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Biomedical subjects

J Klingler

Publications and source records attributed to J Klingler.

7 recordsLinked to original sources
PubMed1997

Site-specific interaction of thrombin and inhibitors observed by fluorescence correlation spectroscopy.

We report on the application of fluorescence correlation spectroscopy (FCS) to observe the interaction between thrombin and thrombin inhibitors. Two site-specific fluorescent labels were used to distinguish between inhibitors directed to the active site, the exosite, or both binding sites of thrombin. For several well-known inhibitors of thrombin, the binding sites observed by FCS correspond to previous studies. The interaction of the recently discovered thrombin inhibitor ornithodorin from the tick Ornithodorus moubata with thrombin was investigated. It was found that this inhibitor, like hirudin and rhodniin, binds to both the active site and exosite of thrombin simultaneously. This study shows the feasibility of FCS as a sensitive and selective method for observing protein-ligand interactions. As an additional technique, simultaneous labeling with both fluorescent labels was successfully demonstrated.

Animals↗
PubMed1995

N-proximal sequence motif in light-harvesting chlorophyll a/b-binding protein is essential for the trimerization of light-harvesting chlorophyll a/b complex.

The major light-harvesting complex (LHCII) of photosystem II can be reconstituted in its native, trimeric form starting from its apoprotein light-harvesting chlorophyll a/b-binding protein (LHCP), pigments, and thylakoid lipids. In this paper we identify segments in the LHCP polypeptide that are essential for the formation of stable LHCII trimers by analyzing N- and C-terminal deletion mutants of LHCP and mutants carrying point-specific amino acid exchanges. C-terminal deletions that do not abolish pigment binding to LHCP do not affect trimerization either. By contrast, on the N-terminus of LHCP, where as many as 61 amino acids can be deleted without significant effects on pigment binding, only 15 amino acids are dispensible for LHCII trimer formation. This indicates that structural elements between amino acids 16 and 61 are involved in the stabilization of LHCII trimers but not monomers. Closer inspection of this protein domain in a more detailed mutation analysis revealed that amino acids W16 and/or Y17 as well as R21 are essential for the formation of LHCII trimers. These amino acids are conserved in virtually all known sequences of LHCII apoproteins but only in some of the minor chlorophyll a/b complexes. Possible functions of the crucial residues are discussed.

Amino Acid Sequence↗
PubMed1994

[School and child health].

A roundtable discussion involving 2 educators and 4 pediatricians with widely varying experience sounded out the negative (pathogenic) and positive (healthy) influences to which a child is exposed in school and which decisively shape his/her physical, mental and psychic development. Concrete case reports and a systematic compilation of harmful factors show that this institution poses major threats to children's health of which pediatricians should be aware. An important cause of childhood suffering is the discrepancy between the uniform and inflexible institutional structures and the variability of children's needs conditioned by biology and social origin. Between ideal visions and the consequent school structures on the one hand, and social reality on the other hand, there are notable contradictions which must be recognized, lived with and--if possible--resolved by reforms. If he believes in the reformability of school, the pediatrician can make essential contribution to promoting health during school age.

Achievement↗
PubMed1991

Core-coat conductor of lipid bilayer and micromachined silicon.

We have etched a groove into a (110) plane of silicon and have covered it with a bilayer of glycerol monooleate. We have varied the depth of the groove, the concentration of salt in the electrolyte and the density of gramicidin in the membrane. We have clamped one end of the groove at a constant voltage with respect to the bath keeping the other end sealed or electrically open with respect to the bath. We have measured (i) the voltage at the center of the groove and at the sealed distal end and (ii) the current through the system in sealed and open configuration. We have found that the spread of voltage is in quantitative agreement with the stationary solutions of Kelvin's equation for a homogeneous cable.

Electric Conductivity↗
PubMed1980

[Skeletal fluorosis in senility (author's transl)].

There are reported two cases of nonprofessional skeletal fluorosis in senility. Causes of origin, clinical and roentgenological picture, histology and bone fluoride contents are specified, the findings discussed in connection with sodium fluoride therapy of osteoporosis.

Aged↗
PubMedDate not supplied

[Sensomotor function while wearing lumbar support ortheses].

AIM: Flexible lumbar corsets should contribute to an improved active and passive stabilisation of the lumbar spine. In the present study, the effects of flexible corsets on sensory-motor abilities have been investigated. METHODS: 24 healthy subjects (m = 10, f = 14, 26.7 years) performed angle- and force-reproduction tasks with and without wearing a flexible corset. The subjects tried to reproduce trunk flexion angles of 20 degrees und 40 degrees as well as forces of 33% and 66% of the maximum strength of the back extensor muscles. Additionally, muscular reactions were measured during destabilizing stimuli. RESULTS: No significant differences were found for the reproduction tasks. When wearing the corset, the left erector spinae muscles showed a delayed onset (+15 ms, p < 0.05), and the obliquus abdominis reached maximal activity more rapidly (-18 ms, p < 0.05). In the preinnervation phase the obliquus abdominis (-33%, p < 0.01), in the eccentric phase the erector spinae (-27%, p < 0.05) and the right obliquus abdominis (-46%, p < 0.05) and in the concentric phase the right obliquus abdominis (-35%, p < 0.01) and the rectus abdominis (-32%, p < 0.05) showed lower activities. CONCLUSION: The reduced muscle activities with destabilizing stimuli can be interpreted as the result of an improved passive stabilisation of the lumbar region by wearing a flexible corset.

Adult↗