Peter H Nissen- MSc, PhD
- Group leader at Aarhus University Hospital
Peter H Nissen
- MSc, PhD
- Group leader at Aarhus University Hospital
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Introduction
Current institution
Publications
Publications (89)
Coronary artery disease (CAD) is a leading cause of morbidity and mortality worldwide, with platelet reactivity playing a central role in its pathogenesis. Recent research has identified microRNAs (miRNAs; miRs) as potential biomarkers for CAD, due to their ability to regulate platelet function and reactivity. This review focuses on four key miRNAs...
Background
Reduced effect of antiplatelet therapy has been reported in patients with ST-segment elevation myocardial infarction (STEMI). This could partly be explained by an increase of highly reactive immature platelets.
Objectives
To investigate changes in platelet maturity and reactivity after acute STEMI.
Methods
Patients diagnosed with STEMI...
It is common practice in laboratories to store biological samples in ultra-low temperature (ULT) freezers. There is growing interest in raising the temperature of ULT freezers in order to save energy and reduce expenses, as energy conservation becomes increasingly important and sustainable laboratory practices gain popularity. In our laboratory, pl...
Background Reduced effect of antiplatelet therapy has been reported in patients with ST-segment elevation myocardial infarction (STEMI). MicroRNAs (miRs) may influence platelet function and maturity, and subsequently the effect of antiplatelet therapy.
Objectives We aimed to explore the association between miR expression and platelet function and m...
The pathophysiological development of Alzheimer's disease (AD) begins in the brain years before the onset of clinical symptoms. The accumulation of beta‐amyloid (Aβ) is thought to be the first cortical pathology to occur. Carrying one apolipoprotein E (APOE) ε4 allele increases the risk of developing AD at least 2–3 times and is associated with ear...
Objectives:
Plasma uracil is a new biomarker to assess the activity of dihydropyrimidine dehydrogenase before cancer treatment with fluoropyrimidine drugs. Knowledge on the biological variation of plasma uracil is important to assess the applicability of plasma uracil as a biomarker of drug tolerance and efficacy.
Methods:
A total of 33 apparent...
Newly produced immature platelets are larger, contain higher amounts of residual RNA, and are more reactive than mature platelets. Flow cytometry using the SYTO-13 dye is a method for the subdivision of immature platelets from mature platelets based on the labelling of intracellular platelet RNA, enabling the simultaneous investigation of the react...
Background New biomarkers are warranted to identify patients with coronary artery disease (CAD) at high risk of recurrent cardiovascular events. It has been reported that the expression of microRNAs (miRs) may influence the development of CAD.
Objectives We aimed to investigate whether the expression of selected candidate miRs is a predictor of car...
When screening for α‐thalassemia in children, adult cut‐offs for mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) are generally applied to guide genetic evaluation. However, the normal ranges for MCV and MCH are lower in children than in adults, so we hypothesized that using age‐matched cut‐offs could lead to a more rational diag...
Introduction
The typical spatial pattern of amyloid-β (Aβ) in diagnosed Alzheimer’s disease (AD) is that of a symmetrical hemispheric distribution. However, Aβ may be asymmetrically distributed in early stages of AD. Aβ distribution on PET has previously been explored in MCI and AD, but it has yet to be directly investigated in preclinical AD (pAD)...
Objectives
No consensus exists upon whether arterial and venous blood samples are equivalent when it comes to coagulation analyses. We therefore conducted a comparative cohort study to clarify if arteriovenous differences affect analyses of primary and secondary hemostasis as well as fibrinolysis.
Methods
Simultaneous paired blood samplings were o...
Increased platelet activity is an important predictor for recurrent cardiovascular events in patients with acute coronary syndromes (ACS). Flow cytometry is an advanced method for evaluation of platelet activity. We aimed to summarize the current literature on dynamic changes in platelet activity analyzed by flow cytometry in patients with ACS. Emp...
