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Biomedical subjects

E Steiner

Publications and source records attributed to E Steiner.

At least 73 records · Page 4Linked to original sources

[CT and MRI of small intestine interposition after oropharyngeal tumor resection].

Freely transplanted, microvascularly anastomosed jejunal patches can be used to cover soft tissue defects in the oral cavity or oropharynx after the resection of malignant tumors. Even a patch without complications or alteration from tumor recurrence is morphologically diverse. Therefore it is difficult to distinguish between malignant and benign alterations, and knowledge of the possible morphological spectrum and the significance of an alteration is of practical interest. Computed tomography (CT; n = 30) and magnetic resonance imaging (MRI; n = 13) were used for follow-up examinations in patients who had an operative reconstruction with a jejunal patch. Three parts of a patch were differentiated with both imaging modalities: the region of the anastomosis, the mesenterial fatty tissue and the intestinal wall. The morphology of the patches correlated with clinical findings in the following cases. The patches were identified satisfactorily by CT and MRI. The appearance of patches without complications was influenced by a variable degree of fibrosis and by persistent intestinal folds. Recurrent tumors only infiltrated the margins of the patches. Destructive alterations in the patches were always less severe than those in the original orofacial soft tissue. Postoperative follow-up examinations with CT and MRI are particularly important when tumor recurrences spread under a patch, since these tumors are invisible in the clinical examinations. CT was advantageous in demonstrating osseous alterations and showed less loss of image quality in patients for whom the implantation of multiple metallic hardware during the operation had been necessary.

Adult↗

Functional characterization of canine connexin45.

Three gap junctional proteins have been identified in canine ventricular myocytes: connexin 43 (Cx43), connexin 45 (Cx45), and connexin 40 (Cx40). We have characterized the functional properties of canine Cx45 and examined how Cx45 functionally interacts with Cx43 in Xenopus oocyte pairs. Homotypic pairs expressing Cx45 were well coupled. Heterotypic pairs composed of Cx45 paired with either Cx43 or Cx38 also developed high levels of conductance. Junctional currents in the heterotypic pairs displayed a highly asymmetrical voltage dependence. The kinetics and steadystate voltage dependence of the heterotypic channels more closely resembled those of the Cx45 channels when the Cx45 cRNA-injected cell was relatively negative suggesting that the Cx45 connexin closes for relative negativity at the cytoplasmic end of the channel. We also show that homotypic and heterotypic channels composed of Cx45 and Cx43 exhibit differences in pHi sensitivity.

Animals↗

Laparoscopic repair of recurrent inguinal hernias.

BACKGROUND: Repair of recurrent inguinal hernias is associated with recurrence rates as high as 30% and complication rates higher than for primary hernias. PATIENTS AND METHODS: In a prospective study, results were evaluated after laparoscopic transabdominal preperitoneal hernia repair in 192 patients with 200 recurrent inguinal hernias. A total of 132 hernia repairs followed one previous repair, 41 followed two repairs, 17 followed three repairs, 6 followed four, 3 followed five, and 1 followed six previous repairs. The surgical technique is described. RESULTS: Follow-up ranged from 9 to 31 months (mean 18.4). Twelve patients (6%) had groin seromas or hematomas; 3 (1.5%) had transient thigh numbness. One patient (0.5%) underwent laparoscopy a second time because of a large hematoma. In 1 patient (0.5%), a staple on the n. cutaneus femoris lateralis was removed laparoscopically. Patients described postoperative pain as being much less severe compared with their previous operation. Of the total group, 76% of patients were able to return to work within 2 weeks of surgery. One recurrence (0.5%) occurred after 6 months because of too small a prosthetic mesh. CONCLUSIONS: This laparoscopic technique can be applied to recurrent hernias, even in difficult cases, with low morbidity rates. Recurrence rates as low as for laparoscopic repair of primary hernias can be expected.

