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Biomedical subjects

J Kjeldsen-Kragh

Publications and source records attributed to J Kjeldsen-Kragh.

At least 19 recordsLinked to original sources
PubMed2005

Six years' experience of using the BacT/ALERT system to screen all platelet concentrates, and additional testing of outdated platelet concentrates to estimate the frequency of false-negative results.

BACKGROUND AND OBJECTIVES: Approximately 1 in every 2000 units of platelets is contaminated with bacteria. The BacT/ALERT automated blood culture system can be used to screen platelet concentrates (PCs) for bacterial contamination. MATERIALS AND METHODS: Data were collected from May 1998 until May 2004. The number of PCs tested during this period was 36 896, most of which were produced from pools of four buffy-coats. On the day following blood collection or platelet apheresis, a 5-10 ml sample of the PC was aseptically transferred to a BacT/ALERT culture bottle for detection of aerobic bacteria. The sample was monitored for bacterial growth during the entire storage period of the PC (6.5 days). When a positive signal was generated, the culture bottle, the PC and the erythrocyte concentrates were tested for bacterial growth. In order to determine the frequency of false-negative BacT/ALERT signals, 1061 outdated PCs were tested during the period from May 2002 to May 2004. RESULTS: Eighty-eight positive signals were detected by the BacT/ALERT system, of which 12 were interpreted as truly positive. Fourteen signals were interpreted as truly false positive. Thirty-three signals were interpreted to be probably false positive. Two of 1061 outdated units tested positive, and Bacillus spp. and Staphylococcus epidermidis, respectively, were isolated from these PCs. CONCLUSIONS: Between 0.03% and 0.12% of the PCs were contaminated with bacteria. BacT/ALERT is an efficient tool for monitoring PCs for bacterial contamination; however, it is important to realize that false-negative results may occur.

Bacillus↗
PubMed2004

The platelet count accuracy of platelet concentrates obtained by using automated analysis is influenced by instrument bias and activated platelet components.

BACKGROUND AND OBJECTIVES: The blood platelet content (in numbers) of platelet concentrates is required for production quality control and to predict clinical responses. MATERIALS AND METHODS: This study compared the performance of automated counting from impedance and optical instruments to data from immunoplatelet reference analysis. RESULTS: All methods showed good linearity with evidence of significant instrument-specific deviations from the line of agreement. Relational formulae largely corrected bias, but did not resolve platelet count variability. A second confounding factor, related to the proportion of small (activated) platelets, was also shown to contribute to intermethod discrepancies. CONCLUSIONS: Blood processing centres should establish correction factors for each instrument compared to reference methods, such as the immunoplatelet count.

Analysis of Variance↗
PubMed2003

Prenatal genotyping of RHD and SRY using maternal blood.

BACKGROUND AND OBJECTIVES: The aim of the study was to perform fetal RHD genotyping in maternal plasma using a fluorescent polymerase chain reaction (PCR) technique. Duplex PCR, amplifying RHD and SRY in the same tube, was undertaken. The effect of varying storage temperatures on the concentration of fetal DNA was investigated in a separate study involving 10 RhD-negative pregnant women. MATERIALS AND METHODS: Primers and probes for the RHD gene's exon 7 and the sex-determining region, Y, were designed, and monoplex and duplex PCR were performed. Blood samples from 10 RhD-negative women were split into four and treated in four different ways before measuring the concentration of fetal DNA by quantitative PCR. RESULTS: DNA extracted from the plasma of 114 RhD-negative pregnant women was tested for the presence of fetal RHD. The discrepancy between genotyping and serological RhD typing of the babies postpartum was 8% when counting one positive replicate as a positive result. Duplex PCR, amplifying RHD and SRY in the same tube, showed a reduced sensitivity for amplification of the SRY gene segment. There was a statistically significant reduction of fetal DNA in blood samples stored at room temperature for 48 h compared with the same sample stored at a temperature of <10 degrees C for the same length of time. CONCLUSIONS: This method is not suitable for routine analysis because of the lack of a positive control for RHD-negative female fetuses and a decrease in PCR sensitivity when performing duplex PCR. Fetal DNA in maternal plasma is better preserved when the blood sample is kept cool.

