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Biomedical subjects

W Maurer

Publications and source records attributed to W Maurer.

At least 73 records · Page 4Linked to original sources
PubMed1979

Evidence for different forms of human chorionic gonadotropin receptor complex in pseudopregnant rat ovaries.

After in vivo application of [125 I]-iodo-hCG to pseudopregnant rats, radioactivity extracted from ovarian particulate fractions can be eluted from Sephadex G--200 columns in three various fractions (Vo, Kav = 0.15, Kav = 0.27) differing from hCG (Kav = 0.35). By lowering the pH 50% of the radioactivity is precipitated and the resuspended material shows a conversion to the smaller complexes. The supernatant material is dissociated to [125I]-iodo-hCG. In alkaline milieu [125I]-iodo-HCG is dissociated completely from the complexes.

Animals↗
PubMed1979

[Functional and oncologic results after bronchial or blood vessel anastomosis in the resection therapy of bronchogenic carcinoma].

In treatment of bronchogenic carcinoma twelve selected patients had economical resections. To avoid a pneumonectomy, lobectomies or bilobectomies were associated twice with bronchial excision, 8 times with bronchial resection (sleeve resection) and twice with resection and anastomosis of pulmonary artery. Nine patients underwent clinical, radiologic and szintigraphic control. Except one case all patients showed good functional results. The anastomosed lobes were perfused and ventilated proportionally to the number of segments. The quality of life after partial pulmonary resections had deteriorated only to a small extent compared with the preoperative state. These results were emphasized by the only poor result which (after atelectasis of the anastomosed lung) corresponded functionally to a pneumonectomy. --The two cases of anastomosis of pulmonary artery showed a short survival. Both corresponded to a stage II of tumor classification. Of the other patients (all stage I) three are alive more than five years.

Aged↗
PubMed1978

Growth fraction and cycle duration of hepatocytes in the three-week-old rat.

The proliferation of hepatocytes in the liver of 3-week-old rats has been investigated by autoradiographic methods. This investigation is a continuation of earlier work on the same topic (Schultze & Maurer, 1972; 1973). 21 days after birth, 102 rats received a single injection of 3H-TdR. The percentage of labelled mitoses was then determined 1 hr later and at various times throughout the interval up to 12 days after application of 3H-TdR. In agreement with earlier work, a first peak of labelled mitoses was found 7 hr after 3H-TdR injection. The area under the peak indicates an S phase duration of 8 hr. In addition a second very broad peak of labelled mitoses was found between 2 and 12 days after pulse labelling. The analysis of the results leads to the conclusion that the hepatocytes of the 3-week-old rat have a growth fraction close to 1 and a doubling time of 6-7 days. This is at variance with earlier results of Post, Huang & Hoffman (1963) and Grisham (1969) who had derived a value of 21.5 hr for the duration of the cell cycle and a value of only 0.1-0.2 for the growth fraction of the hepatocytes.

Animals↗
PubMed1978

Differentiation between benign and malignant monoclonal gammopathies by discriminant analysis on serum and bone marrow parameters.

Bone marrow samples of 28 individuals with clinically benign and of 41 patients with malignant monoclonal gammopathy were analyzed for the total number of lymphoplasmocellular elements containing cytoplasmic immunoglobulins and for the monoclonal fraction of these cells. Monoclonal immunoglobulin components were determined in sera. A discriminant analysis was performed on the data: the variables were transformed and in a stepwise procedure used for the construction of a discriminant function which by adividing point allowed a good distinction between the two groups of patients. By use of this discriminant function, 91% of the patients in the sample were correctly classified.

Adult↗
PubMed1977

The phosphoenolpyruvate-dependent phosphotransferase system of Staphylococcus aureus. 3. 1H and 31P nuclear-magnetic-resonance studies on the phosphocarrier protein HPr; tyrosine titration and denaturation studies.

The phosphocarrier protein HPr has been investigated by proton nuclear magnetic resonance (NMR) at 270 MHz in order to evaluate structural properties of the whole molecule and its active site. The titration behaviour of the three tyrosines of the HPr protein was analysed by monitoring the chemical shifts of the aromatic proton resonances of these residues as a function of pH. It was found that the HPr protein contains a lot of slowly exchanging NH backbone protons which suggested a relatively rigid secondary structure of the protein molecule itself although it contains no disulfide bridges. The HPr protein shows a sharp reversible denaturation behaviour at alkaline pH values. Between pH 10.8 and 11.1 two C-2 proton resonance peaks for the single histidine residue could be observed together with abrupt changes in the aromatic and aliphatic absorption region of the HPr protein which are due to chemical exchange processes. The NMR spectrum of the HPr protein is only changed a little upon raising the temperature from 14 degrees C to 70 degrees C. At 76 degrees C all resonances in the spectrum broaden and almost disappear. This process is irreversible.