Adult↗

The production of an amyloidogenic metabolite of the Alzheimer amyloid beta precursor protein (APP) in thyroid cells is stimulated by interleukin 1 beta, but inhibited by interferon gamma.

Thyroid epithelial cells have been shown to have a high APP expression and to produce large amounts of its metabolic derivatives, namely secreted APPs and a potentially amyloidogenic 41-kDa C-terminal fragment. It was the aim of the present study to analyze how APP production and metabolism were regulated in human thyroid cells. The effects of three cytokines, interferon gamma (IFN gamma), interleukin 1beta (IL-1 beta) and transforming growth factor (TGF) beta, were investigated. Cell extracts and supernatants were studied by immunoblotting using specific N- and C-terminal APP antibodies. Quantification was performed by densitometric scanning. We demonstrate that IFN gamma has a strong suppressive effect on the production and metabolism of APP. From a concentration of 30 U/ml upwards it reduces the cellular APP content, decreases the amounts of secreted APPs and inhibits the generation of the 41-kDa amyloidogenic APP fragment. In contrast, IL-1 beta has a stimulatory influence on the generation of the amyloidogenic 41-kDa APP metabolite, but does not affect the cellular holoprotein or APPs. TGFbeta has no significant effect on APP. Our results demonstrate that cytokines can regulate APP production and metabolism in thyroid cells. IFN gamma is the first naturally occurring agent described to inhibit the generation of amyloidogenic APP fragments. It may be of relevance in preventing amyloid deposition during inflammatory processes in the thyroid gland, but may exert a similar protective effect in other non-neuronal and neuronal tissues.

Adult↗

Quantitative CT assessment of the lumbar spine and radius in patients with osteoporosis.

OBJECTIVE: We undertook this study to quantify the relationship between bone mineral assessments of the lumbar spine using quantitative CT (QCT) and of the radius using peripheral QCT (pQCT) and to test the sensitivity of both techniques in detecting changes in bone mass that are related to age and osteoporosis. SUBJECTS AND METHODS: Forty-two healthy premenopausal, 38 healthy postmenopausal, and 97 osteoporotic postmenopausal women were examined with pQCT of the distal radius and with QCT of the lumbar spine (L1-L4). The bone mineral density (BMD), bone mineral content (BMC), and a cross-sectional area of cortical bone were assessed at the distal radius. The BMD of trabecular and total bone and the BMC of total bone were assessed at the midvertebral bodies of the lumbar spine. RESULTS: In the healthy women, correlations of radial BMD with spinal trabecular and total BMD were modest (r = .39 and r = .49, respectively) but were higher for total BMC (r = .79). All correlations in osteoporotic women (r = .19 for trabecular BMD, r = .31 for total BMD, and r = .47 for total BMC) were lower than those in healthy women. For measurement of spinal bone mass in healthy women, trabecular BMD showed a higher correlation with age (r = .81) and a larger relative annual decrease (1.2%) than did total BMD (r = .75, .78%) or total BMC (r = .54, .55%). At the radius, the highest correlations with age were found for total BMC (r = .57, .53%), cortical area (r - .52, .67%), and cortical BMC (r = .48, .78%). Age-adjusted odds ratios for prevalent vertebral fractures were highest for total (4.5) and trabecular (4.4) spinal BMD. For radial measurements, odds ratios were highest for both total BMD (2.3) and cortical area (2.3). CONCLUSION: QCT of spinal trabecular bone showed the strongest capability for assessment of age-related bone loss and for discrimination of osteoporotic vertebral fractures. In comparison, pQCT of radial trabecular bone showed the weakest capability for these applications, and pQCT of radial cortical or total bone showed intermediate capability.

Aged↗

Ganglia and cysts around joints.

