Biomedical subjects
Publications and source records attributed to W Maurer.
The authors report a case of an oesophageal cancer limited to the mucosa and the submucosa. This case is interesting because of its long history for more than 18 months, the difficulty of fiberoptic diagnosis and the diagnostic value of rigid instruments completed via vital staining by o-toluidine.
Mean transit times as well as variances of the transit times through the individual phases of the cell cycle have been determined for the crypt epithelial cells of the jejunum of the mouse. To achieve this the fraction of labelled mitoses (FLM) technique has been modified by double labelling with [3H] and [14C]thymidine. Mice were given a first injection of [3H]thymidine, and 2 hr later a second injection of [14C]thymidine. This produces a narrow subpopulation of purely 3H-labelled cells at the beginning of G2-phase and a corresponding subpopulation of purely 14C-labelled cells at the beginning of the S-phase. When these two subpopulations progress through the cell cycle, one obtains FLM waves of purely 3H- and purely 14C-labelled mitoses. These waves have considerably better resolution than the conventional FLM-curves. From the temporal positions of the observed maxima the mean transit times of the cells through the individual phases of the cycle can be determined. Moreover one obtains from the width of the individual waves the variances of the transit times through the individual phases. It has been found, that the variances of the transit times through successive phases are additive. This indicates that the transit times of cells through successive phases are independently distributed. This statistical independence is an implicit assumption in most of the models applied to the analysis of FLM curves, however there had previously been no experimental support of this assumption. A further result is, that the variance of the transit time through any phase of the cycle is proportional to the mean transit time. This implies that the progress of the crypt epithelial cells is subject to an equal degree of randomness in the various phases of the cycle.
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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.
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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.
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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.
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.
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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.
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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.
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.
Experiments are described on synchronizing L 1210 ascites tumor cells and jejunal crypt cells of the mouse with vincristine. In both cases the percentage of mitoses increases to a peak value 4 hrs after application of vincristine and decreases during the following 8 hrs ("releasing time") to the level of the normal mitotic index. Following this first mitotic peak no futher peak of neither the mitotic nor the labeling index was observed during 48 hrs in L 1210 ascites tumor cells and during 38 hrs in crypt epithelia. Thus, in both cell types it was not possible to obtain a synchronizing effect by applying vincristine. Based on cell kinetic considerations it was examined whether peaks of the mitotic as well as the labeling index can be expected at all under the given circumstances. The results show that the theoretical course of the mitotic index coincides with the measured values. This means that no peak of the mitotic index can be expected from the theoretical point of view. In calculating the time course of the labeling index the theoretical curve proved to depend to a high degree on the variations of the cycle time which are not known in detail, especially not after application of vincristine. However, the theoretical conditions show that also in the case of the labeling index no peak can be expected. This agrees with the experimental results. The general significance of a long "releasing time" of 8 hrs or more for the lack of a synchronizing effect is discussed.
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