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L Persson

Publications and source records attributed to L Persson.

At least 19 recordsLinked to original sources
PubMed2004

Haemodynamic and metabolic disturbances in the acute stage of subarachnoid haemorrhage demonstrated by PET.

OBJECTIVE: To investigate the occurrence of early haemodynamic and metabolic changes in the acute stage of subarachnoid haemorrhage (SAH). MATERIAL AND METHODS: Eleven SAH patients were studied. Regional cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2) and oxygen extraction ratio (OER) were measured with positron emission tomography (PET) 22-53 h after haemorrhage, utilizing 15O-labelled water bolus and the 15O-inhalation technique. Ten volumes of interest (VOIs) representing vascular territories were outlined in each patient according to a standardized procedure. The occurrence of irreversible ischaemia, penumbra, oligaemia, hyperperfusion and normal haemodynamics according to PET criteria was investigated. These pathophysiological categories were related to final tissue outcome as determined by follow-up computed tomography (CT). RESULTS: All five tissue subtypes were represented in the vascular region VOIs; oligaemia was the predominant pathophysiological pattern. When global changes were analysed, blood flow was reduced in three, oxygen metabolism was reduced in four, and OER was increased in four of seven unsedated patients, respectively. The sedated patients all had markedly reduced CBF and CMRO2 and OER in the high or supranormal range. CONCLUSION: Haemodynamic and metabolic disturbances proved to be common after SAH. These abnormalities probably reflect the primary brain injury caused by the initial haemorrhage. The impact of secondary insults such as acute hydrocephalus, brain oedema, vasospasm, seizures, hypotension and hypoxaemia are likely to be dependent on the degree of primary injury, which can be assessed by PET.

Acute Disease↗
PubMed2003

Rat stomach ECL cells: mode of activation of histidine decarboxylase.

Histidine decarboxylase (HDC) occurs in ECL cells in the oxyntic mucosa of rat stomach. It is activated by gastrin. Refeeding of fasted rats or treatment with the proton pump inhibitor omeprazole promptly raised the serum gastrin concentration and consequently the HDC activity and the HDC protein content of the oxyntic mucosa. The food- and omeprazole-induced increase in HDC mRNA expression in the oxyntic mucosa was modest by comparison. Blockade of translation (cycloheximide) but not transcription (actinomycin D) prevented the postprandial rise in HDC activity. The half-life of HDC activity (after blockade of translation) was 94 min in omeprazole-treated rats and 55 min in fasted controls. The rate of enzyme synthesis was estimated to be 15 times higher in omeprazole-treated rats than in fasted controls. Inhibition of histamine uptake into ECL-cell granules by reserpine, a blocker of the vesicular monoamine transporter type-2, lowered the HDC activity and prevented the gastrin-induced HDC activation. We suggest that HDC activation reflects enhanced transcription, translation and/or posttranslational enzyme activation as well as stabilization, and that a high cytosolic histamine concentration suppresses HDC activation.

Animals↗
PubMed2003

Turnover of trypanosomal ornithine decarboxylases.

Interestingly, there is a major difference in turnover rate between ornithine decarboxylases (ODCs) from various trypanosomatids. ODCs from Trypanosoma brucei and Leishmania donovani are both stable proteins, whereas ODC from Crithidia fasciculata is a metabolically unstable protein in the parasite. C. fasciculata ODC is also rapidly degraded in mammalian systems, whereas the closely related L. donovani ODC is not. The degradation of C. fasciculata ODC in the mammalian systems is shown to be dependent on a functional 26 S proteasome. However, in contrast to the degradation of mammalian ODC, the degradation of C. fasciculata ODC does not involve antizyme. Instead, it appears the degradation of C. fasciculata ODC may be associated with poly-ubiquitination of the enzyme.

Animals↗
PubMed2003

Human cytomegalovirus, human herpesvirus-6 and human herpesvirus-7 in neutropenic patients with fever of unknown origin.

