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B Pedersen

Publications and source records attributed to B Pedersen.

At least 19 recordsLinked to original sources
PubMed2005

MEAD: an interdisciplinary study of the marine effects of atmospheric deposition in the Kattegat.

This paper summarises the results of the EU funded MEAD project, an interdisciplinary study of the effects of atmospheric nitrogen deposition on the Kattegat Sea between Denmark and Sweden. The study considers emissions of reactive nitrogen gases, their transport, transformations, deposition and effects on algal growth together with management options to reduce these effects. We conclude that atmospheric deposition is an important source of fixed nitrogen to the region particularly in summer, when nitrogen is the limiting nutrient for phytoplankton growth, and contributes to the overall eutrophication pressures in this region. However, we also conclude that it is unlikely that atmospheric deposition can, on its own, induce algal blooms in this region. A reduction of atmospheric nitrogen loads to this region will require strategies to reduce emissions of ammonia from local agriculture and Europe wide reductions in nitrous oxide emissions.

Agriculture↗
PubMed2004

Impact of the sex of first child on the prognosis in secondary recurrent miscarriage.

BACKGROUND: The carriage of a male fetus often initiates maternal immunological reactions against male-specific minor histocompatibility (HY) antigens, which, in theory, could result in subsequent recurrent miscarriage (RM). METHODS: Information about subsequent pregnancy outcome was procured among 182 women with RM after a birth (secondary RM) referred since 1986 using questionnaires, telephone interviews and registers. RESULTS: Significantly more of the women had had a male first-born as compared with a female first-born (110 versus 72; P < 0.02). By January 2002, 58% of those who had a male first-born had given birth to a second live infant compared with 76% of those who previously had had a female first-born (P = 0.01). Women in the former group had a significantly lower chance of having a second child than those in the latter (adjusted hazard ratio 0.59; 95% confidence interval 0.41-0.86). The number of miscarriages after admission and the risk of secondary infertility were significantly greater in women with a male first-born than among those with a female first-born (P < 0.001 and P = 0.02; respectively). CONCLUSIONS: A male first-born seems to be associated with a less favourable reproductive potential among women with secondary RM. Maternal immunization against HY antigens may be responsible for these findings.

Abortion, Habitual↗
PubMed2002

Tissue factor deficiency causes cardiac fibrosis and left ventricular dysfunction.

Exposure of blood to tissue factor (TF) activates the extrinsic (TF:FVIIa) and intrinsic (FVIIIa:FIXa) pathways of coagulation. In this study, we found that mice expressing low levels of human TF ( approximately 1% of wild-type levels) in an mTF(-/-) background had significantly shorter lifespans than wild-type mice, in part, because of spontaneous fatal hemorrhages. All low-TF mice exhibited a selective heart defect that consisted of hemosiderin deposition and fibrosis. Direct intracardiac measurement demonstrated a 30% reduction (P < 0.001) in left ventricular function in 8-month-old low-TF mice compared with age-matched wild-type mice. Mice expressing low levels of murine FVII ( approximately 1% of wild-type levels) exhibited a similar pattern of hemosiderin deposition and fibrosis in their hearts. In contrast, FIX(-/-) mice, a model of hemophilia B, had normal hearts. Cardiac fibrosis in low-TF and low-FVII mice appears to be caused by hemorrhage from cardiac vessels due to impaired hemostasis. We propose that TF expression by cardiac myocytes provides a secondary hemostatic barrier to protect the heart from hemorrhage.

Animals↗
PubMed2002

Guidelines for the use of EEG methodology in the diagnosis of epilepsy. International League Against Epilepsy: commission report. Commission on European Affairs: Subcommission on European Guidelines.

The Commission of European Affairs of the International League Against Epilepsy published 'Appropriate Standards for Epilepsy Care Across Europe' which contained recommendations for the use of electroencephalography (EEG) in the diagnosis of epilepsy (Brodie et al. Epilepsia 1997; 38:1245). The need for a more specific basic document of EEG methodology was recognized and the Subcommission on European Affairs was asked to produce more detailed guidelines to be used across Europe recognizing the range of practices in EEG laboratories. There are many general guidelines published on EEG methodology but this document focuses on the diagnosis of epilepsy. Details from previously published guidelines are included in references and in an appendix. These guidelines are not meant to be used as minimal standards but recommendations that can be applied to all EEG laboratories despite variations in equipment.

Adult↗
PubMed2001

Activation of natural killer T cells potentiates or prevents experimental autoimmune encephalomyelitis.

