Search PubMed⌕ Search

Biomedical subjects

U Müller

Publications and source records attributed to U Müller.

At least 271 records · Page 15Linked to original sources
PubMed1995

Clinical and molecular genetic findings in five patients with Miller-Dieker syndrome.

Five patients with type 1 lissencephaly, typical features of Miller-Dieker syndrome and apparently normal karyotypes were investigated for microdeletions in chromosome 17p13.3. Analysis of loci D17S5 and D17S379 by polymerase chain reaction and fluorescence in situ hybridization revealed a deletion in three cases. No deletion was observed in the remaining two cases. Given the almost identical clinical picture of the five patients, the great variation in the molecular findings argues against Miller-Dieker syndrome being a contiguous gene syndrome.

Abnormalities, Multiple↗
PubMed1995

Immune defence in mice lacking type I and/or type II interferon receptors.

Mice lacking the receptor for type I interferon (IFN-alpha beta, A129 mice), for type II interferon (IFN-gamma, G129 mice) or for both receptors (AG129 mice) have been generated by embryonic stem cell mediated gene targeting and inter-crossing A129 x G129, respectively. The role of the two IFN systems in controlling a range of infections has been studied using these mice. Type I IFN is shown to be responsible for the immune defence against most viral infections tested (Lymphocytic Choriomeningitis Virus, Semliki Forest Virus, Theiler's Virus, Vesicular Stomatitis Virus), type II IFN seems to be of little importance. In Vaccinia Virus and Theiler's Virus infection, however, both IFN systems were found to play a nonredundant role. IFN-gamma was critical for the defence against intracellular bacteria (Mycobacterium, Listeria) and parasites (Leishmania), whereas IFN-alpha beta was not. IFN-alpha beta is produced by virus-infected cells within hours and plays an important role in preventing virus spread early. Production of IFN-gamma on the other hand needs activation of the immune system and plays a major role later, i.e. mostly during the immune response. Data obtained with the mice described here show that both IFN systems seem to have evolved to complement each other in the host defence against a wide variety of infectious agents.

Animals↗
PubMed1995

Thyroid hormone regulation of myosin heavy chain isoform composition in young and old rats, with special reference to IIX myosin.

The effects of 4 weeks of thyroid hormone (3,5,3'-triiodothyronine, T3) treatment on the myosin heavy chain (MHC) composition were compared in the slow-twitch soleus and the fast-twitch extensor digitorum longus (EDL) muscles from young (3-6 months) and old (20-24 months) male albino rats. Four MHC isoforms were separated on silver-stained 6% sodium dodecyl sulphate polyacrylamide gel electrophoresis. According to immunoblotting experiments with specific MHC monoclonal antibodies, the four MHCs corresponded to types I, IIB, IIX and IIA. In the soleus, the type I MHC content was higher in the old than in the young animals, and the type IIA content lower. Type IIX myosin was observed in some young control soleus, but not in old ones. After T3 treatment, the content of type I MHC decreased substantially in both young and old animals and that of type IIA increased. After T3 treatment, type IIX myosin was observed in both young and old animals, with a slightly higher IIX myosin content in old age, but the age-related difference in the contents of types I and IIA was diminished. In EDL, the type IIX MHC content was significantly higher in the old animals, at the expense of a lower content of type IIB MHC. MHC composition was not affected significantly by T3 treatment in EDL, either in young or old animals. In conclusion, an age-related motor unit transformation is observed in both the slow-twitch soleus and the fast-twitch EDL and the capacity for MHC isoform switching in response to T3 treatment is not impaired in old age.

Aging↗
PubMed1995

Reverse transcription PCR to detect enteroviruses in surface water.

We have developed a simple, fast, and efficient procedure to detect enteroviruses in water samples. Aliquots of water are subjected to two-step filtration, with the second filter containing a positively charged nylon membrane that holds back virus particles. Viruses thus adsorbed are directly lysed, and RNA is isolated by hybridization to specific oligonucleotides bound to magnetic beads. The solution used contains guanidine thiocyanate, which lyses virus particles, inactivates enzymes, e.g., RNases, allows mild hybridization conditions, and does not influence biotin-streptavidin interaction on magnetic beads. Detection and specific identification are accomplished by reverse transcription PCR of the highly conserved noncoding region at the 5' end of virus RNA combined with Southern hybridization. The system was tested with tap water artificially spiked with poliovirus vaccine and yielded a detection limit of 20 50% tissue culture infective doses per liter. We used the same procedure to investigate the water quality of surface water at public beaches by rivers and lakes. Of 40 samples tested, 7 were positive for enteroviruses. A comparison with enterobacterial contamination determined by PCR and classical microbiological methods in parallel showed that enteroviruses were found only in samples also positive for Escherichia coli. In conclusion, this procedure can easily be adapted to test large water samples and is simple enough to be used for routine determinations of water quality in terms of virus contamination.

