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P Toft

Publications and source records attributed to P Toft.

At least 19 recordsLinked to original sources
PubMed2001

Epitope mapping porcine reproductive and respiratory syndrome virus by phage display: the nsp2 fragment of the replicase polyprotein contains a cluster of B-cell epitopes.

We screened phage display libraries of porcine reproductive and respiratory syndrome virus (PRRSV) protein fragments with sera from experimentally infected pigs to identify linear B-cell epitopes that are commonly recognized during infection in vivo. We identified 10 linear epitope sites (ES) 11 to 53 amino acids in length. In the replicase polyprotein, a total of eight ES were identified, six of which localized to the Nsp2 replicase polyprotein processing end product. In the structural proteins, a total of two ES were identified, in the ORF3 and ORF4 minor envelope glycoproteins. The ORF4 ES was previously identified by monoclonal antibody mapping (J. J. M. Meulenberg, A. P. van Nieuwstadt, A. van Essen-Zandenbergen, and J. P. M. Langeveld, J. Virol. 71:6061-6067, 1997), but its immunogenicity had not been examined in pigs. We found that six experimentally PRRSV-infected pigs consistently had very high antibody titers against the ORF4 ES. In some animals, sera diluted 1:62,500 still gave weak positive enzyme immunoassay reactivity against the ORF4 ES. This hitherto unrecognized immunodominance likely caused phages displaying the ORF4 ES to outcompete phages displaying other ES during library screening with porcine sera and accounted for our failure to identify more than two ES in the structural genes of PRRSV. Genetic analysis showed that variable ES were also the most immunogenic in vivo. Serological analysis indicated differences in the immunoglobulin A responses between short-term and longer-term viremic pigs towards some ES. The implications of these findings for PRRSV diagnostics and immunopathogenesis are discussed.

Amino Acid Sequence↗
PubMed2000

[Continuous venovenous hemodiafiltration in critically ill patients with acute renal failure].

The development of computerized machines with a simple user-friendly interface to perform continuous venovenous hemodiafiltration (CVVHDF) has resulted in a break-through of CVVHDF in the treatment of acute renal failure (ARF) in Danish intensive care units. During CVVHDF the blood is submitted to a combination of dialysis and ultrafiltration. In contrast to intermittent haemodialysis (HD), CVVHDF can be used in critically ill patients with unstable circulation. Biocompatible membranes are used. During treatment with CVVHDF, cytokines are removed from the blood partly by ultrafiltration, partly by adsorption to the filter. The clinical importance of this is not yet known. Patients with ARF treated with CVVHDF seem to be more likely to show renal recovery than those treated with HD. There are few prospective investigations of the effect of CVVHDF on mortality, but all comparisons of CVVHDF with HD indicate a trend in favor of CVVHDF.

Acute Kidney Injury↗
PubMed2000

Emergence of porcine reproductive and respiratory syndrome virus deletion mutants: correlation with the porcine antibody response to a hypervariable site in the ORF 3 structural glycoprotein.

By using porcine immune sera to select a library of phage-displayed random peptides, we identified an antigenic sequence (RKASLSTS) in the C-terminus of the ORF 3 structural glycoprotein of European-type porcine reproductive and respiratory syndrome virus (PRRSV). Through the use of overlapping reading frames, the same PRRSV genetic locus codes for the ORF 3 "RKASLSTS" sequence, and a previously described ORF 4 epitope (Meulenberg, J. J. M., Van Nieuwstadt, A. P., Van Essen-Zandbergen, A., and Langeveld, J. P. M., 1997, J. Virol. 71, 6061-6067). Sequence analysis identified naturally occurring deletion mutants at this ORF 34 site. Phylogenetic analysis showed the presence of a highly accurate ORF 3 molecular clock, according to which deletion mutants and nondeleted viruses evolved at differing speeds. Furthermore, deletion mutants and nondeleted viruses evolved as separate lineages. These distinctions suggested that deletion mutants were a hitherto unrecognized subtype of European-type PRRSV. Currently, deletion mutants appear to be outcompeting nondeleted viruses in the field, highlighting the importance of the porcine antibody response against the minor structural glycoproteins of European-type PRRSV for viral evolution.

