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Biomedical subjects

L Jacobsson

Publications and source records attributed to L Jacobsson.

At least 91 records · Page 5Linked to original sources
PubMed1998

Functional conservation of the effector protein translocators PopB/YopB and PopD/YopD of Pseudomonas aeruginosa and Yersinia pseudotuberculosis.

Virulent Yersinia species cause systemic infections in rodents, and Y. pestis is highly pathogenic for humans. Pseudomonas aeruginosa, on the other hand, is an opportunistic pathogen, which normally infects only compromised individuals. Surprisingly, these pathogens both encode highly related contact-dependent secretion systems for the targeting of toxins into eukaryotic cells. In Yersinia, YopB and YopD direct the translocation of the secreted Yop effectors across the target cell membrane. In this study, we have analysed the function of the YopB and YopD homologues, PopB and PopD, encoded by P. aeruginosa. Expression of the pcrGVHpopBD operon in defined translocation-deficient mutants (yopB/yopD) of Yersinia resulted in complete complementation of the cell contact-dependent, YopE-induced cytotoxicity of Y. pseudotuberculosis on HeLa cells. We demonstrated that the complementation fully restored the ability of Y. pseudotuberculosis to translocate the effector molecules YopE and YopH into the HeLa cells. Similar to YopB, PopB induced a lytic effect on infected erythrocytes. The lytic activity induced by PopB could be prevented if the erythrocytes were infected in the presence of sugars larger than 3 nm in diameter, indicating that PopB induced a pore of similar size compared with that induced by YopB. Our findings show that the contact-dependent toxin-targeting mechanisms of Y. pseudotuberculosis and P. aeruginosa are conserved at the molecular level and that the translocator proteins are functionally interchangeable. Based on these similarities, we suggest that the translocation of toxins such as ExoS, ExoT and ExoU by P. aeruginosa across the eukaryotic cell membrane occurs via a pore induced by PopB.

Amino Acid Sequence↗
PubMed1998

Mycobacterium marinum wrist arthritis: local and systematic dissemination caused by concomitant immunosuppressive therapy.

The diagnostic difficulties and the potential serious course of Mycobacterium marinum synovitis are illustrated in a patient in whom treatment with local steroid injections and immunosuppressive therapy resulted in local destruction of the wrist and systemic reactions. Healing was achieved after correct medical and surgical treatment was initiated.

Arthritis, Infectious↗
PubMed1998

Evaluation of attenuation corrections using Monte Carlo simulated lung SPECT.

SPECT (single photon emission computed tomography) images are distorted by photon attenuation. The effect is complex in the thoracic region due to different tissue densities. This study compares the effect on the image homogeneity of two different methods of attenuation correction in lung SPECT; one pre-processing and one post-processing method. This study also investigates the impact of attenuation correction parameters such as lung contour, body contour, density of the lung tissue and effective attenuation coefficient. The Monte Carlo technique was used to simulate SPECT studies of a digital thorax phantom containing a homogeneous activity distribution in the lung. Homogeneity in reconstructed images was calculated as the coefficient of variation (CV). The isolated effect of the attenuation correction was assessed by normalizing pixel values from the attenuation corrected lung by pixel values from the lung with no attenuation effects. Results show that the CV decreased from 12.8% with no attenuation correction to 4.4% using the post-processing method and true densities in the thoracic region. The impact of variations in the definition of the body contour was found to be marginal while the corresponding effect of variations in the lung contour was substantial.

Algorithms↗
PubMed1998

GFR measurement with iohexol and 51Cr-EDTA. A comparison of the two favoured GFR markers in Europe.

BACKGROUND: The aim of the present study was to compare the most commonly used GFR markers for clearance measurements, 51Cr-EDTA and iohexol, using two different methods for iohexol analysis, HPLC and X-ray fluorescence, referring both to the multiple-sample and single-sample calculations, using 51Cr-EDTA as the reference method. METHODS: Forty-nine patients with an estimated GFR >40 ml/min were included. 51Cr-EDTA and iohexol were injected simultaneously and blood samples were taken 150, 195 and 240 min after injection of the respective marker. RESULTS: The multiple-point clearances, determined from HPLC and X-ray fluorescence, compared to 51Cr-EDTA correlated highly (r=0.92 and 0.95 respectively). The results from single-point clearance comparison, iohexol measured by HPLC vs 51Cr-EDTA, yielded a correlation of r=0.91, while single-point clearance from iohexol, analysed by X-ray fluorescence, obtained a correlation of 0.93 and an intercept statistically different from origo. CONCLUSIONS: Iohexol and 51Cr-EDTA are comparable as GFR markers for multiple-point clearance measurements. The single-sample method for GFR >40 ml/min can be used with a high accuracy. The precision and accuracy of X-ray fluorescence analysis of low concentrations of iohexol were less than those of HPLC. Care should therefore be taken when using X-ray fluorescence that the injected dose of iohexol should result in a plasma concentration level of iodine of at least 0.06 mg/ml at the time of blood sampling.

Adult↗
PubMed1998

Administered activity of 99Tcm-DMSA for kidney scintigraphy in children.

