Search PubMed⌕ Search

Biomedical subjects

I Christiansen

Publications and source records attributed to I Christiansen.

At least 19 recordsLinked to original sources
PubMed2006

Improvement of real-time polymerase chain reaction for quantifying TNF-alpha mRNA expression in inflamed colorectal mucosa: an approach to optimize procedures for clinical use.

OBJECTIVE: The precise measurement of local tumor necrosis factor alpha (TNF-alpha) expression in tissue is important in understanding the pathogenesis of inflammatory bowel diseases (IBD). Real-time polymerase chain reaction (PCR) is a sensitive, versatile method and is becoming a commonly used tool for the quantification of gene expression. The aim of this study was to optimize the laboratory procedure for biopsy sampling, storage and calibration of result for TNF-alpha mRNA quantification with real-time PCR of colorectal biopsies. MATERIAL AND METHODS: Endoscopic biopsies from the colorectum were obtained from 18 patients with ulcerative colitis (UC), 11 patients with Crohn's disease (CD) and 18 normal controls. Optimization of procedures for real-time PCR performance was carried out. RESULTS: The transport medium, RNAlater, exhibited a high preservation effect against RNA degradation even after 8 days of storage at room temperature; one biopsy from each patient was sufficient for RNA extraction, cDNA synthesis and TNF-mRNA quantification. An assay was established with a technical reproducible sensitivity of 100 copies/microL. The observed interassay variations were 7.4 % coefficient of variation (CV) and 7.2 % CV in low and high TNF-alpha mRNA expression biopsies, respectively. TNF-alpha mRNA levels in colorectal biopsies from patients with either CD or moderate to severe UC were markedly increased, and 8 approximately 9-fold higher than those in healthy controls. CONCLUSIONS: This optimization improves the clinical use of real-time PCR for quantification of TNF-alpha gene expression in colorectal biopsies and provides a sensitive reproducible assay.

Adult↗
PubMed2003

The effect of nitric oxide synthase inhibition on histamine induced headache and arterial dilatation in migraineurs.

We have previously proposed that histamine causes migraine via increased NO production. To test this hypothesis, we here examined if the NOS inhibitor, L-NG methylarginine hydrochloride (L-NMMA:546C88), could block or attenuate histamine induced migraine attacks and responses of the middle cerebral, temporal and radial arteries. In a double blind crossover design 12 patients were randomized to receive pretreatment with L-NMMA (6 mg/kg) or placebo i.v. over 15 min followed on both study days by histamine (0.5 microg/kg/min) i.v. for 20 min. Headache scores, mean maximal blood velocity (Vmean) in the middle cerebral artery (MCA) (transcranial doppler) and diameters of temporal and radial arteries (high resolution ultrasound) were repeatedly measured. Pre-treatment with L-NMMA, had no effect on histamine induced headache or migraine, but also had no effect on the magnitude of histamine induced-decrease in MCA blood velocity, or dilatation of neither the temporal nor the radial artery. L-NMMA constricted the temporal artery by 8% before histamine infusion, whereas the radial artery was unaffected. The temporal artery dilated 4-5 times more than the radial artery during histamine infusion. In conclusion the use of a NOS inhibitor in the highest possible dose did not block the histamine-induced headache response or arterial dilatation. Either the concentration of L-NMMA reaching the smooth muscle cell was insufficient or, histamine dilates arteries and causes headache via NO independent mechanisms. Our results showed for the first time a craniospecificity for the vasodilating effect of histamine and for the arterial effects of NOS inhibition.

Adult↗
PubMed2000

Glyceryl trinitrate induced headache in migraineurs - relation to attack frequency.

