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S Müller

Publications and source records attributed to S Müller.

At least 415 records · Page 23Linked to original sources
PubMed1992

Immuno- and flow cytometric analytical methods for biotechnological research and process monitoring.

In this article, the applications of immunoanalysis and flow cytometry for research and process monitoring in biotechnology are discussed. Brief reviews of the two analytical methods are followed by descriptions of actual applications in various areas of biotechnology. In the case of immunoanalysis, emphasis is placed on systems for on-line bioprocess monitoring, and examples are given for a thermostable pullulanase, a mouse IgG, and antithrombin III. Although flow cytometry is not currently an on-line analytical technique, its value as an off-line method is illustrated by examples of the measurement of shear stress effects, lipid content, and sterol content.

Animals↗
PubMed1992

Laufband locomotion with body weight support improved walking in persons with severe spinal cord injuries.

After low transection of the spinal cord mammalian quadrupeds can be trained to walk on a driven surface indicating that coordinating neuronal circuits persist in the spinal cord segments caudal to the lesion. We trained 8 persons with incomplete spinal cord lesion on a Laufband (driven treadmill) for 1 1/2 to 7 months (5 days a week, 30-60 minutes daily) starting 5 to 20 months after injury and found significant improvement in the utilisation of the paralysed limbs during locomotion. Locomotion is described in one additional patient who had trained independently on parallel bars for several years. Five patients had complete functional paralysis in one lower limb when tested in a resting position. In EMG recordings voluntary activity (ie activity induced upon command) was absent or residual in the main flexor and extensor muscles of this limb. In contrast, during locomotion flexion and extension movements were performed and phasic EMG activity was present. In these 5 patients, and in all others reported here, skin sensibility and proprioception are preserved to different degrees in all limbs. In the course of locomotive training of 4 severely paralysed patients the initially habituating flexion reflexes could be entrained in the paralysed limbs as was the case for knee extension during stance. Subsequently, initial body weight support (BWS) of 40% could be reduced to 0%. The distance covered on the Laufband (0-104 m in the first week) increased significantly (200-410 m) in the last week of training as did speed (0-10 to 14-23 m/min). More importantly, this training subsequently allowed patients to walk on a static surface for 100 to 200 meters while voluntary activity remained absent in the paralysed limb when tested at rest. Similar progress was achieved in the 4 less severely paralysed patients. The one patient who had trained independently on parallel bars for several years is described walking on a static surface for 40 meters with the help of a walker, though he had one completely and one near completely paralysed lower limb. It appears that bipedal stepping with consequent knee extension and stabilisation can be taught after unilateral complete or near complete loss of voluntary activity, suggesting the manifestation of complex reflex motor patterns at the spinal level.

Adult↗
PubMed1992

Assessment of brain maturation by T2-weighted MRI.

MRI is a noninvasive method to assess the maturation of the brain. T2 values decrease after birth in proportion to histologically ascertained maturational changes of cortical and subcortical structures. T2 values of 8 anatomical brain structures were sampled in 5 healthy children aged 8 years, four healthy children aged 10 years and 8 healthy adults aged 24 or 25 years. The results of the study indicated that T2 values decrease after the first decade of life, consistent with maturational changes of the CNS persisting into the 2nd and 3rd decades of life.

Adolescent↗
PubMed1992

Changes in peptidergic innervation in chronic pancreatitis.

We sought to identify characteristics of peptidergic innervation that altered in patients with chronic pancreatitis. Pancreatic tissue removed from patients with chronic pancreatitis was analyzed by immunohistochemistry using antisera against neuropeptide Y, tyrosine hydroxylase, vasoactive intestinal polypeptide, peptide histidine isoleucine, calcitonin gene-related peptide, and substance P, respectively. In accordance with recent findings, the number and diameter of intralobular and interlobular nerve bundles were found to be increased as compared with control pancreas from organ donors. The striking change in the peptidergic innervation pattern in chronic pancreatitis concerned these altered nerves. It consisted of an intensification of the immunostaining for calcitonin gene-related peptide and substance P in numerous fibers contained in these nerves. Adjacent sections showed that immunoreactive substance P and immunoreactive calcitonin gene-related peptide coexisted in these fibers. Because both of these peptides are generally regarded as pain transmitter candidates, our findings provide further evidence that changes in pancreatic nerves themselves might be responsible for the long-lasting pain syndrome in chronic pancreatitis.

