PubMed Health⌕ Search

Biomedical subjects

M Palm

Publications and source records attributed to M Palm.

At least 19 recordsLinked to original sources
PubMed2005

Creatinine concentration in plasma from dog, rat, and mouse: a comparison of 3 different methods.

BACKGROUND: There are numerous methods for analyzing creatinine concentration in plasma, including the Jaffé alkaline picrate method in various modifications, enzymatic tests, and chromatographic methods. OBJECTIVE: The purpose of this study was to evaluate whether an enzymatic method could replace a Jaffé method for routine creatinine measurements in plasma from dogs, rats, and mice. The enzymatic method and a compensated Jaffé method were tested against a high-pressure liquid chromatography (HPLC) method, regarded as the gold standard for creatinine measurement. METHODS: Heparinized plasma samples were obtained from 20 beagle dogs, 20 Wistar rats, and 20 CD1-strain mice. The 2 test kits (Roche Diagnostics), Creatinine Jaffé Compensated and the enzymatic Creatinine Plus Version 2 reagent, were used on a Cobas Integra 400. The Jaffé compensated method used a calibration adjustment of 18 micromol/L to correct for the protein matrix in serum and plasma. The HPLC method was an isocratic method using a weak cation-exchange column following protein precipitation. RESULTS: Creatinine concentrations obtained using the enzymatic and the Jaffé methods differed significantly from the results obtained by the HPLC method. For dog plasma, mean values of 61.2, 61.8, and 67.8 micromol/L were obtained by the compensated Jaffé, enzymatic and HPLC methods, respectively. In the rat, respective mean values were 26.7, 21.9, and 23.0 micromol/L, and in the mouse, respective mean values were 14.2, 5.4, and 9.2 micromol/L. CONCLUSION: The enzymatic method can replace the Jaffé method for plasma creatinine determination in dogs, rats, and mice because results from the enzymatic method were closer to HPLC values than were those of the Jaffé method.

Animals↗
PubMed2001

Enhanced green fluorescent protein (EGFP) for space radiation research using mammalian cells in the International Space Station.

In the endeavour to assess radiation risks for humans in space the concerted action of all stimuli (e.g. radiation and microgravity) has to be known already at a cellular level. The introduction of reporter genes into mammalian cells which allows the visualisation of modified gene expression levels, signal transduction rates and cell metabolism activities will supply basic information on the cellular response to space radiation. The cloning of the gene for green fluorescent protein (GFP) from the jellyfish Aequorea victoria and its subsequent expression in heterologous systems has established GFP as a unique genetic reporter system for use in a variety of organisms. Unlike other reporters, GFP fluorescence emerges in the absence of substrates or cofactors and allows for non-invasive monitoring in living and in paraformaldehyde-fixed cells. Enhancement of wild-type GFP by human codon optimisation and fluorophore mutation (EGFP) resulted in higher expression levels in mammalian cells and brighter fluorescence. The suitability of EGFP for gene expression studies to be performed on the ISS is shown for recombinant mammalian cells in response to UVC exposure.

Animals↗
PubMed1998

The incidence of chronic progressive nephrosis in young Sprague-Dawley rats from two different breeders.

Chronic progressive nephrosis (CPN) in rats may not only become a problem in long-term toxicity studies but also in short-term studies, if the breeding stock is not carefully selected with respect to the kidney function. This paper presents differences in kidney function between young rats of the same strain, Sprague-Dawley, but from two different breeders ('set A' and 'set B' rats). In set A rats, protein in the urine was present in the males, which is a common finding. In set B rats, not only the males but also the females excreted protein in the urine. The method used to detect protein in the urine does not normally show a positive protein result in the young female rats. At the age of 3 months signs of chronic progressive nephrosis were observed in 55% of the males and in 15% of the females in set B. Two months later, the incidence had increased to about 70-80% in males and 50% in females. At 8 months, the incidence was similar, but the severity had increased. These values were compared with those obtained from the set A rats, none of which showed any signs of the disease at the age of 5 months and only 5% of the males and females at the age of 8 months. The results indicated that an increased excretion of protein in the urine may be used as an indicator for chronic progressive nephrosis in the rat and that not only the strain but also the source is important in selecting laboratory rats for toxicity studies.

