| 1. |
- Malmqvist, K. G., et al.
(författare)
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PIXE and proton microprobe advances at the Lund Institute of Technology
- 1989
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Ingår i: Nuclear Inst. and Methods in Physics Research, B. - 0168-583X. ; 40-41:PART 1, s. 685-689
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Tidskriftsartikel (refereegranskat)abstract
- A review of recent advances in high-energy ion beam analysis at the Lund Institute of Technology is presented. A nonvacuum specimen chamber allows chemical speciation using a combination of ion beam analysis and controlled heating. The development of a new versatile scanning proton microbeam based on a new dedicated accelerator, an achromatic triplet lens and an advanced specimen chamber is outlined together with the performance of a microVAX-II/VMEbus-based data acquisition system.
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| 2. |
- Englund, E., et al.
(författare)
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Tumours of the central nervous system. Proton magnetic resonance relaxation times T1 and T2 and histopathologic correlates
- 1986
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Ingår i: Acta Radiologica Diagnosis. - : SAGE Publications. - 0567-8056. ; 27:6, s. 653-659
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Tidskriftsartikel (refereegranskat)abstract
- Proton MR relaxation times T1 and T2 were determined in vitro in 136 small specimens of astrocytomas grades I-IV, of oligodendrogliomas, metastases of adenocarcinomas, meningiomas and acoustic neuromas. In addition, 7 samples of peritumoural white matter were analysed. The analysed specimens were studied microscopically in their entirety regarding tumour type and occurrence of necrosis and non-tumour tissue admixture, such as fibrosis and haemorrhage. Most of the gliomas had longer relaxation times than normal white matter and T2 was significantly longer than in the other three tumour groups. The metastases had longer T1 than normal white matter, while T2 varied. The astrocytomas tended to show shorter relaxation times with increasing degree of malignancy, and shortening of T1 and T2 correlating with the proportion of tissue necrosis. Similarly, the metastases with tissue necrosis had shorter T1 and T2 than non-necrotic samples. The meningiomas had T1 values comparable with normal cortex, while the T2 values varied. Tumours containing a large proportion of fibrous tissue had shorter relaxation times than the others. Acoustic neuromas had only slightly longer T1 than normal white matter, while T2 was not prolonged. Both T1 and T2 were significantly shorter than in all other tumours studied. Peritumoural white matter had prolonged relaxation times compared with normal white matter, correlating to increased water content. These in vitro differences regarding relaxation times in various types of tumours of the central nervous system, dependent on various types of tissue alterations, should be of interest for the interpretation of in vivo images.
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| 3. |
- Györffy-Wagner, Z., et al.
(författare)
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Proton magnetic resonance relaxation times T1 and T2 related to postmortem interval : An Investigation on Porcine Brain Tissue
- 1986
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Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 0567-8056. ; 27:1, s. 115-118
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Forskningsöversikt (refereegranskat)abstract
- In order to establish the validity of in vitro determination of the proton magnetic resonance (MR) relaxation times T1 and T2 in brain tissue at increasing time delay after death or operative excision, 81 brain tissue samples from 23 pigs were analyzed repeatedly. These samples, representing cortex, caudate nucleus and white matter, were studied microscopically after MR measurements. The T1 values exhibited no time dependence and the T2 values decreased slightly during the interval 2 to 90 hours after death. The samples were stored at +8°C between the measurements. These results indicate that reliable in vitro measurements can be obtained in autopsy or surgical brain tissue specimens within 90 hours after death or excision, if handled properly.
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| 4. |
- Larsson, E. M., et al.
(författare)
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Regional differences in the proton magnetic resonance relaxation times T1 and T2 within the normal human brain
- 1986
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Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 0567-8056. ; 27:2, s. 231-234
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Forskningsöversikt (refereegranskat)abstract
- The proton magnetic resonance (MR) relaxation times T1 and T2 were determined in autopsy specimens from 13 different regions of normal human brains. One hundred and seventy-four tissue samples from 25 brains were examined in a pulsed MR analyzer of 0.25 T and were then also studied histologically. There were regional differences in T1 and T2 within the cerebral gray matter but not within the white matter. These regional differences might reflect the different composition and cytoarchitectonic structure of the cortical regions and should be taken into consideration in the interpretation of cortical lesions on MR images.
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| 5. |
- Belew, M, et al.
(författare)
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Structure-activity studies on synthetic analogs to vasoactive peptides derived from human fibrinogen.
- 1980
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Ingår i: Biochimica et Biophysica Acta. - 0006-3002 .- 1878-2434. ; 632:1, s. 87-94
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Tidskriftsartikel (refereegranskat)abstract
- Counterparts to two vasoactive peptides previously isolated from fibrin(ogen) degraded by plasmin (EC 3.4.21.7) were synthesized by the solid phase procedure. The synthetic undecapeptide (Ser-Gln-Leu-Gln-Lys-Val-Pro-Pro-Glu-Trp-Lys) was isolated in a homogeneous state by chromatography on Sephadex G-25 and DEAE-Sepharose CL-6B and the pentapeptide (Ala-Arg-Pro-Ala-Lys) by chromatography on BioGel P-6 and column zone electrophoresis. The effect of these two peptides and of fifteen analogs to the pentapeptide on microvascular permeability in rat skin was investigated. The two synthetic counterparts were as potent as the natural peptides. With respect to the analogs, the influence of different functional groups was first studied. This was followed by attempts to minimize the active structure, induce or relieve rigidity of the peptide back-bone or otherwise accomplish modifications by a change in chirality at critical positions. Our results show that the tetrapeptide Arg-Pro-Ala-Lys has the same effect on microvascular permeability as the pentapeptide in the assay system used. Basic amino acids at both ends, as well as a proline residue adjacent to the N-terminal amino acid appear important for full or essentially full activity. On the other hand, substitution of the Ala at position 4 with several other amino acids did not result in a significant loss in biological potency.
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| 10. |
- Lannering, Birgitta, 1948, et al.
(författare)
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Early onset group B streptococcal disease. Seven year experience and clinical scoring system.
- 1983
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Ingår i: Acta paediatrica Scandinavica. - 0001-656X. ; 72:4, s. 597-602
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Tidskriftsartikel (refereegranskat)abstract
- Early onset group B streptococcal disease was reviewed for the seven year period between 1975 to 1981 at Vanderbilt University Medical Center. One hundred and twenty cases were identified. The disease varied from asymptomatic bacteremia to fatal cardiopulmonary collapse. Factors associated with a poor outcome were prematurity, low Apgar score at 5 min, the presence of shock, leukopenia, rupture of membranes for more than 12 hours, and a delay in treatment after the onset of symptoms. A scoring system for probability of death based on these 6 factors was then developed. Over the seven year period mortality decreased from 50% to 10%. The only factor identified with the decrease in mortality was a significant decrease in the number of hours between the onset of symptoms and the beginning of treatment. Early recognition and prompt treatment seem to be the major causes of the decreasing mortality over the seven years of this report.
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