Kidney scintigraphy using 99Tcm-dimercaptosuccinic acid (DMSA) is a common gamma camera investigation in paediatric patients. The present study deals with methods of calculating the activity to be administered to children. Our aim is to find a method of calculation which gives the same count density in the gamma camera images for all ages. Four different methods, based on body weight, height, body surface area and a theoretical model, are compared. The count density in the images of the kidneys was studied retrospectively in 85 patients aged between 3 weeks and 19.5 years. Fourteen young adults aged 22.0-31.9 years were also studied. Two of the calculation methods, based on body surface area and the theoretical model, showed no apparent age dependency (i.e. a constant count density was observed for all ages). The variation between individuals was similar with both methods, but only the body surface area method gave a count density comparable to that for the young adults. As the method based on body surface area is also easy to implement, this method is recommended.

Adolescent↗
PubMed1998

Personality and defenses: a cross-cultural study of psychiatric patients and healthy individuals in Nicaragua and Sweden.

This study examined cross-cultural variability in personality and defenses among Nicaraguan and Swedish healthy individuals, patients with borderline personality disorder and schizophrenic disorders by means of the projective perceptual Defense Mechanism Test. The over-all aim was to test the hypothesis proposed by Anthony Marsella of 'severity related cross-cultural variability' suggesting that differences in symptom profile or personality patterns between cultures are most pronounced among healthy individuals and less so among individuals with severe mental disorders as they are perceived as more universal and less culturally determined. The over-all results showed that cross-cultural differences were in accordance with the proposed hypothesis. In addition, there were significant intracultural differences between the different diagnostic groups in both countries. The conclusion is that the Defense Mechanism Test and Partial Least Squares analysis seem to be powerful methods for personality assessment and potentially for cross-cultural research, and culture-specific norms in the Defense Mechanism Test must be employed.

Adult↗
PubMed1998

Law and mental health--on the role of lawmaking in the process of developing psychiatric care.

Mental health (as well as somatic health) depends on individual biological, psychological and social factors as well as more general societal factors. If one wishes to promote health, it is necessary to work in many different fields hopefully in a synergistic way. As a psychiatrist and clinician one is inclined to believe that developments in psychiatric science and practice are the most important activities to improve the mental health situation in a population. But, at the same time it is apparent that societal processes of social, political and economic nature also play a decisive role. One of the most important factors in the development of society is lawmaking by which its nature is setting the norms in a society and which is also usually combined with some kind of sanction system to support the norms. Lawmakers also have the possibility to interfere in the process of developing knowledge and practice in different fields, for example through supporting treatment and research of a special kind or even to forbid special kinds of treatment and research in certain areas. Lawmakers are also inclined to believe that if there is a law this will be enough to answer these challenges. I think it is extremely important that lawmaking in the field of mental health is in broad agreement with the development in the scientific and practical field of psychiatry and other mental health disciplines. This is the subject of this paper.

Civil Rights↗
PubMed1998

Radioiodine treatment of hyperthyroidism in a pregnant women.

UNLABELLED: We describe the effects of radioiodine treatment of a pregnant thyrotoxic woman. METHODS: The woman received 500 MBq of (131)I in her 20th gestational week. The pregnancy was discovered 10 days after radioiodine administration. A gamma camera examination of the abdomen at that time showed a distinct focus of activity, which was interpreted as the fetal thyroid. Gamma camera examinations of the mother and fetus were performed at 10, 11, 12, 13 and 18 days after administration of the therapeutic activity and were the basis of dose calculations. The child was examined by hormone tests and mental performance tests, up to 8 yr after birth. RESULTS: The uptake at 24 hr postadministration was calculated to be 10 MBq (2%) in the fetal thyroid gland. The effective half-life was 2.5 days, giving a calculated absorbed dose to the fetal thyroid gland of 600 Gy, which is considered to be an ablative dose. The calculated absorbed dose to the fetal body, including brain, was about 100 mGy, and 40 mGy to the fetal gonads. Doses were estimated taking contributions from radioiodine in the mother, the fetal body and the fetal thyroid into consideration. The woman was encouraged to continue her pregnancy and received levothyroxine in a dose to render her slightly thyrotoxic. At full term, an apparently healthy boy, having markedly raised cord blood serum thyroid-stimulating hormone concentration and subnormal thyroxine (T4) and low-normal triiodothyronine (T3) concentrations, was born. Treatment with thyroxine was initiated from the age of 14 days, when the somatosensoric evoked potential latency time increased to a pathological value and hormonal laboratory tests repeatedly confirmed the hypothyroid state. At 8 yr of age, the child attends regular school. A neuropsychological pediatric examination showed that the mental performance was within normal limits, but with an uneven profile. He has a low attention score and displays evidently subnormal capacity regarding figurative memory. CONCLUSION: Radioiodine treatment in pregnancy in the 20th gestational week does not give a total absorbed dose to the fetal body that justifies termination of pregnancy. A high absorbed dose to the fetal thyroid, however, should be the basis of the management of the pregnancy and offspring.

