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Biomedical subjects

E Steiner

Publications and source records attributed to E Steiner.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Stroboscopy and imaging in interdisciplinary diagnosis of early stages of laryngeal carcinoma].

The laryngostroboscopy is regarded to be the most important functional investigation in laryngologic and phoniatric diagnostics. She allows an analysis of vocal fold vibrations during phonation. Stroboscopic evaluations permit to early detect infiltrative processes of the vocal folds. Superficial alterations of the mucous membrane that invade into the muscle cause a phonatory "standstill" of the vocal fold in the stroboscopy, i.e. a complete lack of vibratory motion. If such a phonatory standstill persists for more than 2 or 3 weeks, a biopsy via microlaryngoscopy is indicated for diagnostic purposes. In comparison to stroboscopy, imaging techniques are not of such great significance in early laryngeal cancer. But in case of suspected infiltration of the tumor a further diagnostic evaluation with CT or MRI is necessary to detect possible neoplastic invasion of the laryngeal cartilage or of extralaryngeal structures. In this paper, we present the principle of laryngostroboscopy, the examination procedure and the stroboscopic parameters. Case reports of early laryngeal cancer illustrate the interdisciplinary diagnostic procedure with CT, MRI and stroboscopy.

Adult↗
PubMed1998

Differentiation of benign and malignant tumors of the parotid gland: value of pulsed Doppler and color Doppler sonography.

To establish criteria for the differentiation of benign and malignant tumors of the parotid gland using color Doppler sonography (CDS) and pulsed Doppler sonography (PDS) we examined 37 patients with parotid tumors by gray-scale ultrasound, CDS, and PDS. Tumor vascularization displayed by CDS was graded subjectively on a 4-point scale (0 = no vascularization, 3 = high vascularization). From the Doppler spectrum, the highest systolic peak flow velocity, the resistive index (RI), and the pulsatility index (PI) were calculated. There were 11 malignant and 26 benign tumors. Tumor vascularization by CDS was grade 0 or 1 in 88.5% of benign lesions, whereas it was grade 2 or 3 in 82% of malignant lesions (P < 0.0001). The highest systolic peak flow velocity was statistically significantly higher in malignant lesions than in benign lesions. Using a threshold systolic peak flow velocity of 25 cm/s, sensitivity was 72% and specificity was 88% for the detection of a malignant tumor. Evaluation of tumor vascularization by CDS and PDS cannot differentiate between benign and malignant parotid tumors with certainty. However, high vascularization and high systolic peak flow velocity in tumor vessels should raise the suspicion of malignancy, even if tumor morphology on gray-scale sonography indicates a benign lesion.

Adenolymphoma↗
PubMed1998

Time course of enzyme induction in humans: effect of pentobarbital on nortriptyline metabolism.

To study the effect of induction we gave six male volunteers 10 mg nortriptyline three times a day for 4 weeks and 0.2 gm pentobarbital on days 8 to 21. Plasma and urinary levels of nortriptyline and metabolites were measured. The rate and extent of induction of the enzyme(s) were estimated by a model with use of nortriptyline concentrations. There was a marked decrease of nortriptyline levels after 2 days of pentobarbital treatment. Total clearance of nortriptyline increased more than twofold (range, 1.6-fold to 4.1-fold). Apparent metabolic clearance by 10-hydroxylation increased markedly. The decrease in nortriptyline levels was more rapid than the increase after pentobarbital cessation, fitting with the theory of the model. The induction of nortriptyline metabolism is probably mainly the result of an increase in a non-CYP 2D6 P450 isozyme, possibly CYP 3A4 or a CYP 2C form. More knowledge of induction characteristics of drugs should lead to better predictions of decreased effects and appearance of adverse effects. The kinetic model used for analysis of our data could then be useful.

Adrenergic Uptake Inhibitors↗
PubMed1998

Immunohistochemical localization of ecdysteroid receptor and ultraspiracle in the epithelial cell line from Chironomus tentans (Insecta, Diptera).

