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PubMed1985

[Erythrocyte aggregation indicator, hematocrit and plasma viscosity in patients with a vascular form of vibration disease].

In 82 men suffering from the vascular form of the vibration disease divided by its advancement into two groups: group I of 42 persons (aged, on average, 40 +/- 7.5) at an early stage of the disease and group II consisting of 40 persons (aged, on average, 49.7 +/- 5.6) at an advanced stage of the disease--haematocrit, plasma viscosity and red-cell aggregation indices were determined. The control group (III) was composed of 100 healthy, average--hard working, men (aged, on average, 41.3 +/- 8.4). In those suffering from the vibration disease the red-cell aggregation and plasma viscosity were found to increase, the rise being more intense in group II.

Adult↗
PubMed1979

[Variations of hematic viscosity due to water-electrolyte disorders induced by muscular stress].

In view of the increasingly widespread tendency of common people to undertake sports activities without adequate athletic preparation, and in consideration of certain cardiovascular alterations detected in subjects cultivating athletic activities of some magnitude for a number of years, the authors set out to explore the effects of severe muscular activity on circulation. More precicely, they measured blood and plasma viscosity at rest and after 50 minutes of intense athletic activity, competitive or otherwise, at the same time looking for possible changes of volemia, blood lipid composition, and hemodynamic parameters. Trained subjects, even if no longer very young, showed viscosity values in the lower range of normal, with no increase following muscular exertion; and likewise no changes of circulating blood volumes. Untrained subjects, conversely, showed more significant increase of both said values, albeit not beyond the limits of norm. The definitely if not dramatically different behavior of the two groups of subjects (trained versus untrained) brings out the value of this simple test. The authors discuss the factors and mechanisms that may be responsible for the observed changes: namely the loss of water and associated changes of electrolyte and protein concentrations, the alterations of blood pH, the changes of paO2, and the increased velocity of blood flow.

Adolescent↗
PubMed1984

Changes in serum albumin hydration at thermoinduced structural transitions in solutions differing in viscosity.

The hydration of human serum albumin in solutions differing in viscosity has been studied in the temperature range of 10-40 degrees C in order to determine the nature of changes in protein hydration at thermoinduced structural transitions. The NMR technique was employed to determine the effective number of protein-bound water molecules (n) considered as a parameter characterizing the protein hydration. It is assumed that the correlation time of the fraction of water molecules (n) in protein solutions is equal to that of HSA macromolecules (tau M). It has been shown that an increase in protein flexibility (tau M decrease) is accompanied by increased n and vice versa. This result confirms the interpretation of cooperative non-denaturational transition based on the dynamic model of protein behaviour suggested earlier. The effect of an increase in protein hydration with the rise in solution viscosity has been shown to be connected with a decrease in the frequency of collisions between macromolecules as well as in the decrease of the destabilizing effect of protein cavity fluctuations over a free solvent. The increase in protein hydration with rising temperature at constant frequency of collisions is explained by the enhancement of the number of water molecules oriented under the influence of charged residues as H-bonds weakened in free solvent water.

Electron Spin Resonance Spectroscopy↗
PubMed1982

[Influence of metabolic control on blood viscosity and platelet activity in insulin requiring diabetics].

Blood and plasma viscosities were determined using respectively a Couette type micro-viscometer (LS 30) and an automatic capillary viscometer (FICA). Plasma beta-thromboglobulin (beta-TG) levels were determined by radioimmunoassay. These parameters were measured in a group of 11 poorly controlled insulin requiring diabetics before and after blood glucose normalization using an artificial pancreas (Biostator GCIIS). Before connection to the artificial pancreas, blood and plasma viscosity and beta-TG levels were significantly higher in diabetics than in controls. The strict metabolic control obtained by the artificial pancreas resulted in a normalization of the hemorheological parameters and in a significant reduction of plasma beta-TG levels after 48 h. These results suggest that the metabolic control of diabetes influences the rheological behavior of blood and the metabolism of platelets.

Adolescent↗
PubMed1984

Abnormal haemostasis and blood viscosity in malignant hypertension.

We have previously shown abnormalities of haemostasis suggestive of intravascular coagulation in patients with malignant hypertension, a condition associated with retinopathy and renal fibrin deposition. To determine whether such abnormalities are specific to malignant hypertension, we have measured several haemostatic and haemorheological variables in 18 patients with malignant hypertension (Group 1), 18 matched healthy controls (Group 2), and 18 patients with non-malignant hypertension (Group 3) matched for renal pathology, blood pressure and serum creatinine with Group 1. Both Groups 1 and 3 had increased mean levels of fibrinogen, factor VIIIc, beta-thromboglobulin, plasma viscosity and blood viscosity (corrected for haematocrit); and decreased mean levels of haematocrit, antithrombin III and platelet count. Mean levels of fast antiplasmin and alpha2-macroglobulin were elevated in Group 1 but not in Group 3. We conclude that most blood abnormalities are not specific to malignant hypertension; are also present in patients with non-malignant hypertension who have similar levels of blood pressure and renal damage; and might result from renal damage as well as promoting further renal damage by enhancing fibrin deposition. However increased levels of fibrinolytic inhibitors in malignant hypertension merit further investigation in relation to removal of renal fibrin.

