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Biomedical subjects

G Reuther

Publications and source records attributed to G Reuther.

At least 19 recordsLinked to original sources
PubMed2000

MRI-based stereolithographic models of the temporomandibular joint: technical innovation.

A new technique of manufacturing dual-colour stereolithographic models of hard and soft tissues of the temporomandibular joint (TMJ) is presented. Sagittal T1/PD weighted magnetic resonance (MR) images of joints with and without disc displacement were obtained in the closed and open mouth positions. Individual interactive contour identification of bony structures and the articular disc followed by binary interpolation provided the data for the generation of acrylic TMJ models. Three dimensional in vivo visualization of the articular disc in relation to bony structures in the closed and open mouth positions allows a new perception of normal and pathological TMJ anatomy.

Acrylic Resins↗
PubMed1997

The Bcr-Abl tyrosine kinase activates mitogenic signaling pathways and stimulates G1-to-S phase transition in hematopoietic cells.

Bcr-Abl is a constitutively active tyrosine kinase that is expressed in Philadelphia chromosome (Ph1)-positive human leukemias. Bcr-Abl has been shown to inhibit apoptosis and cause anchorage independent growth. However, its ability to activate mitogenic signaling pathways is controversial. Here we show that Bcr-Abl signaling prevents down-regulation of cyclin-dependent kinase activity and cell cycle arrest after growth factor deprivation of hematopoietic progenitor cells. Using an inducible system to regulate Bcr-Abl expression, we also demonstrate that Bcr-Abl expression is sufficient to induce G1-to-S phase transition, DNA synthesis, and activation of cyclin-dependent kinases in cells that were arrested in G0 by growth factor deprivation. Furthermore, Bcr-Abl activates Ras, Erk, and Jnk pathways as a primary consequence of expression. These data show that Bcr-Abl is one of a select group of oncogenes that is capable of both inhibiting apoptosis and deregulating cell proliferation. The combination of these activities is likely to be important for the progression of CML.

Apoptosis↗
PubMed1997

Visualization of urinary tract dilatation: value of single-shot MR urography.

The purpose of this study was to evaluate detection of urinary tract dilatation, depiction of obstruction level and determination of cause with single-shot MR imaging in an acquisition time of 2.8 s. Heavily T2-weighted single-shot MR images in 50 patients with ureterohydronephrosis as suspected by ultrasound were prospectively compared with IV urography and clinical outcome. Imaging techniques were obtained within a maximum time interval of 4 h and assessed independently on the same day. Single-shot MR urography was able to demonstrate dilatation and obstruction levels in 96 % of urinary tracts in accordance with X-ray urograms. In 4 patients with a unilaterally negative IV urogram, obstruction levels were demonstrated in single-shot MR urography. Single-shot MR urography did not depict 2 of 7 collecting systems with mild dilatation and contralateral undilated ureters were not adequately visible. Single-shot MR urography consistently visualizes dilated urinary tracts and obstruction levels in moderate and severe dilatation. Single-shot MR urography may be an alternative for IV urography in cases of renal impairment, when iodinated contrast or the application of X-rays is contraindicated, and may help in avoiding direct ureteropyelography. Single-shot MR urography rarely allows determination of the cause of urinary tract dilatation.

Adult↗
PubMed1996

[The Schnitzler syndrome as a cause of recurrent fever of unknown origin].

