Biomedical subjects

S Steiner

Publications and source records attributed to S Steiner.

At least 55 records · Page 3Linked to original sources

PubMed1996

Cyclosporine A decreases the protein level of the calcium-binding protein calbindin-D 28kDa in rat kidney.

Despite the widespread use of cyclosporine A (CsA), its mechanism of action and side effects are not yet completely understood. There exists a large body of evidence suggesting that disturbance of calcium homeostasis is a critical step in the cascade of cellular and molecular events induced by the drug. As recently shown in our laboratory by two-dimensional protein gel electrophoresis (2-DE) analysis of kidney homogenates, CsA induced numerous changes in several kidney proteins. One kidney protein in particular was shown to be strongly down-regulated by the drug. In this work we report the identification of the strongly decreased kidney protein as calbindin-D 28kDa, a vitamin D-dependent calcium-binding protein associated with calcium handling by cells. The assignment of the down-regulated protein spot is based on its internal amino acid sequence analysis and its specific reaction with a monoclonal antibody raised against calbindin-D 28kDa. In kidney homogenates of male Wistar rats treated with 50 mg/kg/d CsA for up to 28 days, calbindin levels were measured by ELISA and were shown to be continuously decreased with prolonged CsA treatment. To our knowledge, this is the first report describing the effect of CsA on kidney calbindin-D 28kDa protein levels. Further studies are needed to elucidate whether the CsA-mediated down-regulation of the calcium-binding protein calbindin-D 28kDa may be a critical factor for the renal adverse effects induced by this drug.

Amino Acid Sequence↗

PubMed1996

Induction of the adipose differentiation-related protein in liver of etomoxir-treated rats.

The effects of etomoxir, an irreversible carnitine palmitoyltransferase I inhibitor, on the liver protein pattern and on liver morphology were examined by two-dimensional gel electrophoresis in female Sprague-Dawley rats treated with 125 mg/kg/day etomoxir for 28 days. In livers of treated animals a protein spot was found which was not present in controls. The spot was identified by internal amino acid sequence analysis as the adipose differentiation-related protein (ADRP). The expression of ADRP in liver is a novel finding as the protein has been described previously as adipocyte-specific. Additionally we found histopathologic evidence of lipid accumulation in the livers of etomoxir rats. The data show that for each treated rat there was a good correlation between ADRP levels and degree of lipid droplet formation. This observation may suggest a potential relationship between drug-induced expression of ADRP in liver and lipid accumulation.

Amino Acid Sequence↗

PubMed1996

[Skull injury in childhood: comparison of ultrasonography with conventional X-rays and computerized tomography].

PURPOSE: The purpose of our study was to compare the value of ultrasound, conventional x-ray diagnosis and CT in detecting skull fractures and intracranial haemorrhage in children suffering from a head injury. MATERIAL AND METHODS: We examined 210 children who had a head injury. In all cases the calvarium was investigated by ultrasound using a 7.0 MHz linear transducer. In children with an open fontanel (n = 190) the cerebrum was screened additionally by ultrasound following a standard protocol. The sonographic findings were correlated to the x-ray examination (n = 21) and CT (n = 13). RESULTS: Ultrasound enabled diagnosis of linear calvarial fractures (n = 29), depressed fractures (n = 6) and intracranial haemorrhage (n = 8). X-Ray and CT examination confirmed the diagnosis of linear calvarial fractures in 16 cases, of depressed fractures in 6 cases. CT confirmed the sonographic diagnosis of intracranial haemorrhage in 8 cases. CONCLUSION: Ultrasound as a primary method can replace the conventional x-ray in detecting calvarial fracture and posttraumatic sequelae. Additional CT examination depends on the sonographic and neurological status.

Age Factors↗

PubMed1995

Effects of cyclosporine A on the rat liver and kidney protein pattern, and the influence of vitamin E and C coadministration.