Introduction
The risk of recurrent cardiovascular events in patients with coronary artery disease (CAD) is determined by multiple factors including platelet function and turnover. MicroRNAs (miRs) may regulate both platelet function and turnover. We aimed to identify candidate miRs associating with platelet function and turnover in a cohort of stab...
Plasminogen activator inhibitor type 1 (PAI-1) is a main inhibitor of fibrinolysis. The PAI-1 gene (SERPINE1) harbors genetic variants with the potential of modifying plasma levels of PAI-1. A delicate balance exists between the coagulation and fibrinolytic system, and changes in PAI-1 have been suggested to compromise establishment of a successful...
Patients undergoing coronary artery bypass graft (CABG) surgery or carotid endarterectomy (CEA) continue antiplatelet therapy perioperatively, which may increase bleeding risk. We aimed to investigate whether Rotational thromboelastometry (ROTEM®) platelet, a newly marketed platelet function analysis, would detect antiplatelet therapy in CABG and C...
Protein S (PS) deficiency is a risk factor for venous thromboembolism (VTE) and can be caused by variants of the gene encoding PS (PROS1). This study aimed to evaluate the clinical value of molecular analysis of the PROS1 gene in PS-deficient participants. We performed Sanger sequencing of the coding region of the PROS1 gene and multiplex ligation-...
Introduction:
Rapid results are needed when plasma concentrations of direct oral anticoagulants (DOACs) are required in acute clinical settings. We evaluated the impact of centrifugation time and pneumatic tube transport on DOAC plasma concentrations with the overall aim of reducing turnaround time.
Methods:
Blood samples were spiked with rivaro...
Laboratory medicine in the European Union is at the dawn of a regulatory revolution as it reaches the end of the transition from IVDD 98/79/EC (https://eur-lex.eur-opa.eu/legal-content/EN/TXT/?uri=CELEX%3A31998L0079&qid=1628781352814) to IVDR 2017/746 https://eur-lex.europa.eu/eli/reg/2017/746. Without amendments and contingency plans, implementati...
Patients with cardiovascular disease (CVD) are at increased risk of suffering myocardial infarction. Platelets are key players in thrombus formation and, therefore, antiplatelet therapy is crucial in the treatment and prevention of CVD. MicroRNAs (miRs) may hold the potential as biomarkers for platelet function and maturity. This systematic review...
Introduction:
Protein C deficiency is a heritable thrombophilia caused by numerous different genetic alterations in the protein C (PROC) gene. We aimed to identify variants causing protein C deficiency in a Danish population.
Material and methods:
Sanger sequencing of the PROC gene was performed in 20 probands and 26 relatives. In total, 30parti...
Background:
Pazopanib can induce liver toxicity in patients with metastatic renal cell carcinoma (mRCC). We assessed the effect of a TA repeat polymorphism in the UGT1A1 (uridine diphosphate glucuronosyltransferase 1A1) gene encoding uridine diphosphate glucuronosyltransferase 1A1 on liver toxicity, dose reductions, and patient outcomes.
Patients...
Objective:
Familial hypocalciuric hypercalcemia (FHH) is an autosomal dominantly inherited disorder with overlapping biochemistry profile with primary hyperparathyroidism (PHPT), making the correct diagnosis a challenge. The objective of the study was to evaluate the results of the clinical work-up of a large group of hypercalcemic individuals.
D...
Essential thrombocythemia (ET) is characterized by persistently elevated platelet counts and an increased risk of thromboembolic events. Dysregulated expression of small noncoding microRNAs (miRNAs) have been shown in ET and may influence platelet maturity and function in ET patients. In this study, we included 22 ET patients and 19 healthy control...
Point of care testing of residual effect of antiplatelet therapy in trauma patients or during major surgery may result in improved clinical management of significant bleeding. We included 121 healthy individuals (57 females and 64 males, aged 22–65 years) in order to establish reference intervals for platelet aggregation induced by adenosine diphos...