Para-articular cysts frequently are seen on routine imaging examinations. They may be clinically asymptomatic or may cause pain, swelling, or impaired joint function. They often are associated with underlying joint disorders, such as trauma, degeneration, or inflammation. This article discusses the cause, symptoms, and appearance of para-articular cysts on various imaging examinations including arthrography, ultrasound, CT scan, and MR imaging. Specific attention is focused on those cystic masses appearing around the hip, knee, ankle and foot, shoulder, elbow, wrist and hand, spine, temporomandibular joints, and periosteum.

Arthrography↗

[The shoulder joint--diagnostic imaging].

In the assessment of shoulder joint abnormalities plain films must still be used today as primary imaging modality. For soft tissue, cartilage, tendon and ligament lesions, CT with arthrography and particularly MRI with arthrography is available today. Especially latter method leads to a significantly extended diagnosis, which in many cases implies a major therapeutical significance.

Arthritis↗

Early destruction of tryptophan residues of apolipoprotein B is a vitamin E-independent process during copper-mediated oxidation of LDL.

The decrease of the tryptophan fluorescence (Ex/Em = 282/331 nm) was used to monitor the kinetics of copper-mediated LDL oxidation. Cu2+ causes a concentration-dependent quenching of the LDL Trp-fluorescence, the maximum of about 22% suggests that 8-9 Trp residues (out of a total of 37) are accessible for Cu2+ ions. Decomposition of LDL tryptophan commences immediately after addition of Cu2+ and proceeds in two stages with quite different rates. At a molar ratio of Cu2+/LDL = 33:1 the LDL particle looses 1 Trp every 13.5 min in the initial slow phase and every 4.1 min in the subsequent rapid The second, stage temporarily coincides with the propagating lipid peroxidation. In the initial phase loss of Trp proceeds with a constant rate for up to 200 min depending on the copper concentration. Whereas lipid peroxidation accelerates after consumption of vitamin E, rate of Trp loss does not increase. Loading of LDL with vitamin E has also no effect on the initial rate of Trp loss. During the initial phase a loss of one Trp residue/LDL is accompanied by the loss of two alpha-tocopherols and the generation of two conjugated lipid hydroperoxides. The results suggest Trp residues play a role in initiating the lipid peroxidation process in the LDL particle. In such kinetic studies, precautions must be taken to avoid photodecomposition of LDL-Trp. The LDL vitamin E fluorescence (Ex/Em = 290/323 nm) does not interfere with the Trp fluorescence even at high concentrations.

Adult↗

[Spontaneous osteonecrosis of the knee joint: MRT compared to CT, scintigraphy and histology].

PURPOSE: We compared MR imaging with scintigraphy and CT in eight patients with spontaneous osteonecrosis of the knee. The histological changes accounting for the MR signal abnormalities were evaluated. METHODS: Eight patients with spontaneous osteonecrosis of the knee joint underwent MR imaging before and after i.v. administration of Gd-DTPA. Nuclear scintigraphy was performed in all 8 patients, three patients also had CT scans of the knee area. Histologic correlation was available in three patients. RESULTS: Increased radionuclide uptake was observed in all patients. In one patient, however, scintigraphy showed increased radionuclide uptake consistent with osteonecrosis only in the medial femoral condyle, while MR imaging demonstrated osteonecrosis both in the medial as well as the lateral femoral condyles. MR demonstrated areas of low signal intensity on precontrast T1-weighted images in the femoral condyle in all patients. All these areas showed high signal intensity on T2-weighted images. On postcontrast T1-weighted images, signal intensity increase was either homogeneous throughout the lesion or it was seen at the periphery of the lesion in a band-like pattern. Histologically, the areas of high signal intensity on T2-weighted and on postcontrast T1-weighted images corresponded to granulation tissue. CONCLUSION: MR imaging detects granulation tissue adjacent to the necrotic zone. Using morphological and signal intensity criteria, MR imaging can be utilised to differentiate spontaneous osteonecrosis of the knee from osteochondritis dissecans, degenerative osteoarthritis, and other conditions affecting the knee joint.