Natural killer (NK) T cells recognize lipid antigens in the context of the major histocompatibility complex (MHC) class 1-like molecule CD1 and rapidly secrete large amounts of the cytokines interferon (IFN)-gamma and interleukin (IL)-4 upon T cell receptor (TCR) engagement. We have asked whether NK T cell activation influences adaptive T cell responses to myelin antigens and their ability to cause experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis. While simultaneous activation of NK T cells with the glycolipid alpha-galactosylceramide (alpha-GalCer) and myelin-reactive T cells potentiates EAE in B10.PL mice, prior activation of NK T cells protects against disease. Exacerbation of EAE is mediated by an enhanced T helper type 1 (Th1) response to myelin basic protein and is lost in mice deficient in IFN-gamma. Protection is mediated by immune deviation of the anti-myelin basic protein (MBP) response and is dependent upon the secretion of IL-4. The modulatory effect of alpha-GalCer requires the CD1d antigen presentation pathway and is dependent upon the nature of the NK T cell response in B10.PL or C57BL/6 mice. Because CD1 molecules are nonpolymorphic and remarkably conserved among different species, modulation of NK T cell activation represents a target for intervention in T cell-mediated autoimmune diseases.

Animals↗
PubMed2001

[Is visual assessment of MRI adequate in the investigation of patients with temporal lobe epilepsy? Evaluation of the diagnostic accuracy of the visual assessment of MRI in mesial temporal sclerosis].

INTRODUCTION: Is visual assessment of MRI adequate in patients with temporal lobe epilepsy? Visual versus quantitative MRI assessment of mesial temporal sclerosis (hippocampal gliosis (HG) and hippocampal atrophy (HA)). MATERIAL AND METHODS: The MRIs of 25 patients with temporal lobe epilepsy were assessed visually by three radiologists with different levels of neuroradiological MRI experience (expert, trained, and inexperienced). Diagnosis obtained earlier by T2-relaxometry and volume measurements were considered to be the gold standard. RESULTS: The diagnostic accuracy of visual assessment was high for unilateral HA, but low for bilateral HA and unilateral and bilateral HG, and it was not better for the expert eye than for the inexperienced. Interobserver agreement on the visual diagnosis of HG and HA (Cohen's Kappa coefficient): 0.49 (HG) and 0.84 (HA). Intraobserver reliability for the expert/trained/inexperienced observer for visual diagnosis (Kappa): 0.83/0.64/0.47 (HG) and 0.88/0.69/0.73 (HA). DISCUSSION: Reproducibility and diagnostic accuracy of visual assessment varied unacceptably from the quantitative MRI-based diagnosis. Quantitative measurements are recommended in patients suspected of MTS.

Atrophy↗
PubMed2001

Complex insomnia: insomnia and sleep-disordered breathing in a consecutive series of crime victims with nightmares and PTSD.

BACKGROUND: Sleep disturbance in posttraumatic stress disorder is very common. However, no previous posttraumatic stress disorder studies systematically examined sleep breathing disturbances, which might influence nightmares, insomnia, and posttraumatic stress disorder symptoms. METHODS: Forty-four consecutive crime victims with nightmares and insomnia underwent standard polysomnography coupled with a nasal pressure transducer to measure airflow limitation diagnostic of obstructive sleep apnea and upper airway resistance syndrome. RESULTS: Forty of 44 participants tested positive on objective sleep studies based on conservative respiratory disturbance indices of more than 15 events per hour; 22 patients suffered from obstructive sleep apnea and 18 suffered from upper airway resistance syndrome. CONCLUSIONS: In an uncontrolled study, insomnia and sleep-disordered breathing were extremely prevalent in this small and select sample of crime victims. Research is needed to study 1) prevalence of sleep-disordered breathing in other posttraumatic stress disorder populations using appropriate controls and nasal pressure transducers and 2) effects of sleep treatment on posttraumatic stress symptoms in trauma survivors with comorbid obstructive sleep apnea or upper airway resistance syndrome. In the interim, some posttraumatic stress disorder patients may benefit from sleep medicine evaluations.

Adult↗
PubMed2001

A comparison of monotherapy with lamotrigine or carbamazepine in patients with newly diagnosed partial epilepsy.