Amino Acid Sequence↗
PubMed2000

The effect of CVVHD and endotoxin on the oxidative burst, adhesion molecules and distribution in tissues of granulocytes.

OBJECTIVE: Extracorporeal circulation, such as cardiopulmonary bypass and haemodialysis, has been associated with an activation of the immune system, especially the granulocytes. Continuous veno-venous haemodiafiltration (CVVHD) is used in critically ill septic patients. During CVVHD cytokines are excreted in the ultrafiltrate. But when the membranes used in CVVHD are cultured with granulocytes, the granulocytes are slightly activated. This effect is potentiated by endotoxin. We therefore, in vivo, compared the effect on granulocyte activation of CVVHD with an endotoxin group and a control group. METHODS: Thirty-one pigs were anaesthetized and mechanically ventilated. In ten pigs CVVHD was performed. Eleven pigs received an infusion of Escherichia coli endotoxin 30 mu/kg(-1) and ten pigs served as a control group. The adhesion molecules CD18 and CD62L were measured using monoclonal antibodies. The oxidative burst activity was assayed as superoxide dismutase-inhibitory reduction of cytochrome c. The number of granulocytes in peripheral blood and in the lungs and liver were counted. RESULTS: The infusion of endotoxin was followed by granulocytopenia, reduced oxidative burst activity, increased expression of CD18 and decreased expression of CD62L on granulocytes. Accumulation of granulocytes in liver and lung tissue was also noted in this group. CVVHD was only associated with a non-significant decrease in CD62L expression on granulocytes. It did not affect any of the other measured immunological parameters. CONCLUSION: In contrast to endotoxin-induced sepsis, the granulocytes were not activated during CVVHD.

Analysis of Variance↗
PubMed1999

[Antibiotic prophylaxis in adult critically ill patients in intensive care units].

OBJECTIVES: To determine whether antibiotic prophylaxis reduces respiratory tract infections (RTI) and overall mortality in an unselected adults intensive care population. SEARCH STRATEGY: Systematic literature search in peer-reviewed journals indexed in MEDLINE, examination of relevant proceedings of scientific meetings and personal contact with trialists. SELECTION CRITERIA: All randomised clinical trials (RCTs), published and unpublished, comparing different forms of antibiotic prophylaxis used to reduce RTIs and mortality in unselected adult intensive care units (ICUs) populations. DATA COLLECTION AND ANALYSIS: Out of the 32 RCTs eligible for this review data have been extracted from published reports and then complemented with information provided by study investigators for 29 trials. Data were available only from published reports in the remaining three RCTs. For each trial the following information has been sought: a) method of randomisation; b) use of blinding techniques; c) number of randomised patients; d) number of patients with RTIs; e) number of deaths; f) number of patients excluded from the published analysis; g) number of RTIs and number of deaths among excluded patients. Pooled estimates of treatment effects across trials have been calculated after grouping RCTs in two main, mutually exclusive, categories: a) 15 trials testing the effect of a combination of a topical and a systemic antibiotic against no prophylactic treatment; b) 17 trials where the experimental treatment was a topical antimicrobial preparation. Crude proportions of RTIs and mortality were used to calculate the overall treatment effect. We also computed the number of ICU patients who need to be treated in order to prevent one infection and one death. MAIN RESULTS: Overall 32 RCTs including 5639 patients were identified. Pooled estimates of the 15 RCTs (including 3273 patients) testing the effect of the topical and systemic antibiotic combination indicate a strong significant reduction of both RTIs (OR = 0.36, 95% CI = 0.30-0.43) and total mortality (OR = 0.80, 95% CI = 0.68-0.93). Five and 23 patients need to be treated to prevent one infection and one death, respectively, using this treatment. When data on the effect of the combination based on topical antimicrobials were pooled from the 17 available trials (including 2366 patients) a marked reduction on RTIs (OR = 0.57, 95% CI = 0.46-0.69) also emerged but no corresponding effect on overall mortality (OR = 1.01; 95% CI = 0.84-1.22) was found. CONCLUSIONS: After 15 years of clinical research this meta-analysis of 32 RCTs shows that a regimen of antibiotic prophylaxis based on a combination of a systemic and topical antibiotic can reduce both RTIs and overall mortality in ICU patients in a way that is both statistically significant and humanly worthwhile. Over and above their personal opinions intensivists should take this evidence into account when defining their policies.

