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Biomedical subjects

G Sigmund

Publications and source records attributed to G Sigmund.

At least 19 recordsLinked to original sources
PubMed2005

Identification of the aromatase inhibitor letrozole in urine by gas chromatography/mass spectrometry.

Letrozole (1-(bis-(4-cyanophenyl)methyl)-1,2,4-triazole) is used therapeutically as a non-steroidal aromatase inhibitor (Femara) to treat hormone-sensitive breast cancer in postmenopausal women. For doping purposes it may be used to counteract the adverse effects of an extensive abuse of anabolic androgenic steroids (gynaecomastia) and to increase the testosterone concentration by stimulation of the testosterone biosynthesis. The use of aromatase inhibitors has been prohibited by IOC/WADA regulations for male and female athletes since September 2001 and January 2005, respectively. Spot urine samples from women suffering from metastatic breast cancer and being treated with letrozole were collected and analysed to develop/optimise the detection system for metabolites of letrozole to allow the identification of athletes who do not comply with the internationally prohibited use of this cancer drug. The assay was based on gas chromatography/mass spectrometry (GC/MS) and the main metabolite of letrozole (bis-4-cyanophenylmethanol) was identified by comparison of its mass spectrum and retention time with that of a bis-4-cyanophenylmethanol reference. The full-scan spectrum, diagnostic ions and a validation of the method for the analysis of bis-4-cyanophenylmethanol are presented.

Aromatase Inhibitors↗
PubMed2003

[Massive localized lymphedema - a rare entity].

Massive localized lymphedema is a rare disease. Only a few cases have been described in the literature. These monstrous pseudotumors of the subcutis are mostly localized in the inguinal region or at the lower extremity. These tumors often show a slow growth for many years. Besides hernias, lipomatous tumors must be distinguished. The therapy of choice is the excision of the tumor. Relapse is not uncommon in the few cases described in the literature so far. The diagnostic procedure and therapy of an 48-year-old women with a massive localized lymphedema weighing about 22 kg are demonstrated and discussed.

Diagnosis, Differential↗
PubMed2002

Identification of the aromatase inhibitor aminoglutethimide in urine by gas chromatography/mass spectrometry.

Aminoglutethimide is used therapeutically as an aromatase inhibitor in the treatment of metastatic breast cancer in post-menopausal women. For doping purposes, aminoglutethimide may be used for treatment of adverse effects of an extensive abuse of anabolic androgenic steroids (gynaecomastia) and to increase the testosterone concentration and stimulation of testosterone biosynthesis. The use of aromatase inhibitors has been prohibited for male athletes since September 1, 2001. The purpose of this study was to develop methods for the identification of the parent compound or its main metabolite and the inclusion of this information into established screening procedures in doping analysis. An excretion study was conducted using oral application of one single therapeutic dose (500 mg) of Orimeten. The analysis was performed by gas chromatography/mass spectrometry (GC/MS). Aminoglutethimide is excreted almost totally as unconjugated parent compound and is detectable by different screening procedures for up to 165 h. Most suitable for the detection of aminoglutethimide is the screening procedure for heavy volatile nitrogen-containing drugs ('Screening 2'). However, since only competition samples are analysed in that screening procedure, the additional inclusion of aminoglutethimide in the screening procedure for anabolic androgenic agents ('Screening 4') is recommended. Full mass spectra and diagnostic ions for the analysis of aminoglutethimide are presented.

Adrenergic Agents↗
PubMed2001

The Trier mummy Paï-es-tjau-em-aui-nu: radiological and histological findings.

The ancient Egyptian mummy Paï-es-tjau-em-aui-nu, now on exhibition in the Rheinische Landesmuseum in Trier, Germany, was examined by conventional X-ray radiography, computed tomography, and digital fluoroscopy. In addition, some tissues were biopsied for further histologic identification. Along with some representative images, the peculiarities of the Trier mummy concerning the mummification process are presented.

Egypt↗
PubMed2000

[Radiology of gastrointestinal stromal tumors (GIST) and a case of Carney syndrome].

