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Biomedical subjects

H Schild

Publications and source records attributed to H Schild.

323 records · Page 18Linked to original sources
PubMed1981

[Special fractures of the capitulum humeri (author's transl)].

Whenever radiographs in the elbow region do not present a clear picture, the physician should consider the possibility of a lesion of the capitulum humeri, despite the fact that this is rather rare. In such cases, the anteroposterior radiographs of the elbow may not present any abnormal findings. In most cases, crescent-shaped or elliptic bone chips in the bend of the elbow or dorsally in the interarticular space of the elbow joint will lead to the proper diagnosis. Classification into groups according to Hahn-Steinthal, Kocher-Lorenz and Krösl can lead to errors if employed too rigidly. In our opinion, lateral tomography of the elbow should always be performed whenever there is any suspicion of a lesion of the capitulum humeri. This will definitely clarify the origin and nature of the fragment, which may be of importance for the selection of the surgical approach and the type of surgical treatment chosen.

Adult↗
PubMed1981

[The trapezium bone--anatomy, radiography and traumatology].

Due to the functional peculiarities of the thumb, fractures of the trapezium are of importance, though being rather rare. Difficulties are often encountered with radiological demonstration and anatomical correlation of findings in this area. The article gives an anatomical-radiological correlation and points out aspects of traumatology.

Carpal Bones↗
PubMed1980

[Focal nodular hyperplasia (author's transl)].

Focal nodular hyperplasia was diagnosed angiographically in 14 patients and confirmed histologically. Differentiation of this benign lesion from other space-occupying diseases of the liver can be very difficult, since focal nodular hyperplasia produces a variable angiographic appearance. The typical angiogram showing radial vessels in the arterial phase and sharply demarcated foci in the parenchyma phase is found in only one third of patients. Angiographic differential diagnosis includes adenomas and carcinomas of the liver. Resection of the tumours in case of malignant tumours is not indicated. Foci at the margin of the liver, or if they are pedunculated, should be removed in case of spontaneous perforation. Tumours in the centre of the liver should be observed (computer tomography). Oral contraceptives stimulate the growth of these foci. They may diminish in size after stopping these drugs. 70% of cases of focal nodular hyperplasia remain clinically silent and were discovered accidentally or at autopsy.

Adenoma↗
PubMed1978

[Changes in liver haemodynamics after mesenterico-caval dacron prosthesis anastomosis ("H-shunt") in portal hypertension (author's transl)].

In fourteen patients with portal hypertension and bleeding from oesophageal varices, mesentericocaval anastomoses using a dacron-velour prosthesis ("H-shunt") were carried out. Evaluation of the haemodynamics showed: 1. Comparison of 13 pre- and post-operative angiograms showed an haemodynamicically effective shunt in 12 and a stenosed shunt in one. 2. The aim of relieving the portal circulation while maintaining antegrade portal flow was achieved in six patients. 3. In six patients, the portal vein was not seen in a splenic or mesenteric portogram despite an open shunt. Functionally, this corresponds to a porto-caval anastomosis. 4. Pressure reduction in the portal circulation can be so marked as to obtain retrograde portal flow from the hepatic artery. 5. If the portal blood flow through the liver disappears, the hepatic artery may obtain additional flow from the superior mesenteric artery (reversed flow in the gastroduodenal artery). 6. Increased arterial flow to the liver is made possible by a reduction in intrahepatic resistance. The role of collaterals, either arterio-portal shunts or shunts between the sinusoids, is discussed. 7. The hepato-fugal collateral circulation was reversed in twelve patients.

Adult↗
PubMedDate not supplied

Enhancement efficacy of magnetic starch microshperes (MSM) in conventional spin-echo and turbo spin-echo sequences at 0.5 T and 1.5 T.

The efficacy of the superparamagnetic contrast agent magnetic starch microspheres (MSM) was evaluated in vitro by NMR relaxometry and in vivo by MR imaging using T2-weighted spin-echo (SE) and turbo spin-echo (TSE) sequences at 0.5 T and 1.5 T in 60 normal rats who received MSM in doses of 10-50 mu mol/kg. MR imaging was performed using T2-weighted SE and TSE sequences. The relaxation rates 1/T1 and 1/T2 for liver and spleen increased linearly with MSM concentrations up to 30 mu mol/kg body weight, and approached almost constant levels for higher doses. The slopes in the linear part of the 1/T2 diagram were 0.62 Hz +/- 0.03 for the liver and 0.51 Hz +/- 0.06 x kg/mu mol for the spleen. On all T2-weighted sequences at 0.5 T and 1.5 T, liver signal-to-noise ratio (SNR) decreased by a factor of 2-3 already at the lowest dose of 10 mu mol/kg. SNR values of TSE sequences exceeded values for SE sequences by 50-80%. The SNR decrease was not significantly different between SE and TSE sequences. Our results show that MSM is well suited as a T2 contrast agent at both magnetic field strengths when using conventional SE and fast TSE sequences.

