1. |
- Fagher, Birger, et al.
(author)
-
Blood viscosity during long-term treatment with ticlopidine in patients with intermittent claudication. : A double-blind study
- 1993
-
In: Angiology. - New York, USA : Westminster Publications, Inc.. - 0003-3197 .- 1940-1574. ; 44:4, s. 300-306
-
Journal article (peer-reviewed)abstract
- Abstract The aim was to test within a randomized, double-blind trial whether the antiaggregant drug ticlopidine might reduce blood viscosity as has been claimed. Sixteen patients with intermittent claudication were studied before and after three years of treatment with ticlopidine, 500 mg/day, or placebo. At baseline, the viscosity values were significantly higher as compared with a reference group of healthy subjects. Whole-blood viscosity, measured at four different shear rates at hematocrit adjusted to a standard 40%, decreased significantly at follow-up, with no difference between ticlopidine treatment and placebo. Hematocrit showed a slight increase in the placebo group. The viscosity parameters were unrelated to lower limb blood flow variables, ankle/brachial index, and walking distances. The mechanism behind the overall decrease in whole-blood viscosity is obscure but could possibly be explained by lifestyle changes. Smoking habits were, however, unaltered. Since plasma viscosity remained increased, it might indicate that some erythrocyte factor, notably red cell aggregability and deformability, had improved. It is concluded that ticlopidine had no long-term effect on blood viscosity.
|
|
2. |
- Gustavsson, Carl Gunnar, et al.
(author)
-
Blood viscosity in relation to blood haemoglobin concentration in healthy subjects and in patients with different cardiovascular diseases
- 1994
-
In: Clinical Hemorheology. - New York, USA : Pergamon Press. - 0271-5198. ; 14:5, s. 677-683
-
Journal article (peer-reviewed)abstract
- Abstract Blood viscosity was measured at different shear rates using a rotational viscometer, and the correlation between blood viscosity and blood haemoglobin concentration was studied. In 10 healthy controls correlation coefficients were: 0,966 at shear rate 40,0 s-1, 0,931 at 19,6 s-l, 0,817 at 2,3 s-1 and 0,816 at 0,8 s-l , p<0,01 to p < 0,001. The regression lines for these relationships were then applied to the patient groups to calculate what blood viscosity should be predicted solely from the individual haemoglobin concentration, "predicted blood viscosity". In 34 patients with cardiovascular diseases (20 patients with coronary artery disease (CAD), 8 patients with idiopathic dilated cardiomyopathy and 6 patients with primary pulmonary hypertension) the correlation between blood viscosity and haemoglobin concentration was less good, for the total patient material 0,748 to 0,613, p < 0,001 at all shear rates, and for the CAD patients 0,664 to 0,428, p < 0,05 at 3 out of 4 shear rates. Apparently the poorer correlation in the patients was due to a larger influence from factors unrelated to haemoglobin concentration/haematocrit, as the quotients between individually measured and predicted blood viscosity correlated with measured blood viscosity when the haematocrit factor had been eliminated by in vitro standardisation of sample haematocrits to 45%. Key words: Blood viscosity; Haemorheology; Haemoglobin concentration; Microcirculation.
|
|
3. |
- Gustavsson, Carl Gunnar, et al.
(author)
-
Changed blood rheology in patients with idiopathic dilated cardiomyopathy
- 1994
-
In: Angiology. - New York, USA : Westminster Publications, Inc.. - 0003-3197 .- 1940-1574. ; 45:2, s. 107-111
-
Journal article (peer-reviewed)abstract
- Abstract Rheologic properties of blood were studied in 8 patients with dilated cardiomyopathy (DCM) and in 10 healthy subjects. Whole-blood viscosity was measured at four different shear rates, by means of a computer-controlled rotational viscometer. The patients had significantly higher blood viscosity at all shear rates, both at their natural hematocrits and after an in vitro adjustment of sample hematocrits to 45%. Erythrocyte filterability (5 μm pore size) was significantly lower, fibrinogen concentration significantly higher, and HDLcholesterol concentration significantly lower in the patient group. No significant differences were found regarding hematocrit, mean corpuscular volume, haemoglobin concentration, leukocyte count and filterability (8 μm pore size), plasma viscosity, and total cholesterol concentration. The measured hemorheologic abnormalities may contribute to the previously reported reduction of coronary blood flow reserve in DCM patients and to myocardial microcirculatory disturbances, which have been suggested as a cause for DCM.
|
|
4. |
- Persson, Sylvi, et al.
