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H Persson

Publications and source records attributed to H Persson.

At least 37 records · Page 2Linked to original sources
PubMed1999

Self-consistent turbulence in the two-dimensional nonlinear Schrödinger equation with a repulsive potential.

The dynamics of dark solitons (vortices) with the same topological charge (vorticity) in the two-dimensional nonlinear Schrödinger (NLS) equation in a defocusing medium is studied. The dynamics differ from those in incompressible media due to the possibility of energy and angular momentum radiation. The problem of the breakup of a multicharged dark soliton, which is a local decrease of the wave function intensity, into a number of chaotically moving vortices with single charge, is studied both analytically and numerically. After an initial period of intensive wave radiation, there emerges a nonuniform, steady turbulent self-organized motion of these vortices which is restricted in space by the size of the potential well of the initial multicharged dark soliton. Separate orbits of finite widths arise in this turbulent motion. That is, the statistical probability to observe a vortex in a given point has maxima near certain points (orbit positions). In spite of the fact that numerical calculations were performed in a finite region, the turbulent distributions of the vortices do not depend on the size of the container when its radius is larger than the size of the potential well of the primary multicharged dark soliton. The steady turbulent distribution of vortices on these orbits can be obtained as the extremal of the Lyapunov functional of the NLS equation, and obeys some simple rules. The first is the absence of Cherenkov resonance with linear (sound) waves. The second is the condition of a potential energy maximum in the region of vortex motion. These conditions give an approximately equidistant disposition of orbits of the same number of vortices on each orbit, which corresponds to a constant rotating velocity. The magnitude of this velocity is mainly determined by the sound velocity. An integral estimation of the self-consistent rotation of the vortex zone is given.

Journal Article↗
PubMed1999

[Comparison between the poisoning severity score and specific grading scales used at the Department of Clinical Toxicology in Krakow].

The aim of the present study has been to assess the concordance in severity grading when using the Poisoning Severity Score (PSS), proposed by IPCS/EC/EAPCCT vs. some specific grading scales. Cases of acute poisoning admitted to the Department of Clinical Toxicology in Kraków during months January, March, May, July, August and October 1998 (n = 820) were evaluated. Severity grading was performed in all cases using both the PSS and special grading scales developed by the poisons centre in Kraków. The PSS is assessing severity on the basis of observed clinical signs and symptoms (at their maximum), but does not take into account potential risks or plasma/serum concentrations. The Kraków scales include both clinical symptoms on admission and results of toxicological analyses. Ethanol (39.4%), drugs (36.2%) and carbon monoxide (7.9%) were the most commonly involved toxic agents. Overall concordance between the PSS and the Kraków scales was at hand in 596 cases (72.7%). The lack of concordance was most evident for ethanol and carbon monoxide cases--the PSS generally giving a lower grade. The discordance was less pronounced for grade 3 (life-threatening) poisonings. Significant number of ethanol poisoning in Kraków centre require medicolegal certification thus ethanol concentration (blood or expired air) is considered while evaluating the poisoning severity. Moreover majority (more than 70%) of acutely ethanol poisoned patients treated at the Department are chronic alcoholics so clinical evidence of intoxication may be minimal at blood ethanol levels higher than 3.0 g/L. For ethanol intoxication the blood ethanol concentration was considered in the Kraków scale but not in the PSS, and when the blood concentrations were disregarded and clinical symptoms only were evaluated the concordance improved between the different systems from 72.7% to 92.3%. Thereby also the overall concordance in the study increased to 82.9%. The less satisfying concordance for carbon monoxide cases was mainly caused by discrepancies in the evaluation of neurological symptoms. Also the blood lactate concentration, COHb level, duration of exposure and patient's age are considered in the Kraków scale but not in PSS. The PSS is intended as a general scheme for grading severity of acute poisoning. In this study an acceptable concordance between the PSS and some locally developed grading scales was at hand in the majority of cases, but it seems that for specific poisons, like carbon monoxide, some modifications and additional criteria may be justified. Further studies to test the reliability of the PSS are encouraged.

Adult↗
PubMed1998

[Risk of lung damage found in fire-eaters. Twelve Swedish hospital cases reported].

