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Biomedical subjects

H Schild

Publications and source records attributed to H Schild.

At least 145 records · Page 8Linked to original sources

Estimation of sex on the basis of radiographs of the calcaneus.

Lateral and anteroposterior radiographs of the ankles of 800 Central Europeans aged 20 to 79 were analyzed with regard to sexual dimorphism. All the distances, but not the angles, of the calcaneus were much larger in males than in females. Approximately 80% of the study sample could be sexed correctly by classifying all specimens greater than 86.0 mm in length as male and those less than 86.0 mm as female. The prevalence of os tibiale externum was 8.0 and 2.6% and the prevalence of plantar heel spur was 16.3 and 6.5% (increasing with age) for males and females, respectively, being significantly more frequent in females. On the other hand, the bone island frequencies were 9.1% in males and 4.8% in females. Our study suggests that radiographs of the ankle are a convenient, rapid, cheap and non-invasive means for estimating sex.

Adult↗

Expression levels of stress protein gp96 are not limiting for major histocompatibility complex class I-restricted antigen presentation.

Immunization of mice with gp96 induces CTL with specificity for proteins that are expressed in the cells from which gp96 was isolated (Arnold et al., J. Exp. Med. 1995. 182: 885, Udono et al., Proc. Natl. Acad. Sci. USA 1994. 91: 3077). Recently, it has been shown that gp96 from cells transfected with vesicular stomatitis virus (VSV) nucleocapsid protein as well as gp96 loaded in vitro with peptides containing an epitope of this protein are taken up by phagocytic cells which obtain thereby the capacity for stimulating VSV-specific cytotoxic T lymphocytes (Suto and Srivastava, Science 1995. 269: 1585). The immunization experiments together with the peptide transfer from gp96/peptide complexes to major histocompatibility complex (MHC) class I molecules of phagocytic cells are consistent with the hypothesis that the endoplasmic reticulum-resident protein gp96 plays a crucial role in the antigen presentation of a cell (Srivastava et al., Immunogenetics 1994. 29: 93). To examine the involvement of gp96 in class I-restricted antigen presentation, we reduced gp96 RNA and protein levels by transfecting P13.1 cells with a vector containing part of gp96 cDNA in antisense orientation to the promotor. We found that antisense clones expressing strongly reduced levels of gp96 mRNA and gp96 protein show normal levels of MHC class I molecules on the cell surface and are recognized by T cells to the same extent as wild-type cells. Thus, our results show that normal levels of gp96 expression in a cell are not limiting for class I-restricted antigen presentation.

Amino Acid Sequence↗

Subacromial fat pad.

The subacromial fat was studied using cadaver dissections and Magnetic Resonance Imaging (MRI). We found that the subacromial fat is not loose connective tissue, but a fat pad surrounded by a fascia. The measurements of this fat pad are presented and the clinical relevance for orthopedics and radiology particularly for the impingement syndrome of the shoulder is discussed.

Acromion↗

[Magnetic resonance tomography of the kidney: the testing of new pulse sequences and comparison with CT in the differential diagnosis of space-occupying lesions].

PURPOSE: To evaluate new pulse sequences (turbo-spin-echo [TSE] and turbo-field-echo [TFE] sequences) for study protocol optimisation and to assess the role of MRI in the differential diagnosis of renal tumours. METHODS: In six volunteers MRI of the kidney was performed at 0.5 T using a conventional T2 weighted spin-echo (SE) sequence (TR/TE 1800/90 ms) and three different TSE sequences (TR 1800-5000 ms, TE 90-150 ms). Additionally CT and MRI was performed in 34 patients with 41 renal masses. Two readers evaluated both images regarding the differentiation between malignant and benign masses. RESULTS: The pilot study showed that the heavily T2-weighted TSE sequence (TR/TE 5500/150 ms) was superior to other sequences with regard to image quality and differentiation of the corticomedullary junction. In the clinical study malignant tumours were correctly classified with CT and MRI in 86.4% and 95.5% of the cases, whereas the accuracy in the diagnosis of benign lesions of CT and MRI was 73.7% and 89.5%, respectively. CONCLUSION: Using new puls sequences MRI is superior to CT in the differential diagnosis of renal tumours. MRI is superior to CT in the differentiation between complicated cysts and cystic or hypovascular renal cell carcinomas.

Diagnosis, Differential↗

[Endovascular balloon occlusion test of the internal carotid artery with increased hemodynamic monitoring for determination of circulatory reserve before planned carotid occlusion].