Animals↗
PubMed1997

An in vitro cellular system for generation of AA-amyloid.

Different conditions for establishing a cell culture system for generation of AA-amyloid were investigated. The most effective system was based on peritoneal macrophages from CBA/J mice that had received repeated injections of Hammersten casein, with subsequent cultivation of the cells at high density, high levels of acute phase serum, and neutral pH. Staining with Congo red, thioflavin T, and anti-AA revealed amyloid-like structures associated with macrophage clusters. The structures increased in number and size from day 2 to 6 of cell cultivation. The concentration of apoSAA in the culture medium fell markedly in the amyloid-producing cell cultures, while the SAP concentration was not reduced. The described cell culture system can be useful in studies of the influence of chaperone molecules and other factors or the formation and degradation of amyloid fibrils.

Acute-Phase Proteins↗
PubMed1996

Evaluation of a patient teaching skills course disseminated through staff developers.

Effective Patient Teaching (EPT), a course designed to improve health professionals' and health professions students' teaching skills, reliably produces gains in participants' skills when presented by its developers. The objective of this dissemination research study was to investigate whether, using a 'training of trainers' approach, seven nurses with staff development responsibilities in five different sites could teach EPT with similar effectiveness. The evaluation included pre- and post-course analysis of audiotaped patient education sessions conducted by 48 health professional participants who took EPT from one of the trainers in their home institutions. Post-course participant satisfaction surveys were also administered. EPT resulted in teaching skill improvements in four of five sites, and overall teaching skills scores improved significantly (P < 0.01). EPT can improve participants' teaching skills when taught by health professional trainers with staff development responsibilities who have recently received EPT training.

Clinical Competence↗
PubMed1991

Immunoadsorption and plasma exchange in multiple sclerosis: complement and plasma protein behaviour.

Three groups of patients suffering from acute attacks or progressive multiple sclerosis (MS) are under investigation. First results revealed remarkable clinical improvements of patients with acute attacks in the groups treated by therapeutic plasma exchange (TPE) and immunoadsorption (IA). Only slight or no improvements were seen in the patients of the control group treated only with steroids. Plasma protein levels (IgG, IgM, IgA, fibrinogen) were considerably reduced in patients of the TPE group after each treatment procedure as expected. The same holds true concerning the total hemolytic capacities (THC) of the complement of the classic (CP) and the alternative (AP) pathway. On the other hand in the IA group only slight decreases of plasma proteins (about 20%) were observed, but the behaviour of THC's were quite similar than those seen in the patients of the TPE group. The THC decreases in both groups can be explained by removal of all complement factors (TPE group) or by the adsorption of single factors (IA group) of both complement pathways according to earlier in vitro investigations. The THC decreases in patients of both groups suffering from acute MS attacks could mean an "antiinflammatory" effect and could--at least partially--contribute to the clinical improvements of these patients.

Blood Proteins↗
PubMed1990

Bleeding times in rats treated with heparin, heparin fragments of high and low anticoagulant activity and chemically modified heparin fragments of low anticoagulant activity.

A template bleeding time study in the rat was undertaken to see if it is possible to correlate bleeding times with the molecular weight, anticoagulant activity or chemical composition of heparin or heparin-derived compounds. Heparin from porcine intestinal mucosa (PM-heparin) and from bovine lung (BL-heparin) as well as heparin fragments from these sources were compared. Heparin fragments of low anticoagulant activity were prepared by affinity chromatography on immobilized antithrombin as well as by chemical modification. A heparin fragment of high affinity for antithrombin (HA-fragment) caused a marked and dose-dependent increase in bleeding time while the corresponding heparin fragment with low affinity for antithrombin (LA-fragment) had a marginal and non-dose dependent effect on the bleeding time. Similar results were also obtained with PM-heparin with high and low affinity for antithrombin. A high anti-FXa activity was not always correlated with a marked bleeding tendency. Provided that a fragment was devoid of activated partial thromboplastin time (APTT) activity, it was not possible to provoke a bleeding time of 20 min or longer, although the compound was administered at a dose of 1,088 U/kg (anti-FXa activity). On the other hand, a N-acetylated chemically oversulphated heparin fragment, with a very low anti-FXa activity (1 U/mg) and with an APTT activity of 34 U/mg, caused a bleeding time of 20 min or longer in 70% of the animals after injection of the same number of APTT units, 1,088 U/kg. These data indicate that the APTT activity is a better and more sensitive indicator of the bleeding than is the anti-FXa activity.