Base Sequence↗
PubMed1995

Antiviral protection by vesicular stomatitis virus-specific antibodies in alpha/beta interferon receptor-deficient mice.

The role of innate, alpha/beta interferon (IFN-alpha/beta)-dependent protection versus specific antibody-mediated protection against vesicular stomatitis virus (VSV) was evaluated in IFN-alpha/beta receptor-deficient mice (IFN-alpha/beta R0/0 mice). VSV is a close relative to rabies virus that causes neurological disease in mice. In contrast to normal mice, IFN-alpha/beta R0/0 mice were highly susceptible to infection with VSV because of ubiquitous high viral replication. Adoptive transfer experiments showed that neutralizing antibodies against the glycoprotein of VSV (VSV-G) protected these mice efficiently against systemic infection and against peripheral subcutaneous infection but protected only to a limited degree against intranasal infection with VSV. In contrast, VSV-specific T cells or antibodies specific for the nucleoprotein of VSV (VSV-N) were unable to protect IFN-alpha/beta R0/0 mice against VSV. These results demonstrate that mice are extremely sensitive to VSV if IFN-alpha/beta is not functional and that under these conditions, neutralizing antibody responses mediate efficient protection, but apparently only against extraneuronal infection.

Animals↗
PubMed1995

Antiviral defense in mice lacking both alpha/beta and gamma interferon receptors.

Alpha/beta interferon (IFN) and gamma IFN exert widely overlapping biological effects. Still, mice with individually inactivated alpha/beta or gamma receptors exhibit variably severely reduced resistance to infection and altered immune responses. To investigate to what extent the two IFN systems are functionally redundant, we generated mice with a combined receptor defect (AG129 mice). Like mice with individual mutations, AG129 mice had no apparent anomalies, confirming that in the mouse the IFN system is not essential for normal development. These mice showed an additive phenotype with respect to antiviral defense and exhibited an increased susceptibility to lymphocytic choriomeningitis virus (LCMV) and notably vaccinia virus infection. Because of unlimited replication and subsequent rapid exhaustion of cytotoxic T lymphocyte (CTL) precursors, these mice were unable to mount a CTL response to LCMV. CD8(+)-mediated immunopathology was absent in LCMV-infected mice, and virus persisted. Vaccinia virus replicated much faster in AG129 mice, and a 10(4)-fold lower dose of vaccinia virus was sufficient to prime these mice. With the normal priming dose of 10(6) PFU, cytopathic effects and overwhelming infection possibly causing partial exhaustion of CTL interfered with the anti-vaccinia virus response. Even though global antiviral immunoglobulin G (IgG) titers were within normal ranges, the IgG subclass distribution was heavily biased toward IgG1.

Animals↗
PubMed1995

[Salmonella diagnosis and expanded bacteriologic differential diagnosis using Rambach agar].

The present study gives not only additional advises and ideas for the use of Rambach agar but also diagnostic support. Resulting from several years of diagnostic experience the medium can be recommended for enlarged routine differential-diagnosis of bacteria and also for improved Salmonella-diagnosis as an alternative medium (under section 35 LMBG; Untersuchung von Lebensmitteln; Nachweis von Salmonellen).

Animals↗
PubMed1995

[Splenic neoformation following trauma-induced splenectomy--diagnosis and function].

GOAL: Regeneration of the spleen after posttraumatic splenectomy has been described in the literature. The goal of this study was to determine the rate of splenosis, its effect on hematology and postoperative infections and the value of sonography in the diagnosis of splenosis. PATIENTS AND METHODS: Fifty patients were examined sonographically one to 14 years after splenectomy. They were questioned concerning infections and a blood count was done. Data concerning the grading of the splenic rupture, additional injuries and postoperative complications were collected from their charts. RESULTS: Splenosis was detected sonographically in 17 patients. It was seen more often, the more severe the injury of the spleen had been. Patients under 30 years in the splenosis group had a shorter ICU and hospital stay and significantly less postoperative infections. Fourteen of 17 patients with splenosis had no hematological changes, while 32 of 33 patients without splenosis demonstrated Howell-Jolly bodies and acanthocytes. CONCLUSIONS: Sonography is a reliable method for visualisation of splenosis. The latter seems to prevent the hematological changes usually found after splenectomy. It also seems to reduce the number of postoperative infections in young patients.

