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Biomedical subjects

K Hartung

Publications and source records attributed to K Hartung.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Estimation of the occupational radiation exposure during radiographic studies of horses].

Radiography of horses in veterinary practice is done normally with quite simple equipment. Thereby radiation protection is easily neglected. In this investigation sources of mistakes are demonstrated. The possible exposure of staff is evaluated by dose measuring over a long period of time. It can be stated that following the most simple radiation protection there will never be a significant exposure of staff.

Animals↗
PubMed1991

Ion channel formation by synthetic transmembrane segments of the inhibitory glycine receptor--a model study.

The inhibitory glycine receptor (GlyR) of rat spinal cord contains an intrinsic transmembrane channel mediating agonist-gated anion flux. Here, synthetic peptides modelled after the predicted transmembrane domains M2 and M4 of its ligand-binding subunit were incorporated into lipid vesicle membranes and black lipid bilayers to analyze their channel forming capabilities. Both types of peptides prohibited the establishment of, or dissipated, preexisting transmembrane potentials in the vesicle system. Incorporation of peptide M2 into the black lipid bilayer elicited randomly gated single channel events with various conductance states and life-times. Peptide M4 increased the conductance of the bilayer without producing single channels. Exchange of the terminal arginine residues of peptide M2 by glutamate resulted in a significant shift towards cation selectivity of the respective channels as compared to peptide M2. In conclusion, the peptide channels observed differed significantly from native GlyR in both conductivity and ion-selectivity indicating that individual synthetic transmembrane segments are not sufficient to mimic a channel protein composed of subunits with multiple transmembrane segments.

Amino Acid Sequence↗
PubMed1991

Testing for association in SLE families.

Systemic lupus erythematosus (SLE) is a complex disease which is partly determined by genetic factors which influence susceptibility to the disease phenotype. In this association study we try to define the high risk haplotypes which are responsible for this disease, together with other environmental factors. In many other association studies a set of SLE patients is compared to a set of controls. The basic assumption about the underlying population is that the disease and control sample should originate from the same genetic population, which is not always completely satisfied in many studies. Therefore, we analyse our family data by applying the Haplotype Frequency Difference (HFD) Method, which constructs its internal control group from those haplotypes not transmitted to the affected individual. Results partially conform with other studies, showing that the haplotypes B8 DR3 as well as B7 DR2 have a high positive association with SLE. When the DR locus was analyzed alone, we found besides the alleles DR2 and DR3 a negative association for DR1, DR5, and DR6.

Adult↗
PubMed1991

Immunoglobulin allotypes are not associated with HLA-antigens, autoantibodies and clinical symptoms in systemic lupus erythematosus. Members of the SLE Study Group.

Immunoglobulin heavy chain (G1m, G2m, G3m, A2m) and kappa light chain (Km) allotype and phenotype frequencies of 323 central European Caucasian patients with systemic lupus erythematosus (SLE) were examined and correlated with various genetic, serologic and clinical markers of SLE. No significant associations were found between immunoglobulin allotypes or phenotypes and all 20 parameters tested (nephritis, vasculitis, arthralgias, photosensitivity, discoid lesions, central nervous system disease, Raynaud's phenomenon, sex, anti-Ro, anti-La, anti-nRNP, HLA-DR1-DR7, HLA phenotypes B8-DR3, B7-DR2). It could therefore be assumed that Gm, A2m and Km allotypes were not associated with HLA-antigens and had no influence on the serologic and clinical expression of SLE.

Autoantibodies↗
PubMed1991

Hetero- and homozygosity of MHC class II gene products in systemic lupus erythematosus. The Members of the Deutsche Multizentrische SLE-Studie.

An analysis of HLA class II antigens in 356 white patients with systemic lupus erythematosus (SLE) showed that all HLA-DR and -DQ homozygous and heterozygous combinations appear with frequencies expected from the observed gene frequencies. HLA-DR2 and HLA-DR3 gene frequencies were both increased in SLE, as were the odds ratios of all DR2 and DR3 hetero- and homozygous combinations. HLA-DR2/C4AQ0 heterozygotes were also not increased over expected values. Therefore, gene complementation at MHC loci does not contribute to susceptibility to SLE, but rather one or two MHC allele(s) in linkage with HLA-DR2 and HLA-DR3.

Alleles↗
PubMed1991

Immunoglobulin allotypes in systemic lupus erythematosus--results of a central European multicenter study. SLE Study Group.

Immunoglobulin heavy chains (G1m, G2m, G3m, A2m) and kappa light chain (Km) allotype and phenotype frequencies were examined in 323 central European Caucasian patients with systemic lupus erythematosus (SLE). No significant differences were found between the different allotype or phenotype frequencies of the SLE patients and a control group of healthy individuals. Our results indicate that Gm, A2m and Km allotypes do not represent susceptibility factors for SLE in Caucasians.

Gene Frequency↗
PubMed1991

Alterations of the nailfold capillary morphology associated with Raynaud phenomenon in patients with systemic lupus erythematosus.

Quantitative analysis of nailfold capillary morphology was performed in age and sex matched groups of 29 patients with systemic lupus erythematosus (SLE) presenting Raynaud phenomenon (RP), 29 RP negative patients with SLE with the same duration of the disease, and 29 healthy controls. Percentages of tortuous, meandering and bushy capillaries were significantly increased in both groups of patients without influence of RP. Capillary density was lower, mean diameters of the capillary loops were higher in patients, especially when RP was present (at the venular branch in microns, mean +/- SD: controls: 15.0 +/- 2.0, RP negative patients with SLE: 17.6 +/- 3.6, RP positive patients with SLE: 20.5 +/- 6.3). In a subgroup of 13 patients with frequent Raynaud's attacks (more than 1/week), diameters were still higher (22.1 +/- 7.1, p to controls less than 0.0005; p to RP negative patients less than 0.05). In patients with SLE, the prevalence of RP seems not to be associated with the increased number of abnormal capillaries but with capillary enlargement, correlating with the frequency of attacks.