Animals↗
PubMedDate not supplied

Gianturco self-expanding stents: clinical experience in the vena cava and large veins.

Twenty-five patients with stenosis of the vena cava (21) and other large veins (4) have been treated with self-expanding Gianturco metallic stents. Eighteen patients had superior vena cava syndrome. In 17, the stricture was due to malignant superior vena cava compression recurrent after maximum tolerance radiotherapy and/or chemotherapy. In 16 of these patients there was early symptomatic relief. In 1 patient with a benign posttraumatic superior vena cava stricture, the stenosis was not relieved, and occlusion occurred after 1 month. Stenoses associated with dialysis shunts were relieved in 2 other patients. Two malignant and one benign inferior vena cava stenoses were relieved either until death, or in the benign case, for 30 months. One malignant subclavian vein obstruction occluded after 24 h due to stent misplacement and another with extrinsic mediastinal compression remained patent until death, extensive thrombus having been lysed prior to stent placement. The results of this short series suggest that the Gianturco self-expanding stent in the vena cava and large veins is easy and safe to place, and in most cases produces almost immediate palliation of the distressing effects of venous obstruction, often in a preterminal and inoperable patient.

Constriction, Pathologic↗
PubMedDate not supplied

Evaluation of polyurethane nasolacrimal duct stents: in vivo studies in New Zealand rabbits.

The purpose of this study was to evaluate the radiographic and biological effects of different polyurethane nasolacrimal duct stents in an animal model. Fifteen polyurethane nasolacrimal duct stents (n = 5 mushroom-type stents, n = 5 newly designed S-shaped TearLeader stents without hydrophilic coating, and n = 5 S-shaped TearLeader stents with hydrophilic coating) were implanted in the nasolacrimal ducts of eight unaffected New Zealand rabbits. One nasolacrimal system served as control. Clinical and radiographic follow-up was performed at 1-, 2-, and 4-week intervals, then after a 3-month interval, after which the animals were euthanized. All stents were implanted without major periprocedural complications. The stents proved to be patent by the end of the procedure. During follow-up, all mushroom-type stents were occluded at 4 weeks. None of these stents opened to forced irrigation. Clinically, all rabbits demonstrated severe dacryocystitis. Three out of five TearLeader stents without hydrophilic coating were blocked at 4 weeks; one out of five was open to irrigation. Best results were observed in the stent group with hydrophilic coating. Follow-up dacryocystography demonstrated patent stents in nasolacrimal ducts of all animals after 4 weeks. In only one of five cases, the coated stent became partially occluded after 2 months. These animals were free of clinical symptoms. After 3 months, at least three out of five stents still opened to forced irrigation and only one stent was completely blocked. Dislocation of the stents was not observed. Refinement of the stent surface and stent design improves the results of nasolacrimal duct stenting in this animal model. Implantation of hydrophilic-coated S-shaped stents is highly superior to conventional mushroom-type stents and noncoated stent types. Hydrophilic coating seems to prevent foreign-body reactions, resulting in maximized stent patency.

Animals↗
PubMedDate not supplied

[Transverse skeletal axes of the lower extremity in coxarthrosis].

Femoral anteversion, anteversion of the acetabulum and tibial torsion of 47 patients with idiopathic osteoarthritis of the hip were determined by computerized tomography. From all these parameters only the anteversion of the acetabulum showed differing values in hips with and without osteoarthritis. There was a considerable range at the individual measured values in all parameters and differences between the male and female groups could be found in femoral anteversion and anteversion of the acetabulum.

Biomechanical Phenomena↗
PubMedDate not supplied

The heat shock protein Gp96 links innate and specific immunity.