(author)
-
Increased blood viscosity and decreased red cell filterability in patients with dilated cardiomyopathy
- 1991
-
In: 7th European Conference on Clinical Haemorheology, Southampton, United Kingdom, July 16-19, 1991..
-
Conference paper (peer-reviewed)abstract
- Abstract Rheological properties o f blood were studied in eight patients with dilated cardiomyopathy (DCM) and ten healthy controls . Whole blood viscosity was measured at 4 different shear rates, using a computer controlled rotational viscometer. Patients had significantly higher blood viscosity at all shear rates, both at the patients natural hematocrits and after in vitro adjustment of sample hematocrits to 45%. Erythrocyte filterability measured by St George's Filtrometer and expressed as red cell transit time (RCTT) were significantly lower in patients. Hematocrits were higher but not statistically significant. No differences were found regarding plasma viscosity, leucocyte count and leucocyte filterability. The blood rheology changes found in this study may contribute to myocardial perfusion disturbances, which have been suggested a s a cause for DCM. The coronary blood flow reserve is reduced in patients with DCM as well as in patients with angina pectoris, both with and without coronary artery stenosis (Syndrome X). In all three patients cathegories we have found increased blood viscosity but DCM differs by by normal plasma viscosity.
|
|
5. |
- Persson, Sylvi, et al.
(author)
-
Studies on blood rheology in patients with primary pulmonary hypertension
- 1990
-
In: 32nd Annual Meeting of the International College of Angiology, Toronto, Canada, June 24-29, 1990.
-
Conference paper (peer-reviewed)abstract
- Abstract Background: Disturbances of blood rheology may create unfavorable changes of blood flow. The present study was performed to reveal possible hemorheologic abnormalities in primary pulmonary hypertension. Methods: Six patients with primary pulmonary hypertension (PPH) and 10 healthy controls of comparable age and smoking habits were studied. Blood viscosity was studied with a computer-controlled rotational viscometer, at natural hematocrit and at standardized hematocrit (45%). A capillary U-tube was used for plasma viscosity studies. Blood cell filterability was measured by theSt. George's Filtrometer (according to Dormandy et a1). Nucleopore filters of 5 (erythrocytes) and 8 (leukocytes) micrometers were used. Results: Whole blood viscosity in PPH patients was higher than in controls at four different shear rates (p<0.025-0.005). This was partly due to a higher concentration of red cells in the patients. After standardization to 45% however, the difference was still there at the highest shear rate used (40 s-1). It was also found that the passage time for erythrocytes through the filter was increased in the patient group, indicating decreased erythrocyte deformability. There were no significant differences between the groups in plasma viscosity, plasma fibrinogen, concentration of leukocytes, or leukocyte deformability. Conclusions: Patients with PPH show increased whole blood viscosity values. This is partly explained by an increased hematocrit. It is also found, however, that the deformability of erythrocytes in these patients is decreased. These changes may influence blood flow in an unfavorable way. Therapeutic measures against hemorheologic disturbances may be a possible complement to the commonly used vasodilatory treatment.
|
|
6. |
- Persson, Sylvi Ulrika, et al.