The effects of cyclosporine A (CsA), a potent immunosuppressive drug, were examined in rat liver and kidney samples using two-dimensional electrophoretic protein analysis. Of a total of 370 liver and 336 kidney spots analyzed, 8% (29 spots) and 6% (19 spots), respectively, showed a significant drug-induced change (p < 0.01), which was predominantly reflected in increased protein abundance (62% and 74% of the changes, respectively). Of the 48 proteins changed in either organ, 14 were most probably common to both tissues and one of these was significantly increased in both the liver and the kidney. Most of the other 13 showed similar trends (either increases or decreases) in both organs. However, the most striking drug effect seen in this study concerned an unidentified protein present only in the kidney, which completely disappeared upon CsA treatment. It was also investigated whether the drug-induced changes could be prevented by the coadministration of the radical scavengers vitamin E and C with CsA. Spots changed by the administration of the drug were classified according to three different categories, based on their response profiles in rats treated with CsA in combination with the vitamins: (i) spots which were changed by CsA as well as by CsA in combination with the vitamins (12 liver and 4 kidney spots), (ii) spots which were changed by CsA and showed an additional increase of this change by CsA plus the vitamins (no liver and 4 kidney spots), and (iii) spots which were changed by CsA but not by CsA in combination with the vitamins (8 liver and 6 kidney spots). These results showed that in both organs the vitamins were able to prevent around 30% of the effects caused by CsA, and that two-dimensional gel electrophoresis is an excellent tool to demonstrate such drug interactions at the molecular level.

Animals↗

PubMed1995

Protein variability in male and female Wistar rat liver proteins.

In the emerging field of mechanistic toxicology, growing attention is being paid to the interpretation of sex-related toxic responses. The Wistar rat outbred stock is a frequently used rodent for toxicity testing. Outbred strains, which display a relatively high degree of genetic variability between the individual animals are often used in risk assessment, as they are considered to best approximate the variability present in a human population. In this study two-dimensional (2-D) protein gel electrophoresis was applied to investigate the liver protein patterns of male and female Wistar rats and to search for (i) sex-related and (ii) interindividual qualitative and quantitative differences in protein expression. Among the sexes, six proteins were detected that were shown to be exclusively present in male rats and one that was present only in females. A male-specific protein was tentatively assigned to alpha 2u globulin. Seven protein spots showed statistically significant abundance changes (p < 0.001) between males and females, one was tentatively assigned to heme oxygenase 1 and another to the 23 kDa morphin-binding protein. Four sets of protein spots were detected that showed positional shifts in the individual patterns and are likely to represent polymorphic proteins inherent in the Wistar rat. These results form a valuable basis for future investigations of drug-induced changes in the male and female Wistar rat liver pattern.

Alpha-Globulins↗

PubMed1995

An updated two-dimensional gel database of rat liver proteins useful in gene regulation and drug effect studies.

We have improved upon the reference two-dimensional (2-D) electrophoretic map of rat liver proteins originally published in 1991 (N. L. Anderson et al., Electrophoresis 1991, 12, 907-930). A total of 53 proteins (102 spots) are now identified, many by microsequencing. In most cases, spots cut from wet, Coomassie Blue stained 2-D gels were submitted to internal tryptic digestion [2], and individual peptides, separated by high-performance liquid chromatography (HPLC), were sequenced using a Perkin-Elmer 477A sequenator. Additional spots were identified using specific antibodies.

Animals↗

PubMed1995

[MRI of focal liver lesions using a 1.5 turbo-spin-echo technique compared with spin-echo technique].

AIM: The aim of our study was to evaluate a T2-weighted turbo-spinecho sequence in comparison to a T2-weighted spinecho sequence in imaging focal liver lesions. METHODS: In our study 35 patients with suspected focal liver lesions were examined. Standardised imaging protocol included a conventional T2-weighted SE sequence (TR/TE = 2000/90/45, acquisition time = 10.20) as well as a T2-weighted TSE sequence (TR/TE = 4700/90, acquisition time = 6.33). Calculation of S/N and C/N ratio as a basis of quantitative evaluation was done using standard methods. A diagnostic score was implemented to enable qualitative assessment. RESULTS: In 7% (n = 2) the TSE sequence enabled detection of further liver lesions showing a size of less than 1 cm in diameter. Comparing anatomical details the TSE sequence was superior. S/N and C/N ratio of anatomic and pathologic structures of the TSE sequence were higher compared to results of the SE sequence. CONCLUSION: Our results indicate that the T2-weighted turbo-spinecho sequence is well appropriate for imaging focal liver lesions, and leads to reduction of imaging time.

Carcinoma, Hepatocellular↗

PubMed1995

Homologous recombination as the main mechanism for DNA integration and cause of rearrangements in the filamentous ascomycete Ashbya gossypii.

