| 1. |
- Li, M H, et al.
(författare)
-
MR imaging of intradural extramedullary tumors
- 1992
-
Ingår i: Acta Radiologica. - 1600-0455. ; 33:3, s. 207-212
-
Tidskriftsartikel (refereegranskat)abstract
- Thirty-one consecutive intradural extramedullary spinal tumors examined with MR at 0.3 T were reviewed. In 13 of the patients myelography had been performed. There were 11 patients with meningeoma, 14 with neuroma, one ependymoma, 3 metastases, and 2 lipomas. All tumors were surgically removed and verified by histology. The intradural extramedullary location of the tumors was accurately assessed by MR imaging in all patients and by myelography in 10 of 13. The MR diagnoses were in accordance with the histologic findings in 74% of cases. Compression of the spinal cord or cauda equina with widening of the subarachnoid space above and below the mass or outward displacement of epidural fat was characteristic of the intradural extramedullary tumors. The signal intensity of meningeoma as well as of neuroma was slightly lower or equal to that of the cord on T1-weighted images, and equal to or higher than cord signal on T2-weighted images. Neuroma had a lower signal intensity on T1-weighted images and a higher signal intensity on T2-weighted images than meningeoma. Meningeoma appeared more homogeneous than neuroma and had a broad base towards the dura.
|
|
| 2. |
- Li, M H, et al.
(författare)
-
MR imaging of spinal lymphoma
- 1992
-
Ingår i: Acta Radiologica. - 1600-0455. ; 33:4, s. 338-342
-
Tidskriftsartikel (refereegranskat)abstract
- Fourteen patients with spinal lymphoma examined by MR imaging were reviewed. Thirteen of them also had extraspinal lymphoma. Vertebral involvement was found in 12 patients, epidural in 10, and paraspinal in 8 patients. On the basis of MR imaging at 0.3 T, spinal lymphoma may be divided into three types of growth pattern according to the main location: paraspinal, vertebral, and epidural. Most frequently, all three locations were found simultaneously on MR (7/14). In one patient the location was vertebral with epidural extension, in one paraspinal with vertebral extension, in 3 it was entirely vertebral, and in 2 entirely epidural. Multiple plane T1-weighted imaging gave complete information about the extent of spinal lymphoma. The signal intensity was lower than or equal to muscle and lower than bone marrow in paraspinal and vertebral lesions on T1-weighted images and high on T2-weighted images. Epidural lesions showed a hypo- or isointense signal relative to the cord on T1-weighted images except in one case and a hyperintense signal on T2-weighted images. Compression of the cord and cauda equina due to bulging of diseased vertebral bodies and epidural lesions was well demonstrated. MR imaging was also found useful in the follow-up of treatment.
|
|
| 3. |
|
|
| 4. |
- Chachaty, C, et al.
(författare)
-
Influence of the polar head size on the dynamics of micellized surfactants
- 1991
-
Ingår i: Journal of Physical Chemistry A. - 1089-5639 .- 1520-5215. ; 95, s. 3830-3836
-
Tidskriftsartikel (refereegranskat)abstract
- The dynamics of micellized quaternary ammonium surfactants has been investigated by means of the frequency dependence of the 13C longitudinal relaxation rates. Trimethyl-, triethyl-, and tributyldodecylammonium bromides were used to systematically vary the bulk of the polar head and examine its influence on the internal and overall motions of the surfactants. The relaxation data were analyzed by means of the two-step model and of a rotational jump model relevant to the trans-gauche isomerizations about the bonds. In the case of the trimethyldodecyl--ammonium bromide an excellent agreement is obtained by the two-step model as the vicinity of the nitrogen is well above the values expected for methylene groups. The jump model shows that this behavior results from a slowing of the internal motions beyond the domain of validity of the two-step model.
|
|
| 5. |
- Grubin, C. E., et al.
