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Biomedical subjects

B Sander

Publications and source records attributed to B Sander.

At least 109 records · Page 6Linked to original sources
PubMed1990

Ultrastructural localization of WGA, RCA I, LFA and SBA binding sites in the seven-day-old mouse embryo.

In the present investigation we localized binding sites for the lectins WGA (wheat germ agglutinin), RCA I (Ricinus communis agglutinin), LFA (Limax flavus agglutinin) and SBA (soya bean agglutinin) in the 7-day-old mouse embryo at the ultrastructural level. Lectin binding sites were localized on formaldehyde fixed embryos, embedded in LR-Gold, using gold-labelled lectins. Binding sites for WGA and RCA I were observed at the surface of the embryonic ectoderm oriented towards the proamnion cavity and the outer surface of the extraembryonic and the embryonic endoderm. Staining for SBA and LFA binding sites was seen in the basement membrane of the ectoderm. Moreover, binding sites for LFA were observed in the nucleoli of cells of the ectodermal, the mesodermal and the endodermal layer and in free ribosomes located in the cytoplasm of these cells.

Animals↗
PubMed1990

Intracranial meningiomas: how frequent are indicative findings in CT and MRI?

Frequencies of CT and MRI findings characteristic of meningiomas were compared in 50 cases. Plain and contrast enhanced examinations with CT and MRI were evaluated retrospectively regarding 12 criteria known to be indicative of the diagnosis of meningiomas. CT proved to be superior in demonstrating calcifications and a typical tumor density. On the other hand. MRI was better suited for identifying the extraaxial location of tumors, the broad contact of tumors to the meninges, tumor capsules and meningeal contrast enhancement adjacent to the tumor. Both methods provided nearly equal results in demonstrating mass effects, hyperostoses, intensive and homogeneous contrast enhancement, and smooth tumor contours after contrast administration. On the whole, neither of the two methods demonstrated a universal superiority for the diagnosis of intracranial meningiomas. Rather, each method displayed distinct advantages.

Adult↗
PubMed1990

Multiple slice FLASH imaging: an improved pulse sequence for contrast enhanced MR brain studies.

A multisclice gradient echo sequence (FLASH) was compared with a conventional spin-echo (SE) technique with regard to its value for contrast enhanced brain studies. In 50 patients with contrast enhancing intracranial lesions, MR studies (0.5 Tesla MR tomograph) were performed with SE images (SE 400/30; four images/3.4 min) and FLASH scans (FLASH 315/14, 90 degrees; 15 images/1.4 min) before and after Gd-DTPA. Based on visual and quantitative assessment diagnostic results of postcontrast SE- and FLASH images were equivalent with respect to contrast enhancement, lesion/brain-contrast, lesion/edema-contrast, and lesion delineation. Although image quality generally was excellent on postcontrast FLASH images, susceptibility artifacts were more severe on FLASH scans than on SE images. However, with the exception of postoperative patients with artifacts due to metal remains, diagnostic information was not decreased by artifacts on postcontrast FLASH images. In conclusion, because of the clearly higher efficiency of the multisclice FLASH technique, this pulse sequence offers the opportunity to speed up contrast enhanced brain imaging.

Adult↗
PubMed1990

[MRI of the cervical spine using T1-weighted multislice FLASH sequences].

A study has been carried out to evaluate contrast and image quality of cervical structures using multislice 2D-flash sequences with long repetition times (TR = 400 ms.) and short echo delay times (TE = 5.8 ms.). The examinations were carried out using ten normals with an MRI of 1.5 Tesla and flip angles of 10, 20, 30, 50, 70 and 90 degrees. The best contrast between intervertebral disc and surrounding tissue was obtained between 50 and 70 degrees, best contrast between compact bone and CSF with 10 degrees. In order to demonstrate degenerative changes of the cervical spine, it appears sensible to use a combination of these angles. The described sequences produce good images of the cervical structures with little image degradation. Compared to T1-weighted spin-echo sequences, the method has a number of significant advantages, such as variations in image contrast, higher maximal number of slices, contiguous imaging and less imaging time.

Adult↗
PubMed1990

[A NMR tomographic follow-up assessment of the replacement plastic repair of the anterior cruciate ligament with an autologous ligamentum patellae transplant].

Reconstruction of the anterior crucial ligament can be performed by using an autogenous transplant from the patellar ligament. Employing postoperative MR investigation, reaction of the non-vascularised tendon was studied. In 16 patients 20 knees were investigated by applying a 1.5 tesla magnet with T1-weighted (TR 500 ms, TE 15 ms) and a T2*-weighted (FISP 3D: TR 30 ms, TE 10 ms, flip angle 40 degrees). Postoperative MR follow-up showed an increase in signal intensity and diameter in T1-weighted images. This represents revascularisation of the transplant.

Anterior Cruciate Ligament↗
PubMed1990

[Magnetic resonance tomographic differentiation of ocular muscle changes in endocrine orbitopathy].

