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Biomedical subjects

H Metzger

Publications and source records attributed to H Metzger.

At least 163 records · Page 9Linked to original sources
PubMed1980

Staining PO2 measurement sites in the rat brain cortex and quantitative morphometry of the surrounding capillaries.

The exact positions of microelectrodes used to measure the PO2 in the cerebral cortex of the rat were determined by staining the tissue with Alcian Blue. The measurement sites were subsequently located under a light microscope and correlated with the capillary and cellular arrangement of the cortex. The microelectrodes used for the PO2 measurements were made of gold glass fibers; the Alcian Blue was injected hydrostatically through a micropipette attached to the PO2 microelectrode. The sites where dye had been deposited were seen under a light microscope as green blue spots about 100 micrometers in diameter. The capillaries were visualized by silver nitrate perfusion. Differences between the local PO2 values in the neo- and the archeocortex were found. In the neocortex the mean PO2 was 31 mm Hg, capillary volume 1.6%, capillary surface area 980/mm2, capillary length 13.5/mm; whereas in the archeocortex these values where 21 mm Hg, 0.9%, 820/mm2 and 9.4/mm respectively. These data indicate a relationship between the microcirculatory transport system and the local oxygen tension and provide further evidence that the mean PO2 level tends to decrease when moving from the surface into the archeocortex.

Alcian Blue↗
PubMed1980

Morphology of Fallopian tubes removed from a patient after failure of clip sterilization.

A bilateral salpingectomy was performed at the time of vaginal hysterectomy in a pregnant patient sterilized 20 months earlier by application of Bleier clips to the fallopian tubes. Clip application to the left tube had been incomplete. Undisturbed tissue (left tube) and clipped tissue (right tube) were examined and compared by light and scanning electron microscopy. The segment of tube fully grasped by the clip had a completely detached lining epithelium with coarse and flattened mucosa, a loose stroma, and disorganized muscular bundles. The left tubal mucosa was normal, whereas the right tube was stenosed at the site of clip placement, with rigid walls and a 0.175 mm luminal diameter. With progressively greater stenosis toward the clip site, mucosal destruction increased. Polypoidal mucosal folds were seen, as well as fibrous adhesions between mucosal folds. These observations indicate that tissue damage is extensive enough after clip application to require excision of the damaged segment of tube and microsurgical re-anastomosis for reversal of sterilization.

Adult↗
PubMed1980

[Irradiation of the breast glands as prophylactic treatment of an estrogen-induced gynecomastia in patients with prostate carcinomas (author's transl)].

One hundred and four patients with histologically demonstrated prostate carcinomas were submitted to a bilateral orchiectomy. Before the beginning of a hormone therapy, both breast glands were irradiated prophylactically. The patients were observed between two and thirty months. The radiotherapy was executed with electrons with an energy of 10 to 12 MeV and by a stationary field which had a size of 10 X 10 cm. A total surface dose of 12,0 Gy was applicated in four single doses of 3,0 Gy each. The symptom-less healing of 45% of the pateints and the rate of only 29% of patients with gynecomastia is considered to be a good result. In view of the success achieved by the hormone therapy, subjective complaints such as hyperesthesia, pains and pruritus are regarded to be less important.

Breast↗
PubMed1980

Larger oligomers of IgE are more effective than dimers in stimulating rat basophilic leukemia cells.

The relative activity of rat IgE oligomers in eliciting secretion from mast cells and tumor basophils was examined using stable oligomers prepared by cross-linking IgE with dimethyl suberimidate. Oligomers were tested in vivo using passive cutaneous anaphylaxis (PCA) and in vitro by measuring their capacity to induce histamine release from normal rat mast cells and [3H]-5-hydroxytryptamine release from rat basophilic leukemia (RBL) cells. The PCA results confirmed previous work that showed no large differences in the activity of dimers, trimers, and higher oligomers of IgE. The same was also true with normal rat mast cells; however, the RBL cells sharply discriminated between the variously sized oligomers. The stimulatory activity of all oligomers on the RBL cells was enhanced by D2O. The findings imply that the manner by which the clustering of the receptors for IgE leads to generation of signals in RBL cells involves a mechanism capable of discriminating between a variety of polymeric states of the receptors. In addition, our results suggest that no more than a few hundred trimers or an even smaller number of higher oligomers are capable of inducing a considerable amount of secretion from these cells.

Animals↗
PubMed1980

[Problems of multiple field technique in radiation therapy of cancer of the breast (author's transl)].

A method of adjustment frequently used for postoperative telecobalt irradiation of the mammary carcinoma was verified with the help of film-dosimetric measurements at a phantom. Special interest was taken in the regions with possible overlapping of contiguous fields, where serious complications may occur as a consequence of overlapping. Thus, apposition of several fields requires consideration of the divergence of rays and of the mapping precision of 50%-isodoses in the radiation field, as there lie the principal reasons. For realization of a nearly homogeneous dose distribution, on the one hand, there is necessary parallelism of marginal rays of the neighbouring useful ray beams, the radiation head being tilted laterally by half the angle of aperture; on the other hand, the 50% boundary lines at the light beam localizer have to be shifted parallel by a corresponding distance. In spite of this possibility of optimization, it is distinctly more advantageous, with regard to time and technical aspects, to use a linear accelerator, being additionally applicable for electron pendulum irradiation of the thoracic wall.

Breast Neoplasms↗
PubMed1980

[Treatment planning with computerized digital radiography (author's transl)].

An essential development in individual treatment planning by means of computed tomography is reported in the present contribution. Digital radiography makes possible a representation of the body segments to be irradiated, visualizing frontal and lateral views in a quality almost equal to conventional X-ray radiographs. As a decisive advantage, beside the image reproduction without distortion, must be regarded digital localization of the field's limits and mid-point in the isocenter and, therefore, accurate localization of the transversal layer for treatment planning. Utilization of computed tomography combined with digital radiography thus appears as a real alternative of the therapy simulator.

Adult↗
PubMed1980

[Computed tomography for individual treatment planning in tumors of the facial bones (author's transl)].

Moving-field irradiation of malignant tumors in the region of the facial bones makes possible the application of high focal doses along with optimal sparing of radiosensitive organs and is yielding very good cosmetic results. An indispensable condition, however, is a correctly scaled, exact representation of bone structures in the medium plane of pendulum irradiation. Standardized transversal sections of the skull or radiometric techniques mostly do not satisfy, being deficient in precision and demanding too much time. Every pendulum plane desired can be represented in the picture obtained by addition from the series of transversal sections with the help of appropriate programming of the computer for tomography. By means of an objective representation of the osseous skeleton, of cavities, soft tissues, and of the tumor contours, individually optimized irradiation planning is possible.

Aged↗