Monotherapy with lamotrigine or carbamazepine was evaluated in a multicentre open trial of patients aged 2 years and above with newly diagnosed partial epilepsy. A total of 417 patients were randomised to treatment with lamotrigine, while 201 patients received carbamazepine. Following a dose escalation period of 6 weeks, maintenance therapy (Weeks 7-24) was adjusted according to response. Efficacy was similar with both treatments (65% with lamotrigine, 73% with carbamazepine, P=0.085). Efficacy was assessed by the proportion of patients seizure free during the last 16 weeks of treatment; all subjects who remained in the study for at least 18 weeks after the week 4 visit were included in the analysis. More patients receiving lamotrigine completed the study (81%), compared with those receiving carbamazepine (77%). This difference was primarily due to discontinuation as a result of adverse events, reported by 34 (8%) of those treated with lamotrigine but 26 (13%) of those treated with carbamazepine. The proportion of patients who experienced adverse events in the lamotrigine group was lower (218 patients, 52%) compared with the carbamazepine group (120 patients, 60%). The proportion of patients with adverse events considered to be drug related was lower in the lamotrigine group (132 patients, 32%) compared with the carbamazepine group (83 patients, 41%). Somnolence was the only adverse event reported at an incidence of greater than 5% and where there was a difference of 5% or more between treatment groups (4% lamotrigine, 11% carbamazepine patients). The small subsets of elderly patients (aged 65 years or over) and paediatric patients (aged 2-12 years) also showed better tolerability to lamotrigine than to carbamazepine. In conclusion, monotherapy with lamotrigine is as effective as carbamazepine in patients with newly diagnosed partial epilepsy. Patients were able to tolerate lamotrigine better than carbamazepine, so more patients receiving lamotrigine were able to remain on therapy.

Adolescent↗
PubMed2001

Recommendations on the clinical use of oxcarbazepine in the treatment of epilepsy: a consensus view.

Extensive clinical use and a series of clinical trials have shown that oxcarbazepine is a valuable antiepileptic drug for the treatment of adults and children with partial onset seizures both in initial monotherapy, for conversion to monotherapy and as adjunctive therapy. The clinically recommended titration scheme for all forms of therapy in adults is to start with 150 mg/day at night and to increase by 150 mg/day every second day until a target dose of 900-1200 mg/day is reached. If necessary, one can go faster and start with up to 600 mg/day and titrate with weekly increments of up to 600 mg/day. In children, treatment can be initiated with 8-10 mg/kg/day body weight in two to three divided doses. Dosage can be increased by 8-10 mg/kg/day in weekly increments if necessary for seizure control. Hyponatremia (serum sodium <125 mmol/l) can develop gradually during the first months of oxcarbazepine therapy in approximately 3% of patients with a previously normal serum sodium. However, there is no need to measure baseline serum sodium concentrations unless the patient has renal disease, is taking medication which may lower serum sodium levels (such as diuretics, oral contraceptives or nonsteroidal anti-inflammatory drugs) or--in rare cases--has clinical symptoms of hyponatremia. During oxcarbazepine maintenance therapy measurement of serum sodium levels should also be considered if medications known to decrease sodium levels are added or symptoms of hyponatremia develop. Oxcarbazepine does not appear to have any clinically notable effects on other safety parameters such as renal and liver function or haematological test results. In summary, oxcarbazepine is a safe and well tolerated antiepileptic drug for partial epilepsy.

Anticonvulsants↗
PubMed2001

Pretreatment leukaemia cell drug resistance is correlated to clinical outcome in acute myeloid leukaemia.

In 85 adult patients diagnosed with acute myeloid leukaemia (AML) and treated at the same institution during a 5-yr period, the clinical significance of in vitro cellular drug resistance to the anthracyclines aclarubicin (Acla) and daunorubicin (Dau) as well as the nucleoside analogue cytarabine (Ara-C) was investigated using a 4-d MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay. In 59 patients of whom 40 were treated by the combination of Acla and Ara-C we found that leukaemia cell drug resistance towards Acla was higher (by a factor 2.80) in patients who failed to enter complete remission (CR) after the first cycle of induction chemotherapy as compared to patients who entered complete remission. The relationship was significant in univariate as well as multivariate analysis (p=0.02 and 0.03, respectively). By contrast, no in vitro single drug resistance values were consistently correlated to other parameters of clinical outcome (overall CR rate, overall survival (OS), or continuous complete remission (CCR)), whereas the combined Acla and Ara-C drug resistance profile (Acla/Ara-C DRP) was of prognostic significance to overall survival of all 85 patients (p=0.004) as well as to the CCR of 39 complete responders (p=0.04). These findings remained statistically significant in multivariate analyses correcting for other variables influencing clinical outcome including patient age, leukocyte count, karyotype, FAB-subtype, and presence/absence of secondary AML. We conclude that the in vitro drug resistance of leukaemia cells at time of disease presentation appears to be independent of prognostic significance to short- and long-term clinical outcome in AML.