Glyceryl trinitrate, a prodrug of nitric oxide, induces a mild to moderate headache in healthy subjects, whilst migraineurs develop a more severe headache, resembling spontaneous migraine attacks. In order to investigate whether this increased nitric oxide sensitivity depends upon the frequency of spontaneously occurring migraine attacks, intravenous infusion of glyceryl trinitrate (0.5 microg/kg/min) was given to 15 migraine patients with rare attacks (</=4 attacks/year) of migraine without aura. Fourteen age-matched migraine patients with frequent attacks of migraine without aura (>/=12 attacks/year) and 14 healthy subjects served as controls. No significant difference between the migraine groups for any of several parameters was detected, although the trend was always towards more headaches in frequent migraineurs. Both migraineurs with frequent and rare attacks experienced a headache that was significantly more severe, longer lasting, and fulfilled the diagnostic criteria for migraine without aura more often, compared to the healthy subjects (P = 0.0001). Conclusively, supersensitivity to glyceryl trinitrate in migraineurs seems to be related to a basic - probably genetically determined - pathophysiological mechanism involving nitric oxide, and not to the environmental influences, which to a large extent determine the expression of migraine.

Adult↗
PubMed2000

Headache characteristics during the development of tolerance to nitrates: pathophysiological implications.

Recent studies suggest that nitric oxide (NO) plays an important role in nitrate-induced headache and in spontaneous migraine attacks. Organic nitrates act as prodrugs for NO and headache is a predominant adverse effect of nitrates but often disappears during continuous treatment. Insight into tolerance to headache could lead to insight into vascular headache mechanisms in general. The specific aim of the present study was therefore to characterize the headache and accompanying symptoms during continuous nitrate administration until a state of tolerance to headache had developed. 5-isosorbide-mononitrate (5-ISMN) 30 mg three times daily was administered orally for 7 days in 11 healthy subjects in a double-blind, randomized placebo controlled cross-over design. Wash-out between periods was 14 days or more. Haemodynamic data from the present study were compared to the observed changes of headache over time. Headache during 5-ISMN was longer lasting and more severe compared to placebo (P<0.004). In 10 subjects the headache fulfilled the pain sub-criteria for migraine and in five subjects all diagnostic criteria for migraine without aura were fulfilled. Conversely, 20 min of intravenous infusion of glyceryl trinitrate caused a milder headache and no migraine. The present results therefore suggest that NO may elicit a migraine attack in many healthy subjects if a high enough dose is given for several hours. A close temporal association between the disappearance of headache and the attenuation of the 5-ISMN induced dilatation of the superficial temporal artery was observed. In contrast, tolerance in the middle cerebral artery already appeared after 24 h, which was earlier than the development of tolerance to headache. If vasodilatation is the cause of headache the results point to extracerebral arteries. However, cytotoxic and pain modulating central nervous system effects of NO, the time courses of which are unknown, may also play a role, involving both intra- and extracranial arteries.

Administration, Oral↗
PubMed2000

Induction of nitrate tolerance is not a useful treatment in cluster headache.

UNLABELLED: The aims of the present study were to investigate whether induction of nitrate tolerance is a useful treatment in cluster headache and to correlate any changes in attack frequency of cluster headache and nitrate-induced headache to the vascular adaptation during continuous nitrate administration. The results were compared to results obtained from studies of nitrate tolerance in healthy subjects. MATERIALS AND METHODS: 5-isosorbide-mononitrate (5-ISMN) 30 mg was administered orally three times daily for 4 weeks in nine sufferers of chronic cluster headache in a double-blind, randomized placebo-controlled cross-over design. Blood velocity in the middle cerebral artery was measured with transcranial Doppler and the diameters of the temporal and radial arteries were measured with high frequency ultrasound. The haemodynamic data were compared to changes in the frequency of cluster headache attacks and interval headaches over time. RESULTS: Tolerance was complete within 24 h in the middle cerebral arteries and after 7 days in the symptomatic temporal artery, while tolerance of the radial artery was not observed within this period. The time profiles of tolerance were almost identical to the time profiles observed in healthy subjects. A close temporal association between the disappearance of nitrate-induced headache and tolerance of the temporal artery was observed but tolerance had no effect on cluster headache attack frequency. CONCLUSIONS: Induction of tolerance to nitrates cannot be used to treat cluster headache. If pain is related to arterial dilatation the results point to extracerebral rather than cerebral arteries as the site of nociception. However, other peripheral and central pain-modulating effects of nitric oxide, the time courses of which are unknown, should also be taken into consideration.