Introduction
Antithrombin deficiency is associated with increased risk of venous thromboembolism (VTE). We aimed to identify variants causing antithrombin deficiency in a Danish population.
Materials and methods
We performed Sanger sequencing and, in relevant cases, multiplex ligation-dependent probe amplification analyses, in 46 individuals (23 i...
Aims
Lamin A/C mutations are generally believed to be associated with a severe prognosis. The aim of this study was to investigate disease expression in three affected families carrying different LMNA missense mutations. Furthermore, the potential molecular disease mechanisms of the mutations were investigated in fibroblasts obtained from mutation...
Background: Essential thrombocytosis (ET) is a myeloproliferative disorder characterized by an increased platelet count. ET is associated with an increased risk of thrombosis, and procoagulant features of the disease may include an increased number of reactive reticulated platelets and an increased aggregation potential. We aimed to explore the ass...
Context
Parathyroid-related hypercalcemia is due to primary hyperparathyroidism (PHPT) or to familial hypocalciuric hypercalcemia (FHH). PHPT can lead to complications that necessitate parathyroidectomy. FHH is a rare genetic disease resembling PHPT; surgery is ineffective. A reliable method for distinguishing FHH from PHPT is needed.
Objective
To...
Background:
The lactase persistence phenotype is controlled by a regulatory enhancer region upstream of the Lactase (LCT) gene. In northern Europe, specifically the -13910C > T variant has been associated with lactase persistence whereas other persistence variants, e.g. -13907C > G and -13,915 T > G, have been identified in Africa and the Middle E...
The calcium-sensing receptor (CaSR) is a G protein–coupled receptor (GPCR) that signals through Gq/11 and Gi/o to stimulate cytosolic calcium (Ca²⁺i) and mitogen-activated protein kinase (MAPK) signaling to control extracellular calcium homeostasis. Studies of loss- and gain-of-function CASR mutations, which cause familial hypocalciuric hypercalcem...
Pneumatic tube is an attractive way to transport blood samples from the emergency department to the central laboratory facility. We aimed to investigate the impact of pneumatic tube transportation on blood samples for analysis of whole blood coagulation and platelet function.
We included 21 healthy adult individuals and measured global coagulation...
Flow cytometry is an increasingly used method for platelet function analysis because it has
some important advantages compared with other platelet function tests. Flow cytometric
platelet function analyses only require a small sample volume (3.5 mL); however, to expand
the field of applications, e.g., for platelet function analysis in children, eve...
Cobalamin (vitamin B12 [Cbl]) is an essential cofactor for many biochemical pathways. Transcobalamin (TC) is required to internalize Cbl into the cells through membrane receptor-mediated endocytosis. Cbl is then processed in the cytoplasm and mitochondria by complementation factors leading to its active metabolites; methylcobalamin and 5-deoxyadeno...
Objective:
Familial hypocalciuric hypercalcemia (FHH) type 1 is caused by mutations in the gene encoding the calcium-sensing receptor (CASR). Recently, mutations affecting codon 15 in the gene AP2S1 have been shown to cause FHH type 3 in up to 26% of CASR-negative FHH patients. Similarly, mutations in the gene GNA11 have been shown to cause FHH ty...
Using functional haemostasis assays, we demonstrated important differences in stability of direct oral anticoagulants (DOACs) in citrated whole blood and plasma from DOAC treated patients. Laboratories and clinicians should take this into consideration and adjust clinical practices accordingly.
Key Clinical Message
Familial hypocalciuric hypercalcemia type 3 should be considered as differential diagnosis in patients with suspected primary hyperparathyroidism and/or suspected multiple neoplasia syndrome, as correct diagnosis will spare the patients for going through multiple futile parathyroidectomies and for the worry of being diagnosed w...
Objective:
Loss-of-function variants in the gene encoding the calcium sensing receptor (CaSR) result in Familial Hypocalciuric Hypercalcemia (FHH), causing hypercalcemia with high normal or elevated parathyroid hormone levels. The CaSR may also influence electrolyte and water homeostasis. It is unknown whether FHH affects cardiovascular health. We...