Aged↗

Overcoming barriers to generalism in medicine: the residents' perspective.

At a 1993 conference sponsored by the U.S. Bureau of Health Professions, a group of residents in several disciplines discussed barriers to generalism in medicine and ways to overcome them. In medical school, the barriers have to do with the lack of strong generalist mentors and lack of appropriate training in ambulatory generalist practice. In residency programs, the system does not support continuity of care and contains too few generalists as preceptors in clinical settings. The ambulatory clinic's inefficiency reinforces residents' frustrations and disillusionment with primary care practice. Further, the culture of medicine denigrates generalism and gives prestige and respect to subspecialists. In academic medicine, the dichotomy between scientist-physicians and clinician-physicians is a barrier. The public has adopted the perception promulgated by the medical leadership that generalists are less skilled and have less to offer than subspecialists. The residents offered recommendations for medical schools (changes in faculty and administration, curriculum, and financial support), for residency programs (changes in curriculum and structure), for the culture of medicine, and for public awareness. To increase the role of the generalist physicians, academic medicine institutions must pursue systematic, broad-based approaches to overcome barriers to generalist education and practice.

Attitude of Health Personnel↗

Thyroid epithelial cells produce large amounts of the Alzheimer beta-amyloid precursor protein (APP) and generate potentially amyloidogenic APP fragments.

The Alzheimer beta-amyloid precursor protein (APP) is a transmembrane glycoprotein from which the amyloid beta-protein is proteolytically derived. The latter is a hydrophobic peptide that can aggregate and forms the core of the senile plaques found in the brains of patients suffering from Alzheimer's disease (AD). In view of the known association between familial AD and thyroid autoimmune disease, the expression pattern and cellular processing of APP in human thyroid cells were investigated. Cultured thyroid epithelial cells and homogenized thyroid tissue from normal and pathological thyroid samples were analyzed by immunoblotting using specific N- and C-terminal APP antibodies as well as by reverse transcription-polymerase chain reaction in which two sets of oligonucleotide primers were used. The results of these studies demonstrated that APP isoforms 770 and 751 were expressed in fresh thyroid extracts as well as in cultured thyroid epithelial cells, with APP 770 being the predominant form. Compared to other types of cells, such as lymphocytes and fibroblasts, thyroid epithelial cells produced larger amounts of APP. Most of the mature protein was cleaved within the amyloid beta region, as a result of which a large N-terminal APP fragment was released into the culture medium, whereas a C-terminal nonamyloidogenic fragment of 14 kilodaltons (kDa) was retained within the cell. Interestingly, thyroid epithelial cells also contained larger C-terminal APP fragments of 21, 35, and 41 kDa. From the sizes of these fragments it could be deduced that they contained the entire amyloid beta sequence and were thus potentially amyloidogenic. The 41-kDa fragment was unique to thyroid cells. These fragments may be released into the circulation after thyroid cell damage. Increased/altered thyroid APP expression in familiar AD may induce alterations in thyroid epithelial cells and cell damage, and thus explain the frequent occurrence of thyroid autoimmunity in this disease.

Adult↗

Case report: epidermoid cyst of the floor of the mouth: diagnostic imaging by sonography, computed tomography and magnetic resonance imaging.

Epidermoid and dermoid cysts are rare benign tumours which may occur anywhere in the body. About 7% of them are found in the head and neck region and only 1.6% are located within the oral cavity. Pre-operative imaging of these lesions provides important diagnostic and anatomical information with regard to the patient's therapeutic management. This case report describes imaging findings in a patient with an extensive epidermoid cyst located within the sublingual space.

Adult↗

Follow-up of spongiosa plugs with contrast enhanced magnetic resonance imaging.

