Search PubMed⌕ Search

Biomedical subjects

U Fischer

Publications and source records attributed to U Fischer.

At least 217 records · Page 12Linked to original sources
PubMed1993

Amplified met gene linked to double minutes in human glioblastoma.

The met proto-oncogene was found to be amplified in a human glioblastoma cell line (T3095) established from a glioblastoma multiform WHO grade IV. Amplification of epidermal growth factor receptor, transforming growth factor alpha and N-myc which have been described previously in glioblastoma were not observed in T3095. There was, however, an 8-fold met amplification. Giemsa-stained metaphases of T3095 cells revealed multiple (> 5) double minutes (dmins) in the majority of cells. Following xenografting in nude mice there was a significant increase in the number and frequency of dmins. The increase in dmins correlates with the level of met amplification (50-fold), suggesting localisation of the amplified met on dmins. Here we report the first case of met amplification in glioblastoma. Correlation between met amplification and extrachromosomal elements (dmins) has not been reported previously.

Animals↗
PubMed1993

[Signal characteristics of malignant and benign lesions in dynamic 2D-MRT of the breast].

In a retrospective study of 400 dynamic MR examinations of the breast the signal/time ratio of 62 histopathologically correlated lesions (19 benign, 42 malignant) was evaluated. Points of evaluation were initial signal enhancement (1st and 2nd minute), post-initial signal appearance (2nd to 5th minute) and signal distribution (homogeneous, marginal). Based on these criteria, a point system was defined to help in the assessment of lesions in dynamic breast-MR imaging. The overall sensitivity of this method was 95.3%, the specificity to 89.5% and the accuracy to 93.5%. Pitfalls resulted in two cases of non-invasive carcinoma and in two patients with fibroadenoma.

Adenofibroma↗
PubMed1993

[The use of the RACE technique for quantitative flow measurements. Evaluation using a clinically relevant flow model].

A phantom has been designed for measuring flow velocities; using pipes of specified diameter and selectable pulse rates, flow rates varying from 0-250 cm/s can be determined. The measurements are made in a superconductive magnet with a field strength of 1.5 Tesla, employing a RACE technique. The reference technique was electromagnetic flow measurement. There was good linear correlation between the electromagnetic and the MRT results with a correlation coefficient of 0.98. It is necessary in the first place to estimate flow speed; if flow velocity is unknown initially, there is no correlation. Hence, in everyday use erroneous results may be obtained, particularly since one cannot always demonstrate vessels in all parts of the body without superimposition. Further clinical studies are required in various vascular territories to evaluate the usefulness of the RACE technique for flow measurements.

Electromagnetic Phenomena↗
PubMed1993

[The acetabular prosthesis: detection of a migration using ruler and pencil? Measurements on a pelvic phantom in comparison with a 3D computer simulation].

Conventional X-ray films were made with varying degrees of tilt of a pelvic phantom containing an acetabular prosthesis. The position of the prosthesis was then reconstructed graphically. The measurement errors were calculated and an estimate was made for the tilt. There is a linear correlation between the measurement error and the tilt of the prosthesis. Therefore a tilt dependent maximum error can be calculated. This error is very small for small degrees of tilt, so that acetabular migration can in this instance be evaluated with greater confidence than with other graphical methods. The error also correlates with the determination of the selected region of the acetabulum, but not with the position of the central focus spot or image magnification.

Acetabulum↗
PubMed1993

[Initial experiences with the MR "magnitude contrast angiography of the lower extremities].

45 patients with occlusive peripheral vascular disease were examined by MR angiography in a retrospective study. A FISP 3D sequence was used by acquiring a rephased and a dephased data set. The individual slices were post-processed by using a maximum-intensity-projection algorithm. The MRA results of the popliteal and tibioperoneal arteries were compared to conventional or digital angiography. In comparing these techniques MR angiography cannot be accepted for pre- and postoperative staging of patients with occlusive peripheral vascular disease. In future new MRA techniques may be useful in postoperative staging of patients with peripheral vascular stenosis.