Adult↗
PubMed1999

Staphylococcus aureus Cowan strain 1 activation of B-chronic lymphocytic leukaemia cells augments the response to CD40 stimulation.

The signals involved in regulating the proliferation, differentiation and survival of B-chronic lymphocytic leukemia (B-CLL) cells are fully understood. B-CLL cells have been found to respond poorly to various activation signals and only after successful Epstein-Barr virus (EBV) transformation has it been possible to maintain such cells in long-term cultures. In this work we describe a new method to activate and induce proliferation in B-CLL cells and to maintain such cells in long-term culture for longer than 1 month. We used a combination of protocols in an attempt to mimic some of the signals of a thymus-dependent immune response. The B-CLL cells were first activated with Staphylococcus aureus Cowan strain 1 (SAC) particles plus thioredoxin (Trx), followed by stimulation with interleukin (IL)-2 + Trx. This treatment primed the cells for further stimulation with anti-CD40 monoclonal antibody (MoAb) presented on irradiated CD32L cells (the CD40-system) or soluble CD40 Ligand, and a combination of Trx and cytokines (IL-4 + IL-10), which allowed the cells to be maintained for up to 1 month with preserved viability and a variable rate of proliferation. However, induced proliferation of the B-CLL cells was limited to approximately 1 month, suggesting that additional signals are required to facilitate further proliferation.

Burkitt Lymphoma↗
PubMed1999

Glyceryl trinitrate induces attacks of migraine without aura in sufferers of migraine with aura.

Migraine with aura and migraine without aura have the same pain phase, thus indicating that migraine with aura and migraine without aura share a common pathway of nociception. In recent years, increasing evidence has suggested that the messenger molecule nitric oxide (NO) is involved in pain mechanisms of migraine without aura. In order to clarify whether the same is true for migraine with aura, in the present study we examined the headache response to intravenous infusion of glyceryl trinitrate (GTN) (0.5 microg/kg/min for 20 min) in 12 sufferers of migraine with aura. The specific aim was to elucidate whether an aura and/or an attack of migraine without aura could be induced. Fourteen healthy subjects served as controls. Aura symptoms were not elicited in any subject. Headache was more severe in migraineurs than in the controls during and immediately after GTN infusion (p=0.037) as well as during the following 11 h (p = 0.008). In the controls, the GTN-induced headache gradually disappeared, whereas in migraineurs peak headache intensity occurred at a mean time of 240 min post-infusion. At this time the induced headache in 6 of 12 migraineurs fulfilled the diagnostic criteria for migraine without aura of the International Headache Society. The results therefore suggest that NO is involved in the pain mechanisms of migraine with aura. Since cortical spreading depression has been shown to liberate NO in animals, this finding may help our understanding of the coupling between cortical spreading depression and headache in migraine with aura.

Adult↗
PubMed1999

Staphylococcal phosphoenolpyruvate-dependent phosphotransferase system--two highly similar glucose permeases in Staphylococcus carnosus with different glucoside specificity: protein engineering in vivo?

