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Biomedical subjects

H Lang

Publications and source records attributed to H Lang.

At least 253 records · Page 14Linked to original sources
PubMed1980

On the interaction of caffeine with nucleic acids. III. 1H NMR studies of caffeine--5'-adenosine monophosphate and caffeine-poly(riboadenylate) interactions.

1) The self-association of both caffeine (Cf) and 5'-adenosine monophosphate (AMP) in aqueous solution has been reinvestigated by 1H NMR. The self-association process is characterized by an isodesmic model. The apparent self-association constants of the vertical stacking process are KCf = (10.6 +/- 1.0) M-1 and KAMP = (1.67 +/- 0.17) M-1. The arrangement of the monomeric units in the stacked aggregates is discussed in terms of isoshielding curves theoretically calculated by Giessner-Prettre and Pullman. Models are proposed which are consistent with these and further previous NMR data. 2) The interaction of Cf and AMP has been studied by 1H NMR. The apparent association constant of the complex Cf-AMP is KC-A = (7.3 +/- 1.2) M-1. Two models of the mutual arrangement of AMP and Cf in the complex are proposed on the basis of the calculated isoshielding curves considering both ring current and local atomic diamagnetic anisotropy effects. 3) The interaction of Cf and poly(riboadenylate), (rA)n, is indicated by a downfield shift of the H-8 line but an upfield shifts of the H-2 line in the 1H NMR spectra of (rA)n. The concentration dependence of the 1H NMR shifts of both Cf and (rA)n can be explained by the existence of two binding mechanisms. We suggest (i) partial insertion of Cf between adjacent base residues of ordered single-stranded regions of (rA)n and (ii) outside binding of Cf in form of monomeric Cf as well as of self-associated aggregates. The complex geometry of insertion proposed on the basis of the calculated isoshielding curves is characterized by a stronger overlapping of the Cf ring and the H-2 proton of (rA)n as compared to the H-8 proton.

Adenosine Monophosphate↗
PubMed1980

On the interaction of caffeine with nucleic acids. IV. Studies of the caffeine-DNA interaction by infrared and ultraviolet linear dichroism, proton and deuteron nuclear magnetic resonance.

The DNA-caffeine interaction at high concentration of caffeine (Cf) leads to an arrangement of Cf molecules outside of the DNA double helix with an orientation parallel to the bases both in the A and B form as demonstrated by infrared linear dichroism. Addition of DNA broadens the 1H NMR lines of Cf in aqueous solution indicating a specific binding. Intercalation is not the predominant mechanism, the deuterium relaxation time T1 = (38 +/- 7) ms and the estimated reorientation correlation time tau cb = 0.17 ns of caffeine-8[2H] in the Cf-DNA complex suggest an outside stacking of the ligand. According to the results a model on the DNA-Cf complex at high Cf concentration (binding process II) is suggested including the caffeine-induced reorientation of the hydration shell of DNA.

Caffeine↗
PubMed1980

Cooperative effects between lymphokine-induced and antibody-dependent macrophage-mediated cytotoxicity in C57NL/10 and C3H/HeJ mice.

Cooperative effects are described between 2 different mechanisms of macrophage-mediated cytotoxicity, the lymphokine-induced and the antibody-dependent cytotoxicity:Macrophages are activated to nonspecific cytotoxicity by a 24 h incubation with lymphokines. Young macrophages cultured from the bone-marrow or obtained from induced peritoneal exudates, but not the resident peritoneal macrophages, have the capacity to kill antibody-coated tumor cells. To obtain a cooperative effect between the 2 mechanisms both the lymphokine and the antibody have been titrated to a dilution, at which the macrophages did not exert any cytotoxicity. At such subthreshold dosages, however, a very good synergistic effect between the 2 mechanisms was observed. This synergism was obtained with bone-marrow macrophages and with thioglycollate-induced peritoneal macrophages. Macrophages of C3H/HeJ mice, which have been reported to be a low responder strain for lymphokine activation, showed synergistic effects with similar lymphokine concentrations as macrophages from the high responder strain C57BL/10. Thus, in this synergistic situation the low responsiveness of C3H/HeJ mice is completely compensated. Since during an immune reaction in most cases lymphokine as well as antibody are produced, this synergistic reaction will be of particular relevance for in vivo-situations.