In 50 patients with Graves' Ophthalmopathy and 9 controls both orbits were examined by MR Imaging at 0.5 Tesla using a surface coil. T1-weighted spin-echo images were obtained in transverse and coronal orientation; additionally, a T2-image was calculated from a multi-echo sequence (8 echoes). Signal intensity of eye muscles on both T1-weighted and T2-weighted MR images was evaluated qualitatively. T2-times were then calculated for all inferior rectus muscles. Eye muscle enlargement was found in 28 out of 50 patients. T2-times of inferior rectus muscles in stage III and IV patients were evaluated significantly (p less than 0.05). Areas of high signal intensity were accordingly found in enlarged eye muscles in 19 out of 50 patients; they were interpreted as edematous tissue changes. Areas of low signal intensity were found in enlarged eye muscles of 5 out of 50 patients; these eye muscles were considered fibrotic. Differentiation of eye muscle changes by MR imaging might help to decide between antiinflammatory medication and surgical therapy in patients with Graves' Ophthalmopathy.

Adolescent↗
PubMed1990

[Polymerization shrinkage of light-hardened composites].

The absolute values of polymerization shrinkage and its time-dependent course were measured for commercially available visible-light-cured composite resins and for composite still under development. About the curing rate of the composites were discussed the influences of the fillers and of the amount of the photoinitiator in the organic matrix.

Composite Resins↗
PubMed1990

[Magnetic resonance tomography of adrenoleukodystrophy].

Adrenoleucodystrophy (ALD) is an uncommon, sex-linked disease, characterised by the accumulation of very long-chain fatty acids in various tissues. There is a great predilection for young boys between the age of three and ten years. The disease ends fatally after a clinical course of several years. The clinical and MR findings of a child with typical ALD are presented. T2-weighted MR demonstrates confluent, symmetrical, hyperintense lesions of the occipital white matter bilaterally. After the application of Gd-DTPA, contrast enhancement is seen in the margins of the lesions indicating active demyelination. MR is recommended as imaging modality of choice in patients with suspected or confirmed diagnosis of adrenoleucodystrophy.

Adrenoleukodystrophy↗
PubMed1989

Detection of individual interleukin 2-producing cells after anti-CD3 antibody activation.

A new intracytoplasmic immunofluorescence staining technique to detect and quantify human interleukin-2 (IL-2)-producing lymphocytes is described. Blood mononuclear cells (MNC) were cultured and stimulated by mitogenic anti-CD3 antibody to produce IL-2. The cells were then fixed and subsequently permeabilized in suspension by the detergent saponin. Cytoplasmic IL-2 could then be demonstrated using polyclonal IL-2 specific antibodies and indirect immunofluorescence staining. A characteristic morphology of the IL-2 staining was noted with a local circle-shaped accumulation in the cytoplasm in a perinuclear position, probably reflecting the presence of the lymphokine in the Golgi stacks. A rapid, but transient IL-2 production peak 6 h after initiation of the cultures was observed. Only 1% of the cells produced IL-2, but each IL-2 stained cell was very bright, indicating a low capacity of anti-CD3 antibody to induce IL-2 production rather than an insensitivity of our detection system. Of the IL-2-producing cells 90% were CD4-positive T cells and 10% were CD8-positive T cells as revealed by two-colour staining of cell surface antigens and cytoplasmic IL-2.

Antibodies, Monoclonal↗
PubMed1989

[Improvement of MR tomography of the liver using a multislice gradient echo sequence].

A prospective study of 52 patients with various focal liver lesions was carried out using a multislice-gradient echo sequence and this was compared with spin-echo sequences. The multislice-gradient echo sequence provides the possibility of obtaining heavily T1-weighted images of the entire liver during one examination, thereby reducing the time of the examination. Contrast is significantly better than that of a T1-weighted spin-echo sequence (p greater than 0.05). The multislice-gradient echo sequence examination, taking 5.4 minutes, provides good and diagnostically useful image quality.

Adult↗
PubMed1989

[Psychomotor epilepsy--a comparison of CT and MR in 100 patients].

The value of CT and MR was studied in 100 patients with temporal lobe epilepsy. Axial CT scans were obtained before and after contrast injection. Coronary MR scans were carried out with T1-(SE 400/30, GE 315/14) and T2-weighted sequences (SE 1600/30 + 70). A circumscribed lesion was demonstrated in fifteen patients by CT and in 25 patients by MR. With the exception of a small area of calcification, all lesions seen on CT could also be recognized on MR. In four patients CT, MR and pathologic specimen could be compared following partial resection of temporal lobe. Localized glial reactions, which were not seen on CT, produced a signal difference on MR. Better sensitivity and improved demonstration of the temporal lobes makes MR the method of choice in the diagnosis of temporal lobe epilepsy.

Adolescent↗
PubMed1989

[Subacute cerebral infarct: native and contrast medium-enhanced MRT].

