| 31. |
- Larsson, Anders, et al.
(författare)
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Chicken antibodies are highly suitable for particle enhanced turbidimetric assays
- 2022
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Ingår i: Frontiers in Immunology. - : Frontiers Media S.A.. - 1664-3224. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Antibody-based assays are commonly used in clinical laboratories for analyzing plasma, serum and other samples for particular protein markers. Although such assays have been traditionally based on antibodies raised in mammals (e.g., mice, rabbits, goats), there are several advantages of using avian antibodies (IgY) raised in chickens, including production volumes, costs, and ethical/animal welfare considerations. A further disadvantage of using mammalian IgG in such assays is the potential for agglutination when exposed to rheumatoid factor (RF) in serum. However, when used in the free form the immune complexes formed with avian antibodies have been reported to have less ability than those formed with mammalian antibodies to cause the light scatter which are used for instrument measurement. In addition, when the amount of antigen exceeds the maximum precipitating point in relation to the amount of antibody, there is a rapid decline in the absorbance values of the immune complexes (antigen excess) when IgY is used. However, when avian antibodies are conjugated to a substrate and used in particle enhanced turbidimetric assays (PETIA), these problems are avoided. Here we investigated three clinical assays using chicken antibodies, one using free (unbound) IgY and two with IgY-based PETIA. The IgY PETIA demonstrated a strong scatter response, even at high antigen concentrations in contrast to the steep decline seen with free IgY antibodies. IgY PETIA reagents can provide test results with low coefficient of variation (<1% for duplicate samples). We also investigated the effect of RF on agglutination of mammalian antibodies (IgG from mouse, rabbit, sheep, and human) and chicken antibodies. Whereas agglutination was observed with all the mammalian antibodies in the presence of RF, this was not observed at all with chicken IgY. Our results support the growing body of evidence that chicken egg yolks can thus be a valuable source of antibodies for use in PETIA in clinical laboratories.
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| 32. |
- Larsson, Anders, et al.
(författare)
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Effects of extensive bleeding in pigs on laboratory biomarkers
- 2021
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Ingår i: Upsala Journal of Medical Sciences. - : Upsala Medical Society. - 0300-9734 .- 2000-1967. ; 126:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: During hemorrhage and resuscitation, clinical and laboratory monitoring is useful to guide further management. However, acute changes in the biochemistry due to blood loss and subsequent crystalloid fluid resuscitation have not been fully studied.Materials and methods: Twelve anesthetized, juvenile pigs were used. Atraumatic exsanguination, corresponding to a total blood loss of 40%, was performed through a catheter and completed 2 h after initiation of the experiment. Arterial samples were analyzed by point-of-care testing and venous samples were analyzed. Oxygen delivery was calculated.Results: Shortly after 40% hemorrhage and concomitant fluid supplementation, there were significant reductions in arterial hemoglobin and hematocrit (approximately 25%, respectively). Oxygen delivery was less than half of the baseline value. Lactate in arterial blood was more than doubled after 40% exsanguination. On average, no other clinically significant changes in any of the analytes were observed, but interindividual dispersion was pronounced.Conclusions: Acute exsanguination was associated with decreased hemoglobin and hematocrit levels and increased lactate levels but limited effects on the other biomarkers that were studied. Increased levels of biomarkers in severely bleeding patients could indicate tissue damage and the source should be further investigated.
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| 33. |
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| 34. |
- Larsson, Anders O., et al.
(författare)
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Shrunken Pore Syndrome Is Frequently Occurring in Severe COVID-19
- 2022
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 23:24
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Tidskriftsartikel (refereegranskat)abstract
- A selective decrease in the renal filtration of larger molecules is attributed to the shrinkage of glomerular pores, a condition termed Shrunken Pore Syndrome (SPS). SPS is associated with poor long-term prognosis. We studied SPS as a risk marker in a cohort of patients with COVID-19 treated in an intensive care unit. SPS was defined as a ratio < 0.7 when the estimated glomerular filtration rate (eGFR), determined by cystatin C, calculated by the Cystatin C Caucasian-Asian-Pediatric-Adult equation (CAPA), was divided by the eGFR determined by creatinine, calculated by the revised Lund-Malmö creatinine equation (LMR). Clinical data were prospectively collected. In total, SPS was present in 86 (24%) of 352 patients with COVID-19 on ICU admission. Patients with SPS had a higher BMI, Simplified Physiology Score (SAPS3), and had diabetes and/or hypertension more frequently than patients without SPS. Ninety-nine patients in the total cohort were women, 50 of whom had SPS. In dexamethasone-naïve patients, C-reactive protein (CRP ), TNF-alpha, and interleukin-6 did not differ between SPS and non-SPS patients. Demographic factors (gender, BMI) and illness severity (SAPS3) were independent predictors of SPS. Age and dexamethasone treatment did not affect the frequency of SPS after adjustments for age, sex, BMI, and acute severity. SPS is frequent in severely ill COVID-19 patients. Female gender was associated with a higher proportion of SPS. Demographic factors and illness severity were independent predictors of SPS.
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| 35. |
- Larsson, Anders, et al.