Among other heat shock proteins (HSPs), the ER-resident chaperone Gp96 has been described as a potent tumour vaccine in animal models. A growing list of data underlines that Gp96 triggers both arms of pathogen defence-innate and specific immunity-in a synergistic and most efficient way: It enables specific immune responses by transferring immunogenic peptides that have been acquired in the ER to the MHC class I pathway of antigen presenting cells (APCs). For this, two important features of Gp96 are required. First, its ability to bind immunogenic peptides. Secondly, its acquisition by specialized antigen presenting cells capable of inducing cellular immune responses. Due to specific receptors on the surface of APCs, this uptake from the extracellular space occurs very efficiently and rapidly. Serving the innate branch of immunity, Gp96 unspecifically activates APCs, which then provide a pro-inflammatory cytokine milieu and co-stimulation to cytotoxic T cells. Thus, Gp96 uses all resources of the immune system to trigger cytotoxic T cell responses against associated peptides.

Animals↗
PubMedDate not supplied

Magnetic resonance spectroscopic and relaxometric determination of bone marrow changes in anorexia nervosa.

OBJECTIVE: The objective of this study was to assess and quantify bone marrow changes in patients with anorexia nervosa using 1H magnetic resonance spectroscopy and relaxometry. METHODS: The bone marrow fat fraction and the longitudinal and transverse relaxation times (T1 and T2, respectively) of water were measured in the lumbar and femoral marrow of 20 patients with anorexia nervosa and 19 healthy control subjects. RESULTS: Patients with anorexia nervosa showed significant hyperhydration and reduction of the fat fraction in their bone marrow, predominantly in the proximal femur. These changes were associated with hematological abnormalities. In a retest of seven patients after psychotherapy and gain of weight, the pathological changes in marrow proved to be largely reversible in correlation with the increase in body mass index. CONCLUSIONS: Fat depletion and excess of tissue water in the bone marrow in anorexia nervosa can be quantified by 1H magnetic resonance spectroscopy and relaxometry. The distribution of the pathological changes in the lumbar and femoral marrow follows the pattern of normal bone marrow conversion from hematopoietic to cellular during childhood.

Adolescent↗
PubMedDate not supplied

[Magnetization transfer contrast (MTC): optimizing off-resonance and on-resonance frequency MTC methods at 0.5 and 1.5 T].

AIM: To compare technical parameters and clinically relevant aspects of on- and off-resonance MTC sequences in mid- and high-field MR systems. MATERIAL AND METHODS: Both on- and off-resonance techniques were combined with an FFE sequence using 0.5 and 1.5 Tesla superconducting systems. Parameters were systematically measured by scanning a cadaveric knee joint. Signal-to-noise ratios and MT ratios for fat, cartilage and reference solution (copper sulphate) were determined. Minimal TR and the energy absorption rate were also compared. RESULTS: The MT effect at 1.5 T was more pronounced. However, using optimized parameters, clinically adequate MT contrast was achieved with both techniques and both MT units. The most important parameters for the off-resonance method are pulse angle and off-centre frequency; for the on-resonance method, pulse angle and number of composite pulse elements. Energy absorption was below 2 W/kg. Minimal TR was prolonged by up to 400%. CONCLUSION: In order to produce MTC images, optimized parameters should be applied. Using optimized pulse parameters, adequate MTC imaging is achievable with mid- and high-field systems using on- and off-resonance techniques. To ensure comparability of MTC studies, the pulse parameters need to be given, and, ideally, standardized.

Arterial Occlusive Diseases↗
PubMedDate not supplied

Treatment of major venous obstruction with an expandable endoluminal spiral prosthesis.

Six patients with extensive iliofemoral and/or caval thrombosis were treated by thrombectomy and subsequent implantation of an expandable endoluminal spiral prosthesis in case of congenital caval stenoses (1) or extravascular compression or traction (5). Five of these patients had undergone previous surgery and thrombosis had developed despite low dose heparin given postoperatively. Three patients had had an unsuccessful thrombectomy prior to spiral implantation. No complications related to the endoluminal prosthesis occurred. There was one retroperitoneal hematoma from guide wire perforation of the inferior vena cava (IVC) necessitating laparotomy and reversal of the previously constructed femoral av-fistula with subsequent iliofemoral rethrombosis. All other endoluminally reconstructed veins remained open at early and late (up to 12 months) review confirmed by phlebography. We conclude that with increasing clinical experience endoluminal relining of obstructed major veins will probably become a valuable method of venous reconstruction with minimal surgical trauma.

Adolescent↗