Aclarubicin↗
PubMed2001

FAB M4 and high CD14 surface expression is associated with high cellular resistance to Ara-C and daunorubicin: implications for clinical outcome in acute myeloid leukaemia.

In 145 adult patients diagnosed with non-M3 acute myeloid leukaemia (AML) the relevance of FAB-subtype and immunophenotype to in vitro cellular drug resistance towards the anthracyclines aclarubicin (Acla) and daunorubicin (Dau), and the nucleoside analogue cytarabine (Ara-C), as well as other antileukaemic drugs, was investigated using a 4-d MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay. We demonstrate that high CD14 expression is highly significantly associated with high cellular Ara-C and Dau resistance in univariate as well as multivariate analyses. FAB subtypes with highest and lowest cellular Ara-C resistance were M4 and M5, respectively (P < 0.01, one-way anova), whereas FAB subtypes with highest and lowest cellular Dau resistance were M4 and M1, respectively (P < 0.01, one-way anova). By contrast, no significant differences in cellular drug resistance towards Acla could be demonstrated among FAB subtypes. Furthermore, in two cohorts of AML patients treated by two different regimens for remission induction over a period of 15 yr (1985-94, n = 159 and 1995-99, n = 76, respectively) we demonstrate in univariate analyses a significance of CD14 expression with respect to clinical outcome. With the exception of significance to probability of obtaining complete remission in the first cohort (P = 0.03, logistic regression), this significance was, however, lost in multivariate analyses. It was demonstrated that FAB-M4 patients were older than M5 patients and that high CD14 expression was associated with the presence of secondary AML and older age. We conclude that although cases with high blast cell CD14 expression (and FAB-M4 cases) were more resistant to Ara-C as well as Dau in vitro, the clinical and biological significance of this may be debatable because of interactions with major prognostic factors in AML.

Aclarubicin↗
PubMed2001

Epilepsy in the elderly: the use of tiagabine.

The incidence of epilepsy increases sharply in patients older than 60 years. There is a clear need for clinical trials designed specifically for this age group, as elderly patients differ from younger patients with epilepsy with respect to seizure etiology, coexisting diseases, concomitant drug therapy, and drug disposition. The new antiepileptic drugs (AEDs) are often associated with fewer side effects than are the traditional AEDs and may be particularly useful in the elderly. The pharmacokinetics of tiagabine (TGB) are not significantly modified in elderly patients, although elimination is more rapid in the presence of enzyme-inducing AEDs. Efficacy and tolerability data on TGB in elderly patients is currently limited, and a formal trial of TGB monotherapy in this age group is needed.

Age Factors↗
PubMed2001

On the association between valproate and polycystic ovary syndrome.

Recent studies by Isojärvi et al. have raised the issue of an increased incidence of polycystic ovary syndrome (PCOS) in women with epilepsy treated with valproate (VPA) and have proposed replacement with lamotrigine (LTG). Polycystic ovaries (PCO) are a common finding, with a prevalence >20% in the general population, and are easily detected by pelvic or vaginal ultrasonography, whereas PCOS is comparatively rare: few women with PCO have fully developed PCOS, which includes hirsutism, acne, obesity, hypofertility. hyperandrogenemia, and menstrual disorders. From an extensive review of the current literature, it appears that there are no reliable data on the actual prevalence of PCOS in normal women and in women with epilepsy. The pathogenesis of PCO is multifactorial, including genetic predisposition and the intervention of environmental factors, among which weight gain and hyperinsulinism with insulin resistance may play a part. The roles of central (hypothalamic/pituitary), peripheral, and local ovarian factors are still debated. PCO and PCOS appear to be more frequent in women with epilepsy, but there are no reliable data showing a greater prevalence after VPA. The recent studies by Isojärvi et al. may have been biased by the retrospective selection of patients. To date, there is no reason to contraindicate the use of VPA in women with epilepsy. However, patients should be informed about the risk of weight gain and its consequences.

Adolescent↗
PubMed2001

Tiagabine: efficacy and safety in adjunctive treatment of partial seizures.