HISTORY AND CLINICAL FINDINGS: For 4 years a 56-year-old woman had been suffering from chronic urticaria. In the past two years she had developed recurrent fever, each 1-3 days in duration. In the last 6 to 8 months she also had severe aching in the legs. There were no significant findings on physical examination other than non-itching urticarial rash over trunk and limbs. INVESTIGATIONS: Blood sedimentation rate was increased (maximum 88/110 mm), as were WBC count (16,200/microliter, 83% neutrophils) and the activity of alkaline leucocyte phosphatase (225 U/l). Monoclonal IgM gammopathy type kappa and circulating IgM immune complex (15.4 mg/dl) were demonstrated in serum. Skin biopsy of a new urticarial lesion revealed vasculitis. Iliac crest biopsy was unremarkable and showed no lymphoid cell infiltration. Bone scintigraphy revealed bilaterally increased storage in femur and tibia. Magnetic resonance imaging demonstrated marrow infiltration without space-occupying features in the affected femur and tibia. TREATMENT AND COURSE: Conjunction of fever, generalised urticaria, joint/bone pain and monoclonal gammopathy of kappa type having established the diagnosis of Schnitzler's syndrome, treatment with ibuprofen was started (initially 1,200 mg daily by mouth, followed by reduction to 600 mg daily). All symptoms rapidly improved and the bone changes regressed, but not the monoclonal gammopathy. But when the ibuprofen dosage had been decreased to 600 mg daily, the urticaria recurred, though in milder form. CONCLUSION: This case demonstrates the efficacy of ibuprofen in the treatment of the Schnitzler's syndrome. Furthermore reversibility of scintigraphic bone lesions could be demonstrated under ibuprofen treatment.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1996

[MR-Cholangiopancreatography as a single-shot projection: techniques and results of 200 examinations].

PURPOSE: Evaluation of utility and value of a selective projection technique for bile and pancreatic ducts in MRI. MATERIAL AND METHODS: 200 patient examinations of the pancreaticobiliary duct system using a turbo-SE pulse sequence in "single-shot" technique were evaluated in retrospect concerning anatomic display and diagnostic accuracy compared to surgery, ERCP, i.v. cholangiography, ultrasound and clinical course. RESULTS: Non-dilated ducts allowed visualisation of gallbladders in 78%, common bile ducts in 97%, cystic ducts in 80%, intrahepatic main ducts in 71% and pancreatic main ducts in 69%. When dilatation was present, all common bile, intrahepatic main and pancreatic ducts were visible. Display of cystic ducts and gallbladders with a detection rate of 69 and 85%, respectively, did not improve. Sensitivities for diagnosing papillary stenoses (n = 6), pancreatic ductal stenoses and dilatation (n = 13), compressions and dilatations of the biliary tree (n = 33) as well as for one choledochal cyst were 100%. Choledocholithiasis could correctly be predicted in 11/15 cases (73%), cholecystolithiasis in 71/120 cases (59%). CONCLUSION: "Single-shot" MR-cholangiopancreatography is a fast and non-invasive modality which can replace i.v. cholangiography and restrict the indication for ERCP to therapeutic indications and problem cases.

Adult↗
PubMed1996

Cholangiography before biliary surgery: single-shot MR cholangiography versus intravenous cholangiography.

PURPOSE: To compare depiction of the biliary tract with magnetic resonance (MR) and intravenous cholangiography before biliary surgery. MATERIALS AND METHODS: Intravenous cholangiograms and heavily T2-weighted single-shot MR images in 60 patients with biliary calculi were compared prospectively. Images obtained with each technique were independently assessed for depiction of anatomy and calculi. RESULTS: The gallbladder was adequately visualized with intravenous cholangiography in 77% of patients and with MR cholangiography in 88%. Rates for visualization of the common bile duct were 97% and 100%, respectively; for the cystic duct, 27% and 75%; and intrahepatic ducts, 28% and 77%. With either technique, calculi in the gallbladder were correctly predicted as solitary or multiple in approximately 80% of patients. Five cases of common bile duct calculi were correctly predicted with this technique, two cases with cystic duct calculi were depicted with only MR cholangiography. CONCLUSION: Single-shot MR cholangiography may replace intravenous cholangiography for visualization of the biliary tract. However, the delineation of tiny gallbladder calculi and shrunken gallbladders with thickened bile is limited.

Bile Duct Diseases↗
PubMed1995

Superior compliance and efficacy of continuous combined oral estrogen-progestogen replacement therapy in postmenopausal women.

