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Biomedical subjects

U Fischer

Publications and source records attributed to U Fischer.

At least 19 recordsLinked to original sources
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↗
PubMed1992

[The tilted screen-cassette ("grid cut-off" effect). A problem of bedside thoracic diagnosis].

Tilting of a grid during portable radiography leads to uneven exposures, and errors greater than 3 degrees can lead to errors in interpretation. Differentiation from abnormal findings can be made by recognising exposure difference of extrathoracic comparable areas. The difficulties caused by tilting of the grid can be reduced by increasing the film focus distance and by using suitable grids. A new cassette holder with an integrated balance makes it possible to correct tilting of the grid rapidly and effectively. This results in improved image quality which can be applied not only to conventional exposure systems but is also of advantage when using digital methods.

Diagnostic Errors↗
PubMed1992

[The value of digital luminescence radiography within the scope of traumatologic follow-up examinations].

At the present time we cannot unhesitatingly recommend the general use of digital luminescence radiography in traumatological follow-up examinations. Marked drawbacks of this method are, for example, sudden changes in contrast in the marginal areas of osteosynthesis material, occasional limitations in the detailed assessment of spongious structures and problems in respect of imaging geometry. By modifying the image processing parameters, increasing the image matrix and enlarging the format spectrum, however, these problems should be capable of being resolved in the future. Positive features, on the other hand, are even now the possibility of reducing the dosage to a marked degree in many traumatological follow-up examinations, especially in children and adolescents, and in case of conservatively treated fractures. In the long run we can foresee the routine use of digitalised examination methods on traumatology coupled with the possibility of storage in an image filing and communication system, although this is at present not yet feasible due to lack of requisite experience and the cost of the necessary equipment.

Computer Systems↗
PubMed1992

[The place of computed tomography and magnetic resonance tomography in the diagnosis of bone sequestra].

Conventional radiographs of 45 patients with chronic osteomyelitis, mostly of posttraumatic origin, were compared with computed tomography (CT) and operative findings. In addition, magnetic resonance imaging (MRI) was performed in 6 of these patients. In 28 patients (65%) bony sequestra were identified and in most cases histologically confirmed by surgical exploration. CT proved to be the method of choice for the preoperative diagnosis of sequestra in patients with chronic osteomyelitis. MRI provided no significant additional diagnostic information, its advantage appears to be a more detailed and accurate imaging of the extent of the intra- or extraosseous inflammation, thereby facilitating surgical planning.

Adult↗
PubMed1991

Electron transfer proteins of the purple phototrophic bacterium, Rhodopseudomonas rutila.

The soluble electron transfer protein content of Rhodopseudomonas rutila was found to consist of two basic cytochromes and a (4Fe-4S) ferredoxin. Cytochrome c' was easily identified by its characteristic high spin absorption spectra. The native molecular weight is 29,000 and the subunit is 14,000. Cytochrome c-550 has low spin absorption spectra and a high redox potential (376 mV) typical of cytochromes c2. The molecular weight is about 14,000. The ferredoxin is apparently a dimer (43,000) of approximately 18,000 Da subunits. There are 1.3 to 1.5 iron-sulfur clusters per monomer of 18- to 21-kDa protein. The N-terminal amino acid sequence is like the (7Fe-8S) ferredoxins of Rhodobacter capsulatus and Azotobacter vinelandii. Remarkably, there are only 2 or 3 out of 25 amino acid substitutions. Difference absorption spectra of Rps. rutila membranes indicate that there is not tetraheme reaction center cytochrome c, such as is characteristic of Rps. viridis. However, there are a high potential cytochrome c and a low potential cytochrome b in the membrane, which are suggestive of a cytochrome bc1 complex. Rps. rutila is most similar to Rps. palustris in microbiological properties, yet it does not have the cytochromes c-556, c-554, and c-551 in addition to c2 and c', which are characteristic of Rps. palustris. Furthermore, the Rps. rutila cytochrome c' is dimeric, whereas the same protein from Rps. palustris is the only one known to be monomeric. The cytochrome pattern is more like that of Rhodospirillum rubrum and Rb. capsulatus, which are apparently only able to make cytochromes c2 and c'.