Measurement of holotranscobalamin (holoTC) is increasingly used as a screening test for cobalamin (Cbl) deficiency. A level well below the reference interval strongly supports a deficient state. We examined a 21-year-old woman diagnosed as Cbl deficient because of an extremely low holoTC level as measured by the Abbott Architect Assay.
The patient...
Objectives:
Epidermal growth factor receptor (EGFR) mutations are important predictors of treatment response to tyrosine kinase inhibitors (TKIs) in patients with non-small cell lung cancer (NSCLC). However, some patients with mutations do not respond and some patients without mutations show response. We therefore need additional biomarkers to imp...
Patients with thrombocytopenia or platelet disorders are at risk of severe bleeding. We report the development and validation of flow cytometry assays to diagnose platelet disorders and to assess platelet function independently of platelet count. The assays were developed to measure glycoprotein levels (panel 1) and platelet function (panel 2) in s...
Platelet aggregation during aspirin treatment displays considerable inter-individual variability. A genetic etiology likely exists, but it remains unclear to what extent genetic polymorphisms determine platelet aggregation in aspirin-treated individuals.To identify platelet-related single nucleotide polymorphisms (SNPs) influencing platelet aggrega...
Aim: Somatic mutations in the epidermal growth factor receptor (EGFR) are predictors of efficacy for treatment with the EGFR tyrosine kinase inhibitor erlotinib in non-small cell lung cancer (NSCLC). However, not all patients with EGFR mutations respond to erlotinib and the duration of the response varies markedly between patients. A CA repeat poly...
AimAutosomal dominant hypocalcaemia (ADH) is caused by activating variants in the calcium sensing receptor (CASR) gene, but detailed information on the paediatric phenotype is limited. The current paper presents a case of severe ADH and systematically reviews the literature on ADH in children.Conclusion
We found that the severity of clinical neurol...
![Table 4 vBMD Assessed by QCT, Median With Interquartile [25 %; 75 %] Range](profile/Lars-Rolighed/publication/262845246/figure/tbl1/AS:601619943149587@1520448780714/BMD-Assessed-by-QCT-Median-With-Interquartile-25-75-Range_Q320.jpg)
Familial Hypocalciuric Hypercalcaemia (FHH) Type 1 is caused by an inactivating mutation in the calcium-sensing receptor (CASR) gene resulting in elevated plasma calcium levels. We investigated whether FHH is associated with change in bone density and structure. We compared 50 FHH patients with age- and gender-matched population-based controls (mea...
The diagnosis of sarcoidosis is challenging and involves radiological, clinical and paraclinical evaluation, the latter including the measurement of serum angiotensin-converting enzyme activity (s-ACE), which is elevated in about 60% of sarcoidosis patients. The normal inter-individual biological variation of s-ACE is large. Approximately 50% of th...
-Arrhythmogenic cardiomyopathy (AC) is a hereditary cardiac condition associated with ventricular arrhythmias, heart failure and sudden death. The disease is most often caused by mutations in the desmosomal gene for plakophilin-2 (PKP2), which is expressed in both myocardial and epidermal tissue. This study aimed to investigate protein expression i...
The serum-angiotensin I converting enzyme (s-ACE) activity is influenced by a genetic insertion/deletion (I/D) polymorphism in the ACE gene, and the resulting large interindividual variation in s-ACE limits the use of normal reference intervals in the evaluation of sarcoidosis. In this study, we developed a new method for genotyping the I/D polymor...
Background:
Familial hypocalciuric hypercalcemia (FHH) is often due to inactivating variants in the calcium-sensing receptor (CASR) gene causing chronically elevated plasma calcium levels with inappropriately normal or elevated parathyroid hormone levels. In patients with primary hyperparathyroidism, the state of hyperparathyroid hypercalcemia is...