Animals↗
PubMed1980

Toxic encephalopathy with hyperammonaemia during high-dose salicylate therapy.

High-dose, long-term aspirin therapy easily overloads the patient's individual capacity to metabolize salicylates and may lead to complex metabolic disturbances including fulminant hepatic failure, hyperammonemia and toxic metabolic encephalopathy. In the two cases presented there was a severe outbreak of hepatotoxic encephalopathy despite the fact that the dosage of salicylates did not exceed that generally recommended for children with rheumatic diseases. The justification of high-dose salicylate therapy is discussed, taking into account the fact that children with juvenile rheumatoid arthritis and allied conditions may have increased susceptibility to liver damage from drugs. EEG abnormalities in these two cases corresponded to those described in other metabolic encephalopathies including Reye's syndrome. The quality of the EEG changes gives prognostic signs, but is of restricted value in establishing the etiology without the anamnestic data of salicylate ingestion. Active therapeutic measures including exchange transfusions are needed to prevent irreversible metabolic and pressure changes in the brain.

Adolescent↗
PubMed1980

Involvement of the central nervous system in acute, uncomplicated measles virus infection.

A prospective study on acute, uncomplicated measles infection was carried out in 59 patients hospitalized for an ordinary measles infection. A clinical and serological diagnosis of an acute measles infection was made in all cases. Serial serum and cerebrospinal fluid (CSF) specimens were taken two to five times from each patient and tested for pleocytosis, albumin, and measles-specific antibodies. Pleocytosis was found in 18 patients (30%), usually shortly after the onset of rash. Nine patients had antibodies against measles virus in their CSF. Six of them seemed to have damage to the blood-brain barrier, but in two cases there was a very high serum antibody titer with a normal serum/CSF ratio. One patient had a local antibody production against measles virus in the central nervous system. Conventional electroencephalography (EEG) was recorded on 22 children, and a separate, quantitative EEG study with two to six consecutive recordings was also performed on a group of nine patients. Moderate or strong slowing of background EEG activity was found in 50% of the patients. In the consecutive recordings, the changes culminated a few days after the onset of rash. No correlation seemed to exist between the changes in the CSF and the age of the patient, on the one hand, and slowing of the EEG, on the other.

Adult↗
PubMed1979

Structural changes of ultraviolet-irradiated DNA derived from hydrodynamic measurements.

The paper reports on sedimentation and viscosity measurements performed on ultraviolet-irradiated DNA from T7 phage and calf thymus. From the hydrodynamic data the relative changes in the mean molecular weight, radius of gyration, and effective Kuhn statistical segment length were calculated. The results show that ultraviolet irradiation (254 nm) leads to a significant decrease of the effective statistical segment length of DNA which may be due to small local helix kinks (produced by the generation of photodimers) and a local increase of chain flexibility. Alterations in the overall DNA conformation may be observed even at low fluences where the mean molecular weight almost stays constant. The locally distorted helix regions possibly may serve as recognition sites in the first step of excision repair.

Animals↗
PubMed1979

The covalent structure of calf skin type III collagen. IV. The amino acid sequence of the cyanogen bromide peptide alpha 1(III)CB5 (positions 552--788).

The cyanogen bromide peptide alpha 1(III)CB5 is 237 amino acid residues in length and occupies position 552--788 along the alpha 1(III) chain. For sequence analysis alpha 1(III)CB5 was fragmented with hydroxylamine, protease from Staphylococcus aureus V8, trypsin and the arginine-specific enzyme from mouse submaxillary gland. The peptides obtained were separated using molecular and ion exchange chromatography and sequenced with the automated Edman degradation procedure.

Amino Acid Sequence↗
PubMed1979

Structural transitions of chromatin induced by netropsin.

Structural changes of chromatin induced by interaction of netropsin (Nt) with DNA has been examined by analysis of CD and electromicroscopic measurements. The results demonstrate the existence of a transition from the condensed globular state of chromatin into nucleosomal fibres generated by extremely low Nt concentration up to 1 mole Nt per 200 nucleotides. A second transition occurs at high Nt ratio per DNA phosphate (v' = 0.3). involving disorganization of nucleosomal particles. The interference of the Nt binding with chromatin proteins maintaining the sub- and superstructure will be discussed.