The aim of this study was to evaluate the extent and duration of the revascularization process in spongiosa plugs when a fibrin sealant was used. 20 patients with tumour-like lesions, benign tumours and tumours with a potential for malignant transformation were studied. After intralesional tumour removal, the defect was filled with homologous spongiosa either combined with or without a fibrin sealant, according to a prospective randomization. Magnetic resonance imaging (MRI) follow-up examinations were performed within 1 week, and 1.5, 3, 4.5, 6, 8, 12, 24 and 36 months after surgery. Those patients without a fibrin sealant showed an increased revascularization zone up to the sixth week. Patients treated with fibrin, however, showed increased revascularization up to 3 months. In the 25% percentile the extent as well as the rate of revascularization is higher in those with a fibrin sealant. It is of clinical relevance that no revascularization should be expected at 3 months after surgery, which is easily demonstrated by MR follow-up.

Adolescent↗

Sonography in the postoperative evaluation of laparoscopic inguinal hernia repair.

We evaluated the use of sonography as a means of assessing hernial occlusion and possible postoperative changes such as hematomas or seromas in the inguinal and scrotal regions after 1139 laparoscopic repairs of hernias between August 1992 and November 1994. Changes after laparoscopic hernia repair were found in 307 patients (27%). Hematomas or seromas were seen in 132 patients, protrusion of the prosthetic mesh in 17, mesh infection in two, and small bowel entrapment in an insufficient peritoneal suture in two. Recurrences were diagnosed correctly in six patients, mobile preperitoneal lipomas in five. Sonography is useful in the evaluation of complications after laparoscopic hernia repair, including recurrent hernia. In the absence of symptoms, sonography is not indicated.

Adolescent↗

Scintigraphic pitfalls in giant parathyroid glands.

We report a case of hyperparathyroidism with surgically confirmed bilaterally enlarged parathyroid glands mimicking a normal thyroid gland. Technetium-99m-pertechnetate-201Tl chloride subtraction scintigraphy was inconclusive because of suppressed thyroidal [99mTc]pertechnetate uptake after coronary angiography. Technetium-99m-sestamibi double-phase scintigraphy showed homogeneous 99mTc-sestamibi uptake that mimicked a normal thyroid gland and no differential washout, thus leading to an erroneous visual interpretation of a normal scan. Semiquantitative assessment of tracer washout, however, can differentiate between normal thyroid tissue and symmetrical parathyroid uptake mimicking normal thyroid tissue. We conclude that semiquantitative assessment of tracer washout increases the diagnostic sensitivity of 99mTc-sestamibi double-phase scintigraphy if: (a) the interpreter is unaware of the anatomical situation, (b) the scintigraphic delineation of the thyroid is hampered by a blocked tracer uptake or (c) the visual interpretation reveals no differential washout in the neck region.

Aged↗

[CT and MRI in elastofibroma. A rare, benign soft tissue tumor].

Elastofibroma is a rare, benign soft-tissue tumor that occurs along the chest wall in the periscapular region. We identified five patients with a surgical diagnosis of elastofibroma who had had CT and/or MR scans. CT and MR imaging were compared to histologic findings in two patients. CT was available in three patients and demonstrated periscapular soft-tissue tumor with an attenuation similar to that of adjacent muscle. In one patient, the tumors appeared homogeneous. In two patients, the tumor showed strands of low density similar to that of adjacent subcutaneous fat on CT. On MR imaging, all five tumors showed predominantly low-signal intensity on both T1 and T2-weighted images. The tumors contained focal areas with high-signal intensity on T1-weighted scans that showed intermediate to high-signal intensity with T2-weighting. The areas of low-signal intensity on both T1 and T2-weighted images corresponded histologically to fibroelastic tissue. The areas of high signal intensity on T1-weighting and intermediate to high-signal intensity on T2-weighting reflected focal areas of fat within the tumor. Although CT and MR imaging findings are not specific, the presence of a soft-tissue tumor along the chest wall in a periscapular location that shows predominantly low intensity on all sequences reflecting fibrous tissue with interspersed focal areas of fatty tissue is highly suggestive of elastofibroma.

Aged↗