Twelve hospital cases and 69 telephone enquiries relating to fire-eating have been registered at the Swedish Poison Information Centre. Chemical pneumonitis with symptoms such as coughing, fever, dyspnoea and hypoxia is common after petroleum distillate ingestion with concomitant aspiration. Pleuritic chest pain is an additional characteristic symptom among fire-eaters. Pulmonary infiltrates and pleural effusions are also frequent findings.

Adolescent↗
PubMed1998

A primary male autosomal linkage map of the horse genome.

A primary male autosomal linkage map of the domestic horse (Equus caballus) has been developed by segregation analysis of 140 genetic markers within eight half-sib families. The family material comprised four Standardbred trotters and four Icelandic horses, with a total of 263 offspring. The marker set included 121 microsatellite markers, eight protein polymorphisms, five RFLPs, three blood group polymorphisms, two PCR-RFLPs, and one single strand conformation polymorphism (SSCP). One hundred markers were arranged into 25 linkage groups, 22 of which could be assigned physically to 18 different chromosomes (ECA1, ECA2, ECA3, ECA4, ECA5, ECA6, ECA7, ECA9, ECA10, ECA11, ECA13, ECA15, ECA16, ECA18, ECA19, ECA21, ECA22, and ECA30). The average distance between linked markers was 12.6 cM and the longest linkage group measured 103 cM. The total map distance contained within linkage groups was 679 cM. If the distances covered outside the ends of linkage groups and by unlinked markers were included, it was estimated that the marker set covered at least 1500 cM, that is, at least 50% of the genome. A comparison of the relationship between genetic and physical distances in anchored linkage groups gave ratios of 0.5-0.8 cM per Mb of DNA. This would suggest that the total male recombinational distance in the horse is 2000 cM; this value is lower than that suggested by chiasma counts. The present map should provide an important framework for future genome mapping in the horse.

Animals↗
PubMed1997

Monosialoganglioside (GM1) immunofluorescence in rat spinal roots studied with a monoclonal antibody.

Gangliosides are characteristic glycolipid components of plasma cell membranes, especially enriched in the CNS and PNS. In some diseases involving the PNS, in particular motor neuropathies associated with conduction block, IgM autoantibodies against ganglioside GM1 have been implicated as a pathogenic factor. In order to study the GM1 distribution in peripheral nerves we have investigated its in situ localization using a new anti-GM1 monoclonal antibody, GM1:1. Immunization and production of the monoclonal antibody was made by common protocols and binding specificity was investigated by using structurally related glycolipids and modified GM1-molecules. The result showed that an alpha 2-3 bound sialic acid together with a terminal galactose moiety were essential for GM1:1 binding. In situ localization of GM1 in rat dorsal and ventral spinal roots was investigated by conventional immunomicroscopy. GM1 immunoreactivity was the same in both roots and appeared like a finely granular, in places confluent, material confined to Schmidt-Lanterman's incisures, to myelin sheath paranodal end segments and to some extent to the abaxonal Schwann cell cytoplasm; all of these structures are likely to be the target for GM1 antibodies in peripheral neuropathies. Nodal gaps and fibre contours showed a weak non-specific fluorescence. The localization of GM1 to the incisures of Schmidt-Lanterman and the paranodal end segments of the myelin sheaths might indicate a role of gangliosides as adhesion molecules.

Animals↗
PubMed1997

First clinical experiences with specific sheep Fab fragments in snake bite. Report of a multicentre study of Vipera berus envenoming.

OBJECTIVES: To evaluate the efficacy and safety of specific, ovine Fab fragments in the treatment of envenoming by the common adder, Vipera berus. DESIGN: Open study with historical controls. SETTING: Multicentre study involving patients (n = 30) with V. berus envenoming, treated in 18 Swedish hospitals during 1991-94. MAIN OUTCOME MEASURES: Initial symptoms, clinical course after treatment, duration of hospital stay and adverse effects of the antivenom were evaluated. Two earlier studied patient groups, given either equine F(ab)2 antivenom (n = 30) or no antivenom (n = 16), were used as controls. RESULTS: Specific ovine Fab fragments influenced favourably the acute symptomatology as well as the long term clinical course. Acute symptoms such as hypotension, shock, vomiting, diarrhoea and CNS-depression resolved quickly. The incidence of extensive swelling involving the trunk and the length of hospital stay were both reduced significantly compared to nontreated patients (23 vs. 88% and 3.5 vs. 6 days). Also the incidence of anaemia was reduced (23 vs. 44%). These results were consistent with those obtained with equine F(ab')2 antivenom, but with ovine Fab there were no immediate anaphylactic reactions or serum sickness. CONCLUSION: Specific Fab fragments produced from sheep immunized with V. berus venom were safe and effective in counteracting the effects of V. berus bite in humans. These results justify further studies of this new treatment for snake envenoming.