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a hereditary cardiac condition associated with ventricular arrhythmias, heart failure, and sudden death. The most frequent ARVC genes encode desmosomal proteins of which mutations in desmoglein-2, account for 10-20% of cases. This study aimed to investigate how DSG2 mutations contribute to t...
Background:
Plasma cobalamin is requested in order to diagnose cobalamin deficiency and low levels confirm a deficient state. Here, we present three family members with unexpected high levels of cobalamin.
Methods:
We included a patient referred for cobalamin measurement due to neurological symptoms, her son and her daughter. Mother and son both...
Background: Arrhythmogenic cardiomyopathy (AC) is a hereditary cardiac condition associated with ventricular arrhythmias, heart failure and sudden death. The disease is most often caused by mutations in the desmosomal gene for plakophilin-2 (PKP2), which is expressed in both myocardial and epidermal tissue. It was the aim of this study to investiga...
Mutations in the gene for desmoplakin (DSP) may cause arrhythmogenic right ventricular cardiomyopathy (ARVC) and Carvajal syndrome (CS). Desmoplakin is part of all desmosomes, which are abundantly expressed in both myocardial and epidermal tissue and serve as inter-cellular mechanical junctions. This study aimed to investigate protein expression in...
Introduction:
Sudden unexplained death account for one-third of all sudden natural deaths in the young (1-35 years). Hitherto, the prevalence of genopositive cases has primarily been based on deceased persons referred for postmortem genetic testing. These deaths potentially may represent the worst of cases, thus possibly overestimating the prevale...
The aim of this investigation was to identify pathogenic variants of the ryanodine receptor 2 (RYR2) gene in a cohort of persons aged 0-40 years who died of sudden unexpected death syndrome (SUD), including a cohort of infants who died of sudden infant death syndrome (SIDS). We genetically screened 29 of the 105 exons of the RYR2 gene associated wi...
Familial hypercholesterolemia (FH) is a genetic disorder that may lead to premature coronary heart disease (CHD) and sudden cardiac death (SCD). Mutations in the LDLR or APOB genes cause FH. We have screened the LDLR and the ligand-binding region of APOB genes in 52 cases of SCD. Deceased patients were younger than 40 years of age and were suspec...
The aim of this investigation was to identify and characterise pathogenic mutations in a sudden cardiac death (SCD) cohort suspected of cardiomyopathy in persons aged 0-40 years. The study material for the genetic screening of cardiomyopathies consisted of 41 cases and was selected from the case database at the Institute of Forensic Medicine. Mutat...
Calcium metabolic disorders like familial hypocalciuric hypercalcemia (FHH) and autosomal dominant familial isolated hypoparathyroidism (FIH) can be caused by rare variants of the calcium sensing receptor gene (CASR). Molecular genetic screening of the CASR is often based on DNA sequencing.
We sought to develop a pre-screening method in the diagnos...
Hypercalcaemia is a potentially life-threatening condition. Familial hypocalciuric hypercalcaemia (FHH) is a rare, lifelong, benign condition. It is important to separate this condition from other hypercalcaemic states such as hypercalcaemia of malignancy and primary hyperparathyroidism (PHPT).
FHH is caused by inactivating mutations in the calcium...
Studies have shown that cancellous bone is relatively preserved in primary hyperparathyroidism (PHPT), whereas bone loss is seen in cortical bone. Familial hypocalciuric hypercalcemia (FHH) patients seem to preserve bone mineral in spite of hypercalcemia and often elevated plasma parathyroid hormone (PTH). The objective of this study was to compare...
Lactase persistence and thereby tolerance to lactose is a common trait in people of Northern European descent. It is linked to the LCT -13910C>T variant located in intron 13 of the MCM6 gene 13.9 kb upstream of the lactase (LCT) gene. In people of African and Middle Eastern descent, lactase persistence can be associated with other variants nearby t...