Adult↗
PubMed1992

Structure of selenocysteine synthase from Escherichia coli and location of tRNA in the seryl-tRNA(sec)-enzyme complex.

Selenocysteine synthase of Escherichia coli catalyses the biosynthesis of selenocysteine in the form of the aminoacyl-tRNA complex, the reaction intermediate being aminoacrylyl-tRNA(sec) covalently bound to the prosthetic group of the enzyme. Selenocysteine synthase and the specific aminoacrylyl-tRNA(sec)-enzyme complex as well as the isolated seryl-tRNA(sec) were investigated in the electron microscope and analysed by means of image processing to a resolution of 2 nm in projection. The stoichiometric composition of the selenocysteine synthase molecule was elucidated by scanning transmission electron microscopic mass determination. The enzyme has a fivefold symmetric structure and consists of 10 monomers arranged in two rings. The tRNA is bound near the margin of the dimeric subunits. Principal component analysis of the tRNA-enzyme complexes revealed that the selenocysteine synthase appears to bind only one seryl-tRNA(sec) per dimer, which is consistent with the result of biochemical binding studies.

Bacterial Proteins↗
PubMed1992

Effect of low frequency air oscillations on nasal mucociliary transport.

Air oscillations of 16 Hz and pressure differences of 200 mmHg were applied to the nose of 30 volunteers. The mucociliary transport was measured by the saccharin test. Tests under the same circumstances were performed with and without oscillations on the same person within the same day. There was a significantly faster mucociliary transport during air oscillations. The possible mechanisms for this effect are discussed.

Adult↗
PubMed1992

[Treatment of aseptic post-traumatic pseudarthrosis].

We report our first experience of using the Ilisarov technique in the treatment of ten patients with aseptic nonunions of fractures. In nine cases there was a nonunion of the tibia. One 76-year-old woman suffered from a nonunion of a supracondylar fracture of the humerus with concomitant rheumatoid arthritis. In this case, treatment failed. In two other cases we had to change the procedure. The mean duration of fixation for the successful cases was 22 weeks. The Ilisarov technique is sophisticated and needs special experience but has advantages in difficult cases.

Adult↗
PubMed1992

[In vivo measurements of electric potentials of the Ilisarov external fixator].

Ilisarov's idea that electrical phenomena could contribute to the efficacy of the ring fixation apparatus prompted us to carry out this preliminary investigation. Patients with lower leg fractures and a four-ring fixation apparatus were selected; the electrical potentials were measured over non-fractured and fractured bones. Patients who could not be studied in the Faraday box were subjected to great disturbances, caused by mains voltage and a neighbouring transmitter; in these cases no objective results could be obtained. Only measurements in the Faraday box yielded reproducible results. The results demonstrate that there is generally a difference in electrical potential among the four rings in patients fitted with an Ilisarov apparatus. Furthermore, weight-bearing on the fixator-bone system causes changes in the electrical potential among the rings.

Bone and Bones↗
PubMed1991

Generation and specificity of monoclonal anti-idiotypic antibodies against human HIV-specific antibodies. I. Cross-reacting idiotopes are expressed in subpopulations of HIV-infected individuals.