Adult↗
PubMed1983

Effect of treatment on retinal circulation, platelet aggregation and blood viscosity in insulin-dependent and noninsulin-dependent diabetics.

In order to investigate the influence of diabetic treatment, especially insulin treatment on diabetic retinopathy, disc-to-macula circulation time, platelet aggregation and blood viscosity were observed before and after treatment for 5 years in 42 diabetics (17 insulin-dependent diabetics [IDD] and 25 noninsulin-dependent diabetics [NIDD]). The disc-to-macula circulation time was significantly correlated with the mean blood glucose level. The platelet aggregation in IDD was enhanced significantly as compared with that in NIDD, however after treatment with insulin, the platelet aggregation revealed a significant decrease in IDD. The inter-period changes in the disc-to-macula circulation time before and after treatment in IDD were correlated with those of platelet aggregation, but not with those of blood viscosity. These results suggested that although the blood glucose level was considered to be one of the important factors influencing the retinal circulation, insulin had a direct effect on the platelet function in improving the retinal circulation in addition to lowering the blood glucose level.

Adult↗
PubMed1978

[Measurement of sinus secretions viscosity (author's transl)].

Viscosity studies of the paranasal sinus secretions reflect the recovery of the damaged secretory mucosa. Effectful treatment leads to an increase associated with a wider range between maximal and minimal viscosity. The type of microorganism is less important.

Humans↗
PubMedDate not supplied

[Determination of the surface area and viscosity of membranes in T- and B-lymphocytes by means of fluorescent probes].

The surface area of lymphocyte membranes was measured by registering Förster's energy transfer on fluorescent probes. Pyrene served as donor, 4-(n-hydroxystyryl)-N-tetradecylpiridinium (HSP) was the acceptor. The surface area B-lymphocyte membranes was shown to be 1,2 times larger than that of T-lymphocytes. The mean value of lymphocyte membranes viscosity was measured using the excimerization effect of pyrene. This value was the same in all the cells investigated Fluorescence of the probe 3-methoxybenzanthrone (MBA) was 2-2.5 times higher in B-lymphocytes and was not proportional to the surface area of T- and B-cells membranes. MBA fluorescence may imply some differences in physical structures of these cells which are not connected with the viscosity of their membrane lipid phase.

Animals↗
PubMed1983

Viscosity adaption for an automated micromethod of flame atomic absorption spectrometry, and intracellular trace-element analysis after pressure decomposition: zinc determination in plasma and erythrocytes.

We measured zinc in the plasma of 50 normal persons, and in erythrocytes of six, by an automated micromethod of atomic absorption spectrometry. Using a rotation viscometer, we measured the viscosity and flow behavior of plasma, undiluted and equi-volume diluted (with water), from 12 patients, and, for comparison, of two- to 20-fold dilutions of an 870 mL/L glycerol solution. Erythrocytes were washed three times, lyophilized, and wet-ashed in a pressure decomposition device. The mean viscosity of equi-volume diluted plasma is about the same as that of the glycerol solution diluted 7.5-fold. The observed concentration of zinc in normal plasma was 13.8 (SD 1.9) mumol/L, with intra-assay CV (n = 30) of 2%, day-to-day CV (n = 22) 3.8%, and accuracy (measurement of an aqueous std.) 2.5%. The mean normal value for erythrocyte zinc was 34.7 micrograms/g, with intra-assay CV (n = 8) 5%, day-to-day CV (n = 6) 5.9%, and accuracy 4.6%. Our results compare well with those by neutron activation analysis, the differences in values being 3% for plasma, 1% for erythrocytes.

Autoanalysis↗
PubMedDate not supplied

[Viscosity of free and protein-bound lipids in membranes].

Structural transitions induced by temperature in the lipid bilayer of rabbit sarcoplasmic reticulum membranes have been detected by means of the hydrophobic fluorescent probe pyren. Using the phenomenon of energy migration from membrane protein tryptophan residues to pyren a correct estimate of lipid viscosity near protein molecules was made by an empirical formula. The structural transitions of free and protein-bound lipids proceeded at the same temperature intervals. It was found that viscosity of protein-bound lipids was higher than that of free lipids, but they became equal at 36--39 degrees C.

Animals↗
PubMedDate not supplied

[Changing characteristic viscosity of DNA interacting with Cu2+ and Mn2+ ions].