OBJECTIVE: We assessed compliance, relief of climacteric symptoms, and impact on lumbar bone mineral density in two groups of 140 patients treated with a sequential estrogen-progestogen or a continuous combined replacement therapy in comparison with controls. STUDY DESIGN: Patients were randomized to 2 mg of estradiol valerate daily and 5 mg of medroxyprogesterone acetate daily for 12 days per month sequentially to induce withdrawal bleeding (group A) or 2 mg of estradiol, 1 mg of estriol, and 1 mg of norethisterone acetate daily continuously to maintain amenorrhea (group B) or a control group (group C). RESULTS: Compliance was 93% after 1 year and 73% after 2 years in group B and 66% and 49% in group A after 1 and 2 years, respectively. Improvement of climacteric symptoms was similar in groups A and B. Uterine bleeding in 24% of patients in group A and 3% in group B was the most frequent reason for discontinuation of drug intake. Only continuous combined therapy (group B) increased bone mineral density after 1 and 2 years compared with baseline: +13% and 17% (p = 0.01). In groups A and C no significant changes in bone mineral density were recorded. Compliance was unrelated to the age of menopause. CONCLUSION: Continuous combined therapy is superior to sequential estrogen progestogen replacement in compliance and prevention of bone loss but not with regard to relief of climacteric symptoms.

Analysis of Variance↗
PubMed1995

Cerebellar herniation in syringomyelia: relation between tonsillar herniation and the dimensions of the syrinx and the remaining spinal cord. A quantitative MRI study.

The dimensions of the syrinx, the remaining spinal cord and the degree of cerebellar herniation were analyzed by one- and two-dimensional MRI studies in 22 patients with syringomyelia. A deep and/or broad cyst tends to be a long one. The dimensions of the syrinx and the spinal cord have an inverse relationship. The degree of cerebellar herniation is not related to the longitudinal or transverse extension of the cyst or the ratio cyst/cord or the remaining spinal cord (neither for diameters nor for cross-sectional areas). The dimensions of cysts are not significantly greater in patients with tonsillar herniation than in patients without. We conclude that cerebellar herniation is not a major prognostic factor and should not be overestimated for the development and progression of the disease.

Adolescent↗
PubMed1994

[CT-guided biopsies of the axial skeleton. The approaches and results].

The value of percutaneous CT-guided biopsies of the axial skeleton for establishing a diagnosis is determined from a series of 75 punctures in 74 patients in retrospect. Indications showed benign conditions to prevail over malignant lesions by a ratio of 1.6:1. Biopsy routes turned out to be strongly determined by regional anatomy allowing for a standardised procedure in each area. 64 out of 75 histological diagnoses were confirmed by open surgery (n = 17) or follow-up (n = 58) accounting for an accuracy of 85.3%. In 7 cases no definite diagnosis could be made from the sample and in 4 cases the diagnosis proved false although tissue cores could be obtained in each case. No serious or irreversible complications occurred. CT-guided punctures of the axial skeleton are considered a safe and highly accurate procedure to establish a definite diagnosis unless there is a primary indication for surgery or the need for decompression.

Adolescent↗
PubMed1994

[Diagnostic value and interpretation of imaging bone densitometry based on quantitative CT].

Quantitative CT of the axial skeleton (aQCT) may serve as an example of the evaluation and interpretation of bone densitometric data as it is the only state-of-the-art technique with valid longitudinal observations. The value of bone density measurements in interindividual cross sections refers to a grading derived from a representative reference population and provides an evaluation of fracture risk. The presence and rate of any bone loss can only be evaluated in an intraindividual longitudinal follow-up. Adequate follow-up for trabecular bone requires at least 3 to 5 years intervals to discriminate between different loss rates. Bone losses induced by steroid therapy or immobilisation may have faster kinetics apparent within months; bone density increase due to hormone substitution may be significant after one to two years. Morphological data allow critical evaluation of the quantitative measurements, eliminating false values and differentiating between rarefying and destructive osteopenia.

Absorptiometry, Photon↗