Acetylation↗
PubMed1990

A newly developed LDL-binding material.

Results of in vitro and ex vivo experiments with a newly developed LDL-binding material are presented. This material consists of macroporous bead cellulose which is capable to bind selectively LDL. LDL-cholesterol is considerably decreased after contacts of plasma or serum samples with this bead cellulose. On the other hand high density lipoproteins (HDL) and other plasma components (proteins, enzymes, electrolytes, and metabolic substances) remained high or unchanged. Triglycerides (TG)--transported by very low density lipoproteins--are also bound up to a certain degree. 1 g of the adsorbent wet mass binds at least 20 mg cholesterol. The capacity suffices to decrease two- to threefold increased cholesterol and LDL plasma levels to the low normal range following passage of the sevenfold plasma volume' through two the three LDL adsorbent columns (results of perfusion experiments). In vitro and dog experiments revealed only slight drops of the hemolytic capacities of the classic complement pathway and moderate decreases of the alternative one. But no detectable side effects were noticed in the dog experiments.

Adsorption↗
PubMed1989

Antithrombotic effects of heparin oligosaccharides.

Size homogeneous heparin oligosaccharides were prepared from nitrous acid depolymerized heparin by means of repeated gel filtration chromatography. These oligosaccharides were then further separated with respect to affinity for antithrombin by means of affinity chromatography. All the high-affinity oligosaccharides thus obtained had a strong ability to potentiate factor Xa inhibition while their ability to inhibit factor IIa abruptly dropped below a chain length of 20 monosaccharides. In a rabbit stasis model, high-affinity oligosaccharides below a chain length of 20 units also showed a continuous decrease in antithrombotic effect with increasing degree of depolymerization. However, there was no distinct drop paralleling the thrombin inhibiting capacity. Low-affinity oligosaccharides also exhibited a weak antithrombotic effect, although they did not always contribute to an increased anti-factor Xa activity ex vivo. This was the case whether or not they were administered alone or in combination with high-affinity oligosaccharides. Low-affinity oligosaccharides may therefore exert an antithrombotic effect per se with a mechanism of action that is independent of antithrombin III.

Animals↗
PubMed1987

Pharmacokinetics of heparin and low molecular weight heparin fragment (Fragmin) in rabbits with impaired renal or metabolic clearance.

The kinetics and tissue distribution of 3H-heparin and a 3H-labelled low molecular weight heparin fragment were compared in normal rabbits as well as in rabbits with blocked renal function or reticuloendothelial system (RES). Radioactivity in plasma, urine, liver and kidneys, as well as anti-FXa activity in plasma were determined. The plasma elimination of heparin was, when compared to normal controls, prolonged both in rabbits with renal dysfunction as well as in rabbits with blocked RES, while renal dysfunction was the only parameter that significantly prolonged the plasma half-life of Fragmin. Studies on tissue distribution in normal rabbits revealed that about 60 per cent of the radioactive heparin dose accumulated in the liver and kidney three hours after the injection, whereas the corresponding value was less than 10 per cent for the Fragmin-derived radioactivity. The recovery of radioactivity in urine within three hours was 5 and 35 per cent of the dose, respectively, for 3H-heparin and 3H-Fragmin. It is concluded from the present study that the rapid plasma elimination of heparin in the rabbit (t1/2 = 17 minutes) is mainly due to a high tissue distribution (liver and kidney) while the plasma elimination of Fragmin (t1/2 = 28 minutes) is mainly caused by renal excretion.