A slow and a fast growth phenotype were observed after transformation of the phytopathogenic fungus Ashbya gossypii using a plasmid carrying homologous DNA and as selectable marker the Tn903 aminoglycoside resistance gene expressed from a strong A. gossypii promoter. Transformations with circular plasmids yielded slowly and irregularly growing geneticin-resistant mycelia in which 1% of nuclei contained plasmid sequences. Occasionally, fast growing sectors appeared which were shown to be initiated by homologous integration of the transforming DNA. Transformants obtained with plasmids linearized within the homology region immediately exhibited fast radial growth. In all 28 transformants analyzed plasmid DNA was integrated homologously. Such apparent lack of nonhomologous recombination has so far not been observed in filamentous ascomycetes. In 14 transformants two to four tandemly integrated plasmid copies were found. They underwent several types of genetic changes, mainly in the older mycelium: excision of whole plasmid copies and rearrangements within the integrated DNA (inversions and deletions). These internal rearrangements involved 360-bp inverted repeats, remnants of IS-elements flanking the resistance gene, and 156-bp direct repeats, originating from the strong A. gossypii promoter. Improved vectors lacking sequence repetitions were constructed and used for stable one-step gene replacement in A. gossypii.

Aminoglycosides↗

PubMed1995

[Diagnosis of cerebral metastasis with standard dose gadobutrol vs. a high dose protocol. Intraindividual evaluation of a phase II high dose study].

PURPOSE: To assess the effectiveness and safety of normal and high doses of Gadobutrol versus a standard dose of Gadolinium DTPA in the MR evaluation of patients with brain metastases. MATERIAL AND METHODS: In a clinical phase-II study 20 patients who had been diagnosed as having brain metastases with CT or MRT were studied prospectively with Gadobutrol, a new nonionic, low osmolality contrast agent. Each patient received an initial injection of 0.1 mmol/kg body weight and an additional dose of 0.2 mmol/kg Gadobutrol 10 min later. Spin-echo images were obtained before and after the two applications of Gadobutrol. Dynamic scanning (Turbo-FLASH) was performed for 3 min after each injection of the contrast agent. Both quantitative and qualitative data were intraindividually evaluated. The primary tumor was a bronchial carcinoma in 11 cases; in 9 other cases there were different primary tumors. RESULTS: Forty-eight hours after the use of Gadobutrol there were no adverse signs in the clinical examination, vital signs or blood and urine chemistry. Statistical analysis (Friedman test and Wilcoxon test) of the C/N ratios between tumor and white matter, percentage enhancement, and visual assessment rating revealed statistically significant superiority of high-dose Gadobutrol injection in comparison to the standard dose. The percentage enhancement increased on average from 104% after 0.1 mmol/kg to 162% after 0.3 mmol/kg Gadobutrol. Qualitative delineation and contrast of the lesions increased significantly. The use of high-dose Gadobutrol improved the detection of 36 additional lesions in 6 patients. CONCLUSION: The first in vivo results prove the excellent contrast capacity of the nonionic contrast agent Gadobutrol for the diagnosis of intracerebral metastases.

Adult↗

PubMed1994

Cloning and sequencing of a gene coding for an actin binding protein of Saccharomyces exiguus.

The actin binding protein Abp1p of the yeast Saccharomyces cervisiae is thought to be involved in the spatial organisation of cell surface growth. It contains a potential actin binding domain and an SH-3 region, a common motif of many signal transduction proteins [1]. We have cloned and sequenced an ABP1 homologous gene of Saccharomyces exiguus, a yeast which is only distantly related to S. cerevisiae. The protein encoded by this gene is slightly larger than the respective S. cerevisiae protein (617 versus 592 amino acids). The two genes are 67.4% identical and the deduced amino acid sequences share an overall identity of 59.8%. The most conserved regions are the 148 N-terminal amino acids containing the potential actin binding site and the 58 C-terminal amino acids including the SH3 domain. In addition, both proteins contain a repeated motif of unknown function which is rich in glutamic acids with the sequence EEEEEEEAPAPSLPSR in the S. exiguus Abp1p.

Actins↗

PubMed1994

Sequence and promoter analysis of the highly expressed TEF gene of the filamentous fungus Ashbya gossypii.

Ashbya gossypii carries only a single gene (TEF) coding for the abundant translation elongation factor 1 alpha. Cloning and sequencing of this gene and deletion analysis of the promoter region revealed an extremely high degree of similarity with the well studied TEF genes of the yeast Saccharomyces cerevisiae including promoter upstream activation sequence (UAS) elements. The open reading frames in both species are 458 codons long and show 88.6% identity at the DNA level and 93.7% identity at the protein level. A short DNA segment in the promoter, between nucleotides -268 and -213 upstream of the ATG start codon, is essential for high-level expression of the A. gossypii TEF gene. It carries two sequences, GCCCATACAT and ATCCATACAT, with high homology to the UASrpg sequence of S. cerevisiae, which is an essential promoter element in genes coding for highly expressed components of the translational apparatus. UASrpg sequences are binding sites for the S. cerevisiae protein TUF, also called RAP1 or GRF1. In gel retardation with A. gossypii protein extracts we demonstrated specific protein binding to the short TEF promoter segment carrying the UASrpg homologous sequences.