Arterial Occlusive Diseases↗
PubMed1993

A cytoplasmically anchored nuclear protein interferes specifically with the import of nuclear proteins but not U1 snRNA.

A cytoplasmically anchored mutant SV40 T antigen, FS T antigen, was shown previously to interfere specifically with the nuclear import of a heterologous nuclear protein, adenovirus 5 fiber protein, in cultured monkey cells (Schneider, J., C. Schindewolf, K. van Zee, and E. Fanning. 1988. Cell. 54:117-125; van Zee, K., F. Appel, and E. Fanning. 1991. Mol. Cell. Biol. 11:5137-5146). In this report, we demonstrate that FS T antigen also interferes with the nuclear import of adenovirus E1A and a peptide-albumin conjugate bearing multiple copies of the T antigen nuclear localization signal, but not with the import of U1 snRNA. A kinetic analysis indicates that nuclear import of the albumin-peptide conjugate is inhibited only when high intracellular concentrations of FS T antigen are reached. After microinjection into the cytoplasm of cultured cells, purified FS T antigen protein does not accumulate at the nuclear periphery, but rather is distributed in a punctate pattern throughout the cytoplasm. These data support a model in which cytoplasmic anchoring of FS T antigen enables the mutant protein to sequester and titrate out a cellular factor which is required for nuclear protein but not U1 snRNA import.

Adenovirus E1A Proteins↗
PubMed1993

Primary health care of diabetic patients in a specialized outpatient setting: a DIABCARE-based analysis.

To assure health care quality requires a tool for establishing the feedback between parameters of patient management and related standards. To assess the current situation and to evaluate the DIABCARE system as a potential monitoring instrument, a retrospective study was performed in 85 randomly assigned insulin-treated patients (72% type 2) who were regularly attending the diabetes outpatient unit (total of 3,595 patients) in a township of approximately 90,000 inhabitants. 1,195 records of sequential medical visits during the years 1987 and 1990 were analyzed. -Selected results (averages in 1987 vs. 1990): (1) Visits per year 6.9 vs 7.1; (2) intensified insulin treatment in 14 vs. 27% of all patients, they were on 4.0 vs. 4.5 injections per day applying doses of 0.8 vs. 0.6 IU kg-1 d-1; (3) glycaemic control: random blood glucose 6.0 vs. 5.8 mmol/l on conventional and 6.4 vs. 5.7 mmol/l on intensified regimes, HbA1 regular measurements in 2 vs. 21% of the patients; (4) body mass index 26.4 vs. 26.6 (conventional) and 24.7 vs. 25.9 (intensified) kg/(m)2; (5) retinopathy prevalence 30 vs. 29%, in 4 vs. 29% of the patients no information; (6) nephropathy prevalence 7 vs. 11%, in 75 vs. 68% of the patients no information; (7) foot complications prevalence 6 vs. 9%, in 91 vs. 84% of the patients no pathological findings. -The DIABCARE monitor proved appropriate but too laborious. The general level of care showed a tendency towards improvement between the two investigated periods but dit not yet meet the standards which must be attained to attain the St. Vincent Declaration.

Adult↗
PubMed1993

The feedback between monitoring and improvement of quality of diabetes care.

The need for permanent, population-wide, improvement in metabolic care of diabetic patients is generally accepted. This paper highlights some related aspects which must be considered by any health care provider: (1) Monitoring metabolic or other variables in diabetic patients is an essential tool in routine metabolic care, where a "short feedback" between monitored data and medical or behavioral measures is permanently established by the patients themselves, the physicians, the nurses etc. (2) Quality insurance requires the closure of a "long feedback" between informations and interventions, such as conditions, tools, methods, used at the different levels of the care system, from the individual patient to a population scale. (3) Appropriate epidemiological studies are required to program and evaluate the effect of any activity aimed at insuring and maybe improving the quality of care of diabetic patients, especially if one considers the time required to reach "hard end-points" such as the evaluation of patient mortality or the outcome of children from diabetic mothers. (4) The knowledge of incidence and prevalence rates of diabetes and its complications, and of risk factors may stimulate the political and economical recognition of the importance of the disease by health care officials. (5) In this way, the medical recognition is also stimulated within the professional team responsible for the establishment of the "long feedback" of quality insurance at the level of a given method, of an individual patient or of a health care unit, and for the actual implementation of generally accepted knowledge, everywhere in routine care.