In this study we have generated monoclonal anti-idiotypic antibodies against human monoclonal and polyclonal anti-HIV antibodies in seropositive sera. A human anti-gp41 mAb (H2, IgM kappa) was used to immunize BALB/c mice and to prepare hybridoma anti-antibodies that react with H2 and not with normal human IgM. Similar monoclonal anti-antibodies were made in BALB/c mice immunized with Ig fraction prepared from a pool of HIV-seropositive sera. Both kinds of anti-idiotypic antibodies reacted with antibodies in pools of seropositive sera and with individual seropositive sera but not with normal human Ig or seronegative sera. The Id-positive Ig from single donors were isolated on two different anti-Id immunoabsorbents and shown to bind to p24 and gp120, respectively. The detection and isolation of idiotypically cross-reactive human anti-HIV antibodies from seropositive donors demonstrated, for the first time, the existence of shared Id expressed by antibodies against HIV Ag. The utility of cross-reacting anti-idiotypic antibodies as tools to dissect the network regulation of the anti-viral immunity in AIDS is discussed.

Animals↗
PubMed1991

Two-phase in vitro culture of explanted chick embryos.

The present study describes a method of culturing chick embryos together with their surrounding area vasculosa on two different culture media in succession. Embryos in the 2nd day of incubation (stages 13, 14, 15 according to Hamburger and Hamilton, 1951) were explanted from the yolk with the aid of a ring of filter paper and transferred dorsal side up to a silicone culture dish containing the first culture medium (89.5% L-15, 10% fetal calf serum, 0.5% Antibiotics). The paper ring was clamped onto the wall of the culture dish by a steel ring so that the embryo was fixed for the culture period. After 4 +/- 1, 8 +/- 1, 12 +/- 1 hrs, the embryos were taken from the culture dishes and transferred to others containing a yolk-albumen mixture as culture medium; 81.2% of embryos survived the first phase of culture. On the second medium 50.3% of explanted embryos were still alive at stage 20 (HH), and 7.9% of them reached the 5th day of development (St 25 HH). The average length of survival in vitro was found to be influenced by both the length of the first culture phase and the stage at which embryos were explanted. This culture method may be useful for teratological tests, since in the first phase of culture, concentrations of test substances and the time of exposure can be exactly adjusted, and in the second phase, the embryo is allowed to develop quite normally, under conditions similar to those in ovo.

Animals↗
PubMed1991

31P MR spectroscopy and 1H MR imaging of the human prostate using a transrectal probe.

1H magnetic resonance imaging and 31P magnetic resonance spectroscopy of the human prostate using transrectal surface coils are discussed. 1H MR images were characterized by a high sensitivity, revealing many details in the prostate. Localized 31P spectra acquired during the same investigation showed phosphorous metabolites, which may help differentiate between benign prostatic hyperplasia and prostate carcinoma. An endoscopic transmit-receive radio frequency (RF) antenna is also described which can be used with very low RF power.

Humans↗
PubMed1991

Effect of bis(benzyl)polyamine derivatives on polyamine transport and survival of Brugia pahangi.

A potent filaricidal effect of bis(benzyl)polyamine derivatives is reported; the addition of 1 microM MDL 27695 to Brugia pahangi maintained in vitro killed the worms within 1 week. Using the labelled derivative, MDL 27391 uptake was demonstrated and evidence was provided for an uptake system that is independent of and clearly distinguishable from those for polyamines. The Km value for the uptake of MDL 27391 was determined to be 2 microM, and that for putrescine, spermidine, and spermine was 4.9, 1.7, and 4.8 microM, respectively. The uptake of MDL 27391 was not affected by polyamines. In contrast, bis(benzyl)polyamines were shown to be strong inhibitors of both the putrescine and the spermidine/spermine uptake system. As shown for MDL 27391, bis(benzyl)polyamines are not metabolized after uptake by Brugia worms; therefore, it is expected that the filaricidal effect of the drug depends on its interaction with potential polyamine-binding sites.

Animals↗
PubMed1991

The galactan-degrading enzymes in the snail Biomphalaria glabrata.