Adult↗
PubMed1999

On clustering fMRI time series.

Analysis of fMRI time series is often performed by extracting one or more parameters for the individual voxels. Methods based, e.g., on various statistical tests are then used to yield parameters corresponding to probability of activation or activation strength. However, these methods do not indicate whether sets of voxels are activated in a similar way or in different ways. Typically, delays between two activated signals are not identified. In this article, we use clustering methods to detect similarities in activation between voxels. We employ a novel metric that measures the similarity between the activation stimulus and the fMRI signal. We present two different clustering algorithms and use them to identify regions of similar activations in an fMRI experiment involving a visual stimulus.

Algorithms↗
PubMed1999

Brain lesions in preterms: origin, consequences and compensation.

Twenty-nine high-risk preterm born children, from a cohort with cerebral blood flow (CBF) measurements in the first 2 d of life, were examined prospectively at the age of 5.5-7 y neurologically, neuropsychologically and by magnetic resonance imaging (MRI). They were compared to 57 control children in terms of neurology and neuropsychology. Abnormal MRI was found in 19 children. Low oxygen delivery to the brain was found in 63% of them, in contrast to 12.5% in those with normal MRI, indicating neonatal hypoxia-ischemia as an important factor. The MRI abnormalities were mainly periventricular lesions (n = 19), especially periventricular leucomalacia (PVL, n = 17). Three of the very preterm children had severe cerebellar atrophy in addition to relatively mild periventricular abnormalities. MRI showed specific morphological correlates for the major disabilities, e.g. spastic CP (involvement of motor tracts), mental retardation (bilateral extensive white matter reduction or cerebellar atrophy) and severe visual impairment (severe optic radiation involvement). A morphological correlate for minor disabilities, i.e. functional variations in motor performance or intelligence, was not found, with the exception that symptoms of attention deficit hyperactivity disorder were related to mild MRI abnormalities. This could mean that with respect to cognitive functions, mild or unilateral periventricular MRI lesions could be compensated. However, as among preterms without mental retardation (n = 19), IQ was generally and significantly lower than in the control group; other, more chronic pathogenetic factors, not detectable by MRI alone, may play a role.

Attention Deficit Disorder with Hyperactivity↗
PubMed1999

The effect of surgical stress and endotoxin-induced sepsis on the NK-cell activity, distribution and pulmonary clearance of YAC-1 and melanoma cells.

Following surgery the activity of natural killer (NK) cells is decreased in the blood. It is possible that sepsis with release of endotoxin will further decrease the NK-cell activity. The purpose of the present study was to investigate the NK-cell cytotoxicity, the clearance in the lungs of YAC-1 and melanoma cells, as well as the distribution of NK-cells in the liver, following abdominal surgery and intraperitoneally (i.p.) administered endotoxin. Ten mice in each group were allocated to abdominal surgery, i.p. endotoxin or anaesthesia alone. Following abdominal surgery, the cytotoxicity of NK-cells isolated from the spleen was decreased and 4 h after injection the clearance of YAC-1 cells from the lungs was only 79.5+/-6.1% compared to 99.5+/-0.3% in the control group. The number of NK-cells in the liver was also significantly reduced following abdominal surgery. In contrast, i.p. endotoxin increased the activity of NK-cells by 28.5% compared to 11.8% in the control group and 8.1% in the surgery group, lowered the number of melanoma metastases in extrapulmonary organs and significantly increased the number of NK-cells in the liver. Following abdominal surgery, activity of NK-cells, pulmonary clearance and number of NK-cells in the liver were decreased. The number of NK-cells in the liver correlated with the NK-cell activity throughout the study. The increased NK-cell cytotoxicity and the increased number of NK-cells in the liver following i.p. administered endotoxin might initially be an appropriate measure against intra-abdominal infection.