Animals↗
PubMed1979

[Properties and significance of macro-creatine kinases (author's transl)].

Sera from seven-patients with an unusual high ratio of creatine kinase-MB versus total creatine kinase, as found in the immunoinhibition test, were investigated. In every case, the electrophoretic separation of the isoenzymes showed a slow moving band, and exclusion chromatography showed the presence of macro-creatine kinase. Further chromatographic, electrophoretic and immunological investigations indicated that the macro-creatine kinases in six cases are complexes of creatine kinase-BB linked to immunoglobulin G.

Aged↗
PubMed1979

Thymidine photoproducts of non-cyclobutane type as a crucial event in the conformation of UV-irradiated DNA.

The UV-light induced conformational effects in deoxyoligonucleotides and polynucleotides have been analyzed by CD measurements and isolation of the photoproducts. The results demonstrate that the essential photoproduct formed on irradiation of thymidylyl-thymidine at 254 nm is of non-cyclobutane type and may be correlated to the primary photoproduct formed in DNAs at low doses Formation of thymine dimers of cyclobutane-type structure appears to be a secondary product generated by treatment with formic acid.

Chromatography, Paper↗
PubMed1978

[Creatine kinase isoenzymes: idiopathic occurrence of creatine kinase BB activities in patient serum (author's transl)].

By differentiation of creatine kinase isoenzyme activities in sera using immunological methods the published data about occurrence of creatine kinase BB activities in patients with different diseases or after surgical treatment, respectively, cannot be verified in general. With a frequency in the order of magnitude of 1 : 1000 in the serum of old patients (age 57 to 85 years with one exception), however, creatine kinase BB activities can be measured. The range of activities is 15 to 234 U/1, or 19 to 94% of total creatine kinase activities, respectively. At the present time there is no possibility to correlate this phenomenon to any specific disease. These cases are detected by abnormally high results of CK-MB activity measurements with the immunoinhibition test (range 60 to 202% of total creatine kinase activities) which lead to a repeated analysis using immunoprecipitation. The results of all CK-BB patients investigated till now are presented and discussed.

Adult↗
PubMed1978

[Isoenzymes of creatine kinase: distribution in the skeletal muscle and in sera of patients with muscular diseases or damages (author's transl)].

In skeletal muscle isoenzymes of CK were determined by immunprecipitation and chromatography. The activity of CK-MB was between 17 and 47 U/g muscle, corresponding to a quota between 2,1 and 4,2% of the total activity. In sera of patients with muscular dystrophy, polymyositis, hypothyroidism, after arterial embolism, epilepsy, hyperventilation, operations and polytrauma with and without injury to the thorax isoenzymes were measure by immune precipitation- and immune inhibition-test. The percentage of CK-MB in all sera was less than 6% of the total CK-activity (range: 0 to 6%). Only patients in the first day after neurosurgical operations showed a quota till to 6.5% CK-MB. In serum of patients after polytrauma without injury to the thorax the percentage of CK-MB ranged from 0-5.7% while after polytrauma with injury to the thorax and a reasonable suspicion of a damage to the myocardium this quota was between 5.1 and 23.6% of the total activity. CK-BB activity was not detectable in any cases. Therefore a disease or damage of the skeletal muscle is more probable, if the percentage of CK-MB in less than 6%, because in sera of patients with myocardial infarction in the first 48 h after beginning of the symptoms this quota of CK-MB in the most cases in more than 6%.

Creatine Kinase↗
PubMed1978

[Hyperlipemic arthropathy in primary hyperlipoproteinemia].

In this paper a case of hyperlipaemic arthropathy with participation of the skin in primary hyperlipoproteinaemia type IIa after Fredrickson is described. The case in question is a clinical picture which is very rarely described. Questions of differential diagnosis and genesis are discussed. The prognosis is to be estimated favourably when the basic disease is recognized and treated. The genesis of the disease is not yet clear. With the help of literature several possibilities of the development are discussed.

Diagnosis, Differential↗