(författare)
-
A novel radioligand binding assay to determine diagnostic accuracy of isoform-specific glutamic acid decarboxylase antibodies in childhood IDDM
- 1994
-
Ingår i: Diabetologia. - 0012-186X. ; 37:4, s. 344-350
-
Tidskriftsartikel (refereegranskat)abstract
- Insulin-dependent diabetes mellitus (IDDM) is associated with autoreactivity against GAD but the diagnostic sensitivity (positivity in disease) and specificity (negativity in health) of isoform-specific GAD antibodies have yet to be defined in assay systems suitable for screening large number of samples. One set of IDDM patient (n=10) and control (n=50) standard sera were used to develop quantitative antibody assays with in vitro synthesized recombinant 35S-methionine-labelled GAD65 and GAD67, respectively, and protein A-Sepharose to separate free from antibody-bound ligand. Binding levels were not normally distributed (p<0.0001) and therefore, the diagnostic accuracy of GAD antibodies was analysed by the ROC plots in population-based, consecutively-diagnosed, recent onset, 0-14 year-old patients (n=105), and matched, healthy control subjects (n=157). The ROC plots showed that the diagnostic sensitivity of GAD65 antibodies was 77% and the specificity 92% compared with 8% and 98%, respectively for GAD67 antibodies. In the IDDM sera, GAD65 and GAD67 antibodies were concordant in 7% (6 of 81) and GAD65 antibodies and ICA in 89% (72 of 81) without a correlation between the autoantibody levels. Autoantibodies to recombinant human islet GAD65 are specific and sensitive markers for childhood IDDM in this immunoassay with in vitro synthesized 35S-methioninelabelled recombinant GAD.
|
|
| 6. |
- Jansson, M, et al.
(författare)
-
Aggregation in tetraalkylammonium dodecanoate systems
- 1991
-
Ingår i: Colloids and Surfaces. - 0166-6622 .- 1873-4340. ; 59, s. 387-397
-
Tidskriftsartikel (refereegranskat)abstract
- Aggregation in some different tetraalkylammonium dodecanoate systems has been studied. The influence of counterions on the phase behaviour of both binary surfactant/water systems and more complicated, multi-component systems were investigated, by applying NMR self-diffusion and Langmuir Blodgett techniques. Increasing the size of the tetra_x001F__x001F_alkylammonium counterions was found to lead to a substantial reduction of the critical micelle concentration. This is due to increased ion-micelle interactions associated with the enhanced hydrophobicity of the larger counterions. Furthermore, the increase in the ion size was found to be correlated with a depression of the tendency of the surfactant to form aggregates with low surface curvature, such as liquid-crystalline phases and rod-like micelles. The importance of the counterion size with regard to the formation of microemulsions in surfactant/water/oil systems was also demonstrated.
|
|
| 7. |
- Kim, Y J, et al.
(författare)
-
A multiprotein mediator of transcriptional activation and its interaction with the C-terminal repeat domain of RNA polymerase II.
- 1994
-
Ingår i: Cell. - 0092-8674 .- 1097-4172. ; 77:4, s. 599-608
-
Tidskriftsartikel (refereegranskat)abstract
- A mediator was isolated from yeast that enabled a response to the activator proteins GAL4-VP16 and GCN4 in a transcription system reconstituted with essentially homogeneous basal factors and RNA polymerase II. The mediator comprised some 20 polypeptides, including the three subunits of TFIIF and other polypeptides cross-reactive with antisera against GAL11, SUG1, SRB2, SRB4, SRB5, and SRB6 proteins. Mediator not only enabled activated transcription but also conferred 8-fold greater activity in basal transcription and 12-fold greater efficiency of phosphorylation of RNA polymerase II by the TFIIH-associated C-terminal repeat domain (CTD) kinase, indicative of mediator-CTD interaction. A holoenzyme form of RNA polymerase II was independently isolated that supported a response to activator proteins with purified basal factors. The holoenzyme proved to consist of mediator associated with core 12-subunit RNA polymerase II.
|
|
| 8. |
- Li, M H, et al.