Amino Acid Sequence↗

PubMed1994

[MRT of the liver in Wilson's disease].

To show that Wilson's disease is one likely cause of multiple low-intensity nodules of the liver we obtained MR images in 16 patients with clinically and histopathologically confirmed Wilson's disease. Corresponding to morphological changes MRI enabled the subdivision of the patients into two groups. Using a T2-weighted spin-echo sequence (TR/TE = 2000/45-90) liver parenchyma showed multiple tiny low-intensity-nodules surrounded by high-intensity septa in 10 out of 16 patients. 5 patients had also low-intensity nodules in T1-weighted images (TR/TE = 600/20). In patients of this group histopathology revealed liver cirrhosis (n = 7) and fibrosis (n = 2). Common feature of this patient group was marked inflammatory cell infiltration into fibrous septa, increase of copper concentration in liver parenchyma and distinct pathological changes of laboratory data. In the remaining 6 patients no pathological change of liver morphology was demonstrated by MRI corresponding to slight histopathological changes of parenchyma and normal laboratory data. As low-intensity nodules surrounded by high intensity septa can be demonstrated in patients with marked inflammatory infiltration of liver parenchyma MRI may help to define Wilson patients with poorer prognosis. In patients with low-intensity nodules of the liver and unknown cause of liver cirrhosis laboratory data and histopathology should be checked when searching for disorders of copper metabolism.

Adolescent↗

PubMed1993

32P-postlabelling methods for cyclic DNA adducts.

32P-Postlabelling procedures coupled with HPLC have been developed to detect and measure a range of cyclic DNA adducts formed by bifunctional genotoxic agents. The methods are based on reverse-phase HPLC, particularly column-switching HPLC, to enrich adduct 3'-monophosphates before labelling. Following 3'-dephosphorylation of the 3'5'-[5'-32P]bisphosphates with nuclease P1, the resulting 5'-[32P]monophosphate adducts are resolved, identified and characterized by co-chromatography with synthetic reference standards. The procedures have been applied to a number of cyclic adducts including those formed by chloroacetaldehyde, glycidaldehyde and malonaldehyde. In general, labelling efficiencies measured as chromatographed 5'-[32P]monophosphates were in the range 30-40%. However, the values for the malonaldehyde deoxyguanosine adduct were much lower. The techniques have been applied to studies on the formation of DNA adducts in the skin of male C3H mice treated cutaneously with glycidaldehyde. The HPLC-32P-postlabelling analysis of epidermal DNA hydrolysates indicated that a single major cyclic adduct was formed by reaction with deoxyadenosine residues in mouse skin DNA. The adduct was identified as a hydroxymethyl ethenodeoxyadenosine adduct by comparison with a synthetic standard. This adduct was highly fluorescent and it was possible to make quantitative comparisons of the amounts of adduct determined by either HPLC-32P-postlabelling or HPLC-fluorescence detection.

Acetaldehyde↗

PubMed1992

Molecular dosimetry of DNA adducts in C3H mice treated with glycidaldehyde.

The formation of DNA adducts in the skin of male C3H mice treated cutaneously with glycidaldehyde (2 or 10 mg/animal) in acetone has been investigated by HPLC coupled with fluorescence detection and 32P-postlabelling analysis. Following a 24 h exposure period, epidermal DNA was isolated from treated dorsal skin and enzymically digested to nucleoside-3'-monophosphates. HPLC-32P-postlabelling analysis of the DNA hydrolysate indicated that a single major cyclic adduct was formed from the reaction of glycidaldehyde with deoxyadenosine residues in mouse skin DNA. This adduct was identified as 3-beta-D-deoxyribofuranosyl-7-(hydroxymethyl)-3H- imidazo[2,1-i]purine-3'-monophosphate by comparison with a synthetic standard. This adduct was stable, strongly fluorescent and readily detected by HPLC with fluorescence detection. There was no evidence for the formation of deoxyguanosine adducts in epidermal DNA of treated animals. Glycidaldehyde also reacted with calf thymus DNA in vitro at pH 7.0 to give the same deoxyadenosine adduct observed in vivo. At pH 10, however, this was a relatively minor product and the major adduct was 5,9-dihydro-7-(hydroxymethyl)-9- oxo-3-beta-D-deoxyribofuranosyl-3H-imidazo[1,2-a]purine-3'- monophosphate formed by the initial reaction of glycidaldehyde with deoxyguanosine residues.