Adolescent↗
PubMed1997

Schilling and protein-bound cobalamin absorption tests are poor instruments for diagnosing cobalamin malabsorption.

OBJECTIVES: To assess the advantage of a protein-bound cobalamin absorption test (PBAT) over the Schilling test in patients with suspected cobalamin (vitamin B12) malabsorption. DESIGN: Clinical study of consecutive patients referred from primary care units, medical and neurological clinics. SETTING: The catchment area of Sahlgrenska University Hospital, Göteborg. SUBJECTS: Referred patients (n = 155) with suspected cobalamin deficiency and at least one serum cobalamin value < 200 pmol L-1. INTERVENTIONS: All patients were investigated with upper gastrointestinal endoscopy with biopsies taken from the gastric body and duodenal mucosa. Serum methylmalonic acid (MMA) and homocysteine (Hcy) were determined in all 109 patients not on cobalamin substitution. A dual isotope cobalamin absorption test was then performed with the concomitant administration of crystalline (Schilling) and protein-bound cobalamin (PBAT). MAIN OUTCOME MEASURES: Number of patients with gastric body atrophy diagnosed with each absorption test and the relation between these results and functional cobalamin deficiency defined as elevated MMA and Hcy, that normalized after cobalamin substitution treatment. RESULTS: The majority of patients with abnormal absorption tests had already developed elevated MMA and/or Hcy. PBAT was more sensitive than the Schilling test in identifying patients with gastric body atrophy but the sensitivity was too low for clinical use. About 1/3 of the patients with gastric body atrophy and normal absorption tests had elevated MMA and/or Hcy, indicating cobalamin deficiency. CONCLUSION: PBAT may be somewhat more sensitive than the Schilling test but neither test is sensitive enough for diagnosing cobalamin malabsorption at an early stage.

Adult↗
PubMed1997

Citalopram overdose--review of cases treated in Swedish hospitals.

BACKGROUND: The toxic effects of acute citalopram overdose are reported by the Swedish Poisons Information Centre. DESIGN: Case reports received from Swedish hospitals during 1995 have been analyzed. Forty-four cases of pure citalopram intoxication have been studied in detail. RESULTS: At doses below 600 mg, mild symptoms were observed. Doses above 600 mg caused ECG abnormalities and convulsions in some patients, while doses greater than 1900 mg caused such symptoms in all patients. CONCLUSIONS: The findings are consistent with previous reports claiming that selective serotonin reuptake inhibitors are less toxic compared to tricyclic antidepressants. However, there is a risk of developing serious symptoms when large doses have been ingested.

Adolescent↗
PubMed1996

Markedly improved skeletal muscle function with local muscle training in patients with chronic heart failure.