Previous sequence analysis of the glucose-specific PTS gene locus from Staphylococcus carnosus revealed the unexpected finding of two adjacent, highly similar ORFs, glcA and glcB, each encoding a glucose-specific membrane permease EIICBA(Glc). glcA and glcB show 73% identity at the nucleotide level and glcB is located 131 bp downstream from glcA. Each of the genes is flanked by putative regulatory elements such as a termination stem-loop, promoter and ribosome-binding site, suggesting independent regulation. The finding of putative cis-active operator sequences, CRE (catabolite-responsive elements) suggests additional regulation by carbon catabolite repression. As described previously by the authors, both genes can be expressed in Escherichia coli under control of their own promoters. Two putative promoters are located upstream of glcA, and both were found to initiate transcription in E. coli. Although the two permeases EIICBA(Glc)1 and EIICBA(Glc)2 show 69% identity at the protein level, and despite the common primary substrate glucose, they have different specificities towards glucosides as substrate. EIICBA(Glc)1 phosphorylates glucose in a PEP-dependent reaction with a Km of 12 microM; the reaction can be inhibited by 2-deoxyglucose and methyl beta-D-glucoside. EIICBA(Glc)2 phosphorylates glucose with a Km of 19 microM and this reaction is inhibited by methyl alpha-D-glucoside, methyl beta-D-glucoside, p-nitrophenyl alpha-D-glucoside, o-nitrophenyl beta-D-glucoside and salicin, but unlike other glucose permeases, including EIICBA(Glc)1, not by 2-deoxyglucose. Natural mono- or disaccharides, such as mannose or N-acetylglucosamine, that are transported by other glucose transporters are not phosphorylated by either EIICBA(Glc)1 nor EIICBA(Glc)2, indicating a high specificity for glucose. Together, these findings support the suggestion of evolutionary development of different members of a protein family, by gene duplication and subsequent differentiation. C-terminal fusion of a histidine hexapeptide to both gene products did not affect the activity of the enzymes and allowed their purification by Ni2+-NTA affinity chromatography after expression in a ptsG (EIICB(Glc)) deletion mutant of E. coli. Upstream of glcA, the 3' end of a further ORF encoding 138 amino acid residues of a putative antiterminator of the BglG family was found, as well as a putative target DNA sequence (RAT), which indicates a further regulation by glucose specific antitermination.

Deoxyglucose↗
PubMed1999

Serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) are elevated in advanced stages of non-Hodgkin's lymphomas.

The serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) were measured in 116 patients with non-Hodgkin's lymphomas (NHL) tested previously for soluble intercellular adhesion molecule-1 (sICAM-1). In contrast to Hodgkin's disease and chronic lymphocytic leukaemia, the sVCAM-1 levels in NHL patients were not significantly different from the levels of healthy controls (n = 31). However, sVCAM-1 was elevated in advanced stage disease, i.e. stages III + IV. Elevated serum levels of sVCAM-1 were associated with significantly poorer disease-free (p = 0.024) and overall (p = 0.02) survival. sVCAM-1 correlated poorly with other known prognostic variables (LDH, sTK and beta 2m) and with sICAM-1. None of the tested markers added prognostic information for disease-free survival independently of Ann Arbor stage and B-symptoms. The expression of VCAM-1 and ICAM-1 in tumour biopsies from 15 patients representing 7 different histologies were examined and compared with the serum levels of the soluble adhesion molecules. No correlation was found between the adhesion molecule expression by vascular endothelium and the corresponding serum levels.

Adult↗
PubMed1998

[A successful attempt with a consulting service for boys].

As adolescence is a critical period of development, and as boys are less inclined than girls to approach the school facility for adolescent counselling, segregated consulting hours were introduced for boys to attract those with problems. The frequency of consultations by boys increased by 25 per cent, and 70 per cent of the boys reported a preference for the segregated consulting hours; 75 per cent appreciated the absence of girls from the waiting room; and of the 42 per cent with special preferences regarding the gender of the staff encountered, half reported preferring a man. Most of the boys presented with defined problems, though many revealed other problems, often relating to sexuality, in the course of consultation. The availability of segregated consulting hours for boys with adolescent problems is important, and often the only way to reach young boys who need help.

Adolescent↗
PubMed1998

Soluble vascular cell adhesion molecule-1 (sVCAM-1) is an independent prognostic marker in Hodgkin's disease.

Serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1. sCD106) were significantly elevated in patients with Hodgkin's disease (HD) (n = 101) compared to controls (n= 31) (P<0.0001). sVCAM-1 correlated with histology, stage, B-symptoms, and prognostic markers (sICAM-1, sCD30, sIL-2R, LDH). sVCAM-1, sICAM-1 and sCD30 added independent prognostic information for both disease-free and overall survival. 14 biopsies from 13 patients with HD were immunostained for VCAM-1 and ICAM-1. The vascular endothelium stained positive for VCAM-1 in 10/12 evaluable biopsies and for ICAM-1 in all evaluable biopsies. A stromal expression of both adhesion molecules precluded a precise evaluation of HRS-cells. This led us to investigate VCAM-1 (and ICAM-1) expression in six Hodgkin cell lines (HDLM-2, L428, L540, L591, DEV, KM-H2). Two cell lines stained positive for VCAM-1 (HDLM-2, L591). All cell lines stained positive for ICAM-1. sVCAM-1 is a new prognostic marker in HD; its predictive power equals or surpasses that of sCD30 and sICAM-1. Furthermore, two Hodgkin cell lines stained positive for VCAM-1. This indicates that VCAM-1 may be expressed by some HD tumour cells in vivo.