OBJECTIVE: To investigate the appearance of cytomegalovirus (CMV) DNA, human herpesvirus-6 (HHV-6) DNA and human herpesvirus-7 (HHV-7) DNA in plasma as a sign of reactivation and possible causes of fever of unknown origin (FUO) during neutropenia. METHODS: From 134 patients with febrile neutropenia following cytotoxic chemotherapy during the years 1996-2000, 20 severely neutropenic patients (granulocyte count < 0.1 x 109/L) were selected. Ten were patients with bacteremia and ten were patients with FUO. Five samples from each patient were selected at the start of chemotherapy, at the time of blood culture and fever, after 24 and 48 hours of fever, and, finally, after two to three days without fever. Virus DNA was detected by real-time quantitative and nested polymerase chain reaction (PCR). RESULTS: CMV-DNA was detected in two out of ten FUO-patients in all samples drawn during fever. From another FUO and during two bacteremia episodes, CMV-DNA was detected after 48 hours of fever. DNA from HHV-6 and HHV-7 was not detected in any of the 20 febrile episodes. CONCLUSIONS: HHV-6 and HHV-7 as a possible explanation for FUO in severely neutropenic patients treated with cytotoxic chemotherapy seems not be very likely. However, CMV was identified in 5/20 patients and the febrile episodes in the two FUO-patients with constant DNA-emia may have been caused by a reactivation of CMV. This implies that CMV infection can be expected not only in transplant patients but also in chemotherapy-treated neutropenic patients.

Adolescent↗
PubMed2002

The common -675 4G/5G polymorphism in the plasminogen activator inhibitor -1 gene is strongly associated with obesity.

AIMS/HYPOTHESIS: Plasminogen activator inhibitor 1 (PAI-1) increases in several insulin-resistant conditions such as obesity. We tested the hypothesis that the PAI-1 gene might be a candidate for obesity and Type II (non-insulin-dependent) diabetes mellitus. METHODS: We investigated the frequency of a common and functional -675 4G/5G promoter polymorphism in the PAI-1 gene in 188 lean, 70 overweight (BMI 25-30 kg/m(2)) and 247 obese otherwise healthy Scandinavian subjects. RESULTS: The genotypic ( p = 0.002), or allelic ( p = 0.0004) distribution differed markedly between the three groups. Homozygosity for 4G was more common among obese people, whereas homozygosity for 5G was more common among lean subjects. Heterozygosity was evenly distributed. The lean and overweight groups did not differ in frequency distribution. The relative risk for being obese in comparison to being lean for 4G/4G was threefold higher ( p = 0.0003). Also, carriers of the 4G allele in the heterozygous or homozygous form were distributed differently between the three groups ( p = 0.006). The 4G carriers were more common among the obese than the lean group. The latter group did not differ from the overweight group. The relative risk of being obese in comparison with lean was twofold increased in 4G carriers ( p = 0.0015). Similar results were obtained in men and women. CONCLUSION/INTERPRETATION: Thus, the common -675 4G/5G polymorphism in the PAI-1 gene is strongly linked to obesity and a markedly increased risk for obesity is associated with the 4G allele in its homozygous form.

Adult↗
PubMed2002

Early cerebral hyperglycolysis after subarachnoid haemorrhage correlates with favourable outcome.

BACKGROUND: Intracerebral microdialysis (MD) was applied in patients with severe subarachnoid haemorrhage treated in a neurosurgical intensive care unit in order to explore their cerebral energy metabolism. METHOD: Brain MD fluid levels of glucose, lactate and pyruvate were measured for 3 to 12 days in 20 patients and 2,635 hourly samples were analysed. The MD data were related to computerized tomography and clinical outcome, assessed by the Glasgow Outcome Scale. FINDINGS: The study showed that most patients who made a good recovery had a specific curve pattern when plotting the studied metabolites over time, characterised by a distinct decrease in MD-glucose and a parallel increase in both MD-lactate and pyruvate. Patients who had an unfavourable outcome lacked this distinct curve pattern and exhibited more irregular changes, including increased levels of both MD-glucose and lactate and low MD-pyruvate levels. INTERPRETATION: This exploratory study suggests that accumulation of interstitial lactate and pyruvate, together with decreasing levels of glucose is a favourable prognostic pattern presumably reflecting increased glucose metabolism. Such hyperglycolysis may be elicited in patients with recovery potential to cope with an extreme metabolic demand set in motion by a brain insult to restore brain cell homeostasis and integrity.