Transcobalamin (TC) deficiency (OMIM# 275350) is a rare, autosomal recessive disorder that presents in early infancy with a broad spectrum of symptoms, including failure to thrive, megaloblastic anemia, immunological deficiency, and neurological symptoms. Here we report a study of a family (parents and three children) with two children suffering fr...
Mutation screening of the CASR by DNA sequencing is commonly used in the diagnosis of disorders of calcium metabolism, such as familial hypocalciuric hypercalcaemia (FHH). Exon copy number variation is not detected by currently used molecular genetic screening methods, and might be a genetic cause of inherited forms of hyper- or hypocalcaemia cause...
Bovine spinal dysmyelination (BSD) is a recessive congenital neurodegenerative disease in cattle (Bos taurus) characterized by pathological changes of the myelin sheaths in the spinal cord. The occurrence of BSD is a longstanding problem in the American Brown Swiss (ABS) breed and in several European cattle breeds upgraded with ABS. Here, we show t...
Bone metabolism is only superficially described in familiar hypocalciuric hypercalcaemia (FHH). We describe and compare biochemical and osteodensitometric variables in FHH and primary hyperparathyroidism (PHPT) and assess whether they can improve the diagnostic discrimination between the groups.
Cross-sectional.
Sixty-six FHH patients with known ca...
Familial hypocalciuric hypercalcemia (FHH) is a lifelong, benign, inherited condition caused by inactivating mutations in the calcium-sensing receptor (CASR) gene. Both FHH and primary hyperparathyroidism (PHPT) are characterized by elevated P-calcium, normal or elevated plasma-parathyroid hormone (P-PTH), and typically normal renal function. In PH...
Familial hypocalciuric hypercalcaemia (FHH) must be differentiated from primary hyperparathyroidism (PHPT) because prognosis and treatment differ. In daily practice this discrimination is often based on the renal calcium excretion or the calcium/creatinine clearance ratio (CCCR). However, the diagnostic performance of these variables is poorly docu...
The autosomal dominantly inherited condition familial hypocalciuric hypercalcemia (FHH) is characterized by elevated plasma calcium levels, relative or absolute hypocalciuria, and normal to moderately elevated plasma PTH. The condition is difficult to distinguish clinically from primary hyperparathyroidism and is caused by inactivating mutations in...
Familial Hypercholesterolemia is a common autosomal dominantly inherited disease that is most frequently caused by mutations in the gene encoding the receptor for low density lipoproteins (LDLR). Deletions and other major structural rearrangements of the LDLR gene account for approximately 5% of the mutations in many populations.
Five genomic delet...
The genes encoding the LDL receptor and apoB were screened for mutations associated with familial hypercholesterolemia (FH) in 408 patients referred to the Lipid Clinic in 1995-2003. The study aimed at testing the ability of three different sets of clinical criteria to predict the results of molecular genetic analysis, and secondly test whether pop...
Familial Hypercholesterolemia (FH) is a common genetic disease and at the molecular level most often due to mutations in the LDL receptor gene. In genetically heterogeneous populations, major structural rearrangements account for about 5% of patients with LDL receptor gene mutations.
In this study we tested the ability of two different quantitative...
Familial hypocalciuric hypercalcemia (FHH) has an autosomal dominant inheritance and is caused by inactivating mutations in the calcium-sensing receptor gene (CaSR) on chromosome 3; its prevalence in the population is 1 in 10,000. FHH is characterized by normoparathyroid or hyperparathyroid hypercalcemia with a low to normal calcium excretion in th...
Familial hypercholesterolemia is a human monogenic disease caused by population-specific mutations in the low density lipoprotein (LDL) receptor gene. Despite thirteen different mutations of the LDL receptor gene were reported from Russia prior to 2003, the whole spectrum of disease-causing gene alterations in this country is poorly known and requi...
Genes of the early growth response (EGR) family encode transcription factors with a highly conserved DNA binding zinc finger domain, which regulate a variety of genes, e.g. late myelin genes. Here, the cloning, genomic structure and expression of the bovine orthologue of the EGR4 gene are reported. The gene consists of two exons and encodes a 482 a...