Adolescent↗
PubMed1998

Elevated serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) closely reflect tumour burden in chronic B-lymphocytic leukaemia.

The present study is the first to report elevated serum levels of soluble (s)VCAM-1 in B-cell chronic lymphocytic leukaemia (B-CLL). A large cohort of 106 untreated patients was studied. sVCAM-1 was compared to known prognostic serum markers (soluble (s)ICAM-1; lactate dehydrogenase, LDH; sCD23; thymidine kinase, TK; beta2microglobulin, beta2m). The serum levels of sVCAM-1 reflected tumour burden as expressed by Binet/Rai stages more closely than any other marker. sVCAM-1 also reflected the kinetics of the disease as revealed by lymphocyte doubling time. sVCAM-1 was the only one of the studied markers which showed elevated levels in smouldering disease compared to controls. sVCAM-1, sICAM-1 and sCD23 (but not LDH, TK, beta2m) separated smouldering from non-smouldering B-CLL. Only sICAM-1, sCD23 and TK added independent prognostic information for survival to that of stage and lymphocyte doubling time. The expression of both adhesion molecules was examined in lymph node and splenic specimens. VCAM-1 and ICAM-1 were overexpressed by vascular endothelium and stroma, but the intensity of expression correlated poorly with serum levels of the soluble molecules. In conclusion, serum levels of sVCAM-1 correlated with tumour burden and other prognostic markers in B-CLL. VCAM-1 was overexpressed in tumour tissue as was ICAM-1. sVCAM-1 could prove a valuable marker in younger early-stage patients eligible for therapeutic trials.

Adult↗
PubMed1998

Nitric oxide synthase inhibition: a new principle in the treatment of migraine attacks.

Glyceryl trinitrate, an exogenous nitric oxide (NO) donor, and histamine, which causes NO formation in vascular endothelium, have been shown to trigger migraine attacks. However, it remains uncertain whether NO is involved in the subsequent phase of migraine attacks. To answer this question we studied the effect of L-NGmethylarginine hydrochloride (546C88), a NO-synthase inhibitor, on spontaneous migraine attacks. In a double-blind study design, 18 patients with migraine without aura randomly received 546C88 (6 mg/kg) or placebo (5% dextrose) i.v. given over 15 min for a single migraine attack (546C88:placebo, 15:3). Furthermore, 11 placebo-treated patients from previous double-blind trials with almost identical design were added to the placebo group in the statistical evaluation. Two hours after the infusion, 10 of 15 L-NGmethylarginine hydrochloride-treated patients experienced headache relief compared to 2 of 14 placebo-treated patients (p = 0.01). Symptoms such as phono- and photophobia were also significantly improved. A similar trend for nausea was not significant. We conclude that NO may be involved in the pain mechanisms throughout the course of spontaneous migraine attacks.

Adolescent↗
PubMed1998

Serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) are elevated in advanced stages of non-Hodgkin's lymphomas.

The serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) were measured in 116 patients with non-Hodgkin's lymphomas (NHL) tested previously for soluble intercellular adhesion molecule-1 (sICAM-1). In contrast to Hodgkin's disease and chronic lymphocytic leukaemia, the sVCAM-1 levels in NHL patients were not significantly different from the levels of healthy controls (n=31). However, sVCAM-1 was elevated in advanced stage disease, i.e. stages III+IV. Elevated serum levels of sVCAM-1 were associated with significantly poorer disease-free (p = 0.024) and overall (p = 0.02) survival. sVCAM-1 correlated poorly with other known prognostic variables (LDH, sTK and beta2m) and with sICAM-1. None of the tested markers added prognostic information for disease-free survival independently of Ann Arbor stage and B-symptoms. The expression of VCAM-1 and ICAM-1 in tumour biopsies from 15 patients representing 7 different histologies were examined and compared with the serum levels of the soluble adhesion molecules. No correlation was found between the adhesion molecule expression by vascular endothelium and the corresponding serum levels.