Adolescent↗
PubMed1995

Assignment of the dystonia-parkinsonism syndrome locus, DYT3, to a small region within a 1.8-Mb YAC contig of Xq13.1.

A YAC contig was constructed of Xq13.1 in order to sublocalize the X-linked dystonia-parkinsonism (XDP) syndrome locus, DYT3. The contig spans a region of approximately 1.8 Mb and includes loci DXS453/DXS348/IL2R gamma/GJB1/CCG1/DXS559. For the construction of the contig, nine sequence-tagged sites and four short tandem repeat polymorphisms (STRPs) were isolated. The STRPs, designated as 4704#6 (DXS7113), 4704#7 (DXS7114), 67601 (DXS7117), and B4Pst (DXS7119) were assigned to a region flanked by DXS348 proximally and by DXS559 distally. Their order was DXS348/4704 #6/4704 #7/67601/B4Pst/DXS559. They were applied to the analysis of allelic association and of haplotypes in 47 not-obviously-related XDP patients and in 105 Filipino male controls. The same haplotype was found at loci 67601 (DXS7117) and B4Pst (DXS7119) in 42 of 47 patients. This percentage of common haplotypes decreased at the adjacent loci. The findings, together with the previous demonstration of DXS559 being the distal flanking marker of DYT3, assign the disease locus to a small region in Xq13.1 defined by loci 67601 (DXS7117) and B4Pst (DXS7119). The location of DYT3 was born out by the application of a newly developed likelihood method for the analysis of linkage disequilibrium.

Adult↗
PubMed1994

Behavioral and anatomical deficits in mice homozygous for a modified beta-amyloid precursor protein gene.

The beta-amyloid precursor protein (beta APP) gene of the mouse was disrupted by inserting into exon 2 a cassette containing a neomycin resistance gene and a putative transcription termination sequence. Contrary to expectation, brain and other tissues from mice homozygous for the insertion still contained beta APP-specific RNA, albeit at a level 5- to 10-fold lower than wild type and lacking the disrupted exon, which had been spliced out. The brain contained shortened beta APP-specific protein at a low level. Mutant mice were severely impaired in spatial learning and exploratory behavior and showed increased incidence of agenesis of the corpus callosum.

Amyloid beta-Protein Precursor↗
PubMed1994

[Fatalities from insect stings in Switzerland 1978 to 1987].

In the years 1978 to 1987 29 patients died in Switzerland following hymenoptera strings, most usually from honey bees and wasps (vespula). The vast majority of these fatalities were due to one single sting and thus most probably caused by IgE-mediated anaphylaxis. Three quarters of the victims were male. The mean age was 60 and most of the patients had a history or autopsy evidence of preexisting cardiovascular or pulmonary disease. Death occurred within 30 minutes of the sting in 50% and within 4 hours in 75% of the victims. Of the 10 patients with previously known hymenoptera sting allergy, none had a suitable emergency kit available when stung and none was on venom immunotherapy. Treatment by the emergency physician must be regarded as inadequate in one third of the patients.

Aged↗
PubMed1994

DXS106 and DXS559 flank the X-linked dystonia-parkinsonism syndrome locus (DYT3).

The locus (DYT3) underlying the X-linked dystonia-parkinsonism syndrome (XDP) was delineated within proximal Xq12-Xq13.1 by analysis of linkage, allelic association, and haplotypes. Short tandem repeat polymorphisms at loci DXS227, DXS559, DXS453, DXS106, DXS339, and DXS135 were studied. The occurrence of a recombination within a three-generation family established DXS559 as the distal flanking marker of DYT3. /phi/ and /delta/ values were determined as indicators of the degree of allelic association between DYT3 and the six marker loci. In addition, haplotype analysis was performed at the loci studied. The findings establish DXS106 as the proximal flanking marker of DYT3. Given an approximate distance between DXS106 and DXS559 of 3.0 Mb, isolation of DYT3 is now feasible by positional cloning techniques.

Alleles↗
PubMed1994

MHC class I expression in mice lacking the proteasome subunit LMP-7.