Twenty-five patients with clinical and CT findings indicating supratentorial cerebral infarct were prospectively studied with MR. MR examinations were performed between the 3rd and 150th day after stroke. T2-weighted axial images were compared with T1-weighted sequences after i.v. administration of Gd-DTPA. T2-weighted images demonstrated parenchymal lesions in all 25 patients. Postcontrast T1-weighted images, however, displayed pathologic contrast enhancement in only 19 areas of infarction. In 5 of the 25 patients, the use of Gd-DTPA provided additional diagnostic information by demonstrating gyral contrast enhancement as a pattern typical for ischemia. In 2 of the 25 patients, pathologic contrast enhancement was observed in an area that was isointense to the surrounding brain tissue on the T2-weighted images. In one patient, Gd-DTPA improved differentiation between areas of subacute and chronic infarction. At present, in the patient with suspected cerebral infarction, MR imaging after i.v. administration of Gd-DTPA appears recommended when clinical findings and CT are equivocal.

Acute Disease↗
PubMed1989

[Malignant chest wall infiltration in MR: comparison with CT and surgical findings].

CT and MRI were performed on 19 patients with pleura related thoracic tumors with respect to the detection of chest-wall invasion. All patients underwent surgery, which confirmed malignant infiltration in 16 cases, while this was excluded in three. CT showed chest-wall invasion in 12/19 patients. MRI demonstrated tumorous involvement in 16 patients. A reliable pattern of chest-wall invasion in MRI were high signal intensity lesions within the chest-wall in the T2-weighted images. However, increased signal intensity of pleural structures was found in inflammatory as well as in malignant lesions. MRI can prove the presence of chest-wall invasion when CT is equivocal.

Adult↗
PubMed1989

Detection of individual interleukin 4- and gamma interferon-producing murine spleen cells after activation with T-cell mitogens.

Murine spleen cells were activated with concanavalin A (Con A), pokeweed mitogen (PWM), or phorbol myristate acetate (PMA) and the calcium ionophore A23187. Cells producing gamma interferon (IFN-gamma) or interleukin 4 (IL-4) could be detected by lymphokine-specific monoclonal antibodies and indirect immunofluorescence. The frequency and kinetics of the lymphokine-producing cells were examined and were approximately the same after stimulation with Con A or PMA and A23187. Thirty hours after activation, 3-9% of the cells produced IFN-gamma. There were few IL-4-producing cells, and the maximal frequency was 1 out of 400 spleen cells 48 h after activation. When the cells were activated with PWM, the frequency of IFN-gamma-producing cells was still high 72 h after culture. The majority of the IFN-gamma-producing cells were CD8+ and expressed receptors for IL-2.

Animals↗
PubMed1989

Graves ophthalmopathy: MR imaging of the orbits.

Thirty-nine patients with Graves ophthalmopathy were examined with magnetic resonance (MR) imaging at 0.5 T with use of a surface coil. T1- and T2-weighted spin-echo images were obtained, and T2 relaxation times of eye muscles and retrobulbar fat were calculated from a multiecho sequence. Normal values for T2 relaxation times of eye muscle were obtained by examining nine control subjects. MR imaging demonstrated eye muscle enlargement in 23 patients. Visual examination of T2-weighted and calculated T2 images showed areas of high signal intensity in enlarged eye muscles of 12 of 23 patients. Calculated T2 relaxation times of eye muscles differed significantly between control subjects and patients with stage III and IV disease. Signal intensity characteristics of these changes, as well as their correlation with well-known histologic findings, suggested their interpretation as edema caused by acute inflammation. Since computed tomography is not able to depict eye muscle edema, the MR findings of structural changes within enlarged eye muscles might have an impact on therapeutic decisions concerning the application of anti-inflammatory drugs.

Adult↗
PubMed1989

[The effect of x-ray contrast media on magnetic resonance tomography of the spinal canal].

The effects of x-ray contrast media on signal intensities were studied. Relaxation times of myelographic contrast media were measured. Whereas relaxation times of Amipaque were longer, compared to CSF, the relaxation times of Duroliopaque, Omnipaque und Solutrast were significantly shorter than that of CSF. Therefore, the qualitative and quantitative effects of different contrast media on signal intensities varied. Most notable was the increase of signal intensity on T1-weighted images due to oily contrast media.

Contrast Media↗
PubMed1989

[A new multislice gradient echo sequence for magnetic resonance tomography of the liver].

A multislice gradient echo sequence was developed for screening the liver and examined in studies on probands. This sequence is characterized by pronounced T1-weighting and low susceptibility to artifacts as well as a good contrast-to-noise ratio. Examination of the probands yielded suitable parameters for the repetition time, the delay echo, the excitation pulse angle and the number of data acquisitions. The optimized sequence yields, at a repetition time of 306 msec and an echo delay of 12 msec, 18 adjacent slices. With these measurement parameters an excitation pulse angle of 90 degrees was found to be adequate. Four data acquisitions (5.4 minutes measurement time) resulted in an effective reduction of motion artifacts. Compared with the T1-weighted spin echo sequences, the entire liver can be measured in half the time when using the multislice gradient echo sequence.

Humans↗