Blood Glucose Self-Monitoring↗
PubMed1993

Diabetes prevalence from health insurance data: evaluation of estimates by comparison with a population-based diabetes register.

UNLABELLED: At present in Germany, data on the prevalence of diabetes can only be obtained by modelling health insurance data. The National Diabetes Register of the former (East) German Democratic Republic which, between 1960 and 1990, monitored approximately 98% of all diabetic subjects, provides a tool for evaluating epidemiological estimates from other data sources. Therefore, the following data bases were compared for the year 1988: (1) a 5% random-sample (n = 6478) of all subjects insured at a local statutory health insurance company in the city of Dormund; (2) related data from the population-based diabetes register of former East-Berlin and (3) of the former German Democratic Republic. All data were standardized by sex and age according to the 1988 population statistics of the Federal Republic of (West) Germany thus resulting in the apparent diabetes prevalence of the Western part of Germany at that time. RESULTS: total prevalence rates were (1) 4.8%, (2) 4.9%, and (3) 4.4% (p < 0.05). The percentages of insulin-treated patients were (1) 18%, (2) 19%, and (3) 16%, respectively. 54% (1), 37% (p < 0.05) (2), and 42% (p < 0.05) (3), of the patients received oral antidiabetic drugs. It is concluded that the three samples are comparable and that the diabetes prevalence rates as estimated from health insurance data and from the two population-based registers give corresponding conclusions. Sample-based health insurance data may provide a useful and reliable tool for epidemiological studies on diabetes mellitus.

Adult↗
PubMed1993

[Experimental reproduction of the respiratory form of infection with the agent of epidemic late abortion of swine].

Porcine reproductive and respiratory syndrome has been observed in a large swine-farm. Diagnostic investigations were undertaken. Piglets infected with homogenate from the lung of a sick gilt developed biphasic fever up to 42 degrees C, inappetence and apathy. A few piglets showed red-blue discolored parts of the ears and of the skin in the abdominal region. A cytopathogenic agent has been isolated on cultivated alveolar-macrophages. Infection of another group of piglets with macrophages-propagated agent resulted in similar clinical signs too. Organs of euthanatized piglets have been examined anatomical, histological and with the fluorescent antibody technique. Specific fluorescence could be seen in tonsils, bronchial lymph nodes, spleen and in pathological-changed parts of the lungs. Antibodies against PRRS-virus were detected in blood samples of experimentally infected pigs.

Abortion, Veterinary↗
PubMed1992

[Is feeding of green silage in areas with hog cholera in wild boar a danger for domestic swine herds? Experimental study].

In an experimental study we tested the survival of hog cholera virus (HCV) contained in pieces of muscular tissue and organs from experimentally infected swine after incubation in silage. In big (diameter greater than 20 cm) muscular pieces HCV survived even in excellent mineral acid silage (pH 3.8-4.0) after a storage of 5 months. On the other hand in smaller parts (musculature tissue, organs less than 20 cm diameter) we never found virulent HCV after 3 months of incubation. Independent of the size of the tested organs we did not find any virulent HCV in silage with pH 5.2 after 3 months. The results of our investigations show, that the feeding of green silage in areas with hog cholera among wild boar is a potential risk for the domestic swine population. In conclusion we propose to feed green silage to unvaccinated pigs in such areas only after a storage of 9 month.

Animals↗
PubMed1992

In vitro reconstitution of U1 and U2 snRNPs from isolated proteins and snRNA.