Animals↗
PubMed1999

The immunological effects of continuous veno-venous haemodiafiltration in critically ill patients.

BACKGROUND: Haemodynamic instability is common in septic patients with acute renal failure. Continuous veno-venous haemodiafiltration (CVVHD) is therefore used as an alternative to conventional haemodialysis. Haemodialysis is associated with an activation of the immune system. The aim of the present study was to test the hypothesis that initiation of CVVHD influences the immune system with release of proinflammatory cytokines followed by a decrease in granulocyte activation, as assessed by the expression of adhesion molecules. RESULTS: Fifteen patients were included. Mean Acute Physiology and Chronic Health Evaluation-2 score before CVVHD was 19 (range 8-27). Mean duration of CVVHD treatment was 9 days (1-21 days). Tumour necrosis factor-alpha and interleukin-8 were detectable in plasma in all patients, whereas interleukin-10 was detectable only in a few patients. Proinflammatory and anti-inflammatory cytokines were detected in the ultrafiltrate. Large intraindividual and interindividual variations were demonstrated for all of the immunological parameters studied. CONCLUSION: The hypothesis that CVVHD induces the release of proinflammatory cytokines followed by a decrease in granulocyte activation was not confirmed in the present study. The heterogeneous group of patients studied, with different underlying diseases and various durations of illness before the start of CVVHD, might have contributed to the difficulty in demonstrating the proposed immunological effect of CVVHD.

Journal Article↗
PubMed1998

[Acute pain service. Organization and results].

Postoperative pain therapy in modern clinical practice still has significant deficits. Establishing acute pain services is reported to be a method of improving pain therapy. In this prospective study, 104 orthopaedic patients were treated with a postoperative epidural infusion of a combination of bupivacaine and sufentanil. Pain intensity and side effects were recorded daily by pain management personnel, and the pain therapy was adjusted according to the patients' need. The results showed that pain control was insufficient in 29 patients, and that side effects developed in 45 patients, included one patient with late respiratory depression. We conclude that acute pain service is essential in order to improve postoperative analgesia.

Acute Disease↗
PubMed1998

The peri-operative cytokine response in infants and young children following major surgery.

The peri-operative cytokine response was studied in 13 infants and young children undergoing major surgery. All children were anaesthetized with a combined general and epidural anaesthetic technique, followed by post-operative epidural analgesia with bupivacaine and fentanyl. Blood samples were taken before and after surgery, 24 h post-operatively, and finally, when the children were mobilized and had regained gastrointestinal function. Plasma samples were analysed for tumour necrosis factor-alpha, interleukin-1 alpha, interleukin-1 beta, interleukin-6, interferon-gamma, interleukin-10 and the interleukin-1 receptor antagonist. The cytokine responses were highly variable. Overall, no significant changes between pre- and post-operative plasma concentrations were found. Tumour necrosis factor-alpha and the interleukin-1 receptor antagonist were detectable in all children, and a trend towards an early increase in the interleukin-1 receptor antagonist levels at the end of surgery was seen. The other cytokines were only detectable at low concentrations among a minority of children. In conclusion, this study showed highly variable peri-operative cytokine responses in infants and young children undergoing major surgery.

Anesthesia, Epidural↗
PubMed1998

Changes in adhesion molecule expression and oxidative burst activity of granulocytes and monocytes during open-heart surgery with cardiopulmonary bypass compared with abdominal surgery.