Gastrointestinal stromal tumors (GIST) represent an extremely rare group of tumors, which are mostly of smooth muscle origin like leiomyomas, leiomyosarcomas and leiomyoblastomas. With the introduction of immunohistochemical analysis an epithelioid and an autonomic nerve variant can be distinguished. The purpose of this review is to demonstrate the image morphological appearance of these rare tumors together with the pathology based upon a retrospective analysis of five of our own cases since 1997. There are no pathognomonic imaging findings for characterizing a gastrointestinal stromal tumor; however, it should be included in the differential diagnosis if one or multiple large, round or oval, well-delineated gastrointestinal tumors occur in combination with central necrosis. Carney's syndrome is characterized by the syndromal association of a gastrointestinal stromal tumor (originally: gastric leiomyosarcoma) with an extra-adrenal paraganglioma and a pulmonary chondroma. In this rare syndrome, the radiological approach is important to diagnose or rule out the--simultaneous or consecutive--appearance of at least two of the three tumor entities (GIST, extra-adrenal paraganglioma, pulmonary chondroma).

Adult↗
PubMed2000

[Evaluation of renal artery stenosis: comparison of angiography and invasive blood pressure measurement and Doppler ultrasound].

PURPOSE: In the procedure of renal artery angioplasty, the angiographically measured degree of stenosis should be compared with the intraarterial transstenotic blood pressure gradient and pre-interventional Doppler findings. METHODS: In a total of 46 renal arteries in 35 patients with renovascular hypertension, the angiographic-morphological parameters: "linear", "geometric" and "densitometric" degree of stenosis are compared with the invasive transstenotic blood pressure gradient and the pre-interventional Doppler ultrasound. RESULTS: All angiographically determined degrees of stenosis ("linear", "geometric" and "densitometric") correlate--moderately--with the transstenotic blood pressure gradient (correlation coefficients: 0.67 ("linear"), 0.65 ("geometric") and 0.49 ("densitometric"), each versus systolic pressure gradient, respectively). Stenoses that are angiographically classified as "low grade" (< 50%) nevertheless have a high number of high transstenotic pressure gradients: 21 of 22 show systolic values > or = 10 mmHg, 13 of 22 even > or = 30 mmHg. All stenoses Doppler sonographically classified as "high or very high grade" (Vmax,syst > or = 3 m/s) are confirmed by angiography and/or pressure measurement. CONCLUSIONS: Angiography has the tendency to underestimate the degree of renal artery stenosis, especially in "low grade" stenoses (< 50%). However, in those > or = 50% a high transstenotic blood pressure gradient can be taken for granted. If the angiographic degree of stenosis seems uncertain, we recommend measurement of blood pressure gradient.

Adult↗
PubMed1996

[Computerized tomography and magnetic resonance tomography studies before and after para-tibial fasciotomy].

Paratibial fasciotomy has been employed since 1981 to treat patients with chronic venous insufficiency (CVI) and therapy-resistant leg ulcers with severe lipodermatosclerosis. The characteristic morphological changes in CVI were evaluated shown before and after paratibial fasciotomy using computerized tomography (CT) and magnet resonance tomography (MRT). 10 patients (6 female, 4 male) were examined by CT and MRT pre- and postoperatively. Preoperatively there is a clear thickening of the dermis and subcutaneous field. In addition, the area around the achilles tendon is thickened, the fasciae are enlarged and the muscles of the lower leg show an increase of fatty tissue. A decrease of the cutaneous and subcutaneous thickening is seen postoperatively. The fasciotomy split is visible in most patients.

Adipose Tissue↗
PubMed1994

False-positive diagnosis of a pheochromocytoma with I-123 metaiodobenzylguanidine.

The rare case of a false-positive scintiscan with I-123 labelled metaiodobenzylguanidine (MIBG) in a patient with suspected pheochromocytoma is reported. Focal accumulation of the tracer in the upper right abdomen, primarily thought to represent a right-sided pheochromocytoma, was subsequently proven to be caused by an ampullary renal pelvis. In cases of unexplained MIBG accumulation the possibility of prolonged retention of the tracer, because of an abnormality of the renal pelvis, should be considered and excluded by ultrasound.

3-Iodobenzylguanidine↗
PubMed1994

Invasive pulmonary aspergillosis. MRI, CT, and plain radiographic findings and their contribution for early diagnosis.