PURPOSE: To evaluate stroke risk assessment of balloon test occlusion of the internal carotid artery (ICA) with enlarged haemodynamic monitoring prior to permanent ICA occlusion. MATERIAL AND METHODS: 24 patients with cervical metastasis (n = 18), cavernous meningiomas (n = 3) or inoperable cavernous aneurysms (n = 3) were examined. The test occlusion was monitored by EEG, neurological examinations and transcranial Doppler sonography of the ipsilateral middle cerebral artery with evaluation of the cerebrovascular reserve capacity. Additionally 99mTc-HMPAO-SPECT imaging was added showing the perfusion during test occlusion. RESULTS: In one (4%) patient the test occlusion had to be interrupted previously due to an acute neurological deficit. This patient and two (8%) patients with highly pathological test results in SPECT and TCD were excluded from permanent carotid occlusion. In 6 (25%) patients quantitative TCD monitoring could improve the stroke risk assessment by differentiating the patients in a low and high risk group. 6 (25%) patients were definitely occluded without haemodynamic complications, but two patients suffered from embolic infarctions which cannot be predicted by this procedure. CONCLUSIONS: The multimodal balloon test occlusion with enlarged haemodynamic monitoring allows haemodynamic stroke risk assessment prior to permanent occlusion of the ICA.

Adult↗

[A new application of MR tomography of the lung using ultra-short turbo spin echo sequences].

PURPOSE: Development of an improved MR sequence for examining the lung. METHOD: T2 weighted ultra-short turbo spin echo sequences were used in five individuals with variations in echo times, delayed triggering and echo intervals. To reduce movement artifacts all examinations were carried out with ECG and respiratory triggering. The sequences giving optimal image quality were then employed in 19 patients having various pulmonary abnormalities. Image resolutions, artifacts, image contrasts and diagnostic value were then judged by two observers and compared with CT. RESULTS: In the first study, a diastole-triggered UTSE sequence with the shortest echo proved optimal (TE = 90 ms, TR = 2-4 s, echo = 9 ms, turbo factor = 19). In the patient series studied, MRT was inferior to CT with regard to resolution and number of artifacts, but better in respect of contrast and diagnostic value. CONCLUSION: Using UTSE of the lung, MRT can produce images of good quality. Compared with CT, contrast is better with MRT, offering diagnostic advantages for MRT.

Diagnosis, Differential↗

[Stent implantation as a palliative therapeutic measure in stenosing tumors of central airways].

PURPOSE: Stent implantation was used to treat patient with malignant tracheobronchial obstructions to determine the effectiveness in producing symptomatic palliation. METHODS: 18 patients (15 men and three women; median age 57 years) with malignant tracheobronchial stenosis were treated by application of metal stents (15 Palmaz-, 10 Gianturco-, 4 Wallstents). The indication for stent implantation was given in 13 patients by clinically significant dyspnea, besides in 5 patients by therapy resistant postobstructive pneumonia. RESULTS: In 17 patients correct positioning of the stents was achieved and the symptoms completely disappeared until tumor related death. Median survival was 137 days (min. 10 days to max. 322 days). In one patient symptoms recurred three months after stent implantation. CONCLUSION: The application of metal stents in patient with malignant tracheobronchial obstruction appears to be a useful palliation procedure. The treatment was well tolerated and very effective.

Adult↗

[Radiologically assisted percutaneous gastro-/enterostomy--a retrospective analysis of 90 procedures].

PURPOSE: To analyse retrospectively the indications, technique and results of radiologically induced gastrostomies or enterostomies. PATIENTS AND METHOD: Radiologically assisted gastrostomies or enterostomies were induced in 90 patients, mostly with high grade obstructions due to head and neck tumours or oesophageal tumours. 19/90 patients had had previous resection of the oesophagus or gastric operations. RESULTS: A catheter was successfully introduced in all patients. In 11/90 patients this was followed by a two-stage procedure. In 16/90 patients puncture was performed under CT control because of some anatomical peculiarity. Serious complication occurred in 9/90 patients but in only one was surgery necessary. There were no deaths resulting from the procedure but mortality after 30 days was 6.7%. CONCLUSION: Radiologically assisted gastrostomies or enterostomies are a reliable and effective form of treatment even amongst difficult patients. The results and complications are comparable to those from endoscopic procedures.

Adult↗

[Intramural hematoma of the thoracic aorta: diagnostic imaging and differential diagnosis].