Adolescent↗
PubMed2001

Changes in intervention and outcome in elderly patients with subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: The elderly constitute a significant and increasing proportion of the population. The aim of this investigation was to study time trends in clinical management and outcome in elderly patients with subarachnoid hemorrhage. METHODS: Two hundred eighty-one patients >/=65 years of age with aneurysmal subarachnoid hemorrhage who were accepted for treatment at the Uppsala University Hospital neurosurgery clinic during 1981 to 1998 were included. Hunt and Hess grades on admission, specific management components, and clinical outcomes were recorded. Three periods were compared: A, 1981 to 1986 (before neurointensive care); B, 1987 to 1992; and C, 1993 to 1998. RESULTS: The volume of elderly patients (>/=65 years of age) increased with time, especially patients >/=70 years of age. Furthermore the proportion of patients with more severe clinical conditions increased. A greater proportion of patients had a favorable outcome (A, 45%; B, 61%; C, 58%) despite older ages and more severe neurological and clinical conditions. In period C, Hunt and Hess I to II patients had a favorable outcome in 85% of cases compared with 64% in period A. This was achieved without any increase in the number of severely disabled patients. CONCLUSIONS: Elderly patients with subarachnoid hemorrhage can be treated successfully, and results are still improving. The introduction of neurointensive care may have contributed to the improved outcome without increasing the proportion of severely disabled patients. A defeatist attitude toward elderly patients with this otherwise devastating disease is not justified.

Age Distribution↗
PubMed2001

Importance of the 3' untranslated region of ornithine decarboxylase mRNA in the translational regulation of the enzyme.

Translational regulation of ornithine decarboxylase (ODC), which catalyses the first step in the biosynthesis of polyamines, appears to be an important mechanism in the strong feedback control as well as in the hypotonic induction of the enzyme. However, the exact mechanisms are not yet understood. The ODC mRNA has long 5' and 3' untranslated regions (UTRs) which may be involved in the translational control of the enzyme. In the present study we have used a series of stable transfectants of Chinese Hamster ovary cells expressing ODC mRNAs with various truncations in the 5' and 3' UTRs to investigate the importance of these regions. It is demonstrated that neither the 5' UTR nor the 3' UTR appears to be involved in the polyamine-mediated feedback control of ODC synthesis. The hypotonic induction of ODC, on the other hand, was shown to be highly dependent on the presence of the 3' UTR, but not on the 5' UTR, of ODC mRNA. Cells expressing ODC mRNAs lacking the 3' UTR showed no, or only a very slight, induction of ODC whether the 5' UTR was present or not, whereas the cell lines expressing ODC mRNAs containing the 3' UTR (with or without the 5' UTR) markedly induced ODC after a hypotonic shock. The present finding of a role for the ODC mRNA 3' UTR in the hypotonic induction of ODC is the first demonstration of a specific effect of the 3' UTR in the regulation of ODC.

3' Untranslated Regions↗
PubMed2001

Intensive care management of head-injured patients in Europe: a survey from the European brain injury consortium.

OBJECTIVES: (a) to describe current practice in the monitoring and treatment of moderate and severe head injuries in Europe; (b) to report on intracranial pressure and cerebral perfusion pressure monitoring, occurrence of measured and reported intracranial hypertension, and complications related to this monitoring; (c) to investigate the relationship between the severity of injury, the frequency of monitoring and management, and outcome. METHODS: A three-page questionnaire comprising 60 items of information has been compiled by 67 centres in 12 European countries. Information was collected prospectively regarding all severe and moderate head injuries in adults (> 16 years) admitted to neurosurgery within 24 h of injury. A total of 1005 adult head injury cases were enrolled in the study from 1 February 1995 to 30 April 1995. The Glasgow Outcome Scale was administered at 6 months. RESULTS: Early surgery was performed in 346 cases (35%); arterial pressure was monitored invasively in 631 (68%), ICP in 346 (37%), and jugular bulb saturation in 173 (18%). Artificial ventilation was provided to 736 patients (78%). Intracranial hypertension was noted in 55% of patients in whom ICP was recorded, while it was suspected in only 12% of cases without ICP measurement. There were great differences in the use of ventilation and CPP monitoring among the centres. Mortality at 6 months was 31%. There was an association between an increased frequency of monitoring and intervention and an increased severity of injury; correspondingly, patients who more frequently underwent monitoring and ventilation had a less favourable outcome. CONCLUSIONS: In Europe there are great differences between centres in the frequency of CPP monitoring and ventilatory support applied to head-injured patients. ICP measurement disclosed a high rate of intracranial hypertension, which was not suspected in patients evaluated on a clinical basis alone. ICP monitoring was associated with a low rate of complications. Cases with severe neurological impairment, and with the worse outcome, were treated and monitored more intensively.

Adult↗
PubMed2001

Contribution of ICP-IDMS to the certification of antimony implanted in a silicon wafer--comparison with RBS and INAA results.