A prospective study was conducted in 38 patients with nodular lesions on plain chest radiographs and the clinical suspicion of invasive pulmonary aspergillosis (IPA) to assess the diagnostic accuracy of magnetic resonance imaging (MRI) and computed tomography (CT). For early diagnosis of IPA (clinical signs and symptoms < 10 days), CT scans with demonstration of the halo sign had a high sensitivity (16/22) and specificity (8/8). Magnetic resonance imaging performed at the same time revealed a relatively higher sensitivity (22/22), but a very poor specificity (0/8). Gadolinium-diethylene-triamine-pentaacetic acid (Gd-DTPA) enhanced images did not improve specificity. In the later course of infection (clinical signs and symptoms > 10 days), MRIs showed typical nodular target-like lesions with Gd-DTPA enhancement of the rim area that was not seen in the early course of the disease or in patients with Pseudomonas or staphylococcal infection. In conclusion, MRI findings are not as characteristic as the CT halo sign in diagnosing IPA in the early course of the disease, but the MRI target sign with Gd-DTPA enhancement of the rim area and the "reverse target" on T2-weighted images are strongly suggestive of IPA at a later stage of the disease.

Aspergillosis↗
PubMed1994

[The value of bone marrow scintigraphy and magnetic resonance tomography in diagnostic imaging of bone marrow].

This article provides an overview of the possibilities and indications for magnetic resonance imaging (MRI) and bone marrow scintigraphy in imaging the bone marrow. After a brief review of the anatomical and physiologic structures of bone marrow, the principles of both methods are described. The radiopharmaceuticals of choice for bone marrow scintigraphy are the newly developed 99mTc-labelled anti-granulocyte monoclonal antibodies. They allow a high-quality, whole-body visualization of haematopetically active bone marrow by specifically targeting granulopoetic bone marrow cells and mature granulocytes. MRI enables us to visualize the bone marrow with high contrast and spatial resolution by assessing different properties of the biological tissue--mainly fat, water, and mineral content. Both methods provide a non-invasive and sensitive approach for imaging the bone marrow in different benign and malignant disorders.

Antibodies, Monoclonal↗
PubMed1994

[Early changes in the hip joint following epiphysiolysis of the femoral head. Results of an MRT study].

With the aim of detecting patients at risk of developing coxarthritis, 34 patients were investigated prospectively by MRI 6-14 years after epiphysiolysis for slipped capital femoral head. In particular, cartilage changes were analysed by gradient-echo sequences. In 40% of the hip joints investigated cartilaginous lesions were present, detectable as irregularity and flattening of contour and more rarely as changes in signal intensity. In contrast, only 18% of the radiographs available revealed any pathology. When pelvic X-rays are normal or reveal slight sclerosis, cartilaginous lesions on MRI are considered early signs of coxarthrosis. This combination was seen especially often in patients with a primarily high angle of dislocation and in those who needed treatment by reposition or osteotomy. Only in 8 of the 17 hip joints showing sclerosis on conventional radiograms, sclerosis was also diagnosed by MRI, possibly because of partial volume and susceptibility effects at high field strength. Even with limited spatial resolution, cartilage examination is warranted in young patients in whom early osteoarthritis can be expected.

Adult↗
PubMed1993

Pheochromocytomas, multiple endocrine neoplasia type 2, and von Hippel-Lindau disease.

BACKGROUND: Pheochromocytoma is a feature of two disorders with an autosomal dominant pattern of inheritance--multiple endocrine neoplasia type 2 (MEN-2) (with medullary thyroid carcinoma and hyperparathyroidism) and von Hippel-Lindau disease (with angioma of the retina, hemangioblastoma of the central nervous system, renal-cell carcinoma, pancreatic cysts, and epididymal cystadenoma). The frequency of these syndromes in patients with pheochromocytoma is not known. METHODS: In an unselected group of patients with pheochromocytoma, we performed pentagastrin tests, parathyroid hormone assays, computed tomography (CT) or magnetic resonance imaging (MRI) of the brain, ophthalmoscopy, CT imaging of the abdomen, and ultrasonography of the testes. We also screened members of families with MEN-2 or von Hippel-Lindau disease for pheochromocytoma by measuring plasma and urine catecholamines and plasma chromogranin A and by performing abdominal ultrasonography, CT and MRI, and metaiodobenzylguanidine scintigraphy. RESULTS: Nineteen of 82 unselected patients with pheochromocytomas (23 percent) were carriers of familial disorders; 19 percent had von Hippel-Lindau disease and 4 percent had MEN-2. Prospectively, in 36 of 79 subjects at risk for pheochromocytoma (46 percent), 42 unsuspected pheochromocytomas were found. Overall, there were 130 patients with 185 pheochromocytomas; 43 had von Hippel-Lindau disease, 24 had MEN-2, and 63 had sporadic tumors. The patients with familial and those with sporadic pheochromocytomas differed in mean age at diagnosis (32 vs. 46 years, P < 0.001), multifocal localization (55 vs. 8 percent, P < 0.001), and cancer (0 vs. 11 percent, P = 0.005); but not in the frequency of extraadrenal tumors (24 vs. 16 percent). Thirty-eight percent of carriers of von Hippel-Lindau disease and 24 percent of carriers of MEN-2 had pheochromocytoma as the only manifestation of their syndrome. CONCLUSIONS: All patients with pheochromocytomas should be screened for MEN-2 and von Hippel-Lindau disease to avert further morbidity and mortality in the patients and their families. All patients in families with MEN-2 or von Hippel-Lindau disease should be screened for pheochromocytoma, even if they are asymptomatic.