(author)
-
Studies on blood rheology in patients with primary pulmonary hypertension
- 1991
-
In: Angiology. - New York, USA : Westminster Publications, Inc.. - 0003-3197 .- 1940-1574. ; 42:10, s. 836-842
-
Journal article (peer-reviewed)abstract
- Abstract The rheologic properties of blood were studied in 6 patients with primary pulmonary hypertension (PPH) and compared with those of a control group of 10 healthy subjects. Blood viscosity was studied with a rotational viscometer and blood cell deformability with a filtrometer giving values for clogging particles (CP) and red cell transit time (RCTT). Blood viscosity at varying shear rates was found to be increased both at natural (p<0.025-0.005) and standardized hematocrit, 45% (p<0.05 at 40 s-1) in patients with PPH. Red cell deformability was reduced as indicated by a significant increase of RCTT (p<0.01). Increased values for hematocrit (p<0.001), hemoglobin concentration (p< 0.001), and erythrocyte count (p<0.005) were found and decreased values for mean corpuscular hemoglobin concentration (MCHC) (p< 0.025) and HDL cholesterol (p<0.005). Plasma viscosity, white cell deformability, white cell count, mean corpuscular volume (MCV), and plasma fibrinogen concentration did not significantly differ from the values found in the control group. It is concluded that patients with PPH have impaired blood rheology. The hemorheologic abnormalities in these patients may be of hemodynamic significance.
|
|
7. |
- Jacobsson, Leif S., et al.
(author)
-
Antiatherosclerotic Effects of the Angiotensin-Converting Enzyme Inhibitors Captopril and Fosinopril in Hypercholesterolemic Minipigs
- 1994
-
In: Journal of Cardiovascular Pharmacology. - 0160-2446 .- 1533-4023. ; 24:4, s. 670-677
-
Journal article (peer-reviewed)abstract
- We evaluated the two angiotensin-converting enzyme (ACE) inhibitors captopril and fosinopril with regard to possible antiatherosclerotic effects in minipigs. Experimental hypercholesterolemia and atherosclerosis was produced in 33 minipigs of the Gottingen strain by an egg yolk/cholesterol-enriched diet for 1 year. One group (n = 11) was fed the atherogenic diet alone and served as a control. A second group (n = 11) received captopril (80 mg/kg/day) added to the atherogenic diet, and a third group (n = 11) was treated in the same manner but with fosinopril (8 mg/kglday). The drug treatments produced significant reduction in serum ACE activity associated with a reactive increase in plasma renin activity (PRA), but had only minor effects on plasma lipids and lipoproteins. At the end of the treatment period, all animals were killed and examined for degree of atherosclerosis. The percentage of atherosclerotic area in the abdominal aorta was significantly lower in both drug-treated groups as compared with controls. Furthermore, accumulation of cholesterol in the thoracic and abdominal aorta was inhibited by drug treatment. Finally, the percentage of intimal thickening in abdominal aorta was significantly reduced in the drug-treated groups. In conclusion, the ACE inhibitors captopril and fosinopril inhibited development of atherosclerosis in hypercholesterolemic minipigs.
|
|
8. |
- Lövblad, Gun, et al.
(author)
-
Miljökonsekvenser vid användning av ammoniak för att reducera utsläppen av kväveoxider
- 1993
-
Reports (other academic/artistic)abstract
- För att minska utsläppen av kväveoxider utnyttjas katalytisk eller icke-katalytisk reduktion av kväveoxider till kvävgas med ammoniak i avgaser från bl a energiproduktion. Genom att driva denna reduktion mot mer effektiv NOx-minsknng krävs större mängder ammoniak och sannolikt kommer större utsläpp av ammoniak till luft att erhållas. Ökade ammoniakhalter i rökgasen ger nackdelar i form av problem med restprodukten men eventuellt även i form av effekter i miljön. Eftersom kväveoxider och ammoniak har olika egenskaper vad gäller atmosfärkemi, depositionshastigheter mm är det inte självklart att man kan nöja sig med att studera hur det totala kväveutsläppet förändras. Genom att släppa ut ammoniak i stället för kväveoxider, kan ändrade förhållanden erhållas bl a vad gäller risker för försurning, kvävemättnad och oxidantbildning. Sett ur de flesta miljöaspekter - effekter av förhöjda NOx-halter, oxidantbildning, nationella - internationella utsläppsstrategier för kväve, etc - är NOx-rening med ammoniak enbart positiv. Den förhöjda kvävedepositionen av ammonium i närområdet, som blir följden av ammoniakutsläpp, jämfört med kvävedepositionen förorsakad av större mängder utsläppt NOx utan rening, kan i det lokala perspektivet ytterligare försura mark och bidra till skador på miljön, t ex skador på barrträd i skogsbryn. Bidragen är dock små och har sannolikt endast viss betydelse i områden som redan är starkt försurade och kvävebelastade. Lokalisering av anläggningar med ammoniakutsläpp bör ske till områden med låg svavel- och kvävebelastning.
|
|
9. |
- Norgren, Lars, et al.