A thin-layer reference material for surface and near-surface analytical methods was produced and certified. The surface density of the implanted Sb layer was determined by Rutherford backscattering spectrometry (RBS), instrumental neutron activation analysis (INAA), and inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) equipped with a multi-collector. The isotopic abundances of Sb (121Sb and 123Sb) were determined by multi-collector ICP-MS and INAA. ICP-IDMS measurements are discussed in detail in this paper. All methods produced values traceable to the SI and are accompanied by a complete uncertainty budget. The homogeneity of the material was measured with RBS. From these measurements the standard uncertainty due to possible inhomogeneities was estimated to be less than 0.78% for fractions of the area increments down to 0.75 mm2 in size. Excellent agreement between the results of the three different methods was found. For the surface density of implanted Sb atoms the unweighted mean value of the means of four data sets is 4.81 x 10(16) cm(-2) with an expanded uncertainty (coverage factor k = 2) of 0.09 x 10(16) cm(-2). For the isotope amount ratio R (121Sb/123Sb) the unweighted mean value of the means of two data sets is 1.435 with an expanded uncertainty (coverage factor k = 2) of 0.006.

Journal Article↗
PubMed2001

Acute leukaemia or highly malignant lymphoma patients' quality of life over two years: a pilot study.

The aim of this study was, first, to investigate the quality of life and sense of coherence for acute leukaemia and malignant lymphoma patients at the start of treatment and over 2 years. A second aim was to compare questionnaire responses with patients' statements in open-ended interviews. A consecutive sample of 16 patients responded to the Quality of Life Questionnaire (QLQ-C30), Lund Gerontological Centre questionnaire and the Sense of Coherence Scale at the start of treatment and after 12 and 24 months. The QLQ-C30 questionnaire was administered also after 4, 8, 16 and 20 months. Tape-recorded open-ended interviews were conducted every 4 months before the patients responded to the questionnaires. Quality of life (QoL) and sense of coherence were scored more highly at the beginning of treatment for patients who did not relapse, than for those who relapsed. This difference remained throughout the study period. There was no correspondence in responses between questionnaire and personal interviews, although the results from the interviews, in some aspects, validated the result from the QLQ-C30. Those patients who relapsed may have had different prerequisites or been in a worse position at the onset of the disease and, reasonably, they needed more compensatory nursing care. More knowledge about the correspondence between a person's perceived QoL when discussed in personal interviews compared with responses given in standardised QoL questionnaires is needed before any assumption about clinical relevance can be made.

Acute Disease↗
PubMed2001

A 16-year haemodynamic follow-up of women with pregnancy-related medically treated iliofemoral deep venous thrombosis.

OBJECTIVES: to evaluate clinical and functional long-term outcomes following pregnancy-related medically treated iliofemoral deep venous thrombosis (DVT). DESIGN: retrospective follow-up of patients identified through a registry search. MATERIAL AND METHODS: twenty-five women underwent clinical examination, colour duplex ultrasound and computerised strain-gauge plethysmography on two occasions a mean of nine and 16 years after DVT. RESULTS: 40% of the patients were completely asymptomatic and 52% had no clinical signs of venous disease after a mean follow-up of 16 years. The clinical signs were in general mild, and none of the 25 patients had skin changes or ulcers. Deep venous reflux was found in 36% of the patients; the same percentage at nine- and 16-years follow-up, and 24% had normal ultrasonographic appearance of all deep veins. None of the patients had plethysmographic evidence of outflow obstruction. There was a significant relationship between measures of venous reflux and the presence of leg swelling, but there was no clear relation between functional abnormalities and the extent of the initial DVT. CONCLUSION: even after 16 years there are relatively mild symptoms and signs of venous disease in women with medically treated pregnancy-related iliofemoral DVT. Our results do not support earlier stated opinions that these patients represent a particular risk group for developing post-thrombotic syndrome.

Adult↗
PubMed2001

An evaluation of the ethical principles of the ICRP's radiation protection standards for workers.

After reviewing international recommendations and national standards for occupational radiation exposures, the article summarizes the major ethical theories so as to analyze which theories various ICRP principles presuppose. It also shows how proponents of each ethical theory would support or criticize various radiation principles and practices. Finally the article discusses four ethical issues crucial to the debate over workplace standards for radiation: (1) how to respond to the uncertainty over effects of low-dose exposures; (2) the conditions under which worker consent legitimates higher exposures; (3) whether there ought to be a double standard for worker, vs. public, exposures; and (4) whether ethics allows money-for-health tradeoffs in radiation protection. The article concludes with several recommendations about how to make occupational exposure to radiation more ethically defensible.