Aldehydes↗

PubMed1992

Molecular dosimetry of DNA adducts in C3H mice treated with bisphenol A diglycidylether.

The formation of a glycidaldehyde-DNA adduct in skin of C3H mice treated with [14C]bisphenol A diglycidylether has been previously reported and it was assumed that the modification occurred on guanine residues. We were interested in elucidating the structure of this glycidaldehyde-DNA adduct by using a non-radioactive approach. Male C3H mice were treated with a single topical dose of 2 mg bisphenol A diglycidylether in acetone for 48, 96 or 192 h. An additional two mice were treated with 2 mg glycidaldehyde in acetone for 24 h. Epidermal DNA was isolated and enzymatically digested to nucleoside-3'-monophosphates. Aliquots of the DNA hydrolysates were separated on HPLC using a reverse-phase column with a potassium dihydrogen phosphate/methanol gradient. Fluorescence analysis of the eluent indicated the presence of a fluorescent DNA adduct, which was identified as hydroxymethylethenodeoxyadenosine-3'-monophosphate by comparison with a synthetic reference standard. Amounts of adducts were determined by fluorescence measurements using a calibration curve obtained with the authentic adduct standard. Irrespective of duration of exposure, all DNA hydrolysates of treated mice contained similar amounts of the deoxyadenosine adduct. The alkylation frequency was 0.1-0.8 and 166 adducts/10(6) normal nucleotides for the treatment with bisphenol A diglycidylether and glycidaldehyde respectively. The limit of detection using 500 micrograms DNA samples for analysis was approximately 0.03 adducts/10(6) normal nucleotides.

Aldehydes↗

PubMed1991

[Therapy of borderline personality disorder].

A short clarification of the diagnosis "Borderline Personality Disorder" is followed by a review of different therapeutic concepts. The patients usually have many social problems, therefore social rehabilitation can be the most important therapeutic measure. The concept of family-therapy is deemed important to counteract splitting phenomena in the triangle patient-family-medical doctor. Various pharmacological treatments are discussed. In the process of psychotherapy the physician should learn how to deal with impulsivity, unstable and intense interpersonal relationships, affective instability, and the tendency for physically self-damaging behavior in his patients.

Borderline Personality Disorder↗

PubMed1991

[Diffuse liver parenchymal diseases: the value of MRI compared to sonography and CT].

29 patients with diffuse liver disease were examined by ultrasound, CT and MRI. MRI imaging was performed using T1-and t2-weighted spin-echo-sequences and fast gradient-echo-sequences. The paramagnetic contrast agent Gd-DTPA was applied intravenously (0.1 mmol/kg). In all patients with hepatitis MRI enabled exact liver biopsy by delineation of inflammatory changes in cases of chronic or focal hepatitis. CT and ultrasound were superior to MRI in the detection of focal or diffuse fatty degeneration. However, MRI enabled an exact differentiation of fatty changes from neoplasm. In cases of fibrotic changes the most accurate findings could be shown by MRI. In patients suffering from hemochromatosis MRI supplied additional information compared to CT and ultrasound revealing significant reduction of signal intensity due to reinforced enhancement of iron. Concerning Wilson's disease MRI showed a characteristic pattern of parenchymal changes. The application of Gd-DTPA in cases of diffuse liver disease adds supplementary information about perfusion of liver parenchyma, but its value for diagnostic accuracy is only secondary.

Contrast Media↗

PubMed1991

[The clinical value of Mn-DPDP: a new paramagnetic hepatobiliary contrast medium for magnetic resonance tomography of the liver].

In an open prospective study the tolerance and diagnostic value of the new hepatobiliary contrast agent Mn-DPDP in MR imaging was evaluated in 20 patients suspected of having focal liver lesions. T1- and T2-weighted spin-echo sequences and T1-weighted gradient-echo sequences were obtained before and after intravenous application of Mn-DPDP. In all patients the signal to noise (S/N) values of normal liver tissue increased significantly after application of Mn-DPDP. All focal lesions could be better localized and differentiated due to increased contrast to noise ratios of lesion to liver. Pathological examination revealed in 14 patients malignant and in 5 patients benign liver lesions; one patient had no pathological findings. In metastatic disease of the liver 25-120% more lesions could be detected in MRI after Mn-DPDP-application, compared with the unenhanced images. In 5 patients the lesions showed significant enhancement of Mn-DPDP (2 cirrhotic nodules, 2 hepatocellular carcinomas, 1 focal nodular hyperplasia). Our preliminary results indicate that Mn-DPDP is a well-tolerated contrast agent useful for the detection and differentiation of liver lesions in MR imaging.

Adult↗