Cardiac and major abdominal surgery are associated with granulocytosis in peripheral blood. The purpose of the present study was to describe the granulocyte and monocyte oxidative burst and the expression of adhesion molecules following cardiac surgery with cardiopulmonary bypass and abdominal surgery. The ability to respond with an oxidative burst was measured by means of flow cytometry using 123-dihydrorhodamine. The adhesion molecules CD11a/CD18, CD11c/CD18, CD44 were measured using monoclonal antibodies. Blood samples from eight patients undergoing open-heart surgery were taken before surgery, 1, 5, 10 and 20 min after aortic clamping, and then 1, 5, 10 and 20 min and 1, 2 and 3 h after declamping. Samples from eight patients undergoing abdominal surgery were taken before surgery, at the end of surgery, and 2 and 3 h post-operatively. A decrease in number of granulocytes and monocytes during cardiopulmonary bypass was observed. The percentage of CD11a-positive granulocytes increased from 30% pre-operatively to 75% following cardiopulmonary bypass, while CD44-positive granulocytes increased from 5% to 13%. Despite the extent of the changes, these were not significant. The oxidative burst of the granulocytes and monocytes decreased after declamping to 15% and 27% of initial values in vitro. Several hours after surgery, there was no significant difference between the two groups. These results can be explained by a granulocyte and monocyte refractory response developing subsequent to an increased per-operative oxidative burst activity, and the induction of adhesion molecules on granulocytes associated with the cardiopulmonary bypass and surgery. In conclusion, open-heart surgery with cardiopulmonary bypass was associated with a rapid and pronounced activation of leukocytes which may play a role in reperfusion injury.

Antibodies, Monoclonal↗
PubMed1997

The cytokine response in a patient undergoing surgery for an ACTH-producing tumor.

The administration of glucocorticoids has been used to inhibit the cytokine production in patients undergoing cardiac surgery during cardiopulmonary bypass. In this case report the cytokine response in a 43-year-old man undergoing operation for an ACTH-producing lung tumor is presented. There had been clinical symptoms for about 18 months and 8 months before operation elevated serum concentrations of ACTH and cortisol were measured. The patient underwent thoracotomy with removal of the tumor and the cytokine response in relation to surgery was measured as plasma concentrations of IL-1 alpha, IL-6, TNF alpha and TNF beta. With the long-lasting high endogenous glucocorticoid production low or undetectable cytokine levels were expected in this patient. However, a marked and prolonged IL-6 and TNF beta response was measured while IL-1 alpha and TNF alpha were detectable in only a few samples. The cytokine response in this patient was different from the response normally found in patients undergoing major surgery.

Adrenocorticotropic Hormone↗
PubMed1997

Expression of adhesion and activation molecules on lymphocytes during open-heart surgery with cardiopulmonary bypass.

Open-heart surgery with cardiopulmonary bypass (CPB) and abdominal surgery are associated with lymphocytopenia. We measured a panel of adhesion and activation molecules on lymphocytes to clarify possible association of CPB with increased expression of these molecules. Eight patients undergoing open-heart surgery and eight with abdominal surgery were studied. The adhesion molecules CD11a/CD18 (LFA-1_, CD11c/CD18 and CD44 and the activation molecules CD25, CD69, CD71 and MHCII were measured, using monoclonal antibodies and flow cytometry. Lymphocytopenia was observed during CPB and for some hours after both open-heart and abdominal surgery. The proportion of CD11a/CD18-positive lymphocytes rose from 67.6 +/- 8% to 86.4 +/- 3% after aortic declamping (p < 0.05). The expression of activation molecules CD25, CD69 and CD71 was unchanged during and after open-heart as well as abdominal operations. Thus CPB was associated with increased expression of the adhesion molecule CD11a/CD18 on lymphocytes, while the expression of activation molecules on lymphocytes was unchanged.

CD18 Antigens↗