Adult↗
PubMed1997

Interleukin-15 + thioredoxin induce DNA synthesis in B-chronic lymphocytic leukemia cells but not in normal B cells.

We have previously shown that Staphylococcus aureus Cowan strain 1 particles (SAC) + thioredoxin (Trx) + IL-2 may induce B-chronic lymphocytic leukemia (B-CLL) cells to proliferate. In this paper we have examined IL-15, which has activities similar to IL-2, for its ability to stimulate B-CLL cells and compared its activity with that of IL-2. We found that B-CLL cells could be induced to DNA synthesis upon treatment with IL-15 + Trx. The presence of Trx was essential for the IL-15-induced DNA synthesis. This contrasts to the effect of IL-15 + Trx on normal CD5+ and CD5- B cells, where IL-15 + Trx alone only induced limited DNA synthesis. IL-15 was as effective in the induction of DNA synthesis in B-CLL cells as IL-2, but about 100-fold less potent with an EC50 of 200 ng/ml. In addition we found that the IL-15 + Trx-induced proliferation was inhibited by CD40 stimulation. We conclude that IL-15 together with a proper costimulus can induce B-CLL cells to proliferate in vitro.

B-Lymphocytes↗
PubMed1997

CD40 ligation inhibits IL-2 and SAC+IL-2 induced proliferation in chronic lymphocytic leukaemia cells.

This paper reports on differences between B cell-type chronic lymphocytic leukaemia (B-CLL) and normal B cells in their response to IL-2+thioredoxin (Trx), Staphylococcus aureus Cowan strain 1 (SAC)+IL-2+Trx, and to CD40 ligation of IL-2+Trx and SAC+IL-2+Trx stimulation. The authors found that Trx acted synergistically with IL-2 and SAC+IL-2 in inducing DNA synthesis in B-CLL cells, but not in the normal B cells. Interestingly, IL-2+Trx alone was found to induce proliferation in B-CLL cells from patients with advanced stages of disease. In addition, we also found that IL-2+Trx and SAC+IL-2+Trx-induced DNA synthesis of B-CLL cells was inhibited by CD40 activation (by soluble anti-CD40 MoAb and anti-CD40 MoAb presented on irradiated CD32L cells). In clear contrast, SAC+IL-2+ Trx-induced DNA synthesis of normal B cells was not inhibited by soluble anti-CD40 MoAb. The authors therefore conclude that B-CLL cells differ from normal B cells in their response to IL-2 (IL-2+Trx) and CD40 ligation.

Adult↗
PubMed1996

Cloning and sequencing of two genes from Staphylococcus carnosus coding for glucose-specific PTS and their expression in Escherichia coli K-12.

Phosphoenolpyruvate (PEP)-dependent phosphorylation experiments have indicated that the gram-positive bacterium Staphylococcus carnosus possesses an EIICBA fusion protein specific for glucose. Here we report the cloning of a 7 kb genomic DNA fragment containing two genes, glcA and glcB, coding for the glucose-specific PTS transporters EII(Glc)1 and EII(Glc)2 which are 69% identical. The translation products derived from the nucleotide sequence consist of 675 and 692 amino acid residues and have calculated molecular weights of 73025 and 75256, respectively. Both genes can be stably maintained in Escherichia coli cells and restore the ability to ferment glucose to ptsG deletion mutants of E. coli. This demonstrates the ability of the PTS proteins HPr and/or EIIA(Glc) of a gram-negative organism (E. coli) to phosphorylate an EIICBA(Glc) from a gram-positive organism (S. carnosus).

Amino Acid Sequence↗