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Biomedical subjects

L Persson

Publications and source records attributed to L Persson.

At least 19 recordsLinked to original sources
PubMed2006

Size-dependent interactions inhibit coexistence in intraguild predation systems with life-history omnivory.

Growth in body size during ontogeny often results in changes in diet, leading to life-history omnivory. In addition, growth is often dependent on food density. Using a physiologically structured population model, we investigated the effects of these two aspects of individual growth in a system consisting of two size-structured populations, an omnivorous top predator and an intermediate consumer. With a single shared resource for both populations, we found that life-history omnivory decreases the likelihood of coexistence between top predator and intermediate consumer in this intraguild predation (IGP) system. This result contrasts with previous unstructured models and stage-structured models without food-dependent development. Food-dependent development and size-dependent foraging abilities of the predator resulted in a positive feedback between foraging success on the shared resource at an early life stage and foraging success on the intermediate consumer later in life. By phenomenologically incorporating this feedback in an unstructured IGP model, we show that it also demotes coexistence in this simple setting, demonstrating the robustness of the negative effect of this feedback.

Animals↗
PubMed2006

Phenotypic and genotypic characterization of coagulase-negative staphylococci isolated in blood cultures from patients with haematological malignancies.

Coagulase-negative staphylococci are the predominant aetiological agents in bacteraemic patients hospitalized for haematological malignancies. The aim of this study was to determine whether differences exist in the prevalence of icaAB genes and in the phenotypic and/or genotypic pattern between blood isolates of coagulase-negative staphylococci, interpreted as representing true bacteraemia, and contaminant isolates from patients with haematological malignancies. Eighty-two isolates representing true bacteraemia and 47 contaminant isolates were found among 76 patients. The most prevalent species in both groups of patients was Staphylococcus epidermidis (n=103; 80%). Biochemical typing using the Phene Plate system and genotyping using pulsed-field gel electrophoresis showed a tendency towards a more homogeneous pattern among isolates causing true bacteraemia compared with contaminant isolates. Two major genotypic groups of S. epidermidis were found in both the true bacteraemia group and the contaminant group, with concordant pulsotypes found as well. These groups may comprise isolates carrying specific virulence factors, but the prevalence of the icaAB genes did not differ between the true bacteraemia group and the contaminant group. No significant difference was seen between the two study groups regarding clinical symptoms or complications, use of central venous catheter, and levels of absolute neutrophil count or C-reactive protein.

Adolescent↗
PubMed2005

The establishment of endovascular aneurysm coiling at a neurovascular unit: report of experience during early years.

The treatment of cerebral aneurysms is changing from surgical clipping to endovascular coiling (EVC) in many neurovascular centres. The aim of this study was to evaluate the technical results and clinical outcome at 6 months in a consecutive series of subarachnoid hemorrhage (SAH) patients treated with EVC, in a situation when the EVC had been established very rapidly as the first line of treatment at a neurovascular centre. The patient material comprised 239 SAH patients (155 women and 84 men, mean age 55 years, age range 16-81) allocated to EVC as the first line of treatment in the acute stage (within 3 weeks of rupture) between September 1996 and December 2000. Clinical grade on admission was Hunt & Hess (H&H) I and II in 42%, H&H III in 25% and H&H grade IV and V in 33% of the patients. The aneurysm was located in the anterior circulation in 82% of the cases. EVC was performed on days 0-3 in 77% of the cases. EVC of the target aneurysm was able to be completed in 222 patients (93%). Complete occlusion was achieved in 126 patients (53%). Procedural complications occurred in 39 patients (16%). Favourable clinical outcome was observed in 57%, severe disability in 28% and poor outcome in 14% of the patients. Favourable outcome was achieved in 77% of H&H I and II patients and in 43% of H&H III-V patients. The multivariate logistic regression analysis revealed that younger age, good neurological grade on admission, absence of intracerebral hematoma and intraventricular hematoma respectively, ICA-PcomA aneurysm location, later treatment and absence of complications were significant predictors of favourable outcome. After interventional training and installation of the X-ray system, the introduction and establishment of EVC at a neurovascular unit can be done in a short period of time and with favourable results. Future studies must concentrate on identifying factors of importance for the choice of interventional or surgical therapy. The results of this study indicate that endovascular therapy may be particularly beneficial in poor-grade patients and in patients with aneurysms in the ICA-PcomA territory.

Adolescent↗
PubMed2005

Vinegar supplementation lowers glucose and insulin responses and increases satiety after a bread meal in healthy subjects.