In this paper we describe a method for preparing native, RNA-free, proteins from anti-m3G purified snRNPs (U1, U2, U4/U6 and U5) and the subsequent quantitative reconstitution of U1 and U2 snRNPs from purified proteins and snRNA. Reconstituted U1 and U2 snRNPs contained the full complement of core proteins, B, B', D1, D2, D3, E, F and G. Both the U1 and U2 reconstituted particles were stable in CsCl gradients and had the expected buoyant density of 1.4 g/cm3. Reconstituted RNP particle formation was not competited by a 50 fold molar excess of tRNA, as determined by gel retardation assays. However, U1 and U2 particle formation was reduced in the presence of an excess of cold U1 or U2 snRNA demonstrating a specific RNA-protein interaction. U1 and U2 snRNPs were also efficiently reconstituted in vitro, utilizing proteins prepared from mono Q purified U1 and U2 snRNPs. This suggests that for the assembly of snRNPs in vitro no auxiliary proteins other than bona fide snRNP proteins appear to be required. The potential of this reconstitution technique for investigating snRNP assembly and snRNA-protein interactions is discussed.

Base Sequence↗
PubMed1992

Subcutaneous glucose monitoring by means of electrochemical sensors: fiction or reality?

Amperometric glucose oxidase/hydrogen peroxide sensors were inserted subcutaneously into the neck of normal and diabetic dogs (n = 10), to elucidate the conditions for stable long-term functioning. Their output current was observed in parallel with measurements of plasma glucose concentrations and their function was checked by means of induced alterations in glycaemia. After between 14 and 96 h the experiments were terminated due to losses in the apparent sensitivity of implanted sensors and/or increasing oscillations following stable measurements. This was accompanied by an inflammatory reaction which was analysed on the basis of the clinical picture and histology. In most cases there was a bacterial ingrowth from the normal skin flora of dogs. The inflammatory exsudate contained only 23 +/- 17% of the simultaneous steady state plasma glucose concentration, which was significantly different from the glucose level in the fluid obtained from non-irritate subcutaneous tissue (95 +/- 12%, separate set of experiments). The in vitro calibration of sensors exhibited essentially comparable sensitivities before and after the in vivo application. No differences in reported findings related to the biomaterials used (polyurethane versus cellulose acetate), the presence of diabetes, the history of individual electrodes and the effective duration of a given experiment were discernible. We conclude that the functional bioinstability of subcutaneous glucose sensors is largely due to the inflammatory tissue reaction which alters the effective glucose concentration within the measuring compartment of the electrodes; these drawbacks may be overcome by further miniaturization including implantable telemetric devices allowing the closure of the skin.

Animals↗
PubMed1992

Immunoglobulin heavy and light chain gene sequences of a human CD5 positive immunocytoma and sequences of four novel VHIII germline genes.

To analyse the V genes expressed by an IgM lambda CD5-positive immunocytoma heavy and light chain V region genes were cloned and sequenced. The heavy chain is composed of a previously undescribed VHIII gene joined to an unknown D gene and to JH4. The light chain V region is composed of a V lambda II gene rearranged to J lambda 1. In an attempt to clone the germline counterpart of the VHIII gene expressed in the immunocytoma PCR amplifications of genomic DNA were carried out and four previously unknown VHIII genes were identified. As several independent clones for the heavy and light chain V region genes were sequenced the rate of somatic mutation of the V genes was calculated to be below 2 x 10(-5)/bp/cell division.

Amino Acid Sequence↗
PubMed1992

[Experiences with digital luminescence radiography (DLR) in pediatric radiology].

X-ray examinations represent a variety of indications with different demands on exposure latitude, spatial and contrast resolution of screen-film-system combinations in paediatric radiography. The value of digital luminescent radiography (DLR) was compared to conventional x-ray examinations carried out with screen-film-systems, speed class 200, by analysing matched digital and conventional exposures in 200 abdominal, 600 skeletal and 300 chest examinations. The exposure of DLR was reduced to 50% of conventional exposure. Analysing the results in abdominal and skeletal radiography, DLR proved to be diagnostically equivalent to conventional radiography despite the reduction in exposure dose. DLR of the newborn chest compared to conventional x-ray studies was not always sufficient due to lower digital spatial resolution.

Adolescent↗