(författare)
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Plasma Leptin Is Increased in Intensive Care Patients with COVID-19—An Investigation Performed in the PronMed-Cohort
- 2022
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Ingår i: Biomedicines. - : MDPI AG. - 2227-9059. ; 10:1, s. 4-4
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: COVID-19 has shaken the world and intensive care units (ICU) have been challenged by numerous patients suffering from a previously unknown disease. Leptin is a polypeptide pleiotropic hormone, mainly expressed by adipocytes. It acts as a proinflammatory cytokine and is associated with several conditions, known to increase the risk of severe COVID-19. Very little is known about leptin in severe viral disorders. Plasma leptin was analyzed in 222 out of 229 patients with severe COVID-19 on admission to an ICU at Uppsala University Hospital, a tertiary care hospital in Sweden, and compared to plasma leptin in 25 healthy blood donors. COVID-19 was confirmed by positive PCR. Leptin levels were significantly higher in patients with COVID-19 (18.3 ng x mL-1; IQR = 30.4), than in healthy controls (7.8 ng x mL-1; IQR = 6.4). Women had significantly higher leptin values (22.9 ng x mL-1; IQR = 29.8) than men (17.5 ng x mL-1; IQR = 29.9). Mortality at 30 days was 23%, but was not associated with increased leptin levels. Neither median duration of COVID-19 before admission to ICU (10 days; IQR = 4) or median length of ICU stay (8 days; IQR = 11) correlated with the plasma leptin levels. Leptin levels in COVID-19 were higher in females than in males. Both treatment (e.g. use of corticosteroids) and prophylaxis (vaccines) have been improved since the start of the COVID-19 pandemic, which may contribute to some difficulties in deciphering relations between COVID-19 and leptin.
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| 36. |
- Larsson, Anders, et al.
(författare)
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Slight Increase of Serum S-100B During Porcine Endotoxemic Shock May Indicate Blood-Brain Barrier Damage.
- 2005
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Ingår i: Anesth Analg. - 0003-2999. ; 101:5, s. 1465-9
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Tidskriftsartikel (refereegranskat)abstract
- Septic shock is a condition that affects many organs, but little is known about the effects on the central nervous system. S-100B, an acidic low molecular weight protein, has attracted considerable interest as a marker for brain damage and disintegration of the blood-brain barrier. It is released into the cerebrospinal fluid and blood from brain tissue after brain damage. We studied S-100B in a porcine model of endotoxemic shock that resembles human Gram-negative septic shock. Ten piglets received IV endotoxin, and plasma samples were collected before the endotoxin infusion and each hour (1-6 h) during the endotoxin infusion. S-100B was measured by sandwich enzyme-linked immunosorbent assay. Low levels of plasma S-100B were detected, but there was a significant increase in S-100B during Hours 1-5 in comparison with the 0 values. We determined that endotoxemia causes a very small but significant increase in the levels of the widely used brain damage marker serum S-100B. However, it cannot be excluded that the increase in S-100B could be caused by release from organs other than the brain.
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| 37. |
- Larsson, Anders, et al.
(författare)
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Studies of fibrinogen binding to porcine platelets by flow cytometry : A method for studies of porcine platelet activation
- 2002
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Ingår i: Platelets. - : Informa UK Limited. - 0953-7104 .- 1369-1635. ; 13:3, s. 153-157
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Tidskriftsartikel (refereegranskat)abstract
- Platelets have a central function in haemostasis. They also participate in arterial thrombus formation in vascular disorders. Platelets have an important role in initiating and mediating ischaemia and related complications of ischemic heart disease. Several research groups are thus studying platelet activation and developing new platelet inhibitors. Platelet function is dependent upon membrane receptors and their interaction with other proteins. Binding of fibrinogen to the platelet glycoprotein (GP) IIb/IIIa receptor is a prerequisite for platelet aggregation and thrombus formation. Thus, several GPIIb/IIIa inhibitors have been developed of which abciximab is the clinically most widely used. Pigs are often used for experimental studies. We have developed a flow cytometry assay for measuring porcine platelet activation utilising an FITC-labelled chicken anti-fibrinogen antibody. ADP, ristocetin and thrombin induce fibrinogen binding to porcine platelets similarly to human platelets. Ristocetin induces platelet aggregation and microvesicle formation from porcine platelets as well as from human platelets.
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| 38. |
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| 39. |
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| 40. |
- Larsson, Anders, et al.
(författare)
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Validation of a Novel Point-of-Care Testing Device Designed for Assessment of NT-pro BNP
- 2023
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Ingår i: Journal of Family Medicine and Primary Care Open access. - : Gavin Publishers. - 2688-7460. ; 7:2
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Our main objective was to compare Point-Of-Care Technology (POCT) to central laboratory immunochemistry testing, to assess N-terminal pro B-type Natriuretic Peptide (NT-proBNP) in ambulatory patients. A second objective was to use POCT to analyze NT-proBNP in a cohort of healthy blood donors to define reference values. Methods: Blood samples were obtained from 102 outpatients and 133 blood donors, respectively. Samples analyzed using a point-of-care instrument [NT-proBNPLumiraDx (LumiraDx, Solna, Sweden)] were compared to a commercial electrochemiluminescence immunoassay method [(NTproBNPRoche) on the Cobas Pro analyzer (Roche Diagnostics, Mannheim, Germany)]. The study was ethically approved (01–367) and complied with the Declaration of Helsinki. Values are given as Median and Interquartile Range (IQR). Results: There was a distinct correlation between the two assays for assessing the circulating levels of NT-proBNP in outpatients (R² = 0.9546). NT-proBNPLumiraDx ranged between 50–3966 ng/L [Median: 276 (IQR: 679)] whereas NT-proBNPRoche ranged between 50–3820 ng/L; (Median: 268 (IQR: 628)]. NT-proBNPLumiraDx was 3% higher than NT-proBNPRoche (p<0.05). NT-proBNPLumiraDx levels were not affected by age in our cohort of blood donors. Conclusion: In cases where short turnaround-times for assessment of NT-proBNP are desirable, the LumiraDx instrument can safely be used as an analytical option.
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