OBJECTIVE: To investigate the potential of acetic acid supplementation as a means of lowering the glycaemic index (GI) of a bread meal, and to evaluate the possible dose-response effect on postprandial glycaemia, insulinaemia and satiety. SUBJECTS AND SETTING: In all, 12 healthy volunteers participated and the tests were performed at Applied Nutrition and Food Chemistry, Lund University, Sweden. INTERVENTION: Three levels of vinegar (18, 23 and 28 mmol acetic acid) were served with a portion of white wheat bread containing 50 g available carbohydrates as breakfast in randomized order after an overnight fast. Bread served without vinegar was used as a reference meal. Blood samples were taken during 120 min for analysis of glucose and insulin. Satiety was measured with a subjective rating scale. RESULTS: A significant dose-response relation was seen at 30 min for blood glucose and serum insulin responses; the higher the acetic acid level, the lower the metabolic responses. Furthermore, the rating of satiety was directly related to the acetic acid level. Compared with the reference meal, the highest level of vinegar significantly lowered the blood glucose response at 30 and 45 min, the insulin response at 15 and 30 min as well as increased the satiety score at 30, 90 and 120 min postprandially. The low and intermediate levels of vinegar also lowered the 30 min glucose and the 15 min insulin responses significantly compared with the reference meal. When GI and II (insulinaemic indices) were calculated using the 90 min incremental area, a significant lowering was found for the highest amount of acetic acid, although the corresponding values calculated at 120 min did not differ from the reference meal. CONCLUSION: Supplementation of a meal based on white wheat bread with vinegar reduced postprandial responses of blood glucose and insulin, and increased the subjective rating of satiety. There was an inverse dose-response relation between the level of acetic acid and glucose and insulin responses and a linear dose-response relation between acetic acid and satiety rating. The results indicate an interesting potential of fermented and pickled products containing acetic acid.

Acetic Acid↗
PubMed2005

Immunoglobulin treatment reduces atherosclerosis in apolipoprotein E-/- low-density lipoprotein receptor-/- mice via the complement system.

Atherosclerosis is associated with activation of the immune system. Intravenously applied normal polyclonal immunoglobulins (IVIg) have broad therapeutic applications in the treatment of autoimmune and systemic inflammatory diseases. Recently, IVIg have been shown to inhibit atherogenesis in experimental animal models. To investigate the role of the complement system in this process, we used third complement component-deficient (C3(-/-)) and control atherosclerosis-prone apolipoprotein E (ApoE) and low-density lipoprotein receptor (LDLR) double knock-out mice fed a normal diet. IVIg treatment reduced lesion fraction area in the aortic root of complement-sufficient mice whereas the lesion fraction area of C3(-/-) mice was not affected. Thus, complement activation plays a role in the anti-atherosclerotic effects of IVIg, possibly by C3-derived fragments generated through Fc-dependent complement activation.

Animals↗
PubMed2005

Childhood abuse in Swedish female users of psychiatric services.

INTRODUCTION: The aims of this study were to investigate: (1) the prevalence of childhood abuse in women admitted to psychiatric services in a county in the south of Sweden; (2) who the perpetrators were; and (3) the women's self-reported consequences of childhood abuse. METHOD: The study had a cross-sectional design and was a part of a more comprehensive study. An anonymous self-reported questionnaire was used which included both closed and open-ended questions. The data material were analysed by means of descriptive statistics, Mann-Whitney U-test and manifest content analysis. RESULTS: The total number of women who participated in the study was 259, 51% of whom reported experiences of abuse during childhood, with 53% of these having been exposed to more than one type of abuse. The most frequent perpetrator was the woman's parents; mainly the fathers but also the mothers turned out to be frequent perpetrators of abuse. Some 75% of the women reported current psychological problems in adulthood related to abuse in childhood. According to a manifest content analysis, five themes of self-reported psychological problems emerged: psychiatric problems, shortcomings in social relations, poor self-confidence, fears and bad memories.

Adolescent↗
PubMed2004

Histamine and histidine decarboxylase are hallmark features of ECL cells but not G cells in rat stomach.

The oxyntic mucosa of the rat stomach is rich in ECL cells which produce and secrete histamine in response to gastrin. Histamine and the histamine-forming enzyme histidine decarboxylase (HDC) have been claimed to occur also in the gastrin-secreting G cells in the antrum. In the present study, we used a panel of five HDC antisera and one histamine antiserum to investigate whether histamine and HDC are exclusive to the ECL cells. By immunocytochemistry, we could show that the ECL cells were stained with the histamine antiserum and all five HDC antisera. The G cells, however, were not stained with the histamine antiserum, but with three of the five HDC antisera. Thus, histamine and HDC coexist in the ECL cells (oxyntic mucosa) but not in G cells (antral mucosa). Western blot analysis revealed a typical pattern of HDC-immunoreactive bands (74, 63 and 54 kDa) in oxyntic mucosa extracts with all five antisera. In antral extracts, immunoreactive bands were detected with three of the five HDC antisera (same as above); the pattern of immunoreactivity differed from that in oxyntic mucosa. Food intake of fasted rats or treatment with the proton pump inhibitor omeprazole raised the HDC activity and the HDC protein content of the oxyntic mucosa but not of the antral mucosa; the HDC activity in the antrum was barely detectable. We suggest that the HDC-like immunoreactivity in the antrum represents a cross-reaction with non-HDC proteins and conclude that histamine and HDC are hallmark features of ECL cells but not of G cells.

Animals↗
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↗