Adolescent↗
PubMed1993

Correlation of ultrasound and renal scintigraphy in children with unilateral hydronephrosis in primary workup.

Ultrasound accurately detects hydronephrosis in infants and children, while nuclear medicine techniques quantify relative renal function in addition to characterizing the urodynamic relevance of hydronephrosis. This prospective study was undertaken to examine the relationship between ultrasound morphological findings and relative renal function, quantified with dynamic 99mtechnetium mercaptotriacetylglycine imaging, in the initial diagnostic workup of children with unilateral hydronephrosis. The ultrasound grade of hydronephrosis and relative renal function ipsilateral to the hydronephrosis were inversely related, indicating that with more severe hydronephrosis ultrasound fails to estimate the potential reduction of relative kidney function. Because renal function is not necessarily affected by hydronephrosis, renal scintigraphy is indicated to assess the functional status of hydronephrotic kidneys.

Child↗
PubMed1993

[Magnetic resonance tomography of so-called transient osteoporosis. Primary diagnosis and follow-up after treatment].

Transient osteoporosis or transient bone marrow oedema is a rare cause of acute hip pain that predominantly affects adults of middle and younger age. We report on the MR image in 8 patients with transient bone marrow oedema of the hip and in one patient with affection of the knee joint. In three of these, sympathetic nerve blockade has been performed. The MR image after sympathicolysis is discussed.

Adult↗
PubMed1993

[Metal abrasion as an imaging artefact in nuclear spin tomography].

Eighteen patients with vertebral body fractures that had been stabilized by an internal spinal skeletal fixation system were prospectively examined by magnetic resonance (MR) imaging between February 1989 and November 1990 at the Department od Diagnostic Radiology of the University Hospital Freiburg 3-7 days after removal of the metallic implants. In most cases imaging artifacts in the paraspinal extensor muscles were evident on MR studies. These were found especially in the region of the previous site of the metal clip jaw bearing. In a few cases artifacts were also present within the vertebral body and/or vertebral arch, but only if the vertebral body had been surgically reconstructed by transpedicular spongiosa implantation. None or only minor artifacts by abrasion of metal were detected if the (modified Schanz's) screws appeared to be tight at surgical removal of the implants. Therefore, marked metal artifacts on MR imaging retrospectively indicate a chronic straining of the implants, which has been shown to be a risk factor for implant loosening. Additional in vitro studies with powdered metallic alloy showed that as little as 1 mg of metal could be detected as artifacts in routine spin-echo sequences. When the metallic pieces were large enough to be seen on conventional radiographs or computed tomograms, they caused severe, distorting artifacts on MR imaging. It is concluded that MR imaging is the method of choice for detection of small amounts of metal.

Adult↗
PubMed1993

["Rare" urography by MRI: an alternative to IVU?].

The authors describe the technique of RARE sequences (Hennig, 1986) and their hydrographic application to urinary imaging, RARE urography. Heavily T2-weighted non-tomographic images of the urinary tract are obtained in less than 30 seconds, without contrast medium or ionizing radiation. The whole urinary tract is visualised on one image with a spatial resolution superior to that of sonography. The semiology of RARE urography is similar to that of the intravenous pyelogram. Silent kidneys are also visualised.

Adult↗
PubMed1993

[Nuclear spin tomographic findings in compensated chronic hemolysis. A case report of a hereditary spherocytosis].

A case report of a 58-year-old patient with hereditary spherocytosis and large paravertebral masses in the thorax and abdomen is presented MRI detects the origin of the masses with typical signal intensities of the masses and the bone marrow in T1 and T2 weighted sequences as extramedullary hematopoiesis. In this special case there is bleeding into these masses and, as often, liver hemosiderosis and splenomegaly.

Chronic Disease↗