The porcine COL10A1 gene, encoding the alpha1(X) chain of type X Collagen, has been sequenced. The gene structure is evolutionarily conserved, consisting of three exons and two introns spanning 7100 bp. Linkage mapping localized the gene to chromosome 1, which is in agreement with human-pig homology maps. Furthermore, protein structure comparison o...
In an inbred pig family founded by commercial breeds, nine microsatellite markers from porcine chromosome 4 were screened to find associations with weight gain and fat deposition traits. In this family showing a linear decrease in weight gain with inbreeding, an association (P <0.05) was found between average daily slaughter gain and markers S0214...
The congenital neurological disorder spinal dysmyelination is seen in cattle breeds upgraded with American Brown Swiss cattle. The disorder is inherited as an autosomal recessive disease. The spinal dysmyelination locus was genetically mapped in a family of Red Danish Dairy breed x American Brown Swiss, using a battery of approximately 200 microsat...
A set of eleven pig breeds originating from six European countries, and including a small sample of wild pigs, was chosen for this study of genetic diversity. Diversity was evaluated on the basis of 18 microsatellite markers typed over a total of 483 DNA samples collected. Average breed heterozygosity varied from 0.35 to 0.60. Genotypic frequencies...
Abstract A set of eleven pig breeds originating from six European countries, and including a small sample of wild pigs, was chosen for this study of genetic diversity. Diversity was evaluated on the basis of 18 microsatellite markers typed over a total of 483 DNA samples collected. Average breed heterozygosity varied from 0.35 to 0.60. Genotypic fr...
Chantier qualité spécifique "Auteurs Externes" département de Génétique animale : uniquement liaison auteur au référentiel HR-Access
Three cDNA clones from a porcine small intestine cDNA library, tentatively identified as transcripts of two different cytochrome P450 (CYP) gene subfamilies, were sequenced and mapped. One of the clones was found to comprise an open reading frame of 503 amino acids and showed up to an 80% similarity to genes from the CYP3A subfamily. Translation of...
Questions
Questions (3)
We have been having clotting issues with our Cytoflex S from Beckman Coulter. Back in December 2020, we had to have the tubing system and sample needles replaced, but we are beginning to observe clotting issues again.
Our current cleaning procedure is to run 5 wells of 2% hypochlorite (60 sec, 60uL/min) followed by the built in “Daily Clean Program” (3 wells of cleaning solution and 5 wells of deionized water) prior to analyzing samples. After analysis, we run 5 wells of Trypsin (60 sec, 60uL/min) followed by the “Daily Clean Program”.
Our Cytoflex is used for a variety of cells, incl. tumor cell lines, PBMCs, monocyte-derived macrophages, and platelet activation studies in whole blood.
Does anyone have experience using these cell types and which cleaning procedures have you implemented to maintain your flow cytometers?
We have observed a decreasing median fluorescence intensity (MFI), and recently extracted data from seven years of analyses (se attached figure) showing a very clear decline in fluorescence intensity. We do not think this has to do with reagents or antibodies. Could it be the red laser declining in activity? Could we somehow compensate (eg. by increasing voltage in the flow cytometry protocol)?
Background: we are running platelets and detect a panel of platelet surface glycoproteins using labelled antibodies. We use a Navios from Beckman-Coulter
Any suggetsions is appreciated.
During melting on the LightScanner 96 instrument, the intensity suddenly makes a sharp drop, before the expected amplicon melting point. The intensity drop ruins the data.
We have tried several things to correct the issue, and often a plate calibration and a new melt works. But the next run might make the same drop again.
We have had Lightscanner for 8 years, and have run in excess of 60,000 samples, but never seen this before. We run four different unlabeled probe and small amplicon assays. We use the recommended plates from Bio-Rad and BioFire LightScanner mastermix.
Any suggestion to correct this would be warmly appreciated.