(author)
-
Immune response to collagen impregnated Dacron double velour grafts for aortic and aorto-femoral reconstructions
- 1990
-
In: European Journal of Vascular Surgery. - 0950-821X. ; 4:4, s. 379-384
-
Journal article (peer-reviewed)abstract
- This study presents 20 patients, randomised to receive either a collagen-treated or an ordinary Dacron graft for aortic reconstructions, and the results of a skin-prick test, blood parameters and ELISA for anti-collagen antibodies as well as NMR pictures during a 6 week follow-up period. Forty per cent (4/11) of those receiving a collagen impregnated graft had a significantly increased titre of antibodies and NMR revealed in two out of 11 patients either a slightly increased amount of fluid or fibrosis around the graft, both collagen impregnated. No differences were found between the graft groups concerning body temperature and leucocyte or platelet counts. The skin-prick test for collagen was negative in all cases.
|
|
10. |
- Persson, Lars
(author)
-
Grusinventering i Gävleborg
- 1994
-
Reports (other academic/artistic)abstract
- Inventeringen omfattar i princip länets samtliga isälvsavlagringar. 1 inventeringsarbetet har ingått b1 a följande delmoment: förberedelser, kartstudier, insamlande och bearbetning av uppgifter, fältbesiktningar, analys, sammanställning och redovisning.Isälvsavlagringarna redovisas på kartklipp av topografiska kartan. Avlagringarnas omfattning är i huvudsak baserad på befintliga jordartskartor med vissa mindre justeringar. Förekomsternas volymer har uppskattas genom olika beräkningsmetoder. Alla förekomster har värderats i tre naturvärdesklasser.Avlagringarna är indelade i avsnitt och för varje avsnitt finns en beskrivning redovisade. En sammanställning med kortfattade uppgifter om samtliga undersökta förekomster redovisas i tabellform för varje kommun.Antalet avsnitt för hela länet är totalt 266. Den uppskattade totala volymen av länets isälvsavlagringar är 2,429 miljoner m³, varav 189 miljoner m³ bedöms vara uttagbara. Det bör dock påpekas att stora delar av denna senare volym är sandigt material, som det inte finns någon större efterfrågan på, eller som ligger så att det inte är exploateringsbart med hänsyn till transportkostnaderna. Indelat i de tre olika naturvårdsklasserna finns i länet 1,328 miljoner m³ i klass 1,960 miljoner m³ i klass 11 och 141 miljoner m³ i klass111.Inventeringen skall förhoppningsvis medverka till att mer medvetna beslut kan fattas om hur tillgångarna bäst bör nyttjas och att man kan finns en lämplig balans mellan bevarandeintressen och materielbehov. Inventeringens uppgifter och rekommendationer bör även kunna användas och bidra till, att riksdagens och naturvårdsverkets intentioner om att kommunala grushushållningsplaner upprättas, främjas. En annan förhoppning är att inventeringen kan ge branschens producenter och konsumenter en ledning i sin verksamhet.Slutligen bör hänsyn tas till att vi lever i en föränderlig värld och detta bör beaktas även när denna inventerings uppgifter och planeringsrekommendationer används. Under de senast åren har materialkonsumtionen tenderat att gå över mot utnyttjandet av berg och grova moräner. Denna tendens torde bli ännu mer märkbar under de kommande åren. Bland de faktorer som påverkar en större användning av berg ät t ex Vägverkets högre krav på vägbyggnadsmaterial och upphandling av större vägbyggen med funktionsgaranti. Detta ligger också i linje med nuvarande inriktning mot en bättre hushållning med befintliga naturresurser. Därmed ökar förutsättningarna för att bevara nu orörda isälvsstråk.
|
|