Ecdysteroid receptor (EcR) and its heterodimerization partner, ultraspiracle (USP), were demonstrated in the epithelial cell line from Chironomus tentans by immunohistochemistry. In untreated cells both proteins are present in nuclei as well as in granular compartments of the cytosol. At 1 day after addition of 1-microM 20-OH-ecdysone (20E) total immunofluorescence had increased in the nuclei, whereas the cytoplasmic staining had disappeared. At the 2nd and 3rd days all cells within a vesicle appear identical according to morphological criteria, but the EcR and USP immunoreactivity becomes restricted into patches of neighbouring cells. The hormonally induced changes in the pattern of localization of functional ecdysteroid receptor, the heterodimer of EcR and USP, are discussed in relation to similar effects of 20E on acetylcholinesterase and muscarinic acetylcholine receptor distribution in this cell line.

Animal Structures↗
PubMed1998

Evaluation of intraocular foreign bodies by spiral computed tomography and multiplanar reconstruction.

OBJECTIVE: This study aimed to evaluate the ability of spiral computed tomography (CT) and multiplanar reconstruction in the assessment of intraocular foreign bodies. DESIGN: The study design was experimental. MATERIAL: Three foreign bodies (metal, glass, and plastic) implanted into the globe of a cadaveric head were studied. INTERVENTION: Spiral CT in the axial plane was used. Beam collimation and table increment were both 3 mm, whereby overlapping axial slices were reconstructed at 1-mm intervals. The data were transferred to a workstation, and reconstructions in the coronal and sagittal plane were performed. MAIN OUTCOME MEASURES: The ability to detect and evaluate localization, shape, and size of the foreign bodies in all three imaging planes was assessed. RESULTS: All foreign bodies were detected in the axial and in both reconstructed planes. The metal foreign body caused imaging artifacts in the axial plane. In the reconstructed planes. imaging artifacts were less severe, and evaluation of localization and shape was improved. Glass and plastic foreign bodies were well seen in all planes, and shape and localization were well demonstrated. Appropriate window settings improved determination of size of the different foreign bodies. CONCLUSIONS: Spiral CT of the orbit and multiplanar reconstruction offers a promising tool for evaluation of intraocular foreign bodies. Advantages of spiral CT compared to conventional CT are data acquisition in only one axial plane; shortened examination time; reduced radiation exposure; reduced imaging artifacts from metallic foreign bodies in the reconstructed planes; and demonstration of localization, shape, and size of the foreign body in three imaging planes.

Eye Foreign Bodies↗
PubMed1998

Analysis of hsp70 mRNA levels in HepG2 cells exposed to various metals differing in toxicity.

Human hepatoma cells (HepG2) were exposed to several heavy metal salts and the induction of heat shock protein 70 (hsp70) mRNA was analysed by the reverse transcriptase-polymerase chain reaction (RT-PCR). Metals were added to the cell medium at concentrations ranging from 0.1 to 100 microM and incubation was continued for 4 h. In addition we analysed the time dependence of hsp70 induction by adding each metal at a certain concentration followed by an incubation for 0.5 to 24 h. CdCl2, NaAsO2, AgNO3 could be classified as very strong inducers (20-, 13- and 10-fold above control level) and they reached their maximum level of induction at 1-10 microM after 2 h. CuCl2, MnCl2, Pb(NO3)2, TlNO3, CoCl2 and NiCl2 were also strong inducing agents, giving a 4-6 fold induction at 10-100 microM after 4-8 h. ZnSO4, Hg(NO3)2 and AlCl3 were only weak inducers (1.5-2 fold at 50-100 microM after 4-8 h) of hsp70 mRNA. Cytotoxic effects (measured by release of lactate dehydrogenase) could only be detected for 100 microM Hg2+ after 4 h and when the cells were incubated with 5 microM Cd2+ for more than 8 h. We also tested a few combinations of these heavy metal salts for their hsp70-inducing ability. Zn2+ and Mn2+ were able to diminish Cd2+ induced hsp70 mRNA levels by 65%. Ag+ mediated induction was reduced by 40% when combined with Cu2+, whereas Hg2+ increased induction by Ag+ about 3-fold and led to a dramatic decrease in cell viability. In our study we were able to demonstrate that the analysis of hsp70 mRNA levels in chemically stressed HepG2 cells by RT-PCR can be a valuable tool for studying mechanisms of toxicity associated with elevated expression of hsp70.