Bacterial Proteins↗
PubMed1977

In vivo cell synchrony in the L1210 mouse leukaemia studied with 5-fluorouracil or 5-fluorouracil followed by cold thymidine infusion.

[3H]-TdR and [3]-udR labelling indices and mitotic indices were followed in tumour-bearing mice after application of either 5-fluorouracil (FU) alone or of FU followed by cold TdR infusion. With FU alone, accumulation of cells at the beginning of S was found, but there was no indication of a synchronous passage of the accumulated cells further round the cycle. When FU injection was followed by cold TdR infusion, a synchronous passage of the accumulated cells through the cycle was observed. However, there was a large variation in the response of individual mice to this treatment.

Animals↗
PubMed1977

The effect of vincristine on mouse jejunal crypt cells of differing cell age: double labelling autoradiographic studies using 3H- and 14C-TdR.

The mechanism of action of the alkaloid vincristine (VCR) has been investigated in vitro on HeLa cells in culture and in vivo on jejunal crypt cells of the mouse. The in vitro experiments with HeLa cells show that VCR affects not only mitotic but also interphase cells. The VCR-affected cells first continue their passage through the cell cycle undisturbed but after reaching mitosis they are arrested in metaphase. This agrees well with the results obtained by Madoc-Jones & Mauro (1968) and Madoc-Jones (1973) on synchronized cell cultures. Until now there has been no investigation of the mechanism of action of VCR in vivo. This is due to the absence of a suitable technique for synchronization in vivo. The present study is based on a method which permits the assessment of the VCR sensitivity as a function of the cell age without synchronization in the usual sense. The jejunal crypt epithelium of the normal mouse was double labelled with 3H- and 14C-thymidine (TdR) in such a way as to produce a narrow subpopulation of crypt cells with a maximum age difference of 1 hr. On autoradiographs these cells can be distinguished by their characteristic labelling from other cells. As this 'pseudo'-synchronized subpopulation passes through the cycle the effect of VCR can be studied, i.e. one can analyse the effect in well-defined time intervals of the cycle. The results show that the effect of VCR is the same in vivo as in vitro. The crypt cells which are affected by VCR in interphase continue their passage through the cycle, but upon entering mitosis they are arrested in metaphase. VCR has, at the concentration used in the present study, no effect on the duration of the S and G2 phases. The necrotic cells seen after VCR application are formed from arrested metaphases.

Animals↗
PubMed1977

[Serum gastrins after duodeno-pancreatectomy].

6 patients who have had a duodeno-pancreatectomy were starved and then given a test meal, to stimulate the serumgastrin which was measured by RIA. The fasting gastrin values were, by all the patients, in the lower range of the normal level (25-50 pg/ml). The stimulation with the meat-extract (25 g with 400 ml of water) did not lead to any significant raising of the fasting serum gastrin.

Adult↗
PubMed1976

15N nuclear magnetic resonance investigations on amino acids.

15N nuclear magnetic resonance investigations of some amino acids were carried out in order to check the applicability of this method to biological problems. Because the natural abundance of the 15N isotope is not sufficient to get readable spectra in a reasonable time, 95% 15N isotope-enriched samples were used for the measurements. Besides the chemical shift values, the line widths, and the nuclear Overhauser enhancement factors, spin lattice relaxation times of the correspondent 15N resonances were measured as functions of pH had temperature.

Amino Acids↗
PubMed1976

Mode of growth of the jejunal crypt cells of the rat: an autoradiographic study using double labelling with 3H- and 14C-thymidine in lower and upper parts of crypts.

The frequency distribution of cells through the mitotic cycle in lower and upper portions of jejunal crypts of the rat was examined by the 3H-14C-thymidine double labelling technique. Isolated crypts were cut perpendicular to the longitudinal axis so that the percentage of cells in the lower portion varied from 16 to 74%. The lower and upper portion of the same crypt were squashed separately on one microscope slide and the number of 3H- and 14C-only labelled cells were scored to determine the flow rate into and out of S for the two portions. The mitotic cycle and its phases of the crypt epithelial cells were also determined. For lower portions of crypts which contained less than 40% of the total cell number in that crypt the flow rate into S was about 1-7 times that of the flow rate out of S indicating that nearly every mitosis in this region produced two proliferative daughter cells. As the proportion of cells in the lower part of the crypt increased the quotient of the flow rate into S divided by the flow rate out of S decreased, and approached the steady state value of 1-0 in lower portions containing 60-74% of the cells. For upper portions of crypts which contained less than 40% of the total crypt cells the flow rate into S was about 0-2 times that of the flow rate out of S, indicating that in this region mitoses predominantly produced non-proliferative daughter cells. The results obtained were in good agreement with the model of crypt cell proliferation proposed by Cairnie, Lamerton & Steel (1965b).

Animals↗