The interaction of DNA with Cu2+ and Mn2+ ions in low ionic strength solutions (10(-3) M NaCl) has been studied by the viscosimetry method. The DNA characteristic viscosity [eta] decreases sharply at low ion concentrations (addition of 10(-5) M Cu2+ leads to [eta] reduction by a factor of 1.4) and attains certain saturation at high concentrations, the saturation magnitude slightly depending on the ion type. The reduction is much lower in solutions containing bivalent ions, in concentration 2 X 10(-2) M NaCl. The experimental data for bivalent and monovalent (Na+) ions have been compared. The results are discussed in terms of equilibrium ion-DNA binding and compared with the Fixman theory. It is discussed if ion binding constants can be determined by visosimetry. It is shown that the cause of the viscosity reduction with time observed by some authors may be the action of DNAases activated by metal ions.

Animals↗
PubMed1982

Viscosity and filtrability measurements of sickle-cell suspensions in the development of anti-sickling drugs.

We have developed two rheological methods for use in the study of the effect of anti-sickling drugs on in vitro sickling: (a) An automated instrument which measures the relationship between the oxygen partial pressure and blood viscosity, and (b) an instrument to measure the relationship between filtrability (through a 3 mu-pore Nuclepore filter) and the oxygen partial pressure. With these instruments, we found that both viscosity and filtration pressure of a sickle-cell suspension increased even at oxygen saturation values above 90%, levels at which morphological changes of sickle cells are not yet pronounced. The effect of anti-sickling drugs was demonstrated by a decrease of the filtration pressure at low oxygen saturation.

Anemia, Sickle Cell↗
PubMed1981

Effects of solvent composition and viscosity on the rates of CO binding to heme proteins.

The rate of CO binding to myoglobin increases 4-fold, from 5 X 10(5) M-1 s-1 to 2 X 10(6) M-1 s-1, in going from 0 to 80% glycerol in phosphate buffer at pH 7, 20 degrees C. Under the same conditions, the rate of CO binding to protoheme decreases monotonically from about 1 X 10(8) M-1 s-1 to 2 X 10(7) M-1 s-1. The kinetic behavior of protoheme at neutral pH is that expected for a diffusion-controlled reaction. Increasing solvent viscosity causes a decrease in the observed second order rate constant. In contrast, the behavior of the myoglobin indicates quite clearly that internal, nondiffusive processes are limiting the speed of the reaction. The rate enhancement is due to an increase in the standard chemical potential of the ligand molecule as the polyalcohol concentration is increased. Both types of behavior are observed for ligand binding to protoheme in 0.1 N NaOH; first an increase and then a decrease in rate is observed as the concentration of glycerol is increased. At low glycerol concentrations, the reaction rate is limited by a first order process. At high concentrations, the rate becomes diffusion-controlled and exhibits a dependence on the reciprocal of the solvent viscosity. The data for all these conditions have been analyzed empirically in terms of a single free energy barrier and more specifically in terms of a consecutive reaction scheme.

Animals↗
PubMed1980

[Blood serum viscosity in patients with advanced vascular forms of vibration disease].

In 35 persons afflicted by advanced angioneurotic vibration syndrome, with no contact with mechanical vibrations for the past several years and recognized invalidity due to vibration disease, specific and reduced blood serum viscosity have been determined, as well as total protein concentration and albumin to globulin concentrations ratio. Control groups were composed of 32 healthy subjects, with no contact with vibration or any other environmental hazards, as well as of 57 professionally active subjects, afflicted by angioneurotic vibration syndrome. A significant increase in specific and reduced viscosity in the group with advanced angioneurotic vibration syndrome, as compared to both the remaining groups, was found. At the same time, the albumin-globulin concentrations ratio was found to be decreased, the total protein concentration remaining unaltered.

Adult↗
PubMed1993

[In vitro modification of plasma viscosity and erythrocyte aggregation by four plasma substitutes].

We tested the haemorheological effects of the addition of 3.5% oxypolygelatine, 10% dextran 40, 6% dextran 75 or 5% albumin, respectively, to fresh donor blood of 25 healthy young persons. We examined the aggregation and the viscosity of substituent plasma mixtures in such various, but constant volume relations as may be present during intravenous infusion. Albumin reduced viscosity and aggregation, but especially dextran 75 increased both parameters significantly.

Adult↗
PubMed1993

Serum viscosity is a sensitive test for monitoring primary Sjögren syndrome.

Primary Sjögren's syndrome (pSS) is characterized by chronic inflammation, resulting in secondary changes in serum protein content. In an attempt to evaluate disease activity we have measured serum viscosity (SV) in 41 patients with pSS and compared SV with laboratory findings such as: total proteins, gamma-globulin concentrations, titre of rheumatoid factor (RF) and level of circulating immune complexes. SV was found to correlate with these laboratory parameters. The pSS patients with low serum viscosity had worse clinical abnormalities than those with the high SV. Thus SV affords a useful monitoring test for pSS patients.

Blood Proteins↗