Cadmium Chloride↗
PubMed1998

Contrast-enhanced computed tomography of freely transplanted jejunal patches after surgery in the oral cavity and oropharynx.

Thirty-two patients with jejunal patches in the oral cavity and oropharynx were examined with contrast-enhanced computed tomography (CT). The morphology of the intestinal wall, the mesenteric fatty tissue, mesenteric lymph nodes and the region of the anastomosis were evaluated and correlated with clinical findings. The size and number of mesenterial lymph nodes, which were found in 16 cases, did not correlate with tumour recurrence. The benign alterations of the intestinal wall ranged from flat surfaces with no enhancement to significant enhancement with persisting folds. In cases with persisting intestinal folds, separation of tumour recurrence was achieved by identification of a typical double-layer configuration of the enhancing mucosa, and the restriction of alterations to the intestinal wall compartment. Tumour recurrences occurred at patch margins and were reliably distinguished from normal patches. For differentiation of findings, an exact localization of jejunum-patch compartments and margins with contrast-enhanced CT was, therefore, necessary.

Adult↗
PubMed1998

The production of the Alzheimer amyloid precursor protein (APP) in extraneuronal tissue does not increase in old age.

Alzheimer's disease (AD) is characterized by the cerebral deposition of beta-amyloid (A beta). A beta plaques also occur in the brains of healthy aged individuals, and A beta concentrations are increased in the cerebrospinal fluid (CSF) in old age. Based on results from an in vitro senescence model on human fibroblasts, it was proposed that the production of the beta-amyloid precursor protein (APP) was increased during aging. No information was available as to whether APP production was also augmented in aged humans. It was therefore the aim of the present study to analyze APP in connective tissue, skeletal muscle, peripheral blood mononuclear cells, and serum samples from young and aged healthy individuals. APP production was assessed by Northern and Western blotting. The expression of the different APP isoforms was studied by reverse transcription-polymerase chain reaction (RT-PCR) technique. The results demonstrate that APP messenger ribonucleic acid (mRNA) and protein concentrations were identical in blood and tissue samples from young and aged individuals and that there were no age-dependent changes in the APP isoform production pattern. Thus, our data strongly argue against the possibility of an altered production of APP during healthy aging and underline the point that in vitro aging models may not accurately reflect the in vivo situation.

Adult↗
PubMed1998

Apolipoprotein B and A-I values in 147576 Swedish males and females, standardized according to the World Health Organization-International Federation of Clinical Chemistry First International Reference Materials.

Serum concentrations of apolipoprotein (apo) B and apo A-I were measured from 1985-1996 in a Swedish population sample of 83 112 males and 64 464 females, ages <20 to >80 years, using an automated immunoturbidimetric method calibrated against fresh pools of human serum and commercial calibrators. All values were recalculated in 1997 after calibration against the WHO-IFCC First International Reference Materials. The recalculation factor was 1.059 for apo B, whereas for apo A-I, the correction was: y = 0.989x + 0.101. The total CVs for both apo B and A-I were generally <7%. The mean value (+/- SD) for apo B was 1.31 +/- 0.35 g/L in all males and 1.22 +/- 0.36 g/L in all females. The mean apo A-I concentration was 1.36 +/- 0.22 g/L in males-10% lower than in females (1.51 +/- 0.24 g/L). The mean value of apo B increased up to 60 years of age in males and up to 70 years of age in females. apo A-I concentrations changed only slightly with age in both males and females. apo A-I concentrations among Swedes are nearly identical to those reported recently by two American studies and those obtained in a Finnish population sample. Mean apo B concentrations differ somewhat between the populations but mirror-as expected-differences in total cholesterol concentrations. The highest values were noted in Swedish subjects. The Swedish sample population is, to our knowledge, the largest describing the distribution of apo B and A-I in a general population of adult males and females of all ages determined with procedures standardized and traceable to the WHO-IFCC First International Reference Materials.