Adult↗
PubMed1990

[Autoantibodies against the complement component C1q in systemic lupus erythematosus].

Autoantibodies against C1q, a subcomponent of the first complement component C1, could be detected in 49.4% of sera from patients with systemic lupus erythematosus (SLE). They are directed against the collagen-like portion of the C1q molecule and recognize only bound, but not fluid-phase C1q. The appearance of these autoantibodies in the course of SLE correlates with the detection of IgG in the C1q-Solid-Phase-Binding-assay, with high titres of dsDNA-antibodies and with depressed total complement activity (CH50) and C1q-values. Our investigations show that autoantibodies against the collagen-like portion of bound C1q but not immune complexes are the main constituent of C1q-binding IgG in SLE.

Autoantibodies↗
PubMed1990

Properties of three different ion channels in the plasma membrane of the slime mold Dictyostelium discoideum.

'Patch-clamp' experiments in the cell-attached configuration have shown the existence of three distinct types of ion channels in the plasma membrane of Dictyostelium discoideum. Channels DI (slope conductance 11 pS) and DII (slope conductance 6 pS) promote an outward current at depolarizing voltages. A third ion channel (HI, slope conductance 3 pS) opens preferentially at hyperpolarization and promotes inward current flow. It is suggested that under physiological conditions current through the DI and DII channels is carried by K+, whereas Ca2+ may be the current carrier in the HI channel. The density of these ion channels in the membrane of D. discoideum is low: approx. 0.1/micron 2 for the DI and HI channel and 0.02/micron 2 for the DII channel. The gating properties of the ion channels appear to be complicated because openings are grouped into bursts of activity. The probability of the DI channel being in the open state increases with depolarization. The mean channel life-time is about 20 ms and voltage-independent. The burst duration increases with depolarization whereas the interburst time decreases. The minimal kinetic model accounting for the behaviour of the DI channel is a three-state model with two closed and one open state. A detailed analysis of the gating of the DII and the HI channel was prevented by their low rate of occurrence (DII) or fast inactivation (HI). The formation of a seal resistance greater than or equal to 1 G omega depends critically on the composition of the pipette solution. Examination of a series of monovalent and divalent cations as well as different organic and inorganic anions has shown that 'gigaseals' are formed only in the presence of at least 1 mM Ca2+ or Sr2+, whereas Ba2+, Mg2+ and monovalent cations (Li+, Na+, K+, Rb+, Cs+) do not support the formation of high seal resistances. Anions seem not to affect the seal formation.

Calcium↗
PubMed1990

[Viruses and arthritis].

A number of virus infections can induce acute, non-erosive arthritis. A thorough exploration of the patient's history and serological testing for viral infections are crucial to the diagnosis of virus-induced arthritis. Musculoskeletal involvement in infection with the HIV-virus is not a rare feature and will have to be considered more often in cases of acute arthritis, as the prevalence of HIV-infection is increasing. Whether chronic arthritis, like rheumatoid arthritis, is induced by viral infection, is still a subject of intensive research efforts.

Arthritis, Infectious↗
PubMed1990

Livedo racemosa generalisata: an evaluation of thirty-four cases.

The results of investigations in 34 patients (28 women, 6 men) with livedo racemosa generalisata are presented. Neurologic or psychiatric symptoms were present in 28 patients. Nineteen patients had had one or more cerebral infarctions, and epilepsy (Sneddon's syndrome) developed in six. In most cases livedo preceded the neurologic disorder. In addition, many patients with livedo racemosa generalisata had Raynaud's phenomenon, cardiac abnormalities, or vascular changes in the ocular fundus.

Adult↗
PubMed1990

[Has the animal owner a right to radiographs taken of his animal?].

In the Federal Republic of Germany a veterinarian owns radiographs taken of animals in his practice. They have to be filed like any other results of diagnostic procedures. This is important, because evidence is required in the case of a law suit. On the other hand, it has to be stressed that taking radiographs is the subject of a free contract between owner and veterinarian. So it is possible to take the radiographs solely with the purpose of giving them to the owner, who may have them analysed by any other veterinarian of his choice. This is especially true in hip radiographs, which are evaluated and filed by an adjudicator of the breed association. In any case the radiologist has the obligation to lend the radiographs to another veterinarian on request for inspection. The second veterinarian has to give them back as soon as possible.

Animals↗
PubMed1989

Association of class I, II, and III MHC gene products with systemic lupus erythematosus. Results of a Central European multicenter study.

Class I, II, and III MHC gene products were examined in 248 Central European SLE patients. The previously reported association with HLA-A1, -B8 and -DR3, and C4AQ0 alleles was confirmed. The frequency of HLA-DR2 was also slightly elevated in SLE patients, while no increase in C4BQ0 alleles was observed. Additional findings were a significantly increased frequency of HLA-B13 and a significant decrease of HLA-B44.

Alleles↗
PubMed1989

[The radiologic description of pleural effusions with special reference to an additional projection].

Pleural effusions refer to many different conditions of the pleura itself or to generalized diseases. Small amounts of fluid may not be apparent on conventional radiographs. Regarding the standard views the ventrodorsal projection shows the earliest signs of effusion, followed by the lateral recumbent. But even in these projections it is not possible to see a small amount of fluid. An additional lateral oblique view which you obtain by lifting the extremities seems to show small amounts of fluid more precisely and earlier than any of the standard projections.

Animals↗