Dose-Response Relationship, Radiation↗
PubMed2001

Increase of interstitial glycerol reflects the degree of ischaemic brain damage: a PET and microdialysis study in a middle cerebral artery occlusion-reperfusion primate model.

OBJECTIVE: To evaluate interstitial glycerol as a marker of ischaemia by studying the changes in glycerol in direct relation to changes in regional cerebral metabolic rate of oxygen (CMRO(2)), the lactate/pyruvate ratio (LP ratio), and glutamate. METHODS: Transorbital 2 hour middle cerebral artery occlusion (MCAO) was performed in eight monkeys, which were studied with continuous microdialysis for 24 hours. Interstitial fluids were collected by microdialysis and analysed for glycerol, lactate, pyruvate, and glutamate with an enzymatic assay and high performance liquid chromatography. Sequential PET studies of cerebral blood flow (CBF), CMRO(2), oxygen extraction ratio (OER), and cerebral blood volume (CBV) were performed. The microdialysis probe regions were classified as severe ischaemia or penumbra, depending on whether the mean CMRO(2) side to side ratio was below or above 60%, respectively. RESULTS: A nine-fold, sustained increase in glycerol was registered after MCAO in severe ischaemia regions. In penumbra regions, the increase in glycerol was five-fold, but the glycerol concentration returned to baseline within 8 hours of clip removal. The difference between severe ischaemia and penumbra glycerol values was statistically significant. As expected from previous studies, the interstitial LP ratio and glutamate increased markedly in severe ischaemia, with a less pronounced change in penumbra regions. There was a time lag between the biochemical changes in severe ischaemia regions, with the LP ratio preceding glutamate, followed by glycerol. CONCLUSIONS: A marked, sustained increase in interstitial glycerol is indicative of severe ischaemia in this stroke model. A transient, diminutive increase in interstitial glycerol may reflect a penumbra situation. Interstitial glycerol in combination with other biochemical markers such as the LP ratio and glutamate may be useful for clinical monitoring of the ischaemic brain, reflecting a sequence of secondary pathophysiological events.

Animals↗
PubMed2001

Middle cerebral artery occlusion and reperfusion in primates monitored by microdialysis and sequential positron emission tomography.

BACKGROUND AND PURPOSE: In a previous investigation concerning the hemodynamic and metabolic changes over time displayed by sequential positron emission tomography (PET) in a middle cerebral artery (MCA) occlusion/reperfusion primate model, a metabolic threshold for irreversible ischemia could be identified (reduction of metabolic rate of oxygen [CMRO(2)] to approximately 60% of the contralateral hemisphere). To evaluate the potential of microdialysis (MD) as an instrument for chemical brain monitoring, the aim of this subsequent study was to relate the chemical changes in MD levels directly to the regional metabolic status (CMRO(2) above or below the metabolic threshold) and the occurrence of reperfusion, as assessed by PET. METHODS: Continuous MD (2 probes in each brain) and sequential PET measurements were performed during MCA occlusion (2 hours) and 18 hours (mean) of reperfusion in 8 monkeys (Macaca mulatta). Energy-related metabolites (lactate, pyruvate, and hypoxanthine) and glutamate were analyzed. The MD probe regions were divided into 3 categories on the basis of whether CMRO(2) was below or above 60% of the contralateral region (metabolic threshold level) during MCA occlusion and whether reperfusion was obtained: severe ischemia with reperfusion (n=4), severe ischemia without reperfusion (n=4), and penumbra with reperfusion (n=5). RESULTS: The lactate/pyruvate ratio, hypoxanthine, and glutamate showed similar patterns. MD probe regions with severe ischemia and reperfusion and probe regions with severe ischemia and no reperfusion displayed high and broad peaks, respectively, during MCA occlusion, and the levels almost never decreased to baseline. Penumbra MD probe regions displayed only slight transient increases during MCA occlusion and returned to baseline. CONCLUSIONS: This experimental study of focal ischemia showed that the extracellular changes of energy-related metabolites and glutamate differed depending on the ischemic state of the brain during MCA occlusion and depending on whether reperfusion occurred. If MD proves to be beneficial in clinical practice, it appears important to observe relative changes over time.

Animals↗