Adult↗
PubMed1997

Tumor necrosis factor alpha augments amyloid beta protein (25-35) induced apoptosis in human cells.

No information is yet available on the effect of tumor necrosis factor alpha (TNFalpha) on amyloid beta protein (Abeta)-induced cytotoxicity in human cells. For this reason the induction of apoptosis by TNFalpha and Abeta (25-35) was studied in primary cultures of human thyroid and kidney cells as well as in the neuroblastoma line SK-N-SH and in DU-145 cells. Apoptosis occurred in all cell types after Abeta (25-35) treatment, but was markedly enhanced when TNFalpha was additionally present. This effect was less pronounced in transformed cell lines than in primary cultures, in which TNFalpha on its own was not cytotoxic. Apoptosis was still more prevalent under serum free culture conditions. The results demonstrate that TNFalpha may support the occurrence of Abeta-mediated cell death and thus contribute to the development of pathological changes in Alzheimer's disease (AD).

Amyloid beta-Peptides↗
PubMed1997

Amyloid beta-protein(25-35) increases cellular APP and inhibits the secretion of APPs in human extraneuronal cells.

Amyloid beta-protein (A beta) is the core component of the senile plaques occurring during Alzheimer's disease and in its aggregated form is cytotoxic for neuronal and extraneuronal cells. In this study, the influence of the spontaneously aggregating fragment A beta(25-35) on the expression and metabolism of beta-amyloid precursor protein (APP) was investigated in human extraneuronal cells. Cellular extracts and conditioned supernatants were analyzed by immunoblotting. A beta(25-35) strongly increased the cellular content of APP in cultured epithelial cells from thyroid glands and kidneys as well as in the promyelogranulocytotic cell line HL-60. At the same time A beta reduced the secretion of soluble APPs to less than one-third of its control value, but did not alter the secretion of fibronectin, which was used as a control protein. Despite these changes, APP transcription was not changed following A beta(25-35) treatment. These results demonstrate that A beta(25-35) strongly increases the APP content of extraneuronal cells by inhibiting its secretory processing. This may result in a deviation of APP metabolism towards an internal, potentially amyloidogenic pathway.

Adult↗
PubMed1997

The yeast CDC37 gene interacts with MPS1 and is required for proper execution of spindle pole body duplication.

The MPS1 gene from Saccharomyces cerevisiae encodes an essential protein kinase required for spindle pole body (SPB) duplication and for the mitotic spindle assembly checkpoint. Cells with the mps1-1 mutation fail early in SPB duplication and proceed through monopolar mitosis with lethal consequences. We identified CDC37 as a multicopy suppressor of mps1-1 temperature-sensitive growth. Suppression is allele specific, and synthetic lethal interactions occur between mps1 and cdc37 alleles. We examined the cdc37-1 phenotype for defects related to the SPB cycle. The cdc37-1 temperature-sensitive allele causes unbudded, G1 arrest at Start (Reed, S.I. 1980. Genetics. 95: 561-577). Reciprocal shifts demonstrate that cdc37-1 arrest is interdependent with alpha-factor arrest but is not a normal Start arrest. Although the cells are responsive to alpha-factor at the arrest, SPB duplication is uncoupled from other aspects of G1 progression and proceeds past the satellite-bearing SPB stage normally seen at Start. Electron microscopy reveals side-by-side SPBs at cdc37-1 arrest. The outer plaque of one SPB is missing or reduced, while the other is normal. Using the mps2-1 mutation to distinguish between the SPBs, we find that the outer plaque defect is specific to the new SPB. This phenotype may arise in part from reduced Mps1p function: although Mps1p protein levels are unaffected by the cdc37-1 mutation, kinase activity is markedly reduced. These data demonstrate a requirement for CDC37 in SPB duplication and suggest a role for this gene in G1 control. CDC37 may provide a chaperone function that promotes the activity of protein kinases.