Proteasomes degrade endogenous proteins. Two subunits, LMP-2 and LMP-7, are encoded in a region of the major histocompatibility complex (MHC) that is critical for class I-restricted antigen presentation. Mice with a targeted deletion of the gene encoding LMP-7 have reduced levels of MHC class I cell-surface expression and present the endogenous antigen HY inefficiently; addition of peptides to splenocytes deficient in LMP-7 restores wild-type class I expression levels. This demonstrates the involvement of LMP-7 in the MHC class I presentation pathway and suggests that LMP-7 functions as an integral part of the peptide supply machinery.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Ca2+/calmodulin-dependent nitric oxide synthase in Apis mellifera and Drosophila melanogaster.

NADPH diaphorase (NADPHd) is a marker enzyme for nitric oxide (NO)-producing cells in vertebrates. This paper investigates the relationship between NADPHd and the NO-producing enzyme NO synthase (NOS) in neuronal tissue of Apis and Drosophila, two insects used for studying learning. First, the NOS and the NADPHd in both species were characterized biochemically. The fixation-insensitive NADPHd activity, which accounts for the staining in NADPHd histochemistry, co-purifies with the insect Ca2+/calmodulin-dependent NOS. Formation of NO from L-arginine depends on NADPH, and half-maximal stimulation is observed with 0.3 microM Ca2+. NOS is competitively inhibited by methyl-L-arginine and nitro-L-arginine, with Ki of 1.7 and 1.9 microM, respectively. The co-purification and the competitive inhibition of NOS by the NADPHd substrate, nitro blue tetrazolium (NBT), are proof that in insects the enzyme responsible for fixation-insensitive NADPHd activity is nitric oxide synthase. Second, the NOS activity was quantified in distinct neuropiles and the NO-producing neuropiles were visualized using NADPHd histochemistry. In both species the highest NOS activity is found in the chemosensory neuropiles of the antennal lobes, intermediate activity in the neuropiles of the central brain and by far the lowest NOS activity in the visual neuropiles. Although in both species the Kenyon cell somata of the mushroom bodies show no detectable staining, the neuropiles of the mushroom bodies of Drosophila and Apis show a distinct staining. The staining pattern of NOS in both species is different to that of all known neurotransmitters.

Amino Acid Oxidoreductases↗
PubMed1994

Functional role of type I and type II interferons in antiviral defense.

Mice lacking the known subunit of the type I interferon (IFN) receptor were completely unresponsive to type I IFNs, suggesting that this receptor chain is essential for type I IFN-mediated signal transduction. These mice showed no overt anomalies but were unable to cope with viral infections, despite otherwise normal immune responses. Comparison of mice lacking either type I or type II IFN receptors showed that, at least in response to some viruses, both IFN systems are essential for antiviral defense and are functionally nonredundant.

Alphavirus Infections↗
PubMed1994

Fallot complex, severe mental, and growth retardation: a new autosomal recessive syndrome?

We report on the syndromic occurrence of the Fallot complex in sibs born to consanguineous Pakistani parents. Additional manifestations included minor facial anomalies, pronounced failure to thrive, and mental retardation. Expression of the syndrome varied. While one of the four patients had cardiac malformations, another sib had only non-cardiac manifestations. The clinical findings suggest a new autosomal recessive syndrome.

Abnormalities, Multiple↗
PubMed1994

B cell function in mice transgenic for mCTLA4-H gamma 1: lack of germinal centers correlated with poor affinity maturation and class switching despite normal priming of CD4+ T cells.

This report outlines the B cell phenotype of transgenic mice that overexpresses the mouse CTLA-4-human gamma 1 (mCTLA4-H gamma 1) protein. Despite the fact that these mice prime CD4+ T cells (Ronchese, F., B. Housemann, S. Hubele, and P. Lane. 1994. J. Exp. Med. 179:809), antibody responses to T-dependent antigens are severely impaired. In contrast, T-independent responses are normal which suggests mCTLA4-H gamma 1 does not act directly on B cells, but acts indirectly by impairing T cell help. The impaired antibody defect is associated with impaired class switching, with low total immunoglobulin (Ig)G and antigen-specific IgG responses, and an absence of germinal center formation in spleen and lymph nodes but not gut-associated tissues. The defective germinal center formation is associated with a reduction in the degree of somatic mutation in hybridomas made from transgenic mice in comparison with those made from normal mice. It seems likely that mCTLA4-H gamma 1 exerts its effect by blocking an interaction between T and B cells that induce T cell help for B cells.

Abatacept↗