PURPOSE: Aortic wall thickening due to intramural hemorrhage may be the only sign of aortic dissection. The aim of this study was to evaluate the incidence, imaging features and differential diagnoses of intramural hemorrhage (IMH) of the thoracic aorta. METHODS: 98 patients with clinically suspected aortic dissection were investigated via Spiral-CT and MRT. Diagnosis of IMH based on the presence of smooth crescentic or concentric wall thickening over a longer segment of the thoracic aorta without flow visualization and without compression or distortion of the aortic lumen. RESULTS: 69 patients had classic aortic dissections and 7 patients were diagnosed to have IMH of thoracic aorta. One patient with IMH of the ascending aorta died of aortic rupture and subsequent pericardial tamponade 12 hours after onset of symptoms. In one patient with IMH of the descending aorta on initial examination, there was a progression of overt aortic dissection at follow-up after three weeks. In two patients with IMH of the descending aorta, wall thickening decreased in size at follow-up (10-15 weeks), whereas in one patient it remained unchanged. CONCLUSION: IMH of the aorta should be considered a precursor of aortic dissection. At follow-up IMH may decrease in size, rupture or progress to overt aortic dissection.

Adult↗

The peptide binding specificity of the MHC class II I-A molecule of the Lewis rat, RT1.BI.

The specificity of peptide binding to MHC molecules is defined by binding motifs composed of several relatively conserved anchor positions. The peptide binding motifs of murine MHC class II I-A molecules are functionally important but poorly characterized. Here we use peptide binding studies and isolation of naturally presented peptides to characterize the peptide binding motif of the MHC class II I-A molecule, RT1.BI, a molecule that is involved in experimental autoimmunity in the Lewis rat. We now report that, similar to other class II motifs, the RT1.BI motif consists of a nonamer sequence with four major anchor positions (P1, P4, P6 and P9). Residues at P4 and P9, rather than at P1, appeared to be particularly important for binding. Negatively charged residues were favored at P9, consistent with the presence of a serine at position 57 of the RT1.BI beta chain. This RT1.BI motif could be observed in the dominant autoantigenic T cell epitopes mapped previously in the Lewis rat. These results highlight a general similarity and some important differences in the organization of MHC class II peptide binding motifs. The reported RT1.BI motif should facilitate the prediction and design of T cell epitopes for the induction and control of experimental autoimmune diseases in Lewis rat models.

Amino Acid Sequence↗

Aortic dissection: a comparative study of diagnosis with spiral CT, multiplanar transesophageal echocardiography, and MR imaging.

PURPOSE: To compare the usefulness of spiral computed tomography (CT), multiplanar transesophageal echocardiography (TEE), and magnetic resonance (MR) imaging in the diagnosis of thoracic aortic dissection and arch vessel involvement. MATERIALS AND METHODS: Forty-nine symptomatic patients with clinically suspected aortic dissection were examined with contrast material-enhanced spiral CT, multiplanar TEE, and 0.5-T MR imaging (T1-weighted, cardiac-gated, spin-echo sequences). Imaging results were confirmed at autopsy (five patients), intraoperative exploration (23 patients), angiography (nine patients), and follow-up (12 patients). RESULTS: Sensitivity in the detection of thoracic aortic dissection was 100% for all techniques. Specificity was 100%, 94%, and 94% for spiral CT, multiplanar TEE, and MR imaging, respectively. In the assessment of aortic arch vessel involvement, sensitivity was 93%, 60%, and 67%, respectively, and specificity was 97%, 85%, and 88%, respectively. CONCLUSION: Spinal CT and multiplanar TEE are as valuable as MR imaging in the detection of thoracic aortic dissection. In the assessment of the supraaortic branches, spiral CT is superior (P<.05).

Adult↗

[Stent implantation for the palliative therapy of upper inflow obstruction in bronchial carcinoma].

AIM OF STUDY: To analyse results obtained in the palliative treatment of obstruction of the upper inflow veins by stent implantation in patients with bronchial carcinoma. PATIENTS AND METHODS: Stents were implanted in 14 patients with upper venous obstruction due to bronchial carcinoma (three women, eleven men: mean age 64 [48-74] years), 4 of the superior vena cava (SVC), 6 of the SVC and brachiocephalic vein, 4 of the SVC and subclavian vein. To prevent thromboembolic phenomena all patients received heparin in therapeutic doses for 1-3 days from the time of stents implantation. RESULTS: Treatment was successful (regression of the clinical signs) in 12 of the 14 patients. Six patients died, without recurrence of the clinical signs, an average of 141 (10-420) days after the procedure. Mean survival time of the six patients who remained without symptoms was 3 months (longest interval 9 months). In one patient thrombotic occlusion of the SVC occurred 6 days after stent implantation. However, local thrombolysis successfully re-opened the vessel. Renewed upper vein obstruction occurred in two patients during follow-up. None of the stent filaments fractured and there was no stent dislocation. CONCLUSION: With a success rate of 86% stent implantation proved to be a sparing procedure in the palliative treatment of upper inflow vein obstruction, especially in patients with extensive malignant disease.