(författare)
-
MR imaging of spinal intramedullary tumors
- 1991
-
Ingår i: Acta Radiologica. - 1600-0455. ; 32:6, s. 505-513
-
Tidskriftsartikel (refereegranskat)abstract
- The MR examinations in 25 patients with intramedullary tumors were analyzed. Seven patients were diagnosed with astrocytoma, 6 ependymoma, 2 unspecified glioma, 3 medulloblastoma, 2 metastasis, one neurinoma, and one teratoma. In 3 patients the diagnosis was uncertain. The tumors frequently involved a large portion of the cord and were often accompanied by intratumor necrosis, cystic degeneration, and edema, which was well demonstrated on MR. Gd-DTPA was used in 6 patients and was helpful in separating solid tumor components from cysts and edema. It was difficult to separate different kind of tumors based on morphologic and signal characteristics on MR. Some prominent features could, however, be distinguished. Complete cystic degeneration was more common in astrocytomas than in other tumors, and ependymomas frequently had a heterogeneous signal pattern on both T1- and T2-weighted sequences. The single teratoma had a characteristic content of fat and calcification, and the melanoma had a signal pattern consistent with blood. CSF pathway spread in cases of medulloblastoma was demonstrated by ill-defined contour of the cord and CSF or tumor nodules on the surface of cord and nerve roots.
|
|
| 9. |
- Li, M H, et al.
(författare)
-
MR imaging of spinal neurofibromatosis
- 1991
-
Ingår i: Acta Radiologica. - 1600-0455. ; 32:4, s. 279-285
-
Tidskriftsartikel (refereegranskat)abstract
- The MR findings in 7 patients with neurofibromatosis involving the spine were evaluated. Six patients had paraspinal tumors at multiple levels. In 4 they were bilateral. Five patients had multiple intraspinal lesions, frequently with growth through the neural foramen. In one patient paraspinal tumors were found in the lumbar sacral plexus and in another bony dysplasia and meningoceles but no tumors were disclosed. In 2 patients the lesions were associated with bilateral acoustic neuromas and multiple intracranial meningeomas. In one of these a spinal meningeoma with signal characteristics close to spinal cord was found. The other tumors had a signal that was equal to or slightly lower than the spinal cord and slightly higher than muscle on T1-weighted images. On T2-weighted images the tumors had a markedly increased signal compared to surrounding tissue. In 3 patients with tumors larger than 4 cm the signal intensity was inhomogeneous with decreased signal in the center on T2-weighted images, indicating the presence of increased fibrous tissue. Gadolinium-DTPA was given to one patient with marked increase in intensity of small tumors on T1-weighted images. The study shows that MR imaging is the modality of choice for evaluating most aspects of spinal and paraspinal neurofibromatosis.
|
|
| 10. |
- Li, M H, et al.
(författare)
-
MRI of extradural spinal tumours at 0.3 T
- 1993
-
Ingår i: Neuroradiology. - 1432-1920. ; 35:5, s. 370-374
-
Tidskriftsartikel (refereegranskat)abstract
- Ninety-one patients with extradural spinal tumours were examined by magnetic resonance imaging. There were 76 metastases (6 from unknown primary tumours). Seven patients had primary spinal tumours and 8 had multiple myeloma. Sixteen had bulging, diseased vertebral bodies compressing the subarachnoid space and 67 had extradural tumour compressing the spinal cord. Sixty patients had paravertebral involvement. Intraspinal involvement did not correlate with the extent of spinal lesions. All patients had vertebral destruction, with hypointense or combined hypo- and isointense signal relative to bone marrow on T1-weighted images. In most of the 22 patients with T2-weighted images the tumours were isointense or slightly hyperintense. It was usually impossible to differentiate the various tumours on the basis of signal intensity and morphology. However, metastases from carcinoma of the prostate were often more hypointense than other tumours on T1- and T2-weighted images. An inhomogeneous pattern in which diffusely low signal is combined with focal lower signal on T1-weighted images may suggest myeloma. In the 22 patients examined with both T1- and T2-weighted images, T1-weighted images gave the best information in 18; in 3 they were equivalent and in 1 inferior to T2-weighted images; they are therefore recommended for routine imaging of epidural spinal tumours.
|
|