Base Sequence↗
PubMed1997

Comparison and histopathological correlation of three parathyroid imaging methods in a population with a high prevalence of concomitant thyroid diseases.

The aim of this prospective study was to evaluate the diagnostic utility of a technetium-99m sestamibi dual-phase protocol enhanced by single-photon emission tomography (SPET) and semiquantitative analysis in comparison to established preoperative staging procedures in patients with primary hyperparathyroidism. Twenty-eight (50%) out of 56 patients had superimposed thyroid disease, and 12 patients had previously undergone neck surgery. Visual and semiquantitative analysis of planar 99mTc-sestamibi dual-phase imaging, SPET of the delayed phase, ultrasonography, and thallium-201 chloride-technetium-99m pertechnetate subtraction scintigraphy was further correlated with the histopathological examination of the surgical specimens. 99mTc-sestamibi dual-phase imaging achieved the highest sensitivity for side localization and precise localization compared with 201Tl-99mTc subtraction scintigraphy and ultrasonography, but the differences reached statistical significance only in comparison to ultrasonsography. Semiquantitative analysis did not enhance sensitivity. Adenoma detection by 99mTc-sestamibi dual-phase imaging was only correlated to serum calcium levels and osteocalcin, not to cell density or oxyphil cell count (SPET yielded additional information for the exact topographical localization of the parathyroid tumour in 22 (39%) patients with superimposed thyroid disease or previous neck surgery but did not enhance the overall detection rate.

Female↗
PubMed1997

[Temporal bone trauma and imaging].

Fractures of the temporal bone result from direct trauma to the temporal bone or occur as one component of a severe craniocerebral injury. Complications of temporal trauma are hemotympanon, facial nerve paralysis, conductive or sensorineur hearing loss, and leakage of cerebrospinal fluid. Early recognition and an appropriate therapy may improve or prevent permanent deficits related to such complications. Only 20-30% of temporal bone fractures can be visualized by plain films (7). CT has displaced plain radiography in the investigation of the otological trauma because subtle bony details are best evaluated by CT which even can be reformatted in multiple projections, regardless of the original plane of scanning. Associated epidural, subdural, and intracerebral hemorrhagic lesions are better defined by MRI.

Ear↗
PubMed1997

MR imaging of meniscal subluxation in the knee.

PURPOSE: The aim of this study was to establish diagnostic criteria for meniscal subluxation, and to determine whether there was any connection between meniscal subluxation and other common meniscal and knee-joint abnormalities. MATERIAL AND METHODS: The normal position of the meniscal body was assessed in 10 asymptomatic volunteers. MR signs of meniscal subluxation were evaluated retrospectively in 60 symptomatic patients with pain in the knee, impaired mobility, and/or joint swelling who had no clear diagnosis after the evaluation of case history, clinical examination, and radiography. The criterion for subluxation of the meniscus was defined as a distance of > or = 3 mm between the peripheral border of the meniscus and the edge of the tibial plateau. RESULTS: In the volunteers, the mean distance from the medial meniscus to the edge of the tibial plateau was 0.07 mm, and that from the lateral meniscus was 0 mm. In 55 symptomatic patients without meniscal subluxation, the mean distance from the meniscus to the edge of the tibial plateau was 0.27 mm. Five patients (8%) had evidence of meniscal subluxation, 4 in the medial meniscus and one in the lateral meniscus. The most commonly associated knee abnormality was joint effusion in 5 knees and osteoarthritis in 2 knees. CONCLUSION: Meniscal subluxation was not a rare finding with MR imaging in patients with painful knees. Meniscal subluxation was associated with other knee abnormalities such as joint effusion or osteoarthritis.

Adolescent↗
PubMed1997

Magnetic resonance imaging of Achilles tendon in patients with rheumatoid arthritis.