Animals↗
PubMed1987

Pharmacokinetics of fragmin. A comparative study in the rabbit of its high and low affinity forms for antithrombin.

A tritium-labelled low molecular weight heparin fragment with an average molecular weight of 4000-6000 (Fragmin), was fractionated into its high and low affinity forms for antithrombin. The fractions obtained were injected into rabbits, and the plasma half-life (t1/2) volume of distribution (Vd), area under the curve (AUC), total body clearance (TCl) and renal clearance (Clr) were determined. When followed by radioactivity, both the high and low affinity forms of Fragmin as well as Fragmin itself were eliminated from plasma in a biexponential manner. Values for AUC were very low compared to those expected from the given dose. This effect was most pronounced for low affinity-Fragmin demonstrating a significantly higher extravascular distribution of molecules lacking affinity for antithrombin. From radio activity data, it was also demonstrated that the fraction of dose that was eliminated from plasma via non-renal (cellular clearance) mechanisms was higher for heparin (95 per cent) than for Fragmin (77 per cent) after a dose of 100 micrograms/kg. This demonstrates that cellular clearance is of less importance in the plasma elimination of low molecular weight heparin fragment, an effect that may explain their longer plasma half-lifes despite the fact that they are more readily and faster excreated into the urine.

Animals↗
PubMed1985

Purified human factor VIII procoagulant protein: comparative hemostatic response after infusions into hemophilic and von Willebrand disease dogs.

The procoagulant protein F.VIII:C is noncovalently bound to von Willebrand factor (vWF) to give the factor VIII macromolecular complex. New highly purified preparations of isolated human F.VIII:C, devoid of vWF and about 500,000-fold purified, were administered to hemophilia A and von Willebrand disease (vWD) dogs to determine their hemostatic effectiveness and survival in the circulation. Two preparations of F.VIII:C were used: peak 1, with active components of Mr 185,000-280,000, and peak 2, with a single component of Mr 170,000. In hemophilic dogs, with no plasma F.VIII:C but normal vWF, both preparations immediately elevated plasma F.VIII:C to expected levels, promptly stopped induced and spontaneous hemorrhages, and gave sustained plasma levels of F.VIII:C. The isolated F.VIII:C immediately complexed with endogenous vWF in hemophilic plasma and was eliminated exponentially, with a half-life (t1/2) of about 9 hr. Survival of peak 2 F.VIII:C was longer than that of peak 1 material. In contrast, F.VIII:C complexed to vWF in a therapeutic concentrate administered to hemophilic dogs was eliminated biexponentially with first-phase t1/2 of 3.2 hr and second-phase t1/2 of 9 hr. In vWD dogs with no vWF and reduced F.VIII:C levels, the isolated F.VIII:C produced supernormal levels of F.VIII:C without effect on induced bleeding. It was rapidly eliminated from plasma with a t1/2 of about 1 hr, as was the complexed F.VIII:C in the concentrate. These data indicate that isolated F.VIII:C promptly complexes with vWF and in this form is highly effective in controlling hemophilic hemorrhages with good survival in plasma. Without endogenous vWF with which to complex, the F.VIII:C is promptly eliminated.

Animals↗
PubMed1985

[Growth behavior of microvein and artery grafts].

In an experimental study with young rats the authors were able to prove that arterial and venous grafts show almost normal growth. With respect to patency rate, growth and integrity of the vessel wall the results with arterial grafts were more satisfactory than those with venous grafts. Examination of thirty-four patients who had undergone replantation or transplantation in infancy or childhood, showed that after digital replantation the extremities grew almost normally and that there was no indication of lag in vessel growth. Three times a slight change in growth after major limb replantations was found, in one case there was a slight increase in growth and in another case the growth was considerably diminished. In the latter there had been total destruction of the epiphyseal line. One large replantation was examined by angiography and normal development of the venous grafts was found.

Adolescent↗