Aged↗

Cross-priming of minor histocompatibility antigen-specific cytotoxic T cells upon immunization with the heat shock protein gp96.

Vaccination of mice with heat shock proteins isolated from tumor cells induces immunity to subsequent challenge with those tumor cells the heat shock protein was isolated from but not with other tumor cells (Udono, H., and P.K. Srivastava. 1994. J. Immunol. 152:5398-5403). The specificity of this immune response is caused by tumor-derived peptides bound to the heat shock proteins (Udono., H., and P.K. Srivastava. 1993. J. Exp. Med. 178:1391-1396). Our experiments show that a single immunization with the heat shock protein gp96 isolated from beta-galactosidase (beta-gal) expressing P815 cells (of DBA/2 origin) induces cytotoxic T lymphocytes (CTLs) specific for beta-gal, in addition to minor H antigens expressed by these cells. CTLs can be induced in mice that are major histocompatibility complex (MHC) identical to the gp96 donor cells (H-2d) as well as in mice with a different MHC (H-2b). Thus gp96 is able to induce "cross priming" (Matzinger, P., and M.J. Bevan. 1977. Cell. Immunol. 33:92-100), indicating that gp96-associated peptides are not limited to the MHC class I ligands of the gp96 donor cell. Our data confirm the notion that samples of all cellular antigens presentable by MHC class I molecules are represented by peptides associated with gp96 molecules of that cell, even if the fitting MHC molecule is not expressed. In addition, we extend previous reports on the in vivo immunogenicity of peptides associated gp96 molecules to two new groups of antigens, minor H antigens, and proteins expressed in the cytosol.

Animals↗

Parosteal osteosarcoma of the talus.

A case of parosteal osteosarcoma in the very rare location of the talus is presented. The radiological, pathological, and clinical characteristics of parosteal osteosarcoma are described and the differential diagnosis discussed.

Adult↗

[The measurement of vascular diameter to determine stent and balloon size in percutaneous procedures in the pelvic circulation].

AIM: Should the sizes of balloons and stents used in the pelvic circulation be determined by the size of the ipsilateral or contralateral vessel? STUDY DESIGN: The angiographic findings in 31 patients were analysed; in 10 an occlusion and in 21 a high grade stenosis (greater than 75%) of the common iliac artery had been treated by stenting (26) or simple PTA (5). RESULTS: In 26 of the 31 patients there was marked reduction in the lumen distal to the lesion up to 40%. In 17 patients this was reversed immediately after the procedure and in five others the lumen increased but a difference between the two sides remained. The changes on the two sides following treatment were statistically significant (external iliac artery: p = 0.00013). CONCLUSION: The results indicate that the "normal" contralateral measurements should be used rather than the distal ipsilateral vessel diameter.

Adult↗

[Spiral computerized tomography, multiplane transesophageal echocardiography and magnetic resonance imaging in the diagnosis of thoracic aortic dissection].

The aim of this study was the evaluation of spiral computed tomography (Spiral-CT), multiplane transesophageal echocardiography (multiplane TEE) and magnetic resonance imaging (MRI) in the diagnosis of thoracic aortic dissection. 41 patients were examined: 30 with clinically suspected acute aortic dissection (14 Stanford A, 7 Stanford B), 11 with aortic repair (7/11 with persisting distal dissection). In 14 patients there was involvement of the supraaortic vessels. Sensitivity of Spiral-CT, multiplane TEE and MRI in the detection of aortic dissection was 100%, specificity was 100, 92, and 91%. In the assessment of involvement of aortic arch vessels sensitivity was 100, 67, and 60%, specificity was 100, 95, and 90%. The new imaging modalities Spiral-CT and multiplane TEE are equal to MRI in the detection of aortic dissection. In the assessment of the supraaortic branches Spiral-CT is superior to multiplane TEE and MRI and might become the method of choice.

Adult↗