1. Embryonic snails incorporate from the perivitelline fluid in which they are embedded a polysaccharide, called galactan, which is composed entirely of D-, or D- and L-galactose. In this investigation the p-nitrophenyl-beta-D-galactoside degrading enzyme of Biomphalaria glabrata which was assumed to be involved in the degradation of the galactans was purified almost to homogeneity and its specificity was studied. 2. It has a mol. wt of 135,000 and is composed of two identical subunits. 3. It could be shown that p-nitrophenyl-beta-D-fucoside was hydrolysed eight times faster, but native galactan was neither decomposed nor was it inhibitory for the hydrolysis of p-nitrophenyl-glycosides. 4. Thus, it is most likely that this galactosidase is not involved in the galactan metabolism. 5. However, a membrane-bound enzyme complex was revealed which was able to metabolize the native galactan of Biomphalaria glabrata completely and which showed graded reactivity towards galactans of other species. 6. Since no intermediate degradation products were found it must be assumed that they were metabolized further in the mitochondria.

Animals↗
PubMed1991

Interrelation of peptidergic innervation with mast cells and ED1-positive cells in rat thymus.

The peptidergic innervation of rat thymus has been investigated by immunohistochemical methods, focusing on the spatial interrelationship of peptidergic nerve fibers with mast cells and macrophages in the rat. An antiserum directed against the protein gene product 9.5 (PGP 9.5) regarded as a pan-neuronal marker revealed a rich innervation, especially in the subcapsular cortex, in interlobular septa, and of the vasculature in the cortex and the corticomedullary boundary. A minor proportion of PGP 9.5-immunoreactive (ir) fibers supplied the thymic parenchyma. The main component of peptidergic innervation consisted of fibers costaining for tachykinins (TKs) and calcitonin gene-related peptide (CGRP), but considerable amounts of neuropeptide Y (NPY)/tyrosine hydroxylase (TH)-positive fibers and vasoactive intestinal polypeptide/peptide histidine isoleucine-positive fibers also were present. There were sparse Leu-enkephalin and galanin immunoreactivities in thymic nerve fibers, while neurotensin was absent from nerve fibers. Close associations of TK/CGRP-ir and NPY-ir fibers with mast cells were frequently detected in the connective tissue areas of the thymus, often adjacent to the vasculature. TK/CGRP-ir fibers and some rare NPY-ir fibers were found adjacent to EDl-positive macrophages and less frequently to mast cells. TK/CGRP-ir and NPY-ir fibers were mainly detected in relation to the vasculature of the cortex and the corticomedullary boundary, but also were found in capsular and subcapsular regions of the thymic cortex. The possible importance of the close spatial relationship between the various peptide-containing nerve fibers and mast cells and ED1-positive macrophages in neuroimmune integration is discussed.

Animals↗
PubMed1991

In vitro assembly of gap junctions.

Gap junction structures were assembled in vitro from octyl-beta-D-glucopyranoside-solubilized components of lens fiber cell membranes. Individual pore structures (connexons), short double-membrane structures, and other amorphous material were evident in the solubilized mixture. Following the removal of the detergent by dialysis, these connexons associated to form single- and double-layered, two-dimensional hexagonal arrays (unit cell size a = b = 8.5 nm). The formation of larger arrays was dependent on the lipid-to-protein ratio and the presence of Mg2+ ions. Crystallographic analysis of electron micrographs revealed that lens junctional connexons consisted of six subunits surrounding a stain-filled channel. Upon further detergent treatment, in vitro assembled gap junctions were insoluble and formed three-dimensional stacks while other components were solubilized. SDS-PAGE and mass data from scanning transmission electron microscopy strongly suggest that a 38-kDa polypeptide, which is a processed form of the lens specific gap junction protein MP70, is a major component of the arrays. The in vitro assembly of gap junctions opens new avenues for the structural analysis of gap junctions and for the study of the intermolecular interactions of connexons during junctional assembly.

Animals↗