BACKGROUND: Reduced heart pump function and skeletal muscle abnormalities are considered important determinants for the low physical exercise capacity in chronic heart failure. Because of reduced ventricular function, traditional physical rehabilitation may cause underperfusion and low local work intensity, thereby producing suboptimal conditions for skeletal muscle training. HYPOTHESIS: The study was undertaken to determine the effects of local exercise training, designed as one- or two-legged knee extensor training, on exercise capacity in patients with moderate chronic heart failure. Because such exercise models use only about one quarter to half the muscle mass used in cycle ergometer training, the influence of a restricted circulatory capacity should therefore be limited. Further, we aimed to determine whether or not chronic heart failure skeletal musculature abnormalities are counteracted with such training. METHODS: Fourteen patients with chronic heart failure [age 58 +/- 3 years, ejection fraction (EF) 28 +/- 4%] were randomized to two different training protocols three times a week for 8 weeks and compared with a nontraining control group (n = 7, age 62 +/- 3, EF 27 +/- 3%). Group 2L (n = 7) underwent simultaneous two-legged knee extensor training (about 4 kg working muscle) for 15 min at 65-75% of VO2 max of the two-legged kick. Group 1L (n = 7) trained each leg at a time for 15 min of continuous one-legged dynamic knee extensor work with the same training load per muscle mass, that is, at 35% of VO2 max of the two-legged kick (about 2 kg working muscle). Peak VO2 of two-legged knee extensor exercise (l/min), two-legged endurance (W), and strength (Nm) were determined before and after the training period. The activity of citrate synthase (CS) was estimated in tissue samples from the quadriceps femoris muscle. RESULTS: Peak VO2 did not change with training. Two-legged knee extensor endurance exercise capacity increased by an average of 40-50% (p < 0.01) in all training patients in both the 2L and 1L groups, while no change was observed in the control group. Depressed skeletal muscle CS activity increased by 25-35% in both training groups (p < 0.01). Strength increased by 16% in the 2L group after training (p < 0.05), while no change was seen in the 1L and control groups. CONCLUSIONS: Skeletal muscle changes in stable moderate chronic heart failure are not entirely irreversible. A major factor contributing to these changes and to exercise limitation is deconditioning. Local muscle training is efficient and can at least partially improve skeletal muscle function in these patients. Different degrees of local activation, that is, one- or two-legged knee extensor exercise, do not seem to differ in terms of their effect on exercise capacity. Depressed skeletal muscle oxidative capacity adapts to such physical training with increased activity to an extent not different from that for healthy volunteers.

Adaptation, Physiological↗
PubMed1996

Presence of sulphatide (3'-sulphogalactosylceramide) in pericytes in the choroid layer of the eye: sharing of this glycolipid autoantigen with islets of Langerhans.

The aim of the study was to investigate the distribution in the eye of sulphatide, an acid glycolipid which has previously been demonstrated in islets of Langerhans, nervous tissue and in kidney glomeruli of diabetic patients, and against which antibodies have been found in patients with newly diagnosed insulin-dependent diabetes mellitus. A specific monoclonal antibody, Sulph I, was used for detection of sulphatide by thin-layer chromatography, and light and electron microscope immunohistochemistry. A distinct, patchy staining was found in the choroid layer and the ciliary processes. The antigen was confirmed to be sulphatide and its concentration in human eyes was 30 nmol sulphatide/g wet tissue. By electron microscopy, anti-sulphatide choroid labelling was demonstrated in pericytes and in smooth muscle cells surrounding vessels. No Sulph I-negative pericytes were seen. Double labelling with Sulph I and anti-smooth muscle actin revealed that only pericytes in the eye contained sulphatide and not those in heart, lung, liver, adrenal, spleen, lymph node, thymus, or pancreatic tissue. Thus, sharing of the autoantigen sulphatide has been demonstrated between islets of Langerhans and pericytes in the choroid layer of the eye.

Aged↗
PubMed1996

Development and clinical application of immunoassays for European adder (Vipera berus berus) venom and antivenom.

An ovine affinity purified Fab antivenom was used in a clinical trial in Sweden to treat European adder (Vipera berus berus) envenoming. Immunoassays were developed to measure V. b. berus venom and antivenom concentrations in clinical samples to help assess the efficacy of treatment. A radioimmunoassay (RIA) was developed, optimized and validated to measure plasma levels of V. b. berus venom and compared with a conventional ELISA. Both showed a similar variation of zero binding in biological samples and the results obtained correlated closely. However, the ELISA was quicker and more sensitive (0.8 compared with 2 micrograms/litre). Before administration of antivenom, V. b. berus venom concentrations in plasma ranged from 10 to 53 micrograms/litre; 12 hr after the Fab infusion, no patient had measurable levels. However, two patients had low venom levels 24 hr after treatment. ELISA and RIA were also developed, optimized and used to measure concentrations of free Fab in plasma. There was a biexponential fall of Fab concentration with a fast distribution phase (t 1/2 = 0.9 hr) and a slower elimination phase (t 1/2 = 18 hr). The amount of Fab excreted in urine was low.

Animals↗