Cytochrome c Group↗
PubMed1991

[Splenogonadal fusion].

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Angiography, Digital Subtraction↗
PubMed1991

Diversity in the signals required for nuclear accumulation of U snRNPs and variety in the pathways of nuclear transport.

The requirements for nuclear targeting of a number of U snRNAs have been studied by analyzing the behavior of in vitro-generated transcripts after microinjection into the cytoplasm of Xenopus oocytes. Like the previously studied U1 snRNA, U2 snRNA is excluded from the nucleus when it does not have the 2,2,7mGpppN cap structure typical of the RNA polymerase II (pol II)-transcribed U snRNAs. Surprisingly, two other pol II-transcribed U snRNAs, U4 and U5, have a much less stringent requirement for the trimethyl cap structure. The gamma-monomethyl triphosphate cap structure of the RNA polymerase III-transcribed U6 snRNA, on the other hand, is shown not to play a role in nuclear targeting. Wheat germ agglutinin, which is known to prevent the import of many proteins into the nucleus, inhibits nuclear uptake of U6, but not of U1 or U5 snRNAs. Conversely, a 2,2,7mGpppG dinucleotide analogue of the trimethyl cap structure inhibits transport of the pol II U snRNAs, but does not detectably affect the transport of either U6 snRNA or a karyophilic protein. From these results it can be deduced that U6 enters the nucleus by a pathway similar or identical to that used by karyophilic proteins. The composite nuclear localization signals of the trimethyl cap-containing U snRNPs, however, do not function in the same way as previously defined nuclear targeting signals.

Animals↗
PubMed1991

Successful treatment of severe premenstrual syndrome by combined use of gonadotropin-releasing hormone agonist and estrogen/progestin.

Although abolishment of ovarian cyclicity by the use of a long-acting GnRH agonist (GnRH-a) provides effective treatment for premenstrual syndrome (PMS), its use is limited by sequellae of the resultant hypoestrogenism. In this study the effects of estrogen/progestin replacement on the symptomatic improvement afforded by GnRH-a were evaluated in eight women with severe PMS. The 8-month study design included 2 months of control, 2 months of GnRH-a alone, and 4 further months in which the exogenous steroids were replaced in randomized, double blind, placebo-controlled cross-over fashion using 1 month each of 1) conjugated equine estrogen (CEE) on days 1-25, 2) 10 mg medroxyprogesterone acetate (MPA) on days 16-25, 3) CEE (days 1-25) plus MPA (days 16-25), and 4) placebo alone. Mood and physical symptoms were measured daily on a valid and reliable instrument, the Calendar of Premenstrual Experiences. As expected, administration of GnRH-a alone resulted in a 75% improvement in luteal phase symptom scores (17.8 +/- 4.8 vs. 4.2 +/- 1.6; P less than 0.01). Combined sequential administration of CEE and MPA in addition to GnRH-a was effective in maintaining the reduced symptom scores seen after GnRH-a alone and was superior to the addition of CEE alone, MPA alone, or placebo. This combination of CEE and MPA resulted in a 60% improvement (P less than 0.05) compared to the luteal phase of control months in both behavioral (14.1 +/- 3.9 vs. 4.2 +/- 0.8) and total (17.8 +/- 4.8 vs. 6.5 +/- 1.8) symptoms. We conclude that the undesirable consequence of ovarian steroid deficiency in the treatment of PMS by GnRH-a can be overcome by the addition of sequential estrogen and progestogen replacements without significantly reducing the effectiveness of GnRH-a in this disorder.

Adult↗
PubMed1991

[Effect of molsidomine infusion on thrombocyte function in acute myocardial infarct].

In 10 patients with acute myocardial infarction i.v. molsidomine was given over 48 h and a number of platelet functions was evaluated before and 3, 24, and 48 h after therapy. There was a significant prolongation of template bleeding time from 290 s to 400 s. The amplitude of spontaneous and induced platelet aggregation remained unchanged. In four of the 10 patients initially high plasma concentrations of beta-TG and PF4, and high serum concentrations of TxB2, decreased, indicating an effect of molsidomine in states of hyperreactive platelets.

Aged↗