance of Blood Rheology. 884
586Â citations
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