RATIONALE AND OBJECTIVES: The authors characterize the appearance of the Achilles tendon in patients with rheumatoid arthritis and differentiate this appearance from degenerative tendinopathy in patients with chronic pain of the heel using magnetic resonance (MR) imaging. METHODS: Thirty patients with rheumatoid arthritis and 28 patients with chronic pain of the heel underwent MR imaging of the ankle and foot. Three radiologists independently assessed the MR images with respect to size, shape, and intratendinal signal characteristics of the Achilles tendon. The Achilles tendon was considered abnormal on MR imaging when intratendinous signal alterations or an anteroposterior measurement greater than 8 mm was seen. Physical examination of the Achilles tendons was accomplished in both groups. Operation confirmed the diagnosis of 13 patients in the second group with chronic pain of the heel. RESULTS: The Achilles tendon of 83% of patients with rheumatoid arthritis demonstrated various intratendinous patterns (longitudinal, reticular, nodular) of intermediate signal intensity on all pulse sequences on MR imaging. Ninety percent of patients with rheumatoid tendinopathy showed no enlargement of the anteroposterior diameter of the Achilles tendon. In addition, all patients with rheumatoid arthritis had findings compatible with an inflammation of the retrocalcaneal bursa on MR imaging, whereas none of the patients with tendinopathy associated with chronic heel pain had retrocalcaneal bursitis. All patients, however, had enlargement of the anteroposterior diameter of the Achilles tendon. Seventy-nine percent showed various intratendinous lesions of intermediate signal intensity on all pulse sequences. Twenty-one percent of patients had an enlargement of the Achilles tendon without intratendinous changes. CONCLUSIONS: Rheumatoid tendinopathy can be distinguished from degenerative tendinopathy in patients with chronic pain of the heel with MR imaging. Inflammation of the retrocalcaneal bursa and the absence of enlargement of the tendon combined with the presence of intratendinous signal alterations are characteristic findings of rheumatoid tendinopathy.

Achilles Tendon↗
PubMed1997

Postoperative radiographic assessment of the Combi 40 cochlear implant.

OBJECTIVE: The aims of this study were to establish a plain radiographic technique for the assessment of the postoperative appearance, position, and insertion depth of the Combi 40 cochlear implant and to correlate the radiologic findings with surgical reports. SUBJECTS AND METHODS: In an experimental study, an electrode of the Combi 40 device was inserted into the cochlea of a cadaveric skull. Digital radiographs were obtained in a modified Chausse III projection, in which the skull was placed supine on the radiography table with the infraorbitomeatal line strictly perpendicular to the film cassette. The skull was then rotated 30 degrees away from the side to be examined, and the central X-ray beam was angled 15 degrees cephalad to the infraorbitomeatal line. On these radiographs, the point of cochleostomy was marked by a needle tip and was projected inferior to the vestibule and on a line drawn through the superior semicircular canal and the vestibule. The appearance and position of the electrode was evaluated. An electrode was defined as completely inserted if all electrode contacts projected medial to the line drawn through the superior semicircular canal and the vestibule. We also studied cochlear implant insertion of the Combi 40 device in 37 patients. Postoperative digital radiographs of these patients were obtained and analyzed for the criteria as defined in the cadaveric study. In addition, the insertion depth of the electrode and the angle of insertion were measured on the radiographs. This depth was correlated with depth of insertion as estimated at surgery. RESULTS: The cadaveric study showed that the completely inserted electrode was seen on radiographs as a nonoverlapping spiral within the cochlea. All electrode contacts projected medial to the line drawn through the superior semicircular canal and the vestibule. In all 37 patients, the electrode could be seen without overlapping. According to our criteria, a completely inserted electrode was seen in 32 patients. In these patients, the insertion depth ranged from 21 to 34 mm and the angle of insertion ranged from 350 degrees to 810 degrees. In two patients, we saw a completely inserted electrode with a bend. In three patients, an incompletely inserted electrode was seen. Excellent correlation existed between the radiologic and surgical results with regard to insertion depth (r = .92). CONCLUSION: Digital radiographs obtained in the modified Chausse III projection allow clear depiction of the electrode and avoid overlapping. Such radiographs enable a reliable and accurate assessment of the position and insertion depth of the electrode of this new cochlear implant. Such images can serve as a baseline for further radiographic examinations when extrusion or slippage of the electrode is clinically suspected.

Adult↗