Adult↗
PubMed1997

The macrophage migration inhibitory factor MIF is a phenylpyruvate tautomerase.

A macrophage migration inhibitory factor (MIF), originally described as a product of activated lymphocytes, has been defined as a 12 kDa protein, expressed in a wide variety of tissues. Here MIF is identified as a phenylpyruvate tautomerase (EC 5.3.2.1) having p-hydroxyphenylpyruvate and phenylpyruvate as its natural substrates. The definition of MIF as an enzyme may yield insight into the mechanism of action of this proinflammatory and immunomodulating cytokine.

Amino Acids↗
PubMed1997

Effect of administered activity on precision in the assessment of renal function using gamma camera renography.

Split and total renal function are commonly assessed from time-activity curves obtained from gamma camera renography with 99Tcm-diethylenetriamine pentaacetate (99Tcm-DTPA) and 99Tcm-mercaptoacetyl-triglycine (99Tcm-MAG3). The impact of the statistical noise associated with these curves on the total precision in split and total renal function impairment was studied at different levels of administered activity by simulation. The simulation consisted of generated time-activity curves, with statistical noise corresponding to the administration of 10-400 MBq 99Tcm-DTPA or 7.5-150 MBq 99Tcm-MAG3. Our results indicate that the error induced by statistical noise in split renal function calculations is generally very low (< 3% at 100 MBq 99Tcm-DTPA or 75 MBq 99Tcm-MAG3) and only affects precision slightly in calculations at 45-50 MBq 99Tcm or more. Similar results were obtained for precision in GFR calculations, where the total error increased from 12.3% at 100 MBq 99Tcm-DTPA to 12.8% at 50 MBq, but decreased to 12.0% at 400 MBq. Consequently, statistical noise has a minor effect on the precision in split and total renal function calculations at commonly used activity levels when it is reduced to approximately 50 MBq.

Gamma Cameras↗
PubMed1997

Selection of collimator for rCBF studies and evaluation of triple-headed SPET using noise-resolution plots.

We investigated the effect of collimator selection on image quality in regional cerebral blood flow (rCBF) studies of the brain performed with 99Tc(m)-HMPAO. A triple-headed SPET system (GE/CGR Neurocam) was used, together with three sets of parallel-hole collimators - general-purpose (GP), high-resolution (HR) and ultra-high-resolution (UHR). Two image quality parameters were used to describe the image quality, namely, noise and resolution. Noise was measured in experimental and Monte-Carlo simulated SPET studies of a cylinder phantom of uniform activity as the pixel root mean square error (RMS) and as the coefficient of variation (CV) of quantitative rCBF values. Resolution was measured as full-width at half-maximum in experimental SPET studies of a line-source. Plots of noise versus resolution for the different collimators were obtained by varying the cut-off frequency of the Hanning filter applied in the reconstruction of transaxial slices. From these noise-resolution plots, we were able to determine which collimator gave the best resolution for a specific noise level. A lowest reasonable noise level may be established by comparison with the inter-observer CV of the quantification method.

Brain↗
PubMed1997

Disturbances of autonomic nervous function in primary Sjögren's syndrome.

Autonomic nervous function was evaluated by deep breathing [expiration/inspiration (E/I) ratio] and tilt table tests [acceleration (AI) and brake indices (BI)] in 19 patients with primary Sjögren's syndrome (pSS) and in 56 age matched controls. The E/I-ratio and systolic blood pressure (at rest, 1, and 8 min after tilt) were found to be significantly reduced (p < 0.001, p < 0.05, p < 0.01, p < 0.01 respectively) in patients with pSS whereas neither AI, BI nor diastolic blood pressure did differ significantly between patients and controls (NS). The van Bijsterveld's score correlated negatively with the AI (r = -0.77, p< 0.001) as well as the BI (r = -0.60, p < 0.01). No correlations were found between the 3 autonomic nerve function parameters (E/I-ratio, AI, BI) and unstimulated whole sialometry or salivary gland scintigraphy. We conclude that autonomic disturbances, mainly affecting the parasympathetic nerves are associated with pSS.

Adolescent↗
PubMed1997

Disturbances of autonomic nervous function in primary Sjögren's syndrome.

Autonomic nervous function was evaluated by deep breathing [expiration/inspiration (E/I) ratio] and tilt table tests [acceleration (AI) and brake indices (BI)] in 19 patients with primary Sjögren's syndrome (pSS) and in 56 age matched controls. The E/I-ratio and systolic blood pressure (at rest, 1, and 8 min after tilt) were found to be significantly reduced (p < 0.001, p < 0.05, p < 0.01, p < 0.01 respectively) in patients with pSS whereas neither AI, BI nor diastolic blood pressure did differ significantly between patients and controls (NS). The van Bijsterveld's score correlated negatively with the AI (r = -0.77, p < 0.001) as well as the BI (r = -0.60, p < 0.01). No correlations were found between the 3 autonomic nerve function parameters (E/I-ratio, AI, BI) and unstimulated whole sialometry or salivary gland scintigraphy. We conclude that autonomic disturbances, mainly affecting the parasympathetic nerves are associated with pSS.

Adolescent↗