Adult↗
PubMed2002

Back-priming of the RCM1 leucocyte-reduction filter: consequences for filtration efficacy.

BACKGROUND AND OBJECTIVES: The RCM1 leucocyte-reduction filter has been incorporated into two types of blood-donation sets of which one uses back-priming of the leucocyte filter with SAG-M solution. In this study we have compared the leucocyte-reduction efficacy of the RCM1 filter with or without back priming with SAG-M solution. MATERIALS AND METHODS: This study was a retrospective analysis of quality control data of 3529 leucocyte-filtered red cell units. Of these, 1002 whole-blood units were collected in a donation set that was back-primed by letting the SAG-M solution in the final storage bag run backwards through the filter into the bag of concentrated red cells. The remaining 2527 units were collected in a donation set that required no back-priming. Postfiltration leucocyte concentration was assessed using flow cytometry. RESULTS: There was a significant trend towards lower leucocyte concentration in the units in which back-priming of the filter preceded filtration, as compared to units filtered without back-priming [chi2trend= 18.8, degrees of freedom (d.f.) = 1, P < 0.0005]. CONCLUSIONS: Back-priming of the RCM1 filter for red cells with SAG-M solution is superior to no back-priming with regard to leucocyte-reduction efficacy.

Blood Preservation↗
PubMed2001

A preliminary study of circadian serum cortisol concentrations in response to a 72-hour fast in rheumatoid arthritis patients not previously treated with corticosteroids.

The aim of the study was to investigate the effects a 72-h fast upon serum total and free cortisol concentrations in RA patients not previously treated with glucocorticoids. Total serum cortisol and transcortin concentrations were measured in four RA patients with active disease at 4-h intervals during two 24-h periods (1200 h-1200 h), the first while eating a normal diet (fed state) and the second during the last 24 h of a 72-h water fast. Free cortisol concentrations were calculated from the total cortisol and transcortin values. The 3-day fast increased overall 24-h free and total cortisol concentrations by 50% and 35%, respectively. This was due largely to a marked increase in nocturnal serum cortisol concentrations during fasting, particularly at 0400 h, when mean total and free cortisol levels were increased by 170% and 260% compared to the fed state. Between 2000 and 0800 h overall total- and free cortisol concentrations were increased by 72% and 99%, respectively. These results suggest that an increase in nocturnal concentrations of cortisol occurs in response to fasting in RA patients not previously treated with glucocorticoids. These increases may mediate the beneficial clinical response previously found in studies of longer fasting periods in RA patients.

Adult↗
PubMed2001

Leukocyte counts and lymphocyte responsiveness associated with repeated bouts of strenuous endurance exercise.

This study compared leukocyte counts and lymphocyte responsiveness during and after a second bout of high-intensity endurance exercise on the same day with the response to a similar but single bout of exercise. Nine athletes participated in three 24-h trials: 1) rest in bed (Rest); 2) one bout of exercise (One); and 3) two bouts of exercise (Two). All bouts consisted of 75 min at approximately 75% of maximal O(2) uptake on a cycle ergometer. Lymphocytes in whole blood were stimulated with monoclonal antibodies against CD2 and assessed by flow cytometry for expression of the early activation molecule CD69. The second bout of exercise in the Two trial was associated with significantly increased concentrations of total leukocytes, neutrophils, lymphocytes, CD4(+), CD8(+), and CD56(+) cells and a significantly decreased percentage of CD56(+) cells expressing CD69 compared with a single bout. Additionally, there was a significantly decreased CD69 fluorescence in CD56(+) cells postexercise. These differences suggest a "carry-over" effect in the immune system from a first to a second bout of exercise on the same day.

Adult↗
PubMed2000

Apheresis-induced platelet activation:comparison of three types of cell separators.