PURPOSE: To assess the efficacy and safety of tiagabine (TGB), a new antiepileptic drug (AED), as add-on therapy in patients with refractory partial seizures. METHODS: This response-dependent study used an open-label screening phase (in which patients were titrated to their optimal TGB dose, < or =64 mg/day) followed by a double-blind, placebo-controlled, crossover phase. Initial eligibility criteria included (a) seizures inadequately controlled by existing AEDs, and (b) six or more partial seizures during an 8-week baseline period. Patients showing benefit from TGB (> or =25% reduction in total seizure rate relative to baseline) were eligible for randomization into the double-blind phase, which comprised two 7-week assessment periods separated by a 3-week crossover period. RESULTS: Forty-four (50%) of the 88 enrolled patients entered the double-blind phase of the study during which there were significant reductions compared with placebo in all partial (p < 0.01), complex partial (p < 0.001), and secondarily generalized tonic-clonic seizure rates (p < 0.05). Thirty-three percent of patients experienced a reduction of > or =50% in the all partial seizure rate. Eight (22%) patients receiving TGB during the double-blind phase reported adverse events, of which dizziness and incoordination were the most frequent. Three patients withdrew from treatment during the double-blind phase because of adverse events; two during treatment with TGB and one during treatment with placebo. TGB did not affect plasma concentrations of other coadministered AEDs. CONCLUSIONS: TGB was significantly better than placebo in terms of seizure rate reduction and was generally well-tolerated in patients with difficult to control seizures.

Adolescent↗
PubMed2001

Expansion of repetitive DNA into cytogenetically visible elements.

Two cases of amplified repetitive elements accidentally identified in cancer samples are reported. In both cases, repeated DNA that is normally not visible by traditional chromosome banding had increased in amount to become cytogenetically visible. In one case, an addition to the short arm of chromosome 1 was originally diagnosed. However, upon molecular analysis the diagnosis could be corrected to an amplification of the D1Z2 repeat. In the second case, a strongly DAPI-positive band was visible at the top of the short arm of chromosome 22, and the original diagnosis was add(22). Staining for telomeric repeats revealed their presence inside the DAPI-positive element, thus confirming that the element in question was truly added to the end of the chromosome. Curiously, no telomeric repeats could be detected distal to the DAPI-positive element. The identity of the DAPI-positive element could not be established, as it was not stained by any of the specific probes applied, nor in a scanning hybridization with labeled Cot-1 DNA. It thus seems to represent an expansion from some lowly repetitive AT-rich DNA translocated to the tip of chromosome 22.

AT Rich Sequence↗
PubMed2001

Large-scale management of insect resistance to transgenic cotton in Arizona: can transgenic insecticidal crops be sustained?

A major challenge for agriculture is management of insect resistance to toxins from Bacillus thuringiensis (Bt) produced by transgenic crops. Here we describe how a large-scale program is being developed in Arizona for management of resistance to Bt cotton in the pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), and other insect pests of cotton. Financial support from growers makes this program possible. Collaboration between the Arizona Cotton Research and Protection Council, the University of Arizona, and government agencies has led to development of resistance management guidelines, a remedial action plan, and tools for monitoring compliance with the proposed guidelines. Direct participation in development of resistance management policies is a strong incentive for growers to invest in resistance management research. However, more research, regularly updated regulations, and increased collaboration between stakeholders are urgently needed to maintain efficacy of Bt toxins in transgenic crops.

Animals↗
PubMed2001

Predicting spring moth emergence in the pink bollworm (Lepidoptera: Gelechiidae): implications for managing resistance to transgenic cotton.

Cultural control methods have been central in the southwestern United States for reducing pink bollworm, Pectinophora gossypiella (Saunders), damage to cotton. Nevertheless, it is not clear at present how such methods could be integrated within the novel pest management framework allowed by introduction of cotton producing a toxin from Bacillus thuringiensis (Bt) for pink bollworm control. Using statewide pheromone trapping and climatic data in conjunction with deterministic simulation models, we investigated whether manipulation of cotton planting date and use of other cultural control methods could represent valuable tactics for control of the pink bollworm in Arizona. Accumulation of heat units from one January accurately predicted the rate of pink bollworm emergence from diapause in 15 cotton-producing regions. Significant variation in rate of emergence from diapause was present among regions, with earlier emergence at higher altitudes. Most adults emerge from diapause too early to reproduce successfully on cotton, a phenomenon known as suicidal emergence. A method for prediction of the fraction of suicidal emergence resulting from adoption of a given cotton planting date is presented. Results from simulation models suggest that manipulation of planting date and implementation of other control cultural methods reduce the rate of application of insecticides and delay the evolution of resistance to Bt cotton in the pink bollworm.

Animals↗