BACKGROUND: Platelet-harvesting technology differs in various cell separators. Alteration in shear stress and biocompatibility of surfaces may give variable platelet activation and thereby affect the quality of the component. STUDY DESIGN AND METHODS: Four groups (n = 10) of single-needle apheresis procedures using three cell separators, were compared: 1) Spectra LRS, 90-minute harvesting time; 2) MCS+, 90-minute harvest; 3) Amicus, 90-minute; and 4) Amicus, 45-minute. Whole-blood samples were collected from the donors as were samples from the final components at intervals during the first 4 hours after cessation of the apheresis. Platelet activation status and platelet activation capacity after agonist stimulation were assessed by flow cytometry. RESULTS: No activated platelets were found in preapheresis and postapheresis samples from the donors. The platelets in the components from the Amicus (90-min) were significantly more activated than those in the other groups of components: that is, there was increased size of platelet aggregates, increased fraction of microparticles, increased degranulation, increased fibrinogen receptor activation, and decreased von Willebrand factor receptor expression. Moreover, the response of these platelets to agonist stimulation was reduced for all activation variables. CONCLUSIONS: After 90 minutes' processing time, platelets obtained with the Amicus cell separator were significantly more activated than platelets harvested with the Spectra and the MCS+.

Blood Component Removal↗
PubMed1999

[Paroxysmal nocturnal hemoglobinuria--diagnosis with the help of flow cytometry].

Paroxysmal nocturnal haemoglobinuria is a clonal, acquired disease affecting the membrane of the blood cells, arising from a somatic mutation at the haematopoietic stem cell level. It results in clones of blood cells deficient in membrane bound proteins, such as the complement regulating molecules Decay Accelerating Factor (DAF = CD55) and Membrane Inhibitor of Reactive Lysis (MIRL = CD59). For many years, Ham's test has been essential for diagnostic testing of erythrocytes for paroxysmal nocturnal haemoglobinuria. We present a 3-colour flowcytometry method used for quantification of CD59-negative erythrocytes and CD55/CD59-negative leukocytes. The results from analysis of blood samples from six patients suffering from paroxysmal nocturnal haemoglobinuria and six healthy blood donors, using the flowcytometry method, Ham's test and a microtyping gelcard method are compared. Our flow cytometric method, using directly conjugated monoclonal antibodies to test both erythrocytes and leukocytes, is the most sensitive method. It is specific and delivers fast results. The method involves a minimum of manipulation of the fragile cells and can be recommended as an alternative to Ham's test and the gelcard test.

Adolescent↗
PubMed1999

[HTLV examination of Norwegian blood donors].

Approximately one third of the Norwegian blood donor population has been tested for infection with human T-lymphotropic virus type I and II (HTLV-I/II). This study was initiated to provide an indication as to whether or not the Norwegian transfusion service should screen the entire donor population for HTLV I/II. No HTLV-I infections were found among the blood donors. One new donor was confirmed HTLV-II positive. This individual had previously used drugs intravenously. HTLV-I/II infection can be regarded as a marker for risk behaviour, and testing can be of significance in the quality assurance of the transfusion service. We recommend that the entire blood donor population be tested for HTLV-I/II infections, and thereafter only new donors. The benefit of this scheme should be evaluated in the future.

Blood Donors↗
PubMed1999

Proteus IgG antibodies and C-reactive protein in English, Norwegian and Spanish patients with rheumatoid arthritis.

The distribution of Proteus antibody levels was compared in English, Norwegian and Spanish patients with rheumatoid arthritis (RA). Using an indirect immunofluorescence method, the IgG antibody titre against Proteus mirabilis was measured in the sera of 27 English, 53 Norwegian and 34 Spanish patients with RA and divided into active and inactive disease groups according to the serum C-reactive protein (CRP) level (> or = 10 mg/l). Serum samples were also collected from 25 English, 30 Norwegian and 14 Spanish healthy individuals who served as controls. The levels of Proteus IgG antibodies were significantly higher in the sera of active RA patients (p<0.001) when compared with the corresponding healthy controls, whether these groups belonged to the English, Norwegian or Spanish populations. Furthermore, active RA patients from each country showed significantly higher levels of Proteus antibodies when compared with inactive English (p<0.01), Norwegian (p<0.001) or Spanish (p<0.001) RA patients. Finally, a significant correlation was observed between Proteus IgG antibody levels and the CRP concentrations in RA patients whether each population was tested individually or all together (p<0.001). The increased levels of Proteus antibodies in RA patients from three different European countries support the concept of a possible aetiopathogenetic role for Proteus microorganisms in the development of RA.

Adult↗
PubMed1999

Decreased CD4+ lymphocyte activation and increased interleukin-4 production in peripheral blood of rheumatoid arthritis patients after acute starvation.

We investigated the effects of acute starvation on mitogen-induced T-cell activation and Th1/Th2 cytokine responses in rheumatoid arthritis (RA) patients. Ten RA patients with active disease underwent a 7-day fast followed by a 2-week refeeding period. Immunological, hormonal, laboratory and clinical evaluations were carried out on days 0, 7 and 21. Using flow cytometry, mitogen-stimulated T-cell activation was assessed in fresh heparinised blood via analysis of CD69 expression. Production of Th1 (interferon-gamma) and Th2 (interleukin-4, IL-4) cytokines was also assessed by ELISA. The 7-day fast significantly decreased the erythrocyte sedimentation rate, C-reactive protein level, joint count, morning stiffness, body weight, CD4+ and CD8+ counts and CD69+ expression on mitogen stimulated CD4+ lymphocytes. A significant increase in mitogen-induced IL-4 production after fasting was found. The fast markedly reduced serum leptin and insulin-like growth factor-1 concentrations. No significant differences occurred in serum cortisol or prolactin before and after fasting. Decreases in CD4+ lymphocyte activation during fasting correlated with decreases in body weight. Our results suggest that the clinical and laboratory improvements in fasting RA patients may be attributed to decreased CD4+ T-cell activation and an increase in the number and/or function of IL-4-producing Th2 cells. Factors associated with loss of body weight during acute starvation appear to have an inhibitory effect on CD4+ lymphocyte activation.

Adult↗
PubMed1999

Rheumatoid arthritis treated with vegetarian diets.

The notion that dietary factors may influence rheumatoid arthritis (RA) has been a part of the folklore of the disease, but scientific support for this has been sparse. In a controlled, single-blind trial we tested the effect of fasting for 7-10 d, then consuming an individually adjusted, gluten-free, vegan diet for 3.5 mo, and then consuming an individually adjusted lactovegetarian diet for 9 mo on patients with RA. For all clinical variables and most laboratory variables measured, the 27 patients in the fasting and vegetarian diet groups improved significantly compared with the 26 patients in the control group who followed their usual omnivorous diet throughout the study period. One year after the patients completed the trial, they were reexamined. Compared with baseline, the improvements measured were significantly greater in the vegetarians who previously benefited from the diet (diet responders) than in diet nonresponders and omnivores. The beneficial effect could not be explained by patients' psychologic characteristics, antibody activity against food antigens, or changes in concentrations of prostaglandin and leukotriene precursors. However, the fecal flora differed significantly between samples collected at time points at which there was substantial clinical improvement and time points at which there were no or only minor improvements. In summary, the results show that some patients with RA can benefit from a fasting period followed by a vegetarian diet. Thus, dietary treatment may be a valuable adjunct to the ordinary therapeutic armamentarium for RA.

Arthritis, Rheumatoid↗
PubMed1999

Changes in plasma free fatty acid concentrations in rheumatoid arthritis patients during fasting and their effects upon T-lymphocyte proliferation.

OBJECTIVE: To measure whether changes in the concentrations of circulating free fatty acids (FFAs) after a 7 day fast in rheumatoid arthritis (RA) patients would inhibit in vitro T-lymphocyte proliferation. METHODS: The concentration and composition of plasma FFAs were measured in nine RA patients at the conclusion of a 7 day fast. A FFA mixture was made up based on these findings (20% linoleic, 43% oleic, 10% stearic, 27% palmitic acid). Mitogen-induced lymphocyte proliferative responses were measured after co-culture of peripheral blood mononuclear cells (PBMC) from healthy individuals in the presence of increasing concentrations of this FFA mixture (from 0 to 2000 microM) and in the presence of FFA mixtures where the relative proportions of fatty acids varied. RESULTS: Both the concentration of the FFA mixture and the ratio between the unsaturated and saturated fatty acids significantly influenced in vitro lymphocyte proliferation (P<0.0001). Unexpectedly, the highest concentrations of the FFA mixture increased lymphocyte proliferation. At equimolar concentrations (600 microM), manipulating the amounts of oleic and linoleic fatty acids relative to stearic and palmitic fatty acids had a potent inhibitory effect upon lymphocyte proliferation. CONCLUSION: Fasting-associated increases in total plasma FFA concentrations do not inhibit, but rather enhance, in vitro lymphocyte proliferation. An inhibitory effect could only be achieved by manipulating the balance between the unsaturated and saturated fatty acids.

Adult↗
PubMed1998

Improved blood preservation with 0.5CPD erythro-sol. Coagulation factor VIII activity and erythrocyte quality after delayed separation of blood.

BACKGROUND AND OBJECTIVES: Delay between blood collection and the separation of its components may result in lowered yield of factor VIII (FVIII) and loss of 2,3-biphosphoglycerate (2,3-BPG). This study was to see whether the use of 0.5 CPD resulted in better preservation of FVIII and maintenance of 2,3-BPG. MATERIALS AND METHODS: 55 units of blood were collected in 0.5CPD and 48 in CPD SAG-M. Ten of the collections were paired, so that the same donors were bled in a single session partly in an 0.5CPD system and partly in CPD SAG-M. After collection, the blood was promptly cooled to 20 degrees C and stored at that temperature for up to 24 h. RESULTS: Preservation of FVIII activity was significantly better in 0.5CPD compared with CPD. The content of von Willebrand factor was stable in the anticoagulant solutions for 24 h at that temperature. Plasma separated from both media had how levels of prothrombin fragment 1 + 2 and complement activation. Paired collections substantiated previous reports that red cell storage is significantly improved in 0.5CPD compared with CPD SAG-M with respect to 2,3-BPG and haemolysis. CONCLUSIONS: Red cell metabolism and oxygen-releasing capacity are kept at acceptable levels in 0.5CPD blood for 24 h at 20 degrees C before component separation. The concentration of red cell 2,3-BPG remained at normal or slightly subnormal levels during further storage in 0.5CPD at 4 degrees C for 2-4 weeks before gradual decay to an average of 39% at 48 days.

2,3-Diphosphoglycerate↗
PubMed1996

[The influence of psychological factors on the immune system and immunological diseases].

During the last 10-20 years it has become clear that the immune system not only protects the individual against potentially harmful intruders but also interacts with both the nervous and endocrine systems. Today we know that immune competent cells have receptors for hormones and neurotransmitters, and that cytokine receptors are expressed in certain areas of the brain. Furthermore, in many animal models immune suppression has been induced by classical conditioning. Several in vitro studies have shown signs of reduced immunity in individuals during acute and chronic stress. Some studies have also indicated that chronic stress may increase the risk of infections and cancer. On the other hand, various psychotherapeutic techniques appear to strengthen the immune system. As for immunological disease, we know that psychological factors are important in the case of allergic asthma. Moreover, serious life events prior to onset of disease are reported more frequently by seronegative than by seropositive rheumatoid arthritis patients. Prospective studies have shown that psychotherapeutic intervention can reduce disability in rheumatoid